阅读说明：本技术 一种醇溶硝化棉光变油墨及其制备工艺 (Alcohol-soluble nitrocellulose light-variable ink and preparation process thereof ) 是由 周贤永 朱丽纯 丁立刚 张敬 于 2019-12-09 设计创作，主要内容包括：本发明公开一种醇溶硝化棉光变油墨,其特征在于：采用乙醇为主溶剂,其它组分及含量为：醇溶性硝化棉16.0-20.0%,醇溶松香4.0-8.0%,乙酰柠檬酸三丁酯0.0-5.0%,光变颜料8.5-9.5%,乙醇45.0-62.0%,乙酸乙酯8.0-12.0%,二丙二醇甲醚2.0-5.0%,醇溶色墨0-0.5%,本发明采用树脂溶解、光变颜料分散、调色及检验工艺方法制备醇溶性光变油墨,旨在制备节能减排、降低成本,满足现有市场对光变油墨的需求的同时,满足环保条件VOC排放指标的需求,具有更高的经济效益和社会效益。(The invention discloses alcohol soluble nitrocellulose light-variable ink which is characterized by comprising the following components in parts by weight: ethanol is used as a main solvent, and other components and contents are as follows: 16.0-20.0% of alcohol-soluble nitrocotton, 4.0-8.0% of alcohol-soluble rosin, 0.0-5.0% of acetyl tributyl citrate, 8.5-9.5% of optically variable pigment, 45.0-62.0% of ethanol, 8.0-12.0% of ethyl acetate, 2.0-5.0% of dipropylene glycol methyl ether and 0-0.5% of alcohol-soluble ink.)

1. An alcohol soluble nitrocellulose optically variable ink is characterized in that: ethanol is used as a main solvent, and other components and contents are as follows: 16.0-20.0% of alcohol-soluble nitrocotton, 4.0-8.0% of alcohol-soluble rosin, 0.0-5.0% of acetyl tributyl citrate, 8.5-9.5% of optically variable pigment, 45.0-62.0% of ethanol, 8.0-12.0% of ethyl acetate, 2.0-5.0% of dipropylene glycol methyl ether and 0-0.5% of alcohol-soluble ink.

2. The process for preparing alcohol-soluble nitrocellulose optically variable ink according to claim 1, wherein: the method comprises the following steps:

(1) resin dissolution: accurately measuring ethanol, ethyl acetate, dipropylene glycol methyl ether and acetyl tributyl citrate, adding into a dispersion kettle, stirring and dispersing at the rotating speed of 600rpm for 5min, continuously adding other raw materials into the dispersion kettle, sealing and dispersing at the rotating speed of 900rpm for 40min after the addition is finished until the raw materials are completely dissolved, and finally filtering by a filter bag;

(2) dispersing optically variable pigments: putting the resin liquid completely dissolved in the step (1) into a material cylinder, stirring at 300rpm for dispersion, synchronously adding the optically variable pigment, and continuing to disperse at 300rpm for 120min after the addition is finished;

(3) color matching and inspection: adding alcohol-soluble ink according to the process requirements, adjusting the color and viscosity, filtering, packaging and warehousing after the inspection is qualified.

3. The preparation process of alcohol-soluble nitrocellulose optically variable ink according to claim 2, wherein the alcohol-soluble nitrocellulose optically variable ink comprises the following steps: in the resin dissolving step, other raw materials are added in sequence according to the sequence of alcohol-soluble nitrocotton and alcohol-soluble rosin.

4. The preparation process of alcohol-soluble nitrocellulose optically variable ink according to claim 2, wherein the alcohol-soluble nitrocellulose optically variable ink comprises the following steps: and in the resin dissolving step, a 200-mesh filter bag is adopted for filtering.

5. The preparation process of alcohol-soluble nitrocellulose optically variable ink according to claim 2, wherein the alcohol-soluble nitrocellulose optically variable ink comprises the following steps: the diameter of a tilted dispersion plate is 400-500mm in the resin dissolving and optically variable pigment dispersing steps, and the linear velocity is 15 m/s.

6. The preparation process of alcohol-soluble nitrocellulose optically variable ink according to claim 3, wherein the alcohol-soluble nitrocellulose optically variable ink comprises the following steps: the filtering in the color matching and detecting steps adopts a 100-mesh filter bag for filtering.

Technical Field

The invention relates to the field of printing ink, in particular to alcohol-soluble nitrocotton optically variable printing ink and a preparation process thereof.

Background

The optically variable ink uses the interference principle of light, natural light with different incident angles in different directions can generate conforming light with different interference wavelengths after being reflected by the surface ink layer, so that an observer can generate visual feelings with different colors at different angles, and the effect cannot be copied by a copying machine, so that the optically variable ink is used as an anti-counterfeiting material to be applied to paper money, securities, tickets and high-grade cigarette and wine packages, and the optically variable ink has very high requirements on production technology and equipment, so that the cost is higher than that of other common inks. The optically variable printing ink for producing cigarette packing material is used mainly in packing box sheet and packing box skin, such as hard cigarette box, cigarette carton and soft cigarette box, and has VOC content of 50-70% and diluting ratio of original printing ink: the diluent is 2:1, so that the release amount of n-propyl acetate and ethyl acetate is large when the variety of products are normally produced, about 400kg and 80kg are respectively used every day, the pungent smell of a workshop is large, the environment is seriously polluted, the global requirements for environmental protection and low carbon are higher and higher, and the cost is increased for the production and preparation of the optically variable ink along with the charging of VOC (volatile organic compound) emission, so that the technical problem of the environmentally-friendly optically variable ink capable of reducing the VOC emission, saving energy and reducing emission needs to be solved urgently.

Disclosure of Invention

Aiming at the problems, the invention provides the alcohol solvent optically variable ink mainly comprising ethanol on the premise of keeping the printing effect of the prior ester-soluble optically variable ink, reduces the VOC discharge amount and the cost, meets the environmental protection requirement, and has better economic benefit and social benefit, and the specific scheme is as follows:

an alcohol soluble nitrocellulose optically variable ink is characterized in that: ethanol is used as a main solvent, and other components and contents are as follows: 16.0-20.0% of alcohol-soluble nitrocotton, 4.0-8.0% of alcohol-soluble rosin, 0.0-5.0% of acetyl tributyl citrate, 8.5-9.5% of optically variable pigment, 45.0-62.0% of ethanol, 8.0-12.0% of ethyl acetate, 2.0-5.0% of dipropylene glycol methyl ether and 0-0.5% of alcohol-soluble ink.

A preparation process of alcohol-soluble nitrocellulose optically variable ink is characterized by comprising the following steps: the method comprises the following steps:

(1) resin dissolution: accurately measuring ethanol, ethyl acetate, dipropylene glycol methyl ether and acetyl tributyl citrate, adding into a dispersion kettle, stirring and dispersing at the rotating speed of 600rpm for 5min, continuously adding other raw materials into the dispersion kettle, sealing and dispersing at the rotating speed of 900rpm for 40min after the addition is finished until the raw materials are completely dissolved, and finally filtering by a filter bag;

(2) dispersing optically variable pigments: putting the resin liquid completely dissolved in the step (1) into a material cylinder, stirring at 300rpm for dispersion, synchronously adding the optically variable pigment, and continuing to disperse at 300rpm for 120min after the addition is finished;

(3) color matching and inspection: adding alcohol-soluble ink according to the process requirements, adjusting the color and viscosity, filtering, packaging and warehousing after the inspection is qualified.

Further, in the resin dissolving step, the other raw materials are added in sequence according to the sequence of alcohol-soluble nitrocotton and alcohol-soluble rosin.

Further, in the resin dissolving step, a 200-mesh filter bag is adopted for filtering.

Furthermore, the diameter of a tilted dispersion plate is 400-500mm, and the linear velocity is 15 m/s.

Further, the filtering in the color mixing and inspection step adopts a 100-mesh filter bag for filtering.

Compared with the prior art, the invention has the following beneficial effects:

compared with the existing ester-soluble printing ink, the alcohol-soluble optically variable printing ink disclosed by the invention has a large amount of volatile organic solvents, is easy to generate pungent odor and pollutes the environment, greatly reduces the emission of VOC in the printing ink, adopts the optically variable printing ink taking ethanol as a main solvent, improves the product quality, obviously reduces the emission of VOC in the optically variable printing ink, meets the requirements of the existing environment-friendly products, protects the environment, reduces the production cost, greatly improves the economic benefit and the social benefit, and is worthy of popularization.

Detailed Description

The technical solutions in the embodiments of the present invention are clearly and completely described below, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without creative efforts, shall fall within the protection scope of the present invention.

An alcohol soluble nitrocellulose optically variable ink is characterized in that: ethanol is used as a main solvent, and other components and contents are as follows: 16.0-20.0% of alcohol-soluble nitrocotton, 4.0-8.0% of alcohol-soluble rosin, 0.0-5.0% of acetyl tributyl citrate, 8.5-9.5% of optically variable pigment, 45.0-62.0% of ethanol, 8.0-12.0% of ethyl acetate, 2.0-5.0% of dipropylene glycol methyl ether and 0-0.5% of alcohol-soluble ink.

In order to prepare the optically variable ink, the following preparation process is adopted:

(1) resin dissolution: accurately metering ethanol, ethyl acetate, dipropylene glycol methyl ether and acetyl tributyl citrate, adding into a dispersion kettle, stirring and dispersing at the rotation speed of 600rpm for 5min, then sequentially adding according to the sequence of alcohol-soluble nitrocotton and alcohol-soluble rosin, hermetically dispersing at the rotation speed of 900rpm for 40min after the addition is finished until the alcohol-soluble nitrocotton and the alcohol-soluble rosin are completely dissolved, and finally filtering by adopting a 200-mesh filter bag;

(2) dispersing optically variable pigments: putting the resin liquid completely dissolved in the step (1) into a material cylinder, stirring at 300rpm for dispersion, synchronously adding the optically variable pigment, and continuing to disperse at 300rpm for 120min after the addition is finished;

(3) color matching and inspection: adding alcohol-soluble ink according to the process requirements, adjusting the color and the viscosity, filtering by adopting a 100-mesh filter bag after the inspection is qualified, and packaging and warehousing the finished product after the filtration.

The performance indexes of the optically variable ink prepared by the process steps are shown in table 1:

TABLE 1 technical indices of optically variable ink products

The alcohol solvent mainly containing ethanol is used as the main solvent of the printing ink, so that the printing ink has low harm to human bodies, meets the requirement of environmental protection, greatly reduces the consumption of petroleum resources, abandons ester-soluble optically variable printing ink, greatly reduces the emission of volatile organic compounds and VOC (volatile organic compounds), does not pollute the working environment such as workshops due to pungent smell in the production process, influences the physical health of workers, and has the advantages of energy conservation and environmental protection;

the alcohol-soluble nitrocotton, namely the L-type nitrocotton, adopted by the invention has low nitrogen content and can be dissolved and diluted by ethanol. The optically variable ink produced by Jiangsu Tiger ink Limited company of the company is mainly printed on the secondary outer layer of a cigarette packet, so that the printing effect is met, meanwhile, the optically variable ink needs to have high heat resistance under the condition of high running speed of a cigarette making machine, and the conditions of no falling, color mixing and color change at 180 ℃ for 0.5s are met, so that the optically variable ink is prepared by replacing the existing ester-soluble nitrocellulose, namely the H-type nitrocellulose, with the L-type nitrocellulose, namely the alcohol-soluble nitrocellulose, and the optically variable ink is prepared by comparing the two, and the performance difference between the H-type nitrocellulose and the L-type nitrocellulose is shown in the following table 2:

species of	Nitrogen content (%)	Film Forming Properties	Solvent releasing property	True solvent	Diluting solvent
						H type	11.5-12.2	Crisp	Height of	Esters and ketones	Alcohols, aromatic hydrocarbons
L-shaped	10.7-11.4	Plasticity of	Is low in	Small amount of esters	Alcohol(s)

TABLE 2 differences in the Performance of the H-and L-type Nitrocellulose

As can be seen from table 2: the viscosity of the H-type nitrocotton is similar to that of the L-type nitrocotton, wherein 5, 1, 1/2, 1/4, 1/8 and 1/16 are all available, but the range of the H-type nitrocotton is wide, the H-type nitrocotton is as low as 1/32, and the H-type nitrocotton is as high as 1500 s; the L-type nitrocotton is plastic, the softening point is 220-240 ℃, the ignition point is 240 ℃, and the L-type nitrocotton is higher than that of the H-type nitrocotton at 180 ℃, so that the L-type nitrocotton has higher safety.

In order to further detect the difference of the two performances, 25% of the two pure nitrocotton solids are dissolved, 30% of ethanol or isopropanol is added into nitrocotton powder to serve as a wetting agent, the wet powder is 36% for detection, and the lowest limit solvent ratio for stable dissolution of the H-type nitrocotton is ethanol: ethyl acetate 54: 10, 1:1 dilution must be with ethyl acetate; the lowest limit solvent ratio for stable dissolution of the L-type nitrocotton is ethanol: ethyl acetate 59: 5, 1:1 dilution can be carried out by using single ethanol, if the proportion of the dissolving solvent is changed to 56:8, the using effect can be kept stable for a long time, and meanwhile, the discharge conditions of two types of nitrocotton solvents are shown in table 3, wherein 36% of nitrocotton powder is adopted in table 3, and the moisture absorption proportion is 1:

TABLE 3 discharge of the H-type and L-type nitrocotton solvents

As can be seen from table 3, with the same amount of the optically variable ink and the diluent, the total solvent release amount is equal to 175 parts, in the H type, 136 parts of ethyl acetate and 39 parts of ethanol, and in the L type, 8 parts of ethyl acetate and 167 parts of ethanol, the ethyl acetate emission amount is reduced by 94%, that is, the VOC emission charge is saved for the enterprise by 94%, the odor of the workshop can be greatly reduced, and the health of the staff can be maintained.

The main resin of the invention is L-type nitrocotton, the auxiliary resin is maleic acid modified alcohol-soluble rosin, the main solvent is ethanol, the real solvent is ethyl acetate, and the volatilization rate of the ethyl acetate is 3 times of that of the ethanol, so that during printing, the insufficient dissolving power of single alcohol to the resin is easily caused by the rapid volatilization of the ethyl acetate, and a pasting plate is formed. In order to solve the problem and ensure that VOC residue meets the requirement, after selection, dipropylene glycol methyl ether (DPM) with the boiling point of 200 ℃ is selected as a cosolvent, the DPM belongs to an environment-friendly alcohol ether solvent and is widely used for water-based ink, compared with propylene glycol methyl ether (PM), the DPM has the advantages of higher boiling point, smaller smell and stronger dissolving power for nitrocotton, and tests show that the addition amount of the DPM is 2-5 percent, so that the printing stability can be remarkably improved, the DPM can exceed 5 percent, the drying speed can not meet the requirement and is lower than 2 percent, the plate pasting phenomenon still exists, in addition, in summer with high humidity, the DPM can also play a role in preventing white water, and can absorb part of water to keep the dissolving power for resin because the DPM can be miscible with alcohol, ester and water.

In order to ensure that the metal oxide layer of the optically variable pigment in the optically variable ink is not damaged due to the process conditions of too large shearing force, too high rotating speed and the like after the preparation process, the friction coefficient of the optically variable pigment is reduced, the printing effect of a product is ensured, and white spots or sand sense is avoided, the optically variable pigment is dispersed by adopting a warping dispersion disc passing through a large disc. As the diameter of the traditional tilted dispersion disc is 320mm plus 180 mm, the rotating speed is 1400rpm at most, the linear velocity is 30m/s, the shearing force is strong, the traditional tilted dispersion disc is suitable for low-viscosity high-rotating speed, the phenomena of resin dispersion and nonuniform dispersion of optically variable pigments exist, and the outer coating layer of the pigments is damaged, the problem is solved, the adhesion of optically variable printing ink is adapted, and the full dispersion of the resin and the optically variable pigments is realized, the tilted dispersion disc is 500mm plus 400 mm in diameter, and the linear velocity is 15m/s, so that the dispersion of the resin and the color mixing process is carried out, the outer coating layer of the pigments is not damaged, and the quality of an optically variable printing ink product is greatly improved.

The above description is only an embodiment of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are included in the scope of the present invention.