Formulation principle of solvent-based polyamide plastic gravure printing ink
2019-02-19 02:21:17
1 Introduction
The printability of the ink includes both the suitability of the print job and the suitability of the print quality. The suitability of the ink for printing operations requires that the ink be compatible with the corresponding type, speed, pressure, and substrate. The print quality of the ink is the fixation, drying, color, and filming of the ink film transferred to the surface. The gloss, fastness, resistance, and other properties that ensure print quality. The aspect of the color effect expressed by the ink is generally called the ink color, and other aspects other than the ink color that are related to the printability of the ink are called ink properties. The ink printing suitability is mainly to solve the optimal matching between ink and ink and printing effect. Plastic gravure ink due to ink structure and printing plate type, substrate, printed matter, and other aspects of the use of special, in the actual use of ink and ink and print jobs and print quality is not suitable for the problem is more prominent, compared to ink transfer tasks Heavy and heavy, according to the author's experience in ink design and application guidance, this paper discusses the principles and methods of the compatibility of commonly used solvent-based polyamide plastic gravure printing inks.
2 Ink color
2.1 ink tone matching method
(1) Analyze the original and determine the color. The color of plastic concave ink is performed on the color sample of the original. In order to reduce the blindness of the color, the color of the original must be analyzed first, that is, the color of the original is determined by mixing the ratios of the three primary colors of the colorant. At present, analytical manuscripts mainly use a combination of instrument colorimetry and visual colorimetry. Instrument colorimetry is the use of spectrophotometers, densitometers, and electronic color separation instruments to measure the optical density or tristimulus value of the original color. The quantized data of the characterization color is obtained; visual colorimetry is the qualitative range of the three primary colors needed to form the original color according to the combination of the original color and experience. Because the color measurement of the instrument is more complicated, and the color is not a pure physical phenomenon after all, but a comprehensive reflection of physical and human visual physiology and psychology, that is, the final effect of printing color depends on the human visual psychology experience, so in the actual ink tone distribution Visual alignment is more straightforward and convenient, and instrument colorimetry is only used for standard analysis of colors.
(2) The base ink hand tone, scraping color comparison. According to the results of original color analysis, the ideal tricolor ink (base ink) is prepared. According to the actual experience of ink transfer, the plastic base ink should also include base ink black and white in addition to red, yellow, and blue. When toning, first, accurately weigh the appropriate amount of base ink (such as 10g), pick up the base ink with a dip Knife and mix it evenly on the glass plate, visually adjust the ink color and the original color, and measure the edge color when adjusting. When the ink color and the original color are similar, it may be desirable to adjust the ink on the scraping paper for scraping, and to carefully compare the face color, the background color, and the ink color, so that the toner may be subjected to repeated and detailed work such as coloring, scraping, and color matching until the color is adjusted. Consistent with the original color. Then, the remaining amount of base ink is accurately weighed, and the remaining amount of the base ink is subtracted from the starting amount of the base ink that is called. This difference can be initially used as the amount of base ink required for preparing the original color, and then This amount weighs each base ink for deployment, scraping, and color matching, corrects the ink color of the transferred ink to match the original color, and finally adopts a scale-up scale to obtain the required ink amount.
3 Modulation
3.1 Suitability of Printing Jobs
(1) Viscosity and its deployment. Viscosity is a major performance index that characterizes the suitability of a gravure printing job. Plastic gravure ink viscosity is lower than other inks, only 50 ~ 110cp/25 °C (coating - Cup: 30 seconds / 25 °C). The viscosity of the ink is too large or too small to be conducive to the printing job. Viscosity over the General Assembly caused by the transmission of ink in the transmission process is not smooth, bad transfer, print bite color, paste version, from orange peel and other defects; viscosity is too low will cause ink stability is poor, easy to bubble in the process of transmission , The printed matter is prone to defects such as pinholes, hair voids, halos, water lines, powdering, and dust falling. In the use of ink, if the viscosity is too large, it can be reconstituted with 5% to 15% of the plastic gravure ink special mixed solvent, the mixed solvent from ethanol:isopropanol: 200# solvent: butanol = 1.4:2 : Composition of 6:1:1. Avoid adding solvents when adjusting. If the viscosity is too small, new ink with the same kind of high viscosity can be used for reconstitution;
(2) Stickiness and blending. Viscosity is a property index that characterizes ink resistance to ink film separation during transfer. Plastic gravure inks are thin and low-viscosity, and tackiness is often not valued. In fact, sticky discomfort can also cause poor printability and further affect print quality. If the stickiness is too large, after the multi-color printing may occur, the back color may pull out the front color, block the plate, blot the surface unevenly, and then dry and have no light. This phenomenon is obvious when the front color is not dry, and the solution is It is appropriate to use a detackifier;
(3) Liquidity and its deployment. The fluidity is related to the viscosity, viscosity, thixotropy, silk and consistency, and is affected by the characteristics of the binder, the structure of the pigment, the solid content of the ink composition, and other factors. Plastic concave ink If the fluidity is too large, such as pattern expansion, unclear gradation, unsaturated ink, and bright color, etc., these faults can be adjusted during the design of the ink by changing the formula, and can be adjusted to the liquidity during use in the production site. Smaller new inks are used to adjust or replace the ink; if the fluidity is too small, ink transfer will be unsmooth, ink will not evenly distribute, and the ink color will be inconsistent. This phenomenon can be used to make thinner materials (ethanol: isopropanol: 200#). Solvent: butanol = 1.4:2.6:1:1) to adjust;
(4) Foam and its elimination. The concave and convex inks are low-viscosity, thin, and liquid-like. In the printing process, ink pumps are used repeatedly to supply ink, and air is inevitably mixed into the flowing ink. Because the surface tension of the ink is relatively large, bubbles are formed. Blistering affects the normal operation of the print job. The method of eliminating foam is to add an anti-foaming agent such as silicone oil with an ink amount of 0.3% to 0.5% on the one hand; on the other hand, to minimize the chance of contact between the ink and the air, as much as possible while ensuring continuous ink supply. The amount of ink pump circulation, the use of non-leaking ink pipe and ensure the ink tube mouth deeper ink tank liquid surface below 30cm;
(5) Stability and deployment. The stability of the plastic concave ink refers to the continuous uniformity of the ink during storage or use. Since the concave plastic ink is a thin, low-viscous liquid, the phenomenon of gradation of the pigment and filler is often caused, and the stability of the ink is improved. Deterioration, thinning in the storage container, unevenness in the ink before and after the printing process. This may be caused by unreasonable formulation, poor viscosity of the binder, excessive pigment content, poor dispersion, and excessive solvent. If this is the case, adjustments can be made by adjusting the recipe design; it is also possible that excessive dilution during use breaks the liquid-solid balance of the ink, so that new ink can be added to the ink fountain for adjustment. In fact, even a well-designed ink will have different levels of delamination during storage, which is usually eliminated by short-time stirring. Therefore, it is necessary for the ink to be shaken sufficiently before using the open bucket.
3.2 Printing Quality Adaptability
(1) Dryness. Plastic concave drying should be dry on the machine, after printing and drying. Drying too fast will cause the ink to have problems such as blocking, no imprinting, or imprinting defects during the transfer process; drying too slowly will result in printing failures after printing, sticky printing, dot enlargement, unclear gradation, curling and sticking, etc. . When the ink is used, it is dried too quickly and a suitable amount of a solvent having a higher boiling point can be added. If the drying is too slow, an appropriate amount of the low boiling point solvent may be added.
(2) Adhesion. The adhesion of the plastic concave ink refers to the dry adhesive properties of the printed film on the surface of the substrate. Plastic Gravure Ink Because the substrate is a smooth, low-polarity polyolefin material, the adhesion of the printing film is difficult. The main way to solve the problem of the adhesion of the printing film is to polarize the plastic surface, but In terms of inks, the first choice is the use of more polar polyamide resin inks; the second is to use thinners and dilutants when diluting or removing light.
(3) resistance. The resistance of the plastic concave ink mainly refers to the durable color retention properties of the printing film to ultraviolet light, water, organic solvents and acid and alkali liquids. Durability is affected by the properties and amount of resin, pigment, filler, and additives. Durability can be improved to some extent by changing the structure of the formula.
(Author: Cui Jinfeng Zhou Ping)
The printability of the ink includes both the suitability of the print job and the suitability of the print quality. The suitability of the ink for printing operations requires that the ink be compatible with the corresponding type, speed, pressure, and substrate. The print quality of the ink is the fixation, drying, color, and filming of the ink film transferred to the surface. The gloss, fastness, resistance, and other properties that ensure print quality. The aspect of the color effect expressed by the ink is generally called the ink color, and other aspects other than the ink color that are related to the printability of the ink are called ink properties. The ink printing suitability is mainly to solve the optimal matching between ink and ink and printing effect. Plastic gravure ink due to ink structure and printing plate type, substrate, printed matter, and other aspects of the use of special, in the actual use of ink and ink and print jobs and print quality is not suitable for the problem is more prominent, compared to ink transfer tasks Heavy and heavy, according to the author's experience in ink design and application guidance, this paper discusses the principles and methods of the compatibility of commonly used solvent-based polyamide plastic gravure printing inks.
2 Ink color
2.1 ink tone matching method
(1) Analyze the original and determine the color. The color of plastic concave ink is performed on the color sample of the original. In order to reduce the blindness of the color, the color of the original must be analyzed first, that is, the color of the original is determined by mixing the ratios of the three primary colors of the colorant. At present, analytical manuscripts mainly use a combination of instrument colorimetry and visual colorimetry. Instrument colorimetry is the use of spectrophotometers, densitometers, and electronic color separation instruments to measure the optical density or tristimulus value of the original color. The quantized data of the characterization color is obtained; visual colorimetry is the qualitative range of the three primary colors needed to form the original color according to the combination of the original color and experience. Because the color measurement of the instrument is more complicated, and the color is not a pure physical phenomenon after all, but a comprehensive reflection of physical and human visual physiology and psychology, that is, the final effect of printing color depends on the human visual psychology experience, so in the actual ink tone distribution Visual alignment is more straightforward and convenient, and instrument colorimetry is only used for standard analysis of colors.
(2) The base ink hand tone, scraping color comparison. According to the results of original color analysis, the ideal tricolor ink (base ink) is prepared. According to the actual experience of ink transfer, the plastic base ink should also include base ink black and white in addition to red, yellow, and blue. When toning, first, accurately weigh the appropriate amount of base ink (such as 10g), pick up the base ink with a dip Knife and mix it evenly on the glass plate, visually adjust the ink color and the original color, and measure the edge color when adjusting. When the ink color and the original color are similar, it may be desirable to adjust the ink on the scraping paper for scraping, and to carefully compare the face color, the background color, and the ink color, so that the toner may be subjected to repeated and detailed work such as coloring, scraping, and color matching until the color is adjusted. Consistent with the original color. Then, the remaining amount of base ink is accurately weighed, and the remaining amount of the base ink is subtracted from the starting amount of the base ink that is called. This difference can be initially used as the amount of base ink required for preparing the original color, and then This amount weighs each base ink for deployment, scraping, and color matching, corrects the ink color of the transferred ink to match the original color, and finally adopts a scale-up scale to obtain the required ink amount.
3 Modulation
3.1 Suitability of Printing Jobs
(1) Viscosity and its deployment. Viscosity is a major performance index that characterizes the suitability of a gravure printing job. Plastic gravure ink viscosity is lower than other inks, only 50 ~ 110cp/25 °C (coating - Cup: 30 seconds / 25 °C). The viscosity of the ink is too large or too small to be conducive to the printing job. Viscosity over the General Assembly caused by the transmission of ink in the transmission process is not smooth, bad transfer, print bite color, paste version, from orange peel and other defects; viscosity is too low will cause ink stability is poor, easy to bubble in the process of transmission , The printed matter is prone to defects such as pinholes, hair voids, halos, water lines, powdering, and dust falling. In the use of ink, if the viscosity is too large, it can be reconstituted with 5% to 15% of the plastic gravure ink special mixed solvent, the mixed solvent from ethanol:isopropanol: 200# solvent: butanol = 1.4:2 : Composition of 6:1:1. Avoid adding solvents when adjusting. If the viscosity is too small, new ink with the same kind of high viscosity can be used for reconstitution;
(2) Stickiness and blending. Viscosity is a property index that characterizes ink resistance to ink film separation during transfer. Plastic gravure inks are thin and low-viscosity, and tackiness is often not valued. In fact, sticky discomfort can also cause poor printability and further affect print quality. If the stickiness is too large, after the multi-color printing may occur, the back color may pull out the front color, block the plate, blot the surface unevenly, and then dry and have no light. This phenomenon is obvious when the front color is not dry, and the solution is It is appropriate to use a detackifier;
(3) Liquidity and its deployment. The fluidity is related to the viscosity, viscosity, thixotropy, silk and consistency, and is affected by the characteristics of the binder, the structure of the pigment, the solid content of the ink composition, and other factors. Plastic concave ink If the fluidity is too large, such as pattern expansion, unclear gradation, unsaturated ink, and bright color, etc., these faults can be adjusted during the design of the ink by changing the formula, and can be adjusted to the liquidity during use in the production site. Smaller new inks are used to adjust or replace the ink; if the fluidity is too small, ink transfer will be unsmooth, ink will not evenly distribute, and the ink color will be inconsistent. This phenomenon can be used to make thinner materials (ethanol: isopropanol: 200#). Solvent: butanol = 1.4:2.6:1:1) to adjust;
(4) Foam and its elimination. The concave and convex inks are low-viscosity, thin, and liquid-like. In the printing process, ink pumps are used repeatedly to supply ink, and air is inevitably mixed into the flowing ink. Because the surface tension of the ink is relatively large, bubbles are formed. Blistering affects the normal operation of the print job. The method of eliminating foam is to add an anti-foaming agent such as silicone oil with an ink amount of 0.3% to 0.5% on the one hand; on the other hand, to minimize the chance of contact between the ink and the air, as much as possible while ensuring continuous ink supply. The amount of ink pump circulation, the use of non-leaking ink pipe and ensure the ink tube mouth deeper ink tank liquid surface below 30cm;
(5) Stability and deployment. The stability of the plastic concave ink refers to the continuous uniformity of the ink during storage or use. Since the concave plastic ink is a thin, low-viscous liquid, the phenomenon of gradation of the pigment and filler is often caused, and the stability of the ink is improved. Deterioration, thinning in the storage container, unevenness in the ink before and after the printing process. This may be caused by unreasonable formulation, poor viscosity of the binder, excessive pigment content, poor dispersion, and excessive solvent. If this is the case, adjustments can be made by adjusting the recipe design; it is also possible that excessive dilution during use breaks the liquid-solid balance of the ink, so that new ink can be added to the ink fountain for adjustment. In fact, even a well-designed ink will have different levels of delamination during storage, which is usually eliminated by short-time stirring. Therefore, it is necessary for the ink to be shaken sufficiently before using the open bucket.
3.2 Printing Quality Adaptability
(1) Dryness. Plastic concave drying should be dry on the machine, after printing and drying. Drying too fast will cause the ink to have problems such as blocking, no imprinting, or imprinting defects during the transfer process; drying too slowly will result in printing failures after printing, sticky printing, dot enlargement, unclear gradation, curling and sticking, etc. . When the ink is used, it is dried too quickly and a suitable amount of a solvent having a higher boiling point can be added. If the drying is too slow, an appropriate amount of the low boiling point solvent may be added.
(2) Adhesion. The adhesion of the plastic concave ink refers to the dry adhesive properties of the printed film on the surface of the substrate. Plastic Gravure Ink Because the substrate is a smooth, low-polarity polyolefin material, the adhesion of the printing film is difficult. The main way to solve the problem of the adhesion of the printing film is to polarize the plastic surface, but In terms of inks, the first choice is the use of more polar polyamide resin inks; the second is to use thinners and dilutants when diluting or removing light.
(3) resistance. The resistance of the plastic concave ink mainly refers to the durable color retention properties of the printing film to ultraviolet light, water, organic solvents and acid and alkali liquids. Durability is affected by the properties and amount of resin, pigment, filler, and additives. Durability can be improved to some extent by changing the structure of the formula.
(Author: Cui Jinfeng Zhou Ping)
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