A plastic printing composite ink and preparation method thereof

Abstract

The present invention belongs to the technical field of ink preparation, and specifically relates to a composite ink for plastic printing and a preparation method thereof. The method comprises: 1) taking raw materials, aromatic sulfonic acid compounds, and phosphorescent fillers and mixing them uniformly to obtain a connecting material; 2) preparing a solvent, adding a catalyst to heat and react, and obtaining a modified solvent; 3) mixing the connecting material, the modified solvent, and the colorant uniformly to obtain a mixture, cooling the mixture after heat treatment, adding an antioxidant to keep the mixture warm after cooling, further cooling the mixture for suction filtration, and removing the catalyst to obtain a composite ink. The composite ink prepared by the present invention has good fluidity and uniform composition, can be evenly coated when applied, does not wrinkle or crack after film formation, and prolongs the service life. In addition, the composite ink prepared by the present invention has high luminous intensity and long afterglow time.

Description

Technical Field

[0001] The invention belongs to the technical field of ink preparation, and in particular relates to a plastic printing composite ink and a preparation method thereof. Background Art

[0002] Ink is a viscous colloidal fluid composed of colorants, additives, binders, etc. According to the different components, it can be roughly divided into water-based ink, oil-based ink, composite ink, etc. At present, most of the water-based inks on the market are made of acrylic emulsions and acrylic emulsions, which have good adhesion. At the same time, after being coated with materials such as sodium silicate, titanium dioxide, and aluminum sulfate, water-based inks have good weather resistance. However, when the fineness of water-based ink is lower than 10μm, it will seriously affect the fluidity and rheology of water-based ink. Due to the characteristics of the composition of water-based ink, the fluidity is relatively large, and the viscosity directly affects the quality of ink transfer. Low viscosity causes light color, and high viscosity causes poor fluidity and slow drying speed, resulting in dirty and paste boards. When storing water-based inks in a high-humidity environment, the ink is prone to problems such as non-resistance to alkali, non-resistance to ethanol and water, and shrinkage of the substrate. During the printing process, it is easy to have anti-sticking phenomenon, resulting in dirty and paste boards.

[0003] Based on these problems, oil-based inks are usually developed in this field, and metal-based inks, polymer-based inks, carbon-based inks, etc. are commonly used. Among them, silver-based conductive inks obviously have high preparation costs, and the molecular chain rigidity of inks with polymers such as polythiophene and polypyrrole as fillers is large, and their processing performance is limited, while carbon-based inks have poor moisture resistance. At the same time, oil-based inks use organic solvents such as toluene, xylene, and industrial alcohol as solvents. In the flexible packaging industry, especially people use gravure printing for plastic flexible packaging more and more frequently. Since oil-based inks use volatile drying as the main method, a large amount of organic volatile pollutants will be generated during the printing process of plastic inks. The lower the boiling point of the solvent, the easier it is to volatilize and release toxic gases. While endangering human health, it exacerbates the greenhouse effect, leading to characteristics such as photochemical smog, and seriously pollutes the environment. After printing, there are also residual toxic substances on the surface of the product.

[0004] At the same time, ink printing technology has been widely used in advertisements, warning signs, etc. As important indicators for evaluating printing quality, afterglow time and luminescence performance are directly related to the effect of printed products. Afterglow time refers to the time required for the light of a printed product to gradually weaken until it is invisible after it glows under light, while luminescence performance refers to the brightness and chromaticity of a printed product under specific lighting conditions. These performance indicators are not only related to the chemical composition and physical structure of the ink, but also affected by printing process parameters and paper materials. Therefore, studying the impact of ink printing technology on afterglow time and luminescence performance is of great significance for improving printing quality and expanding application areas. Summary of the invention

[0005] Based on the above content, in order to solve the problems of water-based ink absorbing moisture and sticking, low viscosity leading to paste, and oil-based ink having strong volatility of organic solvents leading to environmental pollution, the present invention provides a plastic printing composite ink and a preparation method of the ink. The purpose of the present invention is to:

[0006] 1. Ensure that the composite ink has uniform composition and good fluidity;

[0007] 2. Improve the flexibility of ink molecules, avoid cracking of molding ink, and extend its service life;

[0008] 3. Improve the luminous life and efficiency of composite ink.

[0009] To achieve the above objectives, the present invention adopts the following technical solutions.

[0010] A method for preparing composite ink for plastic printing,

[0011] The method comprises:

[0012] 1) taking raw materials, aromatic sulfonic acid compounds, and phosphorescent fillers and mixing them evenly to obtain a connecting material;

[0013] 2) preparing a solvent, adding a catalyst and heating the solvent to obtain a modified solvent;

[0014] 3) The connecting material, the modified solvent and the colorant are mixed uniformly to obtain a mixture, and the mixture is cooled after heat treatment. After cooling, an antioxidant is added to keep the mixture warm, and the mixture is further cooled and filtered to remove the catalyst to obtain a composite ink.

[0015] As a preference,

[0016] Step 1) The raw material is rosin-modified phenolic resin;

[0017] Step 1) The aromatic sulfonic acid compound is 4,4′-biphenyldisulfonic acid, and its dosage is 0.06-0.08 g / g raw material;

[0018] Step 1) The phosphorescent filler is carboxymethyl chitosan and sodium alginate, which are prepared in a mass ratio of 1: (0.2-0.4), and the amount used is 0.6-0.7 g / g raw material.

[0019] As a preference,

[0020] Step 2) The solvent is soybean oil or tung oil, and the dosage is 0.7-1 mL / g raw material. The soybean oil and tung oil are prepared in a volume ratio of 1: (0.3-0.4).

[0021] As a preference,

[0022] Step 2) The catalyst is 9,10-anthraquinone, and its dosage is 0.03-0.08 g / mL solvent;

[0023] The heating reaction in step 2) is carried out in an inert gas atmosphere at 200-220° C. for 0.5-1 h.

[0024] As a preference,

[0025] Step 3) The colorant is bromotetrachlorofluorescein (also known as tetrabromofluorescein, CAS No. 15086-94-9), and its usage is 0.01-0.1 g / g raw material.

[0026] As a preference,

[0027] Step 3) The heat treatment is carried out at 220-240° C. for 2-2.5 hours.

[0028] As a preference,

[0029] Step 3) The cooling treatment is specifically as follows:

[0030] First cool down to 150-160℃, keep the temperature constant for 1-1.5h, add antioxidant and mix evenly, then cool down to 45-55℃ and filter.

[0031] As a preference,

[0032] Step 3) The antioxidant is antioxidant 264, and its dosage is 0.1-0.3 g / g mixture.

[0033] A composite ink for plastic printing.

[0034] In the technical solution of the present invention, a high-viscosity resin is used. As the amount of rosin-modified phenolic resin increases, the viscosity of the binder increases, while the solubility decreases. In addition, its amount has no obvious effect on the characteristic emission peak position of the binder. The ring structure of the rosin-modified phenolic resin is combined with the chain structure of the solvent to provide good solubility for the ink molecules, ensuring that the ink has good component uniformity. Furthermore, the present invention utilizes the effect of strong hydrogen bonds of phosphorescent fillers to provide a rigid structure for the raw materials, while stabilizing the ink and increasing cohesion. The amount of raw materials, aromatic sulfonic acid compounds, and phosphorescent fillers is linearly related to the viscosity of the ink. As the amount of phosphorescent fillers increases, the relative movement of fluid molecules is hindered, and its fluidity changes accordingly.

[0035] The present invention adopts aromatic sulfonic acid compounds as guest phosphorescent molecules, and the molecular structure of aromatic sulfonic acid affects the luminescent properties of ink. If aniline-2,5-disulfonic acid monosodium salt and 2-naphthalenesulfonic acid are used instead, the afterglow time of the ink obtained is significantly shorter than that of the ink obtained by 4,4′-biphenyldisulfonic acid. Although 4,4′-biphenyldisulfonic acid has low molecular mobility, the intramolecular spatial conjugation is more stable. Compared with 4,4′-biphenyldisulfonic acid, aniline-2,5-disulfonic acid monosodium salt makes the molecule show more active molecular mobility, its luminescent wavelength peak gradually blue-shifts, and its phosphorescence lifespan decreases significantly. At the same time, the molecule presents greater rigidity, and the yield of the target product is reduced. Compared with 4,4′-biphenyldisulfonic acid, 2-naphthalenesulfonic acid has a high degree of conjugation, the energy required for intermolecular transition is reduced, its luminescent wavelength peak gradually red-shifts, and the absorption intensity is enhanced. However, 2-naphthalenesulfonic acid is more flexible, has a poor effect on the non-radiative transition of phosphorescent molecules, and has a strong quenching effect. Since the wavelength of commonly used excitation light sources, such as flashlights, is much lower than the excitation wavelength of the ink obtained from 2-naphthalenesulfonic acid, it is not conducive to the production of plastic anti-collision reflective warning columns, plastic signboards, etc. from a macroscopic point of view. According to the above content, it can be analyzed that the spatial conjugated structure will affect the luminescent properties of the weak acting group. In addition, if 4-amino-5-hydroxy-2,7-naphthalene disulfonic acid monosodium salt and product are used instead, the ink will not have room temperature phosphorescence effect, only has fluorescence characteristics, its luminescence life is short, and the Stokes shift is small, which leads to serious crosstalk between the excitation spectrum and the emission spectrum, and the fluorescence quenching phenomenon is serious. The present invention cooperates with carboxymethyl chitosan and sodium alginate to ensure that the ink produces room temperature phosphorescence effect. After a series of experiments, it is found that with the increase of the amount of sodium alginate, the afterglow time of the ink after film formation increases first and then decreases. The amount of sodium alginate is large, and the raw material components are stacked tightly, isolating the quenching effect of external oxygen, thereby achieving a longer afterglow time. With the further increase of the amount of sodium alginate, the phosphorescent molecules are difficult to disperse and local agglomeration occurs, inducing the quenching of the phosphorescent molecules. At the same time, if the content of carboxymethyl chitosan is too low, cracks will appear after the ink is film-formed, and the phosphorescent molecules will be quenched, resulting in the attenuation of phosphorescent properties and shortened afterglow time. In addition, if sodium cellulose is used instead, the ink viscosity is low; if gum arabic is used instead, the ink film-forming property is poor.

[0036] Due to the film-forming properties of some organic solvents, the ink film drying time is long, slow drying causes large penetration of the binder, and it is difficult to form a film on the ink surface. To solve this problem, the present invention prepares a modified solvent, which can effectively replace the traditional petroleum-based mineral solvents, not only inhibiting volatile organic compounds, but also providing good anti-emulsification and gloss for the ink. Compared with the use of traditional petroleum-based mineral solvents, the composite ink molecules of the present invention undergo electronic transitions of π→π* or n→π* under light excitation, and the wavelength corresponding to the phosphorescence peak is slightly red-shifted. With the addition of solvent, the maximum luminous intensity of the product decreases because the solvent absorbs some visible light. Among them, soybean oil is mainly linoleic acid, which contains fewer double bonds. After compounding with tung oil, the drying time is shortened, and the solvent adhesion and tinting power are significantly improved. In order to study the influence of the compounding ratio of soybean oil and tung oil on the ink, the present invention conducted a series of experiments and found that within a certain range, the ink does not wrinkle after film formation, and the drying time is significantly shortened with the increase of solvent dosage. However, using too much solvent will cause the ink film to wrinkle, and adding too much tung oil will affect the transparency of the ink layer, its oxidation drying effect is poor, and the ink surface will wrinkle.

[0037] The catalyst 9,10-anthraquinone used in the present invention is a condensed ring compound, which promotes the long chain combination of soybean oil and tung oil, and the auxiliary solvent is combined with carboxymethyl chitosan, which is conducive to the uniform dispersion of dye molecules containing polar groups. The composite ink after a series of heat treatments and cooling treatments has a large viscosity. The ink prepared according to the temperature conditions specified in the present invention is more in line with the plastic printing suitability standards. The beneficial effects of the present invention are as follows:

[0038] (1) The composite ink prepared by the present invention has good fluidity and uniform composition, and can be evenly coated when used;

[0039] (2) The composite ink prepared by the present invention does not wrinkle or crack after film formation, thereby extending the service life;

[0040] (3) The composite ink prepared by the present invention has high luminous intensity and long afterglow time. DETAILED DESCRIPTION

[0041] The present invention is further described in detail below in conjunction with specific embodiments. Those of ordinary skill in the art will be able to implement the present invention based on these descriptions. In addition, the embodiments of the present invention involved in the following description are generally only embodiments of a part of the present invention, rather than all embodiments. Therefore, based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative work should fall within the scope of protection of the present invention.

[0042] Unless otherwise specified, the raw materials used in the examples of the present invention are all commercially available or available to those skilled in the art; unless otherwise specified, the methods used in the examples of the present invention are all methods known to those skilled in the art.

[0043] Embodiment 1: A method for preparing a composite ink for plastic printing, the method comprising:

[0044] 1) 5 g of rosin-modified phenolic resin, 0.3 g of 4,4′-biphenyl disulfonic acid, 2.5 g of carboxymethyl chitosan, and 0.5 g of sodium alginate were mixed uniformly to obtain a connecting material;

[0045] 2) Take 3 mL of soybean oil and 0.9 mL of tung oil, add 0.2 mL of 9,10-anthraquinone, and keep the mixture at 220° C. in a nitrogen atmosphere for 0.5 h to obtain a modified solvent;

[0046] 3) 0.05 g of bromotetrachlorofluorescein was mixed evenly with the binder and the modified solvent to obtain a mixture, which was kept at a constant temperature at 240° C. for 2 h, then cooled to 160° C. and kept at a constant temperature for 1 h, 0.1 g of antioxidant 264 was added per gram of the mixture to keep the mixture warm, and the mixture was cooled to 50° C. and filtered to remove the catalyst to obtain a composite ink.

[0047] The following performance tests were performed on the composite ink obtained in this example.

[0048] 1. Adhesion strength:

[0049] The test was carried out according to the disc peeling method in GB / T 13217.7-2023 “Test method for ink adhesion”. The number of grids for each test was 100 (10×10 array), and a total of 10 tests were performed and the average value was recorded.

[0050] 2. High temperature resistance:

[0051] Using IGT printability tester (AIC2-5), the prepared ink was coated on a full rubber roller with a thickness of 1 mm. The composite ink obtained in this example was evenly printed on a PVC sheet. After embossing and cutting, multiple 20 mm wide strips were obtained. The strips were treated for 24 hours at a constant temperature of 100°C and a relative humidity of 80%. A 2 kg load weight was then placed vertically at one end of the strip to tear the strip with the load weight to detect whether the ink layer was peeled off. If it was successfully peeled off, it was marked as "×", otherwise it was marked as "√".

[0052] 3. Drying and curing:

[0053] Using an IGT printability tester (AIC2-5), the prepared ink was coated on a full-plate rubber roller with a thickness of 1 mm. The composite ink obtained in this example was evenly printed on a PVC sheet. After embossing and cutting, a number of 20 mm wide strips were obtained. Paper was repeatedly placed on the surface of the strips and the printed surface of the strips was rubbed at specified intervals until no ink marks appeared on the paper surface. The required time was recorded, which was the drying time of the ink.

[0054] 4. Bending resistance:

[0055] Using an IGT printability tester (AIC2-5), the prepared ink was coated on a full-plate rubber roller with a thickness of 1 mm. The composite ink obtained in this example was evenly printed on a PVC sheet. After embossing and cutting, a plurality of 20 mm wide strips were obtained. The strips were bent repeatedly 1000 times, and the strips were bent 180° at a uniform speed and then restored. If no ink fell off in the form of powder, flakes or blocks, it was recorded as "√", otherwise it was recorded as "×".

[0056] 5. Friction resistance:

[0057] Using IGT printability tester (AIC2-5), the prepared ink was coated on a full rubber roller with a thickness of 1 mm. The composite ink obtained in this example was evenly printed on a PVC sheet. After embossing and cutting, multiple 20 mm wide strips were obtained. The strip surface was subjected to friction and wear test using a WTM-2E friction and wear tester at 20°C and 60% humidity. A load of 150 g was applied, the speed was set to 700 r / min, and silicon nitride was used as the dual ball. The wear volume of the wear scar on the coating surface was characterized using a UPLambda laser confocal three-dimensional profiler to calculate its wear rate.

[0058]

[0059] Where: C is the wear rate; V is the wear scar volume on the coating surface; D is the sliding distance of the dual balls; F is the normal load.

[0060] 6. Low temperature performance:

[0061] At 5°C, take 15 mL of ink and add it to the NDJ-79 rotary viscometer. Measure it at a current frequency of 50 Hz through the absolute system tester of Unit II. When the sample to be tested is completely immersed, start measuring the viscosity. Read the value after the pointer stabilizes and record the result.

[0062] 7. Initial brightness:

[0063] Using an IGT printability tester (AIC2-5), the prepared ink was coated on a full-plate rubber roller with a thickness of 1 mm. The composite ink obtained in this example was evenly printed on a PVC sheet. After embossing and cutting, multiple 20 mm wide strips were obtained. The strips were irradiated with 2000 lm (lumen) of light for 10 minutes and immediately placed in a dark box to detect their initial brightness.

[0064] 8. Afterglow time:

[0065] Based on test (7), record the sample from luminescence to brightness ≤ 1cd / m 2 time.

[0066] The results are as follows.

[0067] Ink adhesion (%) High temperature resistance Drying time (min) Bending resistance 0.2 √ 29 √ Wear rate (%) Low temperature viscosity (mpa·s) <![CDATA[Initial brightness (cd / m 2 )]]> Afterglow time(s) 0.51 3315 11.04 63

[0068] First, as the thickness of the ink printing increases, oxygen is more difficult to penetrate. According to the afterglow time of the product, it can be analyzed that when the printing thickness is 1mm, the product phosphorescence effect is better. Further increase the printing thickness, the ink flows laterally after printing, the pattern expands and causes a paste board, which affects the printing effect. Secondly, the composite ink has uniform components and good fluidity. It can not only level quickly, but also dry completely in a short time. According to the results in the table, the composite ink has good adhesion, high temperature resistance, bending resistance, and wear resistance. In addition, in this example, the sample strip was immersed in water for 24 hours and rolled up. The sample strip did not show "anti-sticking" phenomenon. It can be seen that compared with commercially available water-based inks, composite inks can be stored in high temperature and high humidity environments, and are also conducive to the application of plastic anti-collision reflective warning columns, plastic signboards and other products in rainy areas in summer.

[0069] Embodiment 2: A method for preparing a composite ink for plastic printing, the method comprising:

[0070] 1) 5 g of rosin-modified phenolic resin, 0.3 g of 4,4′-biphenyl disulfonic acid, 2.5 g of carboxymethyl chitosan, and 0.8 g of sodium alginate were mixed uniformly to obtain a connecting material;

[0071] 2) Take 3 mL of soybean oil and 0.9 mL of tung oil, add 0.2 mL of 9,10-anthraquinone, and keep the mixture at 220° C. in a nitrogen atmosphere for 0.5 h to obtain a modified solvent;

[0072] 3) 0.05 g of bromotetrachlorofluorescein was mixed evenly with the binder and the modified solvent to obtain a mixture, which was kept at a constant temperature at 240° C. for 2 h, then cooled to 160° C. and kept at a constant temperature for 1 h, 0.1 g of antioxidant 264 was added per gram of the mixture to keep the mixture warm, and the mixture was cooled to 50° C. and filtered to remove the catalyst to obtain a composite ink.

[0073] The composite ink obtained in this example was subjected to the same performance test as in Example 1, and the results are as follows.

[0074] Ink adhesion (%) High temperature resistance Drying time (min) Bending resistance 0.1 √ 27 √ Wear rate (%) Low temperature viscosity (mpa·s) <![CDATA[Initial luminance (cd / m 2 )]]> Afterglow time(s) 0.50 3295 11.16 73

[0075] As the amount of sodium alginate increases, the afterglow time of the ink after film formation increases. When the amount of sodium alginate is large, the raw material components are stacked tightly, isolating the quenching effect of external oxygen, thereby achieving a longer afterglow time. At the same time, the amount of raw materials, aromatic sulfonic acid compounds, and phosphorescent fillers is linearly related to the viscosity of the ink. As the amount of phosphorescent fillers increases, the relative movement of fluid molecules is hindered, and its fluidity changes accordingly, and the low-temperature viscosity of the ink is higher.

[0076] Embodiment 3: A method for preparing a composite ink for plastic printing, the method comprising:

[0077] 1) 5 g of rosin-modified phenolic resin, 0.3 g of 4,4′-biphenyl disulfonic acid, 2.5 g of carboxymethyl chitosan, and 1 g of sodium alginate were mixed uniformly to obtain a connecting material;

[0078] 2) Take 3 mL of soybean oil and 0.9 mL of tung oil, add 0.2 mL of 9,10-anthraquinone, and keep the mixture at 220° C. in a nitrogen atmosphere for 0.5 h to obtain a modified solvent;

[0079] 3) 0.05 g of bromotetrachlorofluorescein was mixed evenly with the binder and the modified solvent to obtain a mixture, which was kept at a constant temperature at 240° C. for 2 h, then cooled to 160° C. and kept at a constant temperature for 1 h, 0.1 g of antioxidant 264 was added per gram of the mixture to keep the mixture warm, and the mixture was cooled to 50° C. and filtered to remove the catalyst to obtain a composite ink.

[0080] The composite ink obtained in this example was subjected to the same performance test as in Example 1, and the results are as follows.

[0081] Ink adhesion (%) High temperature resistance Drying time (min) Bending resistance 0.2 √ 27 √ Wear rate (%) Low temperature viscosity (mpa·s) <![CDATA[Initial luminance (cd / m 2 )]]> Afterglow time(s) 0.52 3271 11.16 69

[0082] As the amount of sodium alginate increases further, the phosphorescent molecules become difficult to disperse and local agglomeration occurs, inducing quenching of the phosphorescent molecules and reducing the afterglow time of the ink after film formation.

[0083] In combination with Examples 1 to 3, the composite ink prepared by the present invention does not wrinkle or crack after film formation, has a long service life and high luminous intensity, a long afterglow time, and can be stored in a high temperature and high humidity environment, which is beneficial to the application of plastic anti-collision reflective warning columns, plastic signboards and other products in rainy areas in summer.

[0084] Comparative Example 1: A method for preparing a composite ink for plastic printing, the method comprising:

[0085] 1) 5 g of rosin-modified phenolic resin, 0.3 g of 4,4′-biphenyl disulfonic acid, 2 g of carboxymethyl chitosan, and 0.8 g of sodium alginate were mixed uniformly to obtain a connecting material;

[0086] 2) Take 3 mL of soybean oil and 0.9 mL of tung oil, add 0.2 mL of 9,10-anthraquinone, and keep the mixture at 220° C. in a nitrogen atmosphere for 0.5 h to obtain a modified solvent;

[0087] 3) 0.05 g of bromotetrachlorofluorescein was mixed evenly with the binder and the modified solvent to obtain a mixture, which was kept at a constant temperature at 240° C. for 2 h, then cooled to 160° C. and kept at a constant temperature for 1 h, 0.1 g of antioxidant 264 was added per gram of the mixture to keep the mixture warm, and the mixture was cooled to 50° C. and filtered to remove the catalyst to obtain a composite ink.

[0088] The composite ink obtained in this example was subjected to the same performance test as in Example 1, and the results are as follows.

[0089]

[0090]

[0091] The present invention utilizes the strong hydrogen bonding of phosphorescent fillers to provide a rigid structure for the raw materials, and at the same time, stabilizes the ink, increases the cohesive force and improves its viscosity to a certain extent, but excessive viscosity is not conducive to actual printing. If the content of carboxymethyl chitosan is too low, cracks will appear after the ink is film-formed, and the phosphorescent molecules will be quenched, thereby causing the phosphorescent performance to decay and the afterglow time to shorten.

[0092] Comparative Example 2: A method for preparing a composite ink for plastic printing, the method comprising:

[0093] 1) 5 g of rosin-modified phenolic resin, 0.3 g of aniline-2,5-disulfonic acid monosodium salt, 2.5 g of carboxymethyl chitosan, and 0.8 g of sodium alginate were mixed to obtain a connecting material;

[0094] 2) Take 3 mL of soybean oil and 0.9 mL of tung oil, add 0.2 mL of 9,10-anthraquinone, and keep the mixture at 220° C. in a nitrogen atmosphere for 0.5 h to obtain a modified solvent;

[0095] 3) 0.05 g of bromotetrachlorofluorescein was mixed evenly with the binder and the modified solvent to obtain a mixture, which was kept at a constant temperature at 240° C. for 2 h, then cooled to 160° C. and kept at a constant temperature for 1 h, 0.1 g of antioxidant 264 was added per gram of the mixture to keep the mixture warm, and the mixture was cooled to 50° C. and filtered to remove the catalyst to obtain a composite ink.

[0096] The composite ink obtained in this example was subjected to the same performance test as in Example 1, and the results are as follows.

[0097] Ink adhesion (%) High temperature resistance Drying time (min) Bending resistance 0.7 √ 37 √ Wear rate (%) Low temperature viscosity (mpa·s) <![CDATA[Initial luminance (cd / m 2 )]]> Afterglow time(s) 0.61 3316 8.99 51

[0098] The present invention adopts aromatic sulfonic acid compounds as guest phosphorescent molecules. The molecular structure of aromatic sulfonic acid affects the luminescent properties of ink. In this example, aniline-2,5-disulfonic acid monosodium salt is used instead. Although it can make the molecule show more active molecular mobility, the molecular luminescence wavelength peak gradually blue-shifts, and its phosphorescence lifetime is significantly reduced. In addition, the molecule exhibits greater rigidity, and the intramolecular spatial conjugation becomes unstable, and the yield of the target product is reduced, which obviously causes a decrease in the performance of the ink.

[0099] Comparative Example 3: A method for preparing a composite ink for plastic printing, the method comprising:

[0100] 1) 5 g of rosin-modified phenolic resin, 0.3 g of 2-naphthalenesulfonic acid, 2.5 g of carboxymethyl chitosan, and 0.8 g of sodium alginate were mixed to obtain a connecting material;

[0101] 2) Take 3 mL of soybean oil and 0.9 mL of tung oil, add 0.2 mL of 9,10-anthraquinone, and keep the mixture at 220° C. in a nitrogen atmosphere for 0.5 h to obtain a modified solvent;

[0102] 3) 0.05 g of bromotetrachlorofluorescein was mixed evenly with the binder and the modified solvent to obtain a mixture, which was kept at a constant temperature at 240° C. for 2 h, then cooled to 160° C. and kept at a constant temperature for 1 h, 0.1 g of antioxidant 264 was added per gram of the mixture to keep the mixture warm, and the mixture was cooled to 50° C. and filtered to remove the catalyst to obtain a composite ink.

[0103] The composite ink obtained in this example was subjected to the same performance test as in Example 1, and the results are as follows.

[0104] Ink adhesion (%) High temperature resistance Drying time (min) Bending resistance 0.4 √ 36 √ Wear rate (%) Low temperature viscosity (mpa·s) <![CDATA[Initial luminance (cd / m 2 )]]> Afterglow time(s) 0.53 3311 10.94 47

[0105] Compared with 4,4′-biphenyldisulfonic acid, 2-naphthalenesulfonic acid has a high degree of conjugation, and the energy required for intermolecular transition is reduced. Its luminescence wavelength peak gradually red-shifts, and the absorption intensity is enhanced. However, 2-naphthalenesulfonic acid is more flexible, has a poor effect on the non-radiative transition of phosphorescent molecules, and has a strong quenching effect, resulting in poor luminescence effect. Since the wavelength of commonly used excitation light sources, such as flashlight light, is much lower than the excitation wavelength of the ink obtained from 2-naphthalenesulfonic acid, from a macroscopic point of view, it is not conducive to the production of plastic anti-collision reflective warning columns, plastic signboards, etc. Comparative Example 4: A method for preparing a plastic printing composite ink, the method comprising:

[0106] 1) 5 g of rosin-modified phenolic resin, 0.3 g of 4-amino-5-hydroxy-2,7-naphthalene disulfonic acid monosodium salt and product, 2.5 g of carboxymethyl chitosan, and 0.8 g of sodium alginate were mixed to obtain a connecting material;

[0107] 2) Take 3 mL of soybean oil and 0.9 mL of tung oil, add 0.2 mL of 9,10-anthraquinone, and keep the mixture at 220° C. in a nitrogen atmosphere for 0.5 h to obtain a modified solvent;

[0108] 3) 0.05 g of bromotetrachlorofluorescein was mixed evenly with the binder and the modified solvent to obtain a mixture, which was kept at a constant temperature at 240° C. for 2 h, then cooled to 160° C. and kept at a constant temperature for 1 h, 0.1 g of antioxidant 264 was added per gram of the mixture to keep the mixture warm, and the mixture was cooled to 50° C. and filtered to remove the catalyst to obtain a composite ink.

[0109] The composite ink obtained in this example was subjected to the same performance test as in Example 1, and the results are as follows.

[0110] Ink adhesion (%) High temperature resistance Drying time (min) Bending resistance 0.4 √ 38 √ Wear rate (%) Low temperature viscosity (mpa·s) <![CDATA[Initial luminance (cd / m 2 )]]> Afterglow time(s) 0.55 3437 7.45 36

[0111] The ink obtained in this example does not produce room temperature phosphorescence effect, but only has fluorescence characteristics, and its luminescence lifetime is short, and the Stokes shift is small, which leads to serious crosstalk between the excitation spectrum and the emission spectrum, and serious fluorescence quenching.

[0112] Comparative Example 5: A method for preparing a composite ink for plastic printing, the method comprising:

[0113] 1) 5 g of rosin-modified phenolic resin, 0.3 g of 4,4′-biphenyl disulfonic acid, 2.5 g of carboxymethyl chitosan, and 0.8 g of sodium alginate were mixed uniformly to obtain a connecting material;

[0114] 2) Take 4 mL of soybean oil and 1.2 mL of tung oil, add 0.2 mL of 9,10-anthraquinone, and keep the mixture at 220° C. in a nitrogen atmosphere for 0.5 h to obtain a modified solvent;

[0115] 3) 0.05 g of bromotetrachlorofluorescein was mixed evenly with the binder and the modified solvent to obtain a mixture, which was kept at a constant temperature at 240° C. for 2 h, then cooled to 160° C. and kept at a constant temperature for 1 h, 0.1 g of antioxidant 264 was added per gram of the mixture to keep the mixture warm, and the mixture was cooled to 50° C. and filtered to remove the catalyst to obtain a composite ink.

[0116] The composite ink obtained in this example was subjected to the same performance test as in Example 1, and the results are as follows.

[0117] Ink adhesion (%) High temperature resistance Drying time (min) Bending resistance 0.6 √ 25 √ Wear rate (%) Low temperature viscosity (mpa·s) <![CDATA[Initial luminance (cd / m 2 )]]> Afterglow time(s) 0.63 3391 10.84 44

[0118] In this case, the amount of solvent was increased. According to the results in the table, the ink drying time was significantly reduced, and the solvent adhesion and tinting strength were significantly improved. However, the ink wrinkled after film formation, and the effective components were easily quenched, which affected the afterglow time.

[0119] Comparative Example 6: A method for preparing a composite ink for plastic printing, the method comprising:

[0120] 1) 5 g of rosin-modified phenolic resin, 0.3 g of 4,4′-biphenyl disulfonic acid, 2.5 g of carboxymethyl chitosan, and 0.8 g of sodium alginate were mixed uniformly to obtain a connecting material;

[0121] 2) Take 3 mL of soybean oil and 1.5 mL of tung oil, add 0.2 mL of 9,10-anthraquinone, and keep the mixture at 220° C. in a nitrogen atmosphere for 0.5 h to obtain a modified solvent;

[0122] 3) 0.05 g of bromotetrachlorofluorescein was mixed evenly with the binder and the modified solvent to obtain a mixture, which was kept at a constant temperature at 240° C. for 2 h, then cooled to 160° C. and kept at a constant temperature for 1 h, 0.1 g of antioxidant 264 was added per gram of the mixture to keep the mixture warm, and the mixture was cooled to 50° C. and filtered to remove the catalyst to obtain a composite ink.

[0123] The composite ink obtained in this example was subjected to the same performance test as in Example 1, and the results are as follows.

[0124] Ink adhesion (%) High temperature resistance Drying time (min) Bending resistance 0.8 √ 48 × Wear rate (%) Low temperature viscosity (mpa·s) <![CDATA[Initial brightness (cd / m 2 )]]> Afterglow time(s) 0.79 3267 8.96 38

[0125] In this example, excessive tung oil was added, which not only affected the transparency of the ink layer, but also resulted in poor oxidation drying effect, wrinkling of the ink surface, and degradation of various properties.

Claims

1. A method for preparing a composite ink for plastic printing, characterized in that: The method comprises: 1) Mix the raw materials, aromatic sulfonic acid compounds and phosphorescent fillers evenly to obtain a connecting material; 2) Prepare a solvent, add a catalyst and heat to react to obtain a modified solvent; 3) The connecting material, the modified solvent and the colorant are mixed evenly to obtain a mixture, and the mixture is cooled after heat treatment. After cooling, an antioxidant is added to keep the mixture warm, and the mixture is further cooled and filtered to remove the catalyst to obtain a composite ink; Step 1) The raw material is rosin-modified phenolic resin; Step 1) the aromatic sulfonic acid compound is 4,4'-biphenyldisulfonic acid, and its dosage is 0.06-0.08 g / g raw material; Step 1) the phosphorescent filler is carboxymethyl chitosan and sodium alginate, the carboxymethyl chitosan and sodium alginate are prepared in a mass ratio of 1: (0.2-0.4), and the amount thereof is 0.6-0.7 g / g raw material; Step 2) the solvent is soybean oil or tung oil, and the amount thereof is 0.7-1 mL / g raw material, and the soybean oil and tung oil are prepared according to a volume ratio of 1: (0.3-0.4); Step 2) the catalyst is 9,10-anthraquinone, and the amount thereof is 0.03-0.08 g / mL solvent; Step 2) the heating reaction is carried out in an inert gas atmosphere at 200-220°C for 0.5-1 h; The afterglow time of the plastic printing composite ink prepared in step 3) is ≥63 s.

2. The method for preparing a composite ink for plastic printing according to claim 1, characterized in that: Step 3) The colorant is bromotetrachlorofluorescein, and the amount used is 0.01-0.1 g / g raw material.

3. The method for preparing a composite ink for plastic printing according to claim 1, characterized in that: Step 3) The heat treatment is carried out at 220-240°C for 2-2.5 hours.

4. The method for preparing a composite ink for plastic printing according to claim 1, characterized in that: Step 3) The cooling treatment is specifically as follows: First cool down to 150-160 ℃, keep constant temperature for 1-1.5 h, add antioxidant and mix evenly, then cool down to 45-55 ℃ and filter.

5. The method for preparing a composite ink for plastic printing according to claim 1 or 4, characterized in that: Step 3) The antioxidant is antioxidant 264, and its dosage is 0.1-0.3 g / g mixture.

6. A composite ink for plastic printing obtained by the method according to any one of claims 1 to 5.

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