Preparation method and application of edible oil-based pigment ink for digital printing

Abstract

The invention discloses a preparation method of edible oil-based pigment ink for digital printing, which comprises the following steps: S1, mixing an aqueous solution with ethanol, adding shellac, stirring and dissolving to prepare a shellac solution; s2, adding polyol, an emulsifier and a pigment, and uniformly dispersing in a dispersion machine at a high speed; s3, grinding in a sand mill; s4, adding a surfactant I, and uniformly dispersing at a high speed; s5, grinding in a nanometer grinding machine to obtain slurry; s6, uniformly stirring the slurry, a surfactant II and an alcoholic solution to prepare ink; and S7, filtering with filter paper. According to the invention, digital printing is applied to the surface of food, a printed pattern is smooth, and a pattern layer formed after printing and drying is good in durability and hardness and has good adhesive force with a grease surface and a hard and smooth surface.

Description

Technical Field

[0001] The invention relates to a preparation method of edible oily pigment ink for digital printing and application thereof, and relates to C09D, and in particular to the field of coating compositions. Background Art

[0002] Printing patterns on the surface of food can increase the beauty of the food and is popular among consumers. Foods with rich oily surfaces, such as candies and chocolates, have poor performance in combining with patterns. Existing printing on the surface of oily foods mostly uses oily inks, but the particles of oily inks are large, the printed patterns are unnatural, the colors are single, and the production efficiency of ink printing on the surface of food is not high; another direct water-based ink printing, and as the temperature changes, oily foods will melt, and when stored in a low-temperature environment, the ink will contact water vapor, causing the pattern to diffuse and fade. Using oily digital printing can improve printing efficiency and solve problems such as pattern diffusion and fading. Therefore, it is crucial to develop a printing ink that can be digitally printed on the surface of oily foods.

[0003] Chinese invention patent CN202410065322.8 discloses a method for preparing a smooth and hard food surface printing ink and its application. The mixed solution of shellac and corn protein can realize gravure printing on the hard and smooth surface of food. It has good adhesion to the hard and smooth surface of food, good ink transferability, clear and smooth printing, and certain water resistance. However, it can only be gravure printed, and digital printing cannot be realized, and the printing efficiency is low. Chinese invention patent CN202410063138.X discloses an edible ink for chocolate direct injection and its preparation method. It controls the use of a specific proportion of ink raw materials to make a stable film-forming liquid, improves the production efficiency and compatibility of the ink, and can be used for digital direct injection printing. The pattern effect is good, but the ink is easy to clog the nozzle in the printer, and it often needs to be shut down for maintenance during use. Summary of the invention

[0004] In order to develop a printing ink that can be digitally printed on the surface of oily food, the first aspect of the present invention provides a method for preparing a digitally printed edible oily pigment ink, comprising the following steps:

[0005] S1: mixing the aqueous solution with ethanol, adding shellac and stirring to dissolve to prepare shellac solution;

[0006] S2 adds polyol, emulsifier and pigment, and puts them in a disperser to disperse them at high speed to obtain mixture I;

[0007] S3: grinding the mixture I in a sand grinder;

[0008] S4 adds surfactant Ⅰ to disperse evenly at high speed to obtain mixture Ⅱ;

[0009] S5: grinding the mixture II in a nano-grinder to obtain a slurry;

[0010] S6 stirs the slurry, surfactant II, and alcohol solution to form ink;

[0011] S7 is obtained by filtering with filter paper.

[0012] As a preferred embodiment, the aqueous solution comprises water, an alkaline substance and an alkyl alcohol, and the weight ratio of the shellac to the aqueous solution is 1:(2-4).

[0013] As a preferred embodiment, the aqueous solution comprises water, an alkaline substance and an alkyl alcohol, and the weight ratio of the shellac to the aqueous solution is 1:(2.5-3.5).

[0014] As a preferred embodiment, the aqueous solution comprises water, an alkaline substance and an alkyl alcohol, and the weight ratio of the shellac to the aqueous solution is 1:3.3625.

[0015] As a preferred embodiment, the alkyl alcohol includes at least one of n-butanol, n-hexanol, isobutanol, neopentyl alcohol and ethanol.

[0016] As a preferred embodiment, the alkyl alcohol is n-butanol, and the weight ratio of the ethanol to n-butanol is (15-25):(30-40).

[0017] As a preferred embodiment, the weight ratio of ethanol to n-butanol is (18-22):(30-35).

[0018] As a preferred embodiment, the weight ratio of ethanol to n-butanol is 18.5:33.

[0019] As a preferred embodiment, the aqueous solution comprises, by weight, 1-3 parts of water, 0.1-0.5 parts of alkaline substance and 30-40 parts of alkyl alcohol.

[0020] As a preferred embodiment, the aqueous solution comprises 2 parts of water, 0.3 parts of alkaline substance and 33 parts of alkyl alcohol in parts by weight.

[0021] As a preferred embodiment, the alkaline substance includes at least one of sodium hydroxide, potassium hydroxide, calcium hydroxide, sodium carbonate, sodium bicarbonate, and potassium carbonate.

[0022] As a preferred embodiment, the alkaline substance is potassium hydroxide.

[0023] As a preferred embodiment, the polyol includes at least one of propylene glycol, ethylene glycol, glycerol, butylene glycol, polyethylene glycol, and sorbitol.

[0024] As a preferred embodiment, the polyol includes propylene glycol and polyethylene glycol, and the weight ratio of the propylene glycol to the polyethylene glycol is (1-5): (1-3).

[0025] As a preferred embodiment, the weight ratio of propylene glycol to polyethylene glycol is (2-3): (1.5-2.5).

[0026] As a preferred embodiment, the weight ratio of propylene glycol to polyethylene glycol is 2.5:2.

[0027] As a preferred implementation, the particle size after frosting in step S3 is less than 20 μm.

[0028] As a preferred embodiment, the emulsifier, surfactant I and surfactant II all include at least one of Span 20, Span 60, Span 80, Tween 20, Tween 60, Tween 80, mono- and di-glycerol fatty acid esters, triacetin, polyglycerol fatty acid esters, and citric acid monoglyceride.

[0029] As a preferred embodiment, the emulsifier comprises a combination of Tween 20 and Span 20, and the weight ratio of Tween 20 to Span 20 is (1-3): (0.2-0.7).

[0030] As a preferred embodiment, the weight ratio of Tween 20 to Span 20 is (1-2): (0.4-0.6).

[0031] As a preferred embodiment, the weight ratio of Tween 20 to Span 20 is 1:0.5.

[0032] As a preferred embodiment, the surfactant I comprises Tween 80 and Tween 20. The weight ratio of Tween 80 to Tween 20 is (1-5): (13-28).

[0033] As a preferred embodiment, the weight ratio of Tween 80 to Tween 20 is (2-4): (15-20).

[0034] As a preferred embodiment, the weight ratio of Tween 80 to Tween 20 is 2:18.

[0035] As a preferred embodiment, the surfactant II is Tween 20.

[0036] As a preferred embodiment, the pigment includes at least one of titanium dioxide, black iron oxide, allure red aluminum lake, yellow aluminum lake, brilliant blue, brilliant blue aluminum lake, indigo aluminum lake, red iron oxide, vegetable carbon black, cochineal red aluminum lake, and turmeric.

[0037] As a preferred embodiment, the particle size after grinding by the nano-grinder in step S5 is less than 200 nm.

[0038] As a preferred embodiment, the alcohol solution includes a combination of n-butanol and glycerol.

[0039] As a preferred embodiment, the weight ratio of n-butanol to glycerol is (40-60):(2-8).

[0040] As a preferred embodiment, the weight ratio of n-butanol to glycerol is (45-55):(4-7).

[0041] As a preferred embodiment, the weight ratio of n-butanol to glycerol is 50:5.

[0042] As a preferred embodiment, the weight ratio of the slurry, surfactant II, and alcohol solution is (90-100): (10-30): (50-60).

[0043] As a preferred embodiment, the weight ratio of the slurry, surfactant II, and alcohol solution is (95-100): (15-25): (53-58).

[0044] As a preferred embodiment, the weight ratio of the slurry, surfactant II and alcohol solution is 95.8:20:55.

[0045] During the experiment, the applicant found that the shellac, alcohol solution and emulsifier were mixed and stirred evenly to work together, which could dissolve and disperse the shellac for use. However, the shellac includes a soft resin part and a hard resin part, and the viscosity of the mixture formed is relatively high. The particle size after sanding by a sander can only reach less than 20 μm, which cannot be used for printing in electronic digital devices and is easy to clog the nozzle of the printer. The inventor further found that adding a surfactant to the coarsely ground mixture and grinding it again can obtain nano-level ink, and achieve ink with appropriate viscosity and uniform particle size, which will neither clog the nozzle with large particles nor cause particle agglomeration with too low viscosity. It is speculated that the possible reason is: when a surfactant is added to the coarsely ground mixture, the surfactant can attach to the surface of the particles for a second time, increase the distance between the particles, and further increase the wettability and dispersibility of the mixture, so that the particles can further contact the grinding roller of the grinder, further reduce the particle size, and thus realize the application of digital printing.

[0046] As a preferred embodiment, the raw materials for preparing the edible oil-based pigment ink include, by weight: 15-20 parts of shellac, 30-50 parts of aqueous solution, 10-20 parts of ethanol, 1-5 parts of polyol, 1-3 parts of emulsifier, 20-25 parts of pigment, 15-25 parts of surfactant I, 15-25 parts of surfactant II, and 50-60 parts of alcohol solution.

[0047] As a preferred embodiment, the raw materials for preparing the edible oil-based pigment ink include, by weight: 16-18 parts of shellac, 30-40 parts of aqueous solution, 15-20 parts of ethanol, 4-5 parts of polyol, 1-2 parts of emulsifier, 23-25 ​​parts of pigment, 18-23 parts of surfactant I, 18-23 parts of surfactant II, and 53-58 parts of alcohol solution.

[0048] As a preferred embodiment, the raw materials for preparing the edible oil-based pigment ink include, by weight: 16 parts of shellac, 35.3 parts of aqueous solution, 18.5 parts of ethanol, 4.5 parts of polyol, 1.5 parts of emulsifier, 23.7 parts of pigment, 20 parts of surfactant I, 20 parts of surfactant II, and 55 parts of alcohol solution.

[0049] As a preferred embodiment, in step S2, the stirring speed is 800-1200 r / min, the stirring temperature is 20-60°C, in step S4, the stirring speed is 800-1200 r / min, the stirring temperature is 20-30°C, and the dispersion time is 20-40 min.

[0050] As a preferred embodiment, in step S2, the stirring speed is 1000 r / min, the stirring temperature is 40° C., in step S4, the stirring speed is 1000 r / min, the stirring temperature is 25° C., and the dispersion time is 30 min.

[0051] As a preferred embodiment, the pore size of the filter paper is 0.2-0.5 μm.

[0052] As a preferred embodiment, the pore size of the filter paper is 0.22 μm.

[0053] The second aspect of the present invention provides an application of a method for preparing a digitally printed edible oily pigment ink, which is applied to printing oily foods with a digital printing device.

[0054] Compared with the prior art, the present invention has the following beneficial effects:

[0055] (1) The method for preparing digital printing edible oil-based pigment ink of the present invention adopts shellac and aqueous solution, which are mixed and stirred evenly after being alkalized by ethanol, so that the shellac can be dissolved and dispersed evenly, and the film-forming effect of the ink is excellent.

[0056] (2) The method for preparing edible oil-based pigment ink for digital printing of the present invention comprises adding surfactant I to the sand-milled mixture, and performing secondary grinding to obtain nano-scale ink, thereby obtaining ink with suitable viscosity and uniform particle size, which will neither cause the ink to clog the nozzle due to large particles nor cause the ink to stratify and sink to the bottom, thereby causing particle agglomeration.

[0057] (3) The digital printing edible oil-based pigment ink of the present invention can be further reduced in particle size by adding a combination of Tween 80 and Tween 20 and grinding together with shellac. The ink can pass through a 0.22 μm filter paper with smooth filtration and can be applied to digital printing.

[0058] (4) The digitally printable edible oil-based pigment ink of the present invention can be firmly attached to the surface of oily food, and can withstand high and low temperature storage, and will not cause pattern deformation when the temperature changes.

[0059] (5) The digitally printable edible oil-based pigment ink of the present invention can be used for digital printing on the surface of food. The printed pattern is smooth, and the pattern layer formed after printing and drying has good durability and hardness, and has good adhesion to greasy surfaces and hard and smooth surfaces. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] Figure 1 A picture printed on the surface of chocolate using the digitally printed edible oil-based pigment ink prepared in Example 1;

[0061] Figure 2 This is a picture printed on the surface of chocolate using the digitally printed edible oil-based pigment ink prepared in Example 6.

[0062] Figure 3 This is a picture of the digitally printed edible oil-based pigment ink prepared in Example 1 printed on the surface of cream. DETAILED DESCRIPTION

[0063] Example 1

[0064] A method for preparing digital printing edible oil-based pigment ink comprises the following steps:

[0065] S1: mixing the aqueous solution with ethanol, adding shellac and stirring to dissolve to prepare shellac solution;

[0066] S2 adds polyol, emulsifier and pigment, and puts them in a disperser to disperse them at high speed to obtain mixture I;

[0067] S3: grinding the mixture I in a sand grinder;

[0068] S4 adds surfactant Ⅰ to disperse evenly at high speed to obtain mixture Ⅱ;

[0069] S5: grinding the mixture II in a nano-grinder to obtain a slurry;

[0070] S6 stirs the slurry, surfactant II, and alcohol solution to form ink;

[0071] S7 is obtained by filtering with filter paper.

[0072] The particle size after grinding in step S3 is less than 20 μm. The particle size after grinding by nano-grinding machine in step S5 is less than 200 nm.

[0073] The raw materials for preparing the digital printing edible oil-based pigment ink are as follows in Table 1:

[0074] Table 1

[0075]

[0076] In step S2, the stirring speed is 1000 r / min, the stirring temperature is 40° C., in step S4, the stirring speed is 1000 r / min, the stirring temperature is 25° C., and the dispersion time is 30 min.

[0077] The pore size of the filter paper is 0.22 μm.

[0078] Example 6

[0079] A method for preparing digital printing edible oil-based pigment ink comprises the following steps:

[0080] S1: mixing shellac with the aqueous solution and stirring to dissolve;

[0081] S2 adds purified water, polyol, emulsifier and pigment, and is placed in a disperser and dispersed uniformly at high speed to obtain mixture I;

[0082] S3: grinding the mixture I in a sand mill to obtain a mixture II;

[0083] S4 grinding the mixture II in a nano grinder to obtain a slurry;

[0084] S5: Stir the slurry, surfactant II and alcohol solution evenly to prepare ink.

[0085] The raw materials for preparing the digital printing edible oil-based pigment ink are the same as those in Example 1.

[0086] Example 7

[0087] A method for preparing edible oil-based pigment ink for digital printing, the specific implementation method is the same as that of Example 1, except that the preparation raw materials include, by weight: 2 parts of shellac, 2 parts of purified water, 5 parts of potassium hydroxide, 8 parts of titanium dioxide, 17.5 parts of anhydrous ethanol, 64.3 parts of n-butanol, 1 part of Tween 20, and 1 part of Span 20.

[0088] A method for preparing digital printing edible oil-based pigment ink comprises the following steps:

[0089] S1: Mix and stir shellac, purified water and potassium hydroxide to dissolve;

[0090] S2 is added with anhydrous ethanol, n-butanol, Tween 20 and titanium dioxide, and placed in a disperser for high-speed dispersion to obtain a mixture I;

[0091] S3: grinding the mixture I in a sand mill to obtain a mixture II;

[0092] S4: grinding the mixture II in a nano-grinder to obtain a slurry;

[0093] S5 stirs the slurry and the pan 20 to make ink.

[0094] Performance Testing

[0095] The particle size, ink stability (standing at 25° C. for 1 year), printing adaptability of the Japanese Ricoh G5 nozzle, and printing smoothness of the digital printing edible oil pigment ink prepared in Examples 1, 6, and 7 are tested and shown in Table 2.

[0096] Table 2

[0097] Grinding particle size Static stability G5 Ricoh printhead adaptability Fluency Example 1 D90≤200nm Does not sink to the bottom, good suspension No plugging Good effect Example 6 D90>500nm Easy to sink to the bottom, clump Plug Disconnection Example 7 D90>500nm Easy to sink to the bottom, clump Plug Disconnection

[0098] The stability and printing stability test results of the digital printing edible oil-based pigment ink prepared in Example 1 are shown in Table 3. The high temperature is 60°C.

[0099] Table 3

[0100]

[0101] After one month of observation, the indicators of Example 1 were normal, the viscosity was within the fluctuation range, the 022 filtration was smooth, and the printing effect was good.

[0102] The digitally printed edible oil-based pigment ink of Example 1 and Example 6 is printed on chocolate, and the effect diagram is shown in FIG. Figure 1 and Figure 2 . Figure 1 The effect is normal. Figure 2 The effect is not good, ink aggregation problem.

[0103] The digitally printed edible oil-based pigment ink of Example 1 is printed on the cream, and the effect is shown in the figure. Figure 3 .

Claims

1. A method for preparing edible oily pigment ink for digital printing, characterized in that: The following steps are involved: S1: mixing the aqueous solution with ethanol, adding shellac and stirring to dissolve to prepare shellac solution; S2 adds polyol, emulsifier and pigment, and puts them in a disperser to disperse them at high speed to obtain mixture I; S3: grinding the mixture I in a sand grinder; S4 adds surfactant Ⅰ to disperse evenly at high speed to obtain mixture Ⅱ; S5: grinding the mixture II in a nano-grinder to obtain a slurry; S6 stirs the slurry, surfactant II, and alcohol solution to form ink; S7 is obtained by filtering with filter paper.

2. The method for preparing digital printing edible oil-based pigment ink according to claim 1, characterized in that: The aqueous solution comprises water, alkaline substances and alkyl alcohol, and the weight ratio of shellac to the aqueous solution is 1:(2-4).

3. The method for preparing digital printing edible oil-based pigment ink according to claim 2, characterized in that: The alkyl alcohol includes at least one of n-butanol, n-hexanol, isobutanol, neopentyl alcohol and ethanol.

4. The method for preparing digital printing edible oil-based pigment ink according to claim 3, characterized in that: The alkyl alcohol is n-butanol, and the weight ratio of the ethanol to n-butanol is (15-25):(30-40).

5. The method for preparing digital printing edible oil-based pigment ink according to claim 1, characterized in that: The polyol includes at least one of propylene glycol, ethylene glycol, glycerol, butylene glycol, polyethylene glycol, and sorbitol.

6. The method for preparing digital printing edible oil-based pigment ink according to claim 5, characterized in that: The polyol comprises propylene glycol and polyethylene glycol, and the weight ratio of the propylene glycol to the polyethylene glycol is (1-5): (1-3).

7. The method for preparing digital printing edible oil-based pigment ink according to claim 1, characterized in that: The particle size after frosting in step S3 is less than 20 μm.

8. The method for preparing digital printing edible oil-based pigment ink according to claim 1, characterized in that: The emulsifier, surfactant I and surfactant II all include at least one of Span 20, Span 60, Span 80, Tween 20, Tween 60, Tween 80, mono- and di-glycerol fatty acid esters, triacetin, polyglycerol fatty acid esters and citric acid monoglyceride.

9. The method for preparing digital printing edible oil-based pigment ink according to claim 1, characterized in that: The particle size after grinding by the nano-grinder in step S5 is less than 200 nm.

10. An application of the method for preparing digitally printed edible oil-based pigment ink according to any one of claims 1 to 9, characterized in that: Used in digital printing equipment to print oily foods.

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