Production method of nano calcium carbonate for ink and an ink

Abstract

The present invention discloses a production method of nano calcium carbonate for ink and an ink, relating to the field of nano calcium carbonate preparation, including: diluting Ca(OH) which has been refined and aged for 24 - 72 h 2 , adjusting the concentration of Ca(OH) 2 to 5% - 10% and the temperature to 12 - 25°C, adding a crystal form control agent and stirring, and then conveying the raw pulp to a carbonization reaction tower; introducing purified and cooled kiln gas into the carbonization reaction tower for carbonization reaction, conveying the cooked pulp to a surface treatment tank to obtain modified nano calcium carbonate; putting the modified nano calcium carbonate into a filter press for pressure filtration and dehydration, and dispersing the filter cake into particles with a particle size of 5 mm - 40 mm by a disintegrator to obtain the finished nano calcium carbonate product. Therefore, the beneficial effects of this solution are as follows: by the combined action of silicone oil containing functional groups, span, rosin emulsion, etc., the nano calcium carbonate has good anti-emulsification performance, fluidity, dispersibility and other indicators.

Description

Technical Field

[0001] The present invention relates to the technical field of nano calcium carbonate preparation, and in particular to a production method of nano calcium carbonate for ink and an ink. Background Art

[0002] With the development of the printing industry towards high speed and multi-color, more and more offset inks are used. Offset inks mainly consist of resin, mineral oil, pigments, fillers, additives, etc. Traditional fillers such as aluminum hydroxide, barium sulfate, lithopone, etc. used in inks can no longer meet the new printing requirements. With the popularization and application of synthetic resin binder materials in the ink industry, these traditional ink fillers have gradually been replaced by nano calcium carbonate. Compared with traditional additives, adding nano calcium carbonate to inks can exhibit excellent dispersibility, good gloss and brightness. Nano calcium carbonate can also significantly improve the adhesion of inks and reduce mechanical wear.

[0003] Offset printing uses the principle of water and ink incompatibility for printing. During the printing process of offset inks, when the ink comes into direct contact with printing fountain solution (fountain solution), the polar substances in the ink will cause emulsification of the ink due to hydrophilicity. These polar substances come from the polar groups in each component. Among them, nano calcium carbonate has a relatively large polarity and a greater impact.

[0004] Therefore, controlling the water-ink balance of the ink (commonly known as anti-emulsification and water resistance) is the key to ensuring the quality of offset printing.

[0005] If the water-ink balance performance of the ink on the printing equipment is not good and the anti-emulsification performance is not good, it will cause a small amount of ink to mix in the fountain solution, resulting in printing paste, and ink also appears on the non-graphic parts, affecting the printing performance of the ink. How to control the emulsification rate of the ink has always been a concern of offset inks. Among them, the pigments and fillers in the ink have the greatest impact. Therefore, the nano calcium carbonate added to the ink needs to have good anti-emulsification performance.

[0006] In "Preparation of Nano Transparent Calcium Carbonate for High-Grade Offset Ink" in Chinese CN1332207A by Gu Da, Yao Cheng, etc., treating nano calcium carbonate with rosin acid results in poor anti-emulsification performance, a relatively large oil absorption value, and poor heat resistance.

[0007] In "A Surface Treatment Method of Nano Calcium Carbonate for Ink" in Chinese CN105885518A by Mo Dongli, Zhu Yong, etc., after wet modification with saturated fatty acid and then dry modification with glycerol polyoxyethylene ether trioleate, the nano calcium carbonate treated with saturated fatty acid has poor compatibility with the ink and cannot be used for high-grade inks.

[0008] In "Preparation of Special Nano Calcium Carbonate for High-grade Ink" (CN 105820601 A) by Yan Gancai, Zhu Yong, etc., the surface treatment agent used is the saponification solution of linseed oil acid and maleic acid, which has good fluidity and high transparency, but poor anti-emulsification performance and is not suitable for high-grade ink.

[0009] In summary, it can be seen that the existing nano calcium carbonate preparation technology is difficult to obtain good fluidity, transparency, and dispersibility while having good anti-emulsification performance. Therefore, it is necessary to improve the above-mentioned disadvantages. Summary of the Invention

[0010] Aiming at the above defects, the purpose of the present invention is to provide a production method of nano calcium carbonate for ink, aiming to solve the problem that nano calcium carbonate in the existing technology is difficult to have good fluidity, transparency, dispersibility, and anti-emulsification performance at the same time.

[0011] To solve the above technical problems, the technical solution of the present invention is as follows:

[0012] A production method of nano calcium carbonate for ink,

[0013] including the following steps:

[0014] Step 1: Dilute Ca(OH) that has been refined and aged for 24 - 72 h, 2 adjust the concentration of Ca(OH) to 5% - 10% and the temperature to 12 - 25 °C, add a crystal form control agent and stir to obtain raw pulp, and then transport the raw pulp to a carbonization reaction tower; 2 Step 2: Pass the purified and cooled kiln gas into the carbonization reaction tower for carbonization reaction, and the gas flow rate of the kiln gas is 10 - 80 m

[0015] / min; The first carbonization terminates the reaction when the pH of the reaction liquid ≤ 8, stirs and ages for 4 - 24 h, and then conducts the second carbonization; The second carbonization continues to over-carbonize for 10 - 30 min when pH ≤ 7.5 to obtain cooked pulp; 3 Step 3: Transport the cooked pulp to a surface treatment tank, heat it to 60 - 90 °C, then add the surface treatment agent to the surface treatment tank, stir at a speed of 800 r / min - 1200 r / min for 60 - 120 min to obtain modified nano calcium carbonate;

[0016] Step 4: Put the modified nano calcium carbonate into a filter press for filter press dehydration to obtain a filter cake with a moisture content of 32% - 42%, then the filter cake is broken into particles with a particle size of 5 mm - 40 mm by a disintegrator, and then the particles are successively sent to a dryer and a pulverizer for drying and pulverization treatment to obtain the finished nano calcium carbonate product;

[0017] Step 5: Send the modified nano calcium carbonate into a filter press for filter press dehydration to obtain a filter cake with a moisture content of 32% - 42%, then the filter cake is broken into particles with a particle size of 5 mm - 40 mm by a disintegrator, and then the particles are successively sent to a dryer and a pulverizer for drying and pulverization treatment to obtain the finished nano calcium carbonate product;

[0018] Step 5, the nanometer calcium carbonate finished product prepared in Step 3 is detected, and the detection results are as follows: specific surface area is 60 - 120 m 2 / g, whiteness is 88% - 93%, oil absorption value is 25 - 40 g DOP / 100 g, moisture content ≤ 0.5%, pH ≤ 9.

[0019] Among them, the crystal form control agent is alcohols and / or sugars, including any one or more of ethylene glycol, propylene glycol, pentaerythritol, butanediol, hexanediol, neopentyl glycol, diethylene glycol, dipropylene glycol, trimethylolpropane, 1,1,1-(trimethylol)-ethane, glycerol, xylitol, sorbitol, citric acid, beet sugar, sucrose, glucose, fructose, ribose, deoxyribose, maltose, lactose; the dosage of the crystal form control agent is 0.5% - 5% of the solid content of Ca(OH) 2 8.

[0020] Among them, the crystal form control agent is water-soluble sulfuric acid or sulfate, including any one or more of sulfuric acid, sodium sulfate, magnesium sulfate, aluminum sulfate, zinc sulfate; the dosage of the crystal form control agent is 1% - 10% of the solid content of Ca(OH) 2 13.

[0021] Among them, the volume content of carbon dioxide in the kiln gas is 25% - 40%.

[0022] Among them, the surface treatment agent includes silicone oil, rosin emulsion, span.

[0023] Among them, the silicone oil is modified silicone oil, including hydrogen-containing dimethyl silicone oil and / or carboxyl silicone oil, and the dosage of the silicone oil is 3% - 5% of the weight of nano-calcium acid.

[0024] Among them, the rosin emulsion is rosin resin emulsion or modified rosin resin emulsion, the solid content of the rosin emulsion is 50% - 60%, and the dosage of the rosin emulsion is 3% - 8% of the weight of nano-calcium carbonate.

[0025] Among them, the HLB of the span ≤ 5, and the dosage of the span is 1% - 3% of the weight of nano-calcium carbonate.

[0026] Among them, it includes 15 - 20 parts of nano-calcium carbonate, 15 - 20 parts of ink oil, 40 - 50 parts of resin oil, 5 - 10 parts of rosin modified phenolic resin, 8 - 15 parts of gum oil, 0.8 - 3 parts of polyethylene wax paste, and 4 - 7 parts of phthalocyanine blue.

[0027] The ink oil is prepared by mixing rosin pentaerythritol resin, linseed oil polymer, and high-boiling kerosene, and the viscosity is 50000 mpa.s.

[0028] After adopting the above technical solution, the beneficial effects of the present invention are:

[0029] First, the present invention uses two kinds of crystal form regulators. One is alcohols and sugars, and the other is sulfates. The main function of polyols and sugars is to increase the solubility of Ca(OH) 2 , and sulfates react with Ca(OH) 2 to form CaSO 4 crystal medium. The CaSO 4 crystal medium is a whisker-like substance, which can make the calcium carbonate particles develop in the direction of the long aspect ratio. The use of two composite crystal form control agents results in nano-calcium carbonate in the form of small cubic long chains, which can make the nano-calcium carbonate loose while the particles are fine, maintaining good dispersibility.

[0030] Second, the combined action of silicone oil containing functional groups, span, rosin emulsion, etc. is adopted to make nano-calcium carbonate have good anti-emulsification performance, fluidity, dispersibility and other indicators.

[0031] Third, the specific surface area of nano-calcium carbonate is high, 60 - 120m 2 / g. According to the empirical formula, the particle size is calculated to be 0.018 - 0.037μm, that is, 18 - 37nm. Since the primary particle size of the present invention is small and the dispersibility is good, when used in ink, it has good transparency and good dispersibility, and is suitable for inks or diluents with high transparency requirements. At the same time, it has good dispersibility, good anti-emulsification performance and good printing adaptability. Fourth, the fluidity is the reciprocal of the viscosity. The greater the fluidity, the thinner it is. The fluidity of the present invention is in a suitable range, making the ink have good processing performance and good dispersibility at the same time. The nano-calcium carbonate of the present invention has good gloss when used in ink. The main reason is that the nano-calcium carbonate of the present invention has good dispersibility, uniform particle size and good dispersibility, and has better light reflection, so the gloss is good. Specific embodiments

[0032] A production method of nano-calcium carbonate for ink includes the following steps:

[0033] Step 1, dilute Ca(OH) 2 which has been refined and aged for 24 - 72h, adjust the concentration of Ca(OH) 2 to 5% - 10% and the temperature to 12 - 25°C, add crystal form control agent and stir to obtain raw pulp, and then transport the raw pulp to the carbonization reaction tower;

[0034] If Ca(OH) 2The concentration is lower than 5%, the output is relatively low, and the industrial production cost is relatively high. If it is higher than 10%, it is difficult to produce very fine nano calcium carbonate. The temperature of the raw slurry is 12 - 25 °C. If the temperature is lower than 12 °C, the temperature is too low, the industrial refrigeration cost is high, and it may also cause a slow reaction rate and large particle size. If the temperature is higher than 25 °C, it is difficult to produce very fine nano calcium carbonate because as the temperature rises, the solubility of Ca(OH) 2 and carbon dioxide in water decreases, resulting in a decrease in the amount of Ca 2+ and HCO 3- , reducing the number of nuclei formed during the reaction. Therefore, the temperature needs to be controlled to carry out the reaction at a low temperature.

[0035] Step 2: Introduce the purified and cooled kiln gas into the carbonation reaction tower for carbonation reaction. The gas flow rate of the kiln gas is 10 - 80 m 3 / min. The first carbonation terminates the reaction when the pH of the reaction liquid ≤ 8, stirs and ages for 4 - 24 h, and then performs the second carbonation. During the second carbonation, when pH ≤ 7.5, continue to over - carbonate for 10 - 30 min to obtain the cooked slurry;

[0036] The volume flow rate of the said kiln gas is 10 - 80 m 3 / min, which is matched according to the size of the carbonation reaction tower. According to the volume of the carbonation tower (m 3 ): the volume flow rate of the kiln gas (m 3 / min) = 1:(0.8 - 3) is better. The larger the ratio of the volume of the carbonation tower (m 3 ) to the volume flow rate of the kiln gas (m 3 / min), the more difficult it is to produce nano calcium carbonate with a high specific surface area. The smaller the ratio of the volume of the carbonation tower (m 3 ) to the volume flow rate of the kiln gas (m 3 / min), although it is easy to produce fine nano calcium carbonate, but the flow rate is too large, the absorption coefficient of the kiln gas is poor, and the cost is wasted.

[0037] Stirring and aging for 4 - 24 hours is beneficial to the precipitation of a small amount of Ca(OH) 2 enclosed in the nano calcium carbonate. At this time, the pH value of the suspension slightly increases to 8 - 11, and then the second carbonation is carried out. When pH ≤ 7.5, over - carbonate for another 10 - 40 minutes to obtain the cooked slurry. If the stirring and aging time is too short, it is not conducive to the precipitation of Ca(OH) 2 , and the pH value of the obtained product may increase, resulting in poor storage stability of the ink. If the stirring and aging time is too long, it may cause recrystallization of the nano calcium carbonate, resulting in a decrease in the specific surface area and it is difficult to obtain nano calcium carbonate particles with a high specific surface area. The flow rate of the kiln gas for the second carbonation is 5% - 30% of the flow rate of the kiln gas for the first carbonation, aiming to extend the reaction time and completely convert Ca(OH)2 It is transformed into calcium carbonate, reducing the pH value of the product nano-calcium carbonate. At the same time, the amount of Ca(OH) in the later stage of the reaction 2 is very small and does not require too large a flow rate to save kiln gas.

[0038] Step 3: Transfer the cooked pulp to the surface treatment tank, heat it to 60 - 90 °C, then add the surface treatment agent to the surface treatment tank, with a stirring speed of 800 r / min - 1200 r / min and a stirring time of 60 - 120 min to obtain modified nano-calcium carbonate;

[0039] Step 4: Put the modified nano-calcium carbonate into a filter press for filter press dehydration to obtain a filter cake with a moisture content of 32 - 42%. Then, the filter cake is broken into particles with a particle size of 5 mm - 40 mm by a disintegrator. Then, the particles are successively sent to a dryer and a crusher for drying and crushing to obtain the finished nano-calcium carbonate product;

[0040] Step 5: Detect the finished nano-calcium carbonate product prepared in Step 3. The detection results are as follows: specific surface area 60 - 120 m 2 / g, whiteness 88% - 93%, oil absorption value 25 - 40 g DOP / 100 g, moisture content ≤ 0.5%, pH ≤ 9.

[0041] The specific surface area of the nano-calcium carbonate is 60 - 120 m 2 / g; According to the empirical formula (1):

[0042] (1)

[0043] In the formula: 6 is the shape factor; S: specific surface area, unit m 2 / g; ρ: density of calcium carbonate, which is 2.7 g / cm 3 ;

[0044] Calculated according to formula (1), the particle size is 0.018 - 0.037 μm, that is, 18 - 37 nm. When the specific surface area is less than 60 m 2 / g, it means that the primary particle size is greater than 37 nm. The larger the particle size, the poorer the transparency and gloss; when the specific surface area is greater than 120 m 2 / g, it means that the primary particle size is less than 18 nm. The smaller the particle size, the poorer the dispersibility, and it is easy to agglomerate. It is possible that the secondary particle size is thick and the dispersibility is poor.

[0045] Industrially, to obtain calcium carbonate with special morphology, crystal form control agents with different functions need to be added during the preparation process to guide the morphology and size of calcium carbonate. The formation of crystals refers to the process of initially forming smaller crystal nuclei and then the continued growth of crystals on the basis of these nuclei. There are mainly three factors affecting crystal morphology: temperature, interface properties, and supersaturation. Therefore, crystal form guiding technology is divided into process guiding and crystal form control agent guiding. By controlling conditions such as temperature, stirring speed, and liquid phase concentration, the reaction rate of the system is controlled, so that both the nucleation rate and precipitation rate of calcium carbonate are increased, thereby controlling the crystal size and morphology.

[0046] To increase the solubility of Ca(OH) 2 , increase the nucleation rate during the reaction, increase the specific surface area, and make the particles of nano-calcium carbonate smaller. Preferably, the crystal form control agent is alcohols and / or sugars, including any one or more of ethylene glycol, propylene glycol, pentaerythritol, butanediol, hexanediol, neopentyl glycol, diethylene glycol, dipropylene glycol, trimethylolpropane, 1,1,1-(trimethylol)-ethane, glycerol, xylitol, sorbitol, citric acid, beet sugar, sucrose, glucose, fructose, ribose, deoxyribose, maltose, lactose; the dosage of the crystal form control agent is 0.5%-5% of the solid content of Ca(OH) 2 . As the addition amount increases, the reaction nucleation rate accelerates, making the particle size of the generated nano-calcium carbonate decrease. If the dosage is less than 0.5%, it is too small and it is difficult to significantly increase the specific surface area. If the dosage exceeds 5%, increasing the dosage further will not have an obvious effect and will waste costs.

[0047] Similarly, the crystal form control agent is water-soluble sulfuric acid or sulfates, including any one or more of sulfuric acid, sodium sulfate, magnesium sulfate, aluminum sulfate, zinc sulfate; the dosage of the crystal form control agent is 1%-10% of the solid content of Ca(OH) 2 . Sulfates react with Ca(OH) 2 to form a CaSO 4 crystal medium. The CaSO 4 crystal medium is a whisker-like substance, which can make the calcium carbonate particles develop in the direction of the long aspect ratio of the orientation. When two composite crystal form control agents are used, the generated nano-calcium carbonate is in the form of small cubic long chains, which can make the nano-calcium carbonate fine while the material is relatively loose and maintain good dispersibility. The dosage is 1%-10% of the solid content of Ca(OH) 2 . If the dosage is less than 1%, the generated chain shape is not obvious, the specific surface area increases less, and the looseness of the material is insufficient. If it exceeds 10%, the specific surface area increases less in the later stage, the generated chain is too long, and the chain structure will break during the later dry powder and pulverization processes, wasting costs.

[0048] The volume content of carbon dioxide in the kiln gas is 25%-40%. If the carbon dioxide concentration in the kiln gas is too low, too few crystal nuclei of nano-calcium carbonate will be formed during the reaction, and it is not easy to obtain nano-calcium carbonate with a high specific surface area. The carbon dioxide concentration in the kiln gas can be too high, but it is not easy for the industrialized industry to obtain carbon dioxide with a concentration exceeding 40%. If pure carbon dioxide is supplemented, it will lead to an increase in cost.

[0049] The surface treatment agent includes silicone oil, rosin emulsion, and span. The dosage of silicone oil is 3%-5% of the weight of nano-calcium carbonate, the dosage of rosin emulsion is 3%-8% of the weight of nano-calcium carbonate, and the dosage of span is 1%-3% of the weight of nano-calcium carbonate. The silicone oil is a modified silicone oil containing functional groups, which can adsorb or chemically react with calcium carbonate, and can uniformly coat nano-calcium carbonate. It is a non-polar substance, which makes nano-calcium carbonate have good anti-emulsification performance, and at the same time provides fluidity and dispersibility, etc. The dosage of silicone oil is 3%-6% of nano-calcium carbonate. If the dosage is too small, it is not enough to coat; if the dosage is too large, it may precipitate and increase the cost at the same time. Rosin emulsion has good affinity with ink, can coat nano-calcium carbonate, and provides dispersibility and fluidity. The specific dosage of rosin emulsion is 3%-8% of nano-calcium carbonate (referring to the weight of the emulsion, including water). If the dosage is too small, it is not enough to provide sufficient fluidity. If the dosage is too large, it may cause poor anti-emulsification effect. Span can provide a dispersing effect, can disperse silicone oil and rosin emulsion, coat nano-calcium carbonate, and at the same time has a low value, HLB<5, has good lipophilic performance and anti-emulsification performance, and the dosage is 1%-3% of nano-calcium carbonate. If the dosage is too small, the dispersing and coating effects are poor. If the dosage is too large, it is easy to foam and waste cost at the same time.

[0050] Preferably, the silicone oil is a modified silicone oil, including hydrogen-containing dimethyl silicone oil and / or carboxyl silicone oil.

[0051] Preferably, the rosin emulsion is a rosin resin emulsion or a modified rosin resin emulsion, and the solid content of the rosin emulsion is 50%-60%. Such as: water-based rosin resin emulsion, water-soluble rosin-modified maleic resin, water-based hydrogenated rosin emulsion, water-soluble rosin-modified maleic acid resin, rosin-modified terpene resin emulsion, etc.

[0052] Preferably, the HLB of the span ≤5. The following can be selected: span 65 (sorbitan tristearate) with an HLB value of 2.1; span 60 (sorbitan monostearate) with an HLB value of 4.7; span 80 (sorbitan monooleate) with an HLB value of 4.3; span 85 (sorbitan trioleate) with an HLB value of 1.8; span 83 (sorbitan sesquioleate) with an HLB value of 3.7, etc.

[0053] To facilitate the application of the nano-calcium carbonate produced by this solution in the ink field, preferably, it includes 15-20 parts of nano-calcium carbonate, 15-20 parts of ink oil, 40-50 parts of resin oil, 5-10 parts of rosin-modified phenolic resin, 8-15 parts of gum oil, 0.8-3 parts of polyethylene wax paste, and 4-7 parts of phthalocyanine blue.

[0054] Among them, the ink oil is prepared by mixing rosin pentaerythritol resin, linseed oil polymer, and high-boiling kerosene, and the viscosity is 50000 mpa.s.

[0055] The carbonation reaction tower is a carbonation tower with high-speed stirring. The stirring paddle is a two-layer or three-layer propeller blade, and the linear velocity of stirring is 8-18 m / s. If it is lower than 8 m / s, it is difficult to stir evenly. If it is higher than 18 m / s, the power consumption is large, the cost is wasted, the equipment requirements are high, and it is difficult to operate for a long time. In the carbonation tower, since the carbonation reaction is an exothermic reaction, the temperature will rise during carbonation, and it is difficult to produce very fine nano-calcium carbonate. Therefore, an internal jacket or coil-type indirect heat exchanger is used to cool by passing cold water, or an external circulation plate heat exchanger or tubular heat exchanger is used to remove the carbonation reaction heat in time. The final carbonation temperature ≤ 45 °C. If it is greater than 45 °C, it is difficult to obtain the very fine nano-calcium carbonate of the present invention. The aspect ratio of the carbonation tower is 1:(1.5~5). If the aspect ratio is too small, it will affect the absorption coefficient of kiln gas. If it exceeds 5, it will increase the design difficulty of the stirrer and waste cost; the volume of the carbonation tower is 5-60m 3 , less than 5m 3 Then the industrial scale is small and the production cost is high. If it is greater than 60m 3 , it is difficult to stir evenly, and coarse crystals may appear in the generated nano-calcium carbonate particles.

[0056] Example 1:

[0057] (1) Dilute the refined and aged Ca(OH) 2 lime milk, adjust the mass concentration of Ca(OH) 2 to 8%, adjust the temperature of the raw pulp to 18 °C, add the crystal shape control agent glycerin, and the dosage is 2% of the solid content of Ca(OH) 2 ; add aluminum sulfate (pre-dissolved into an aqueous solution with a solid content of 20%), and the dosage is 5% of the nano-calcium carbonate, and then transport it to the carbonation reaction tower;

[0058] (2) The volume of the carbonation tower is 25M 3 , the aspect ratio of the carbonation tower is 1:3, start stirring, adjust the linear velocity of stirring to 12 m / s, and pass in the purified kiln gas with a volume concentration of carbon dioxide of 30%, and the kiln gas flow rate is 40m 3 / min. During the reaction, cool water at 18 °C is passed through the coil on the outer wall of the reaction tower to control the increase in the slurry temperature of the reaction. When the reaction reaches 75 min and the pH = 7.3, the reaction is terminated. At this time, the temperature is 38 °C, and it is stirred and aged for 10 hours. At this time, the pH of the suspension is 9.0. Then, purified kiln gas with a volume concentration of carbon dioxide of 30% is passed in, and the kiln gas flow rate is 10 m 3 / min. When the pH = 7.2, carbonation is continued for another 15 minutes to obtain cooked slurry.

[0059] (3) Transfer the cooked slurry obtained in (2) to the surface treatment tank, heat it to 65 °C, add the prepared surface treatment agent for surface treatment, and stir at high speed for 60 - 120 min to obtain modified nano calcium carbonate; the surface treatment agent is hydrogen-containing dimethyl silicone oil (model KF-99), and the dosage is 3% of the solid content of nano calcium carbonate; Span 65 (sorbitan tristearate), and the dosage is 1.5% of the solid content of nano calcium carbonate; MS-720 (water-soluble rosin-modified maleic resin), with a solid content of 55%, and the dosage is 4% of the solid content of nano calcium carbonate; the above three substances are mixed, and hot water at 85 °C is used to prepare a concentration of 15%, and stirred evenly.

[0060] (4) Filter and dehydrate the modified nano calcium carbonate obtained in (3). The moisture content of the filter cake is 35%. The filter cake is passed through a disintegrator and disintegrated into particles with a particle size of 5 - 40 mm, and added to the drying and grinding machine through a screw, and hot air is passed in. The drying temperature is controlled at 110 °C for drying and pulverization to obtain nano calcium carbonate special for ink.

[0061] (5) Use 20 parts of nano calcium carbonate, 20 parts of ink oil, 40 parts of resin oil, 5 parts of rosin-modified phenolic resin, 10 parts of gum oil, 1 part of polyethylene wax paste, and 4 parts of phthalocyanine blue, and stir and mix to make ink.

[0062] Detect the nano calcium carbonate special for ink in (4) and the ink in (5). The detection results are as follows:

[0063]

[0064] Example 2:

[0065] (1) Dilute the refined and aged Ca(OH) 2 lime milk, adjust the mass concentration of Ca(OH) 2 to 7.5%, adjust the temperature of the raw slurry to 17 °C, add the crystal form control agent xylitol, and the dosage is 2% of the solid content of Ca(OH) 2 solid content, add zinc sulfate (pre-dissolved into an aqueous solution with a solid content of 20%), and the dosage is 5% of nano calcium carbonate, and then transfer it to the carbonation reaction tower;

[0066] (2) The volume of the carbonization tower is 25 M 3 , the aspect ratio of the carbonization tower is 1:3, start stirring, adjust the linear velocity of stirring to 13 m / s, and introduce purified kiln gas with a volume concentration of carbon dioxide of 30%. The flow rate of the kiln gas is 40 m 3 / min. During the reaction, cool water at 18 °C is introduced into the coil outside the reaction tower to control the increase in the temperature of the reaction slurry. When the reaction reaches 75 min and the pH = 7.2, the reaction is terminated. At this time, the temperature is 35 °C. Stir and age for 12 hours. At this time, the pH of the suspension is 9.3. Then introduce purified kiln gas with a volume concentration of carbon dioxide of 30%. The flow rate of the kiln gas is 10 m³ / min. When the pH = 7.2, carbonize for another 20 minutes to obtain cooked pulp.

[0067] (3) Transfer the cooked pulp obtained in (2) to the surface treatment tank, heat it to 65 °C, add the prepared surface treatment agent for surface treatment, and stir at high speed for 60 - 120 min to obtain modified nano calcium carbonate; the surface treatment agent is carboxyl silicone oil: such as Dow Corning BY16 - 880, with a dosage of 3% of the solid content of nano calcium carbonate; Span 85 (sorbitan trioleate), with a dosage of 1.8% of the solid content of nano calcium carbonate; Resin 968 (rosin modified terpene resin) with a solid content of 55%, with a dosage of 4.5% of the solid content of nano calcium carbonate. Mix the above three substances, use hot water at 85 °C to prepare a 15% concentration, and stir evenly.

[0068] (4) Filter and dehydrate the modified nano calcium carbonate obtained in (3). The moisture content of the filter cake is 35%. The filter cake passes through a disintegrator and is broken into particles with a particle size of 5 - 40 mm. Add it to the drying and grinding machine through a screw, introduce hot air, control the drying temperature at 120 °C, and perform drying and pulverization to obtain nano calcium carbonate special for ink.

[0069] (5) Use 20 parts of nano calcium carbonate, 20 parts of ink oil, 40 parts of resin oil, 5 parts of rosin modified phenolic resin, 10 parts of gum oil, 1 part of polyethylene wax paste, and 4 parts of phthalocyanine blue, and stir and mix to make ink.

[0070] Detect the nano calcium carbonate special for ink in (4) and the ink in (5). The detection results are as follows:

[0071]

[0072] Example 3:

[0073] (1) Dilute the refined and aged Ca(OH) 2 lime milk, adjust the mass concentration of Ca(OH) 2 to 7%, adjust the temperature of the raw pulp to 17 °C, and add the crystal form control agent sorbitol, with a dosage of Ca(OH)2 3% of the solid content, zinc sulfate (pre-dissolved in an aqueous solution with a solid content of 20%) is added, and the dosage is 3% of the nano calcium carbonate, and then it is transported to the carbonation reaction tower;

[0074] (2) The volume of the carbonation tower is 25 M 3 , the aspect ratio of the carbonation tower is 1:3, the stirring is started, the linear velocity of the stirring is adjusted to 14 m / s, purified kiln gas with a volume concentration of carbon dioxide of 30% is introduced, and the kiln gas flow rate is 40 m 3 / min. During the reaction, cooling water at 18 °C is introduced into the coil outside the reaction tower to control the increase in the temperature of the reaction slurry. When the reaction reaches 75 min and the pH = 7.2, the reaction is terminated, and the temperature at this time is 34 °C. Stir and age for 15 hours. At this time, the pH of the suspension is 9.5. Then, purified kiln gas with a volume concentration of carbon dioxide of 30% is introduced again, and the kiln gas flow rate is 10 m³ / min. When the pH = 7.2, carbonation is carried out for another 20 minutes to obtain the cooked slurry.

[0075] The cooked slurry obtained in (2) is transported to the surface treatment tank, heated to 65 °C, and the prepared surface treatment agent is added for surface treatment. High-speed stirring is carried out for 60 - 120 min to obtain modified nano calcium carbonate; the surface treatment agent is carboxyl silicone oil: such as Dow Corning BY16 - 880, and the dosage is 3% of the solid content of the nano calcium carbonate; Span 80 (sorbitan monooleate), the dosage is 1.5% of the solid content of the nano calcium carbonate; the model is 918 (rosin emulsion) with a solid content of 60%, and the dosage is 4.5% of the solid content of the nano calcium carbonate; the above three substances are mixed, and hot water at 85 °C is used to prepare a concentration of 15%, and stirred evenly.

[0076] The modified nano calcium carbonate obtained in (3) is filtered and dehydrated by pressure filtration. The moisture content of the filter cake is 37%. The filter cake passes through a disintegrator and is broken into particles with a particle size of 5 - 40 mm, and is added to the drying and grinding machine by a screw, and hot air is introduced to control the drying temperature at 115 °C for drying and pulverization to obtain nano calcium carbonate special for ink.

[0077] (5) 20 parts of nano calcium carbonate, 20 parts of ink oil, 40 parts of resin oil, 5 parts of rosin-modified phenolic resin, 10 parts of gum oil, 1 part of polyethylene wax paste, and 4 parts of phthalocyanine blue are used, and stirred and mixed to prepare ink.

[0078] The nano calcium carbonate special for ink in (4) and the ink in (5) are tested, and the test results are as follows:

[0079]

[0080] Comparative Example 1:

[0081] This comparative example is substantially the same as Example 1, with the differences being: for surface treatment, a rosin emulsion with model number 918 and a solid content of 60% is used, and the dosage is 8% of the solid content of nano-calcium carbonate. 85°C hot water is used to prepare a 15% concentration, and it is stirred evenly.

[0082] Comparative Example 2:

[0083] This comparative example is substantially the same as Example 2, with the differences being: the surface treatment agent is a rosin-modified terpene resin with model number 968 and a solid content of 55%, and the dosage is 8% of the solid content of nano-calcium carbonate. 85°C hot water is used to prepare a 15% concentration, and it is stirred evenly.

[0084] Comparative Example 3:

[0085] This comparative example is substantially the same as Example 3, with the differences being: the surface treatment agent is sodium rosinate, and the dosage is 6% of nano-calcium carbonate. 85°C hot water is used, and 1 part of rosin reacts with 0.15 parts of NaOH for 20 - 30 minutes to prepare a 15% concentration, and it is stirred evenly.

[0086] The products obtained from Comparative Examples 1 - 3 were respectively tested, and the results are as follows:

[0087]

[0088] By comparing Examples 1 - 3 with Comparative Examples 1 - 3, it can be seen that the water absorption of the inks prepared in Comparative Examples 1, 2, and 3 is large, indicating poor anti-emulsification performance; the water absorption of the inks prepared in Examples 1 - 3 is small, indicating good anti-emulsification performance and achieving good water-ink balance. The offset printing ink made of the nano-calcium carbonate special for the ink of the present invention has a lower oil absorption value, greater fluidity, better transparency, good anti-emulsification performance, fine fineness, good dispersibility, and stable product quality compared with conventional modified nano-calcium carbonate.

[0089] In summary, the beneficial effects of the present invention are as follows: First, the present invention uses two crystal form regulators, one is alcohols and sugars; the other is sulfates. The main function of polyols and sugars is to increase the solubility of Ca(OH) 2 , and sulfates react with Ca(OH) 2 to form a CaSO 4 crystal medium. The CaSO4 crystal medium is a whisker-like substance, which can make the calcium carbonate particles develop in the direction of the long aspect ratio of the long diameter. The use of two composite crystal form control agents generates nano-calcium carbonate in the form of small cubic long chains, which can make the nano-calcium carbonate have fine particles while the material is relatively loose, maintaining good dispersibility. Second, the combined action of silicone oil containing functional groups, span, and rosin emulsion is used to make the nano-calcium carbonate have good anti-emulsification performance, fluidity, dispersibility and other indicators. Third, the specific surface area of the nano-calcium carbonate is high, being 60 - 120 m2 / g. According to the empirical formula, the particle size is calculated to be 0.018 - 0.037 μm, that is, 18 - 37 nm. Since the primary particle size of the present invention is small and the dispersibility is good, when used in inks, it has good transparency and good dispersibility, and is suitable for inks or diluents with high transparency requirements. At the same time, it has good dispersibility, good anti-emulsification performance, and good printing adaptability. Fourth, fluidity is the reciprocal of viscosity. The greater the fluidity, the thinner it indicates. The fluidity of the present invention is within a suitable range, enabling the ink to have good processing performance and good dispersibility. The nano-calcium carbonate of the present invention has good gloss when used in inks. The main reason is that the nano-calcium carbonate of the present invention has good dispersibility, and products with uniform particle size and good dispersibility have better light reflection, so the glossiness is good.

[0090] The present invention is not limited to the above specific embodiments. Those of ordinary skill in the art starting from the above conceptions and making various transformations without creative labor all fall within the protection scope of the present invention.

Claims

1. A production method of nano calcium carbonate for ink, characterized in that, it comprises the following steps: Step 1: Dilute Ca(OH) that has been refined and aged for 24 - 72 h 2 to adjust the concentration of Ca(OH) 2 to 5% - 10%, with a temperature of 12 - 25°C. Add a crystal form control agent and stir to obtain raw pulp, and then transport the raw pulp to a carbonization reaction tower; Step 2: Introduce the purified and cooled kiln gas into the carbonation reaction tower for carbonation reaction. The gas flow rate of the kiln gas is 10 - 80 m 3 / min. The first carbonation terminates the reaction when the pH of the reaction liquid ≤ 8, followed by stirring and aging for 4 - 24 h, and then the second carbonation is carried out. During the second carbonation, when the pH ≤ 7.5, continue over-carbonation for 10 - 30 min to obtain the cooked pulp; Step 3: Transport the cooked pulp to the surface treatment tank, heat it to 60 - 90 °C, then add the surface treatment agent to the surface treatment tank, stir at a speed of 800 r / min - 1200 r / min for 60 - 120 min to obtain modified nano calcium carbonate; Step 4: Put the modified nano calcium carbonate into a filter press for pressure filtration and dehydration to obtain a filter cake with a moisture content of 32 - 42%, then disperse the filter cake into particles with a particle size of 5 mm - 40 mm by a disintegrator, and then send the particles to a dryer and a crusher in sequence for drying and crushing treatment to obtain the finished nano calcium carbonate product; Step 5: Detect the finished nano calcium carbonate product obtained in Step 3, and the detection results are as follows: specific surface area 60 - 120 m2 / g, whiteness 88% - 93%, oil absorption value 25 - 40 g DOP / 100 g, moisture ≤ 0.5%, pH ≤ 9; The surface treatment agent includes silicone oil, rosin emulsion, and span. The dosage of silicone oil is 3% - 5% of the weight of nano calcium carbonate, the dosage of rosin emulsion is 3% - 8% of the weight of nano calcium carbonate, and the dosage of span is 1% - 3% of the weight of nano calcium carbonate; The silicone oil is modified silicone oil, including hydrogen-containing dimethyl silicone oil and / or carboxyl silicone oil; The rosin emulsion is rosin resin emulsion or modified rosin resin emulsion, and the solid content of the rosin emulsion is 50% - 60%; The HLB of the span ≤ 5.

2. The production method of nano calcium carbonate for ink according to claim 1, characterized in that, The crystal form control agent is an alcohol and / or a saccharide, including any one or more of ethylene glycol, propylene glycol, pentaerythritol, butanediol, hexanediol, neopentyl glycol, diethylene glycol, dipropylene glycol, trimethylolpropane, 1,1,1-(trimethylol)-ethane, glycerol, xylitol, sorbitol, citric acid, beet sugar, sucrose, glucose, fructose, ribose, deoxyribose, maltose, lactose; the dosage of the crystal form control agent is 0.5% - 5% of the solid content of Ca(OH) 2 2 3. The production method of nano calcium carbonate for ink according to claim 1, characterized in that, The crystal form control agent is a water-soluble sulfuric acid or sulfate, including any one or more of sulfuric acid, sodium sulfate, magnesium sulfate, aluminum sulfate, and zinc sulfate; the dosage of the crystal form control agent is 1% - 10% of the solid content of Ca(OH) 2 2.

4. The production method of nano calcium carbonate for ink according to claim 1, characterized in that, The volume content of carbon dioxide in the kiln gas is 25% - 40%.

5. An ink prepared from the nano calcium carbonate described in claims 1 - 4, characterized in that, it includes 15 - 20 parts of nano calcium carbonate, 15 - 20 parts of ink oil, 40 - 50 parts of resin oil, 5 - 10 parts of rosin modified phenolic resin, 8 - 15 parts of gum oil, 0.8 - 3 parts of polyethylene wax paste, and 4 - 7 parts of phthalocyanine blue.

6. The ink according to claim 5, characterized in that, The ink oil is prepared by mixing rosin pentaerythritol resin, linseed oil polymer, and high-boiling kerosene, and the viscosity is 50000 mpa.s.

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