Printing process

Abstract

The invention belongs to the technical field of ink printing, and discloses a green, environment-friendly and waste-reducing printing process with excellent finished product quality. The printing process comprises the following steps: (1) ink preparation: mixing waste residues of sodium carbonate prepared by a modified ammonia-alkali method, diisocyanate, polymer polyol, a chain extender, a catalyst and a pigment, and then adding water for emulsification to obtain ink; and (2) ink printing: carrying out ink printing on the printing base material, and then curing to obtain the printed product. The waste residue of sodium carbonate prepared by a modified ammonia-alkali method is added, so that the solid waste is utilized, meanwhile, the waste residue is used as a filler of the ink, the curing speed of the obtained ink and the adhesive force of the cured ink on a printed substrate can be remarkably improved, and the service life of a printed product is prolonged. According to the printing method, resources can be saved, a large amount of solid waste is used, and pollution of the solid waste to the environment is reduced.

Description

Technical Field

[0001] This invention relates to the field of ink printing technology, and in particular to a green, environmentally friendly, waste-reducing printing process that produces high-quality finished products. Background Technology

[0002] The printing industry is a vast sector. Current printing technology is no longer limited to traditional book printing; it now extends to posters, advertisements, promotional materials, ceramics, wood products, and metal products, all involving surface printing. Printing is the process of transferring ink from original manuscripts (text, pictures, photographs, anti-counterfeiting materials, etc.) to the surface of materials such as paper, textiles, plastics, and leather through processes like plate making, inking, and pressure application, thus mass-producing the original content. Ink is a major source of pollution in the printing process. Current printing processes use inks containing large amounts of benzene compounds and organic solvents. The inks used in printing processes are mostly solvent-based, including chlorinated polypropylene inks, polyurethane inks, and polyacrylate inks. These inks contain high levels of harmful substances, placing a significant burden on the environment, failing to meet green environmental protection requirements, and impacting the health of printing workers. Furthermore, because traditional printing processes cannot achieve good ink adhesion to the printing substrate, printed products are prone to fading and ink stripping during long-term use and exposure, affecting the quality of the printed products.

[0003] Chinese invention patent CN109532257A discloses an environmentally friendly printing process, which solves the problem of existing inks requiring organic solvents, thus being environmentally unfriendly. However, this technical solution requires the use of dampening agents to treat the printing substrate, which increases the complexity of the printing process. Chinese invention patent CN110920287A discloses an environmentally friendly and energy-saving printing process, which uses acrylic resin, polypropylene glycol, latex binder, 2,6-di-tert-butyl-p-cresol, pigments, and dimethyl silicone oil as ink raw materials. While this avoids the environmental pollution caused by benzene compounds and organic solvents in traditional inks during the printing process, the resulting printed products have a short lifespan, making them unsuitable for applications requiring higher standards of printing quality.

[0004] The waste residue generated from the ammonia-soda process in soda ash production is a common type of solid waste. Currently, this waste residue is mainly used to produce calcium chloride and ultrafine calcium carbonate, but the complex production process requires steps such as desulfurization, resulting in low utilization rates of solid waste. Therefore, how to utilize the waste residue from the ammonia-soda process in soda ash production has become an urgent issue in this field. Since the waste residue from the ammonia-soda process contains a large amount of calcium carbonate, and ultrafine calcium carbonate is a commonly used filler in printing inks, how to combine solid waste with printing processes to provide a green, environmentally friendly, waste-reducing printing process with excellent product quality is also urgently needed in this field. Summary of the Invention

[0005] The purpose of this invention is to provide a green, environmentally friendly, waste-reducing printing process with excellent finished product quality, in order to solve the defects of existing printing processes, such as high cost, lack of environmental protection, and short service life.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] This invention provides a green, environmentally friendly, waste-reducing printing process with excellent finished product quality, comprising the following steps:

[0008] (1) Ink preparation: The waste residue from the modified ammonia-soda method for preparing soda ash, diisocyanate, polymer polyol, chain extender, catalyst and pigment are mixed and then emulsified with water to obtain ink; (2) Ink printing: The printing substrate is printed with ink and then cured to obtain printed products.

[0009] Preferably, the raw materials used in the ink are in the following proportions by mass: 10-20 parts of waste residue from the modified ammonia-soda process for preparing soda ash, 20-40 parts of diisocyanate, 60-80 parts of polymer polyol, 0.5-2 parts of chain extender, 0.2-0.6 parts of catalyst, 10-15 parts of pigment, and 100-130 parts of water.

[0010] Preferably, the preparation of the waste residue from the modified ammonia-soda process for preparing soda ash includes the following steps: mixing the waste residue from the ammonia-soda process for preparing soda ash, polymerizing monomers, initiators, surfactants, and water for emulsion polymerization to obtain the waste residue from the modified ammonia-soda process for preparing soda ash.

[0011] Preferably, the polymeric monomers include viscous monomers, cohesive monomers, and functional monomers; the viscous monomer is ethyl acrylate and / or isooctyl acrylate; the cohesive monomer is one or more of styrene, acrylonitrile, and vinyl acetate; the functional monomer is one or more of methacrylic acid, maleic anhydride, and hydroxyethyl acrylate; and the mass ratio of the viscous monomer, cohesive monomer, and functional monomer is 20-30:20-30:2-5.

[0012] Preferably, the initiator is ammonium persulfate; the surfactant is sodium dodecyl sulfonate and OP-10; the mass ratio of sodium dodecyl sulfonate and OP-10 is 1-1.5:0.5-1; the mass ratio of the waste residue from the ammonia-soda process for preparing soda ash, the polymer monomer, the initiator, the surfactant, and water is 40-60:40-50:0.2-0.5:2-3:30-60.

[0013] Preferably, the emulsion polymerization temperature is 40–50°C and the emulsion polymerization time is 2–3 hours.

[0014] Preferably, the diisocyanate is one or more selected from toluene diisocyanate, isophorone diisocyanate, diphenylmethane 4,4-diisocyanate, and tetramethylphenyldimethyl diisocyanate; the polymeric polyol is polycaprolactone and / or polycarbonate; the chain extender is 2,2,4-trimethyl-1,3-pentanediol and / or neopentanediol or 1,6-hexanediol; the catalyst is an organobismuth catalyst; and the pigment is carbon black.

[0015] Preferably, the printing substrate is washed and dried sequentially before printing.

[0016] Preferably, the mixing is carried out under stirring conditions, with a stirring rate of 1000–2000 r / min; the mixing temperature is 80–100°C, and the mixing time is 2–3 h; the emulsification temperature is 40–60°C.

[0017] Preferably, the curing temperature is 60–80°C and the curing time is 10–20 min.

[0018] As can be seen from the above technical solution, compared with the prior art, the beneficial effects of the present invention are as follows:

[0019] This invention utilizes waste residue from the modified ammonia-soda process for soda ash production, thus making use of solid waste. Simultaneously, by using this waste residue as a filler in ink, the curing speed and adhesion of the cured ink to the printing substrate are significantly improved, extending the lifespan of printed products. The printing method described in this invention saves resources, enabling the extensive use of solid waste and reducing its environmental pollution. Furthermore, the printing process is simple, eliminating the need for ink grinding or dispersion treatments, thus simplifying the process. Detailed Implementation

[0020] This invention provides a green, environmentally friendly, waste-reducing printing process with excellent finished product quality, comprising the following steps:

[0021] (1) Ink preparation: The waste residue from the modified ammonia-soda method for preparing soda ash, diisocyanate, polymer polyol, chain extender, catalyst and pigment are mixed and then emulsified with water to obtain ink; (2) Ink printing: The printing substrate is printed with ink and then cured to obtain printed products.

[0022] In this invention, before printing on the printing substrate, the printing substrate is sequentially washed with water and dried; the number of times the water is washed is preferably 2 to 4 times, more preferably 3 times; the drying temperature is preferably 60 to 80°C, more preferably 70 to 75°C; the drying time is preferably 30 to 50 minutes, more preferably 40 to 45 minutes.

[0023] In this invention, the raw materials used in the ink are in the following proportions by mass: 10-20 parts of waste residue from the modified ammonia-soda process for preparing soda ash, 20-40 parts of diisocyanate, 60-80 parts of polymer polyol, 0.5-2 parts of chain extender, 0.2-0.6 parts of catalyst, 10-15 parts of pigment, and 100-130 parts of water. The preferred amount of waste residue from the modified ammonia-soda process for preparing soda ash is 11-18 parts, more preferably 12-16 parts; the preferred amount of diisocyanate is 25-35 parts, more preferably 28-32 parts; the preferred amount of polymer polyol is 65-78 parts, more preferably 70-75 parts; the preferred amount of chain extender is 0.8-1.8 parts, more preferably 1-1.5 parts; the preferred amount of catalyst is 0.3-0.5 parts, more preferably 0.4 parts; the preferred amount of pigment is 11-14 parts, more preferably 12-13 parts; and the preferred amount of water is 110-120 parts, more preferably 115-118 parts.

[0024] In this invention, the preparation of the waste residue from the modified ammonia-soda process for preparing soda ash includes the following steps: mixing the waste residue from the ammonia-soda process for preparing soda ash, polymerizing monomers, initiators, surfactants, and water for emulsion polymerization to obtain the waste residue from the modified ammonia-soda process for preparing soda ash.

[0025] In this invention, the specific steps for mixing the waste residue from the ammonia-soda process for preparing soda ash, the polymer monomer, the initiator, the surfactant, and the water are as follows: the surfactant and 2 / 3 of the total initiator are mixed, the waste residue from the ammonia-soda process for preparing soda ash, the polymer monomer, and 9 / 10 of the total water are added to the mixture for prepolymerization, and finally the remaining initiator and the remaining water are added dropwise. After the addition is completed, emulsion polymerization is carried out.

[0026] In this invention, the prepolymerization is carried out under stirring conditions, with the stirring rate preferably being 500-800 r / min, more preferably 600-700 r / min; the prepolymerization temperature preferably being 20-30°C, more preferably 25-28°C; the prepolymerization time preferably being 10-30 min, more preferably 15-20 min; and the dropping rate of the mixture preferably being 5-8 drops / min, more preferably 6-7 drops / min.

[0027] In this invention, the particle size of the waste residue from the ammonia-soda process for preparing soda ash is 0.05–1 μm, more preferably 0.07–0.09 μm.

[0028] In this invention, the polymerizable monomers preferably include viscous monomers, cohesive monomers, and functional monomers; the viscous monomers are preferably ethyl acrylate and / or isooctyl acrylate; the cohesive monomers are preferably one or more of styrene, acrylonitrile, and vinyl acetate; the functional monomers are preferably one or more of methacrylic acid, maleic anhydride, and hydroxyethyl acrylate; the mass ratio of the viscous monomer, cohesive monomer, and functional monomers is preferably 20-30:20-30:2-5, more preferably 25-28:22-25:3-4.

[0029] In this invention, the initiator is preferably ammonium persulfate; the surfactant is preferably sodium dodecyl sulfonate and OP-10; the mass ratio of sodium dodecyl sulfonate and OP-10 is preferably 1-1.5:0.5-1, more preferably 1.2-1.4:0.6-0.8; the mass ratio of the waste residue from the ammonia-soda process for preparing soda ash, the polymer monomer, the initiator, the surfactant, and water is preferably 40-60:40-50:0.2-0.5:2-3:30-60, more preferably 50-55:42-48:0.3-0.4:2.5-2.8:40-50.

[0030] In this invention, the emulsion polymerization temperature is preferably 40-50°C, more preferably 42-48°C; the emulsion polymerization time is preferably 2-3 hours, more preferably 2.5 hours.

[0031] In this invention, the diisocyanate is preferably one or more of toluene diisocyanate, isophorone diisocyanate, diphenylmethane 4,4-diisocyanate, and tetramethylphenyldimethyl diisocyanate; the polymeric polyol is preferably polycaprolactone and / or polycarbonate; the chain extender is preferably 2,2,4-trimethyl-1,3-pentanediol and / or neopentanediol or 1,6-hexanediol; the catalyst is preferably an organobismuth catalyst; and the pigment is preferably carbon black.

[0032] In this invention, the mixing is carried out under stirring conditions, with the stirring rate preferably being 1000-2000 r / min, more preferably 1200-1500 r / min; the mixing temperature preferably being 80-100℃, more preferably 90-95℃; the mixing time preferably being 2-3 h, more preferably 2.5 h; the emulsification temperature preferably being 40-60℃, more preferably 50-55℃; and the emulsification time preferably being 10-30 min, more preferably 15-20 min.

[0033] In this invention, the specific steps of the printing are as follows: the printing substrate is transferred to the printing equipment, and after positioning treatment, ink is printed on the surface of the pretreated printing substrate.

[0034] In this invention, the curing temperature is preferably 60-80°C, more preferably 70-75°C; the curing time is preferably 10-20 min, more preferably 15-18 min.

[0035] The waste residue from the modified ammonia-soda process for preparing soda ash can serve as a filler in printing inks, reducing costs and increasing volume. This waste residue has fine particles (0.02-1.0 μm in diameter) and a large specific surface area, offering advantages such as high oil absorption and good stability. Furthermore, as a solid waste, this process utilizes solid waste while maintaining low costs, avoiding environmental pollution. The surface of this waste residue contains active groups that can adjust ink viscosity. These active groups also improve the dispersibility of raw materials in the ink system, preventing agglomeration and its negative impact on printing quality, resulting in excellent printing performance without side effects. The large specific surface area of ​​this waste residue leads to rapid drying, exhibiting excellent ink absorption and drying properties. Additionally, the small particle size of this waste residue contributes to excellent dispersibility and stability in inks. Printed products produced by the ink described in this invention are delicate and have complete halftone dots.

[0036] The technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0037] All parts in the following examples are by weight.

[0038] Example 1

[0039] Preparation of waste residue from the modified ammonia-soda process for producing soda ash:

[0040] The waste residue from the ammonia-soda process for producing soda ash was ground in a grinder to obtain a particle size of 0.08 μm. 1.5 parts sodium dodecyl sulfate, 0.5 parts OP-1, and 0.2 parts ammonium persulfate were mixed, and then 50 parts of the waste residue from the ammonia-soda process with a particle size of 0.08 μm, 20 parts ethyl acrylate, 20 parts styrene monomer, 2 parts methacrylic acid, and 54 parts water were added. Prepolymerization was carried out at 25°C with a stirring speed of 500 r / min for 20 min to obtain a prepolymer. A mixture of 0.1 parts ammonium persulfate and 6 parts water was added dropwise to the prepolymer at a rate of 5 drops / min. After the addition was complete, emulsion polymerization was carried out at 45°C for 2 h to obtain modified waste residue from the ammonia-soda process for producing soda ash.

[0041] Ink preparation:

[0042] 15 parts of waste residue from the modified ammonia-soda method for preparing soda ash, 20 parts of toluene diisocyanate, 65 parts of polycaprolactone, 1 part of 2,2,4-trimethyl-1,3-pentanediol, 0.2 parts of organobismuth catalyst, and 15 parts of carbon black were mixed at 80°C with a stirring rate of 1000 r / min for 2 h. After mixing, the mixture was cooled to 40°C and emulsified with water for 20 min to obtain ink.

[0043] print:

[0044] The printing substrate is first washed with water three times, then placed in an oven and dried at 60°C for 30 minutes to obtain a pretreated printing substrate. The printing substrate is then transferred to the printing equipment for positioning treatment, and ink is printed onto the surface of the pretreated printing substrate. After printing, the printed product is placed in an oven and cured at 60°C for 10 minutes to obtain the printed product.

[0045] Example 2

[0046] Preparation of waste residue from the modified ammonia-soda process for producing soda ash:

[0047] The waste residue from the ammonia-soda process for producing soda ash was ground in a grinder to obtain a particle size of 0.05 μm. 1.2 parts sodium dodecyl sulfate, 1 part OP-1, and 0.3 parts ammonium persulfate were mixed, and then 45 parts of the waste residue from the ammonia-soda process with a particle size of 0.05 μm, 22 parts isooctyl acrylate, 23 parts styrene, 2.1 parts maleic anhydride, and 54 parts water were added. The mixture was prepolymerized at 25°C with a stirring speed of 600 r / min for 20 min to obtain a prepolymer. A mixture of 0.15 parts ammonium persulfate and 6 parts water was added dropwise to the prepolymer at a rate of 6 drops / min. After the addition was complete, emulsion polymerization was carried out at 48°C for 2.5 h to obtain modified waste residue from the ammonia-soda process for producing soda ash.

[0048] Ink preparation:

[0049] 10 parts of waste residue from the modified ammonia-soda method for preparing soda ash, 30 parts of isophorone diisocyanate, 65 parts of polycaprolactone, 0.8 parts of 2,2,4-trimethyl-1,3-pentanediol, 0.3 parts of organobismuth catalyst, and 12 parts of carbon black were mixed at 85°C with a stirring rate of 1000 r / min for 2 h. After mixing, the mixture was cooled to 45°C and emulsified with water for 20 min to obtain ink.

[0050] print:

[0051] The printing substrate is first washed with water three times, then placed in an oven and dried at 65°C for 30 minutes to obtain a pretreated printing substrate. The printing substrate is then transferred to the printing equipment for positioning treatment, and ink is printed onto the surface of the pretreated printing substrate. After printing, the printed product is placed in an oven and cured at 70°C for 12 minutes to obtain the printed product.

[0052] Example 3

[0053] Preparation of waste residue from the modified ammonia-soda process for producing soda ash:

[0054] The waste residue from the ammonia-soda process for producing soda ash was ground in a grinder to obtain a particle size of 0.09 μm. 1.5 parts sodium dodecyl sulfate, 0.5 parts OP-1, and 0.2 parts ammonium persulfate were mixed, and then 58 parts of the waste residue from the ammonia-soda process with a particle size of 0.09 μm, 20 parts ethyl acrylate, 20 parts acrylonitrile, 2 parts hydroxyethyl acrylate, and 54 parts water were added. The mixture was prepolymerized at 26°C with a stirring speed of 600 r / min for 10 min to obtain a prepolymer. A mixture of 0.1 parts ammonium persulfate and 6 parts water was added dropwise to the prepolymer at a rate of 5 drops / min. After the addition was complete, emulsion polymerization was carried out at 45°C for 2.5 h to obtain modified waste residue from the ammonia-soda process for producing soda ash.

[0055] Ink preparation:

[0056] 20 parts of waste residue from the modified ammonia-soda method for preparing soda ash, 20 parts of toluene diisocyanate, 70 parts of polycaprolactone, 1 part of neopentyl glycol or 1,6-hexanediol, 0.2 parts of organobismuth catalyst, and 15 parts of carbon black were mixed at 80°C with a stirring rate of 1000 r / min for 2 h. After mixing, the mixture was cooled to 40°C and emulsified with water for 20 min to obtain ink.

[0057] print:

[0058] The printing substrate is first washed with water three times, then placed in an oven and dried at 60°C for 30 minutes to obtain a pretreated printing substrate. The printing substrate is then transferred to the printing equipment for positioning treatment, and ink is printed on the surface of the pretreated printing substrate. After printing, the printed product is placed in an oven and cured at 75°C for 10 minutes to obtain the printed product.

[0059] Example 4

[0060] Preparation of waste residue from the modified ammonia-soda process for producing soda ash:

[0061] The waste residue from the ammonia-soda process for producing soda ash was ground in a grinder to obtain a waste residue with a particle size of 1 μm. 1.2 parts sodium dodecyl sulfate, 0.8 parts OP-1, and 0.2 parts ammonium persulfate were mixed, and then 50 parts of the waste residue from the ammonia-soda process with a particle size of 1 μm, 20 parts isooctyl acrylate, 20 parts vinyl acetate, 2 parts hydroxyethyl acrylate, and 54 parts water were added. The mixture was prepolymerized at 25°C with a stirring speed of 700 r / min for 20 min to obtain a prepolymer. A mixture of 0.1 parts ammonium persulfate and 6 parts water was added dropwise to the prepolymer at a rate of 6 drops / min. After the addition was complete, emulsion polymerization was carried out at 48°C for 2 h to obtain modified waste residue from the ammonia-soda process for producing soda ash.

[0062] Ink preparation:

[0063] 18 parts of waste residue from the modified ammonia-soda process for preparing soda ash, 35 parts of toluene diisocyanate, 72 parts of polycarbonate, 1.8 parts of 2,2,4-trimethyl-1,3-pentanediol, 0.5 parts of organobismuth catalyst, and 12 parts of carbon black were mixed at 80°C with a stirring rate of 1500 r / min for 2 h. After mixing, the mixture was cooled to 40°C and emulsified with water for 20 min to obtain ink.

[0064] print:

[0065] The printing substrate is first washed with water three times, then placed in an oven and dried at 70°C for 30 minutes to obtain a pretreated printing substrate. The printing substrate is then transferred to the printing equipment for positioning treatment, and ink is printed on the surface of the pretreated printing substrate. After printing, the printed product is placed in an oven and cured at 60°C for 12 minutes to obtain the printed product.

[0066] Example 5

[0067] Preparation of waste residue from the modified ammonia-soda process for producing soda ash:

[0068] The waste residue from the ammonia-soda process for producing soda ash was ground in a grinder to obtain a waste residue with a particle size of 1 μm. One part sodium dodecyl sulfonate, one part OP-1, and 0.2 parts ammonium persulfate were mixed, and then 50 parts of the waste residue from the ammonia-soda process with a particle size of 1 μm, 24 parts ethyl acrylate, 22 parts styrene monomer, 2 parts methacrylate, and 54 parts water were added. Prepolymerization was carried out at 25°C with a stirring speed of 500 r / min for 20 min to obtain a prepolymer. A mixture of 0.1 parts ammonium persulfate and 6 parts water was added dropwise to the prepolymer at a rate of 8 drops / min. After the addition was complete, emulsion polymerization was carried out at 45°C for 2 h to obtain modified waste residue from the ammonia-soda process for producing soda ash.

[0069] Ink preparation:

[0070] 20 parts of waste residue from the modified ammonia-soda method for preparing soda ash, 35 parts of toluene diisocyanate, 78 parts of polycaprolactone, 0.5 parts of 2,2,4-trimethyl-1,3-pentanediol, 0.6 parts of organobismuth catalyst, and 15 parts of carbon black were mixed at 95°C with a stirring rate of 1000 r / min for 2 h. After mixing, the mixture was cooled to 55°C and emulsified with water for 20 min to obtain ink.

[0071] print:

[0072] The printing substrate is first washed with water three times, then placed in an oven and dried at 60°C for 30 minutes to obtain a pretreated printing substrate. The printing substrate is then transferred to the printing equipment for positioning treatment, and ink is printed onto the surface of the pretreated printing substrate. After printing, the printed product is placed in an oven and cured at 60°C for 10 minutes to obtain the printed product.

[0073] The properties of the printed products obtained in Examples 1 to 5 were tested, and the test methods and results are as follows:

[0074] Adhesion test: The test was conducted according to GB / T 13217.7-1991. The judgment criteria were as follows: more than 90% of the ink remained on the printing substrate, indicating very good adhesion; 80-90% of the ink remained on the printing substrate, indicating good adhesion; 70-80% of the ink remained on the printing substrate, indicating relatively good adhesion; 60-70% of the ink remained on the printing substrate, indicating average adhesion; and less than 60% of the ink remained on the printing substrate, indicating poor adhesion.

[0075] Water resistance test: The printed products described in Examples 1-5 were weighed and recorded as W1. The printed products described in Examples 1-5 were then immersed in distilled water for 24 hours, removed, and their surface moisture was wiped dry. The weight of each product was recorded as W2. Water absorption rate was used to characterize water resistance: Water absorption rate % = (W2 - W1) / W1 × 100%. The lower the water absorption rate, the better the water resistance. The degree of ink adhesion on the surface of the printed products was also observed.

[0076] The results of the adhesion and water resistance tests are shown in Table 1.

[0077] Table 1. Performance test results of the printed products obtained in Examples 1-5

[0078]

[0079] As shown in Table 1, the peel strength of the ink obtained by this invention can reach 42-47 MPa, and the peel strength of the ink in the printed products obtained by this invention did not change significantly after immersion in water, indicating that the printed products obtained by this invention have excellent weather resistance and a long service life. Furthermore, testing shows that the ink adhesion of the printed products obtained by this invention can reach a high level, meeting the requirements for printed products with higher specifications.

[0080] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A green, environmentally friendly, waste-reducing printing process with excellent finished product quality, characterized in that, Includes the following steps: (1) Ink preparation: The waste residue from the modified ammonia-soda method for preparing soda ash, diisocyanate, polymer polyol, chain extender, catalyst and pigment are mixed and then emulsified with water to obtain ink; (2) Ink printing: The printing substrate is printed with ink and then cured to obtain the printed product.

2. The green, environmentally friendly, waste-reducing printing process with excellent finished product quality according to claim 1, characterized in that, The raw materials used in the ink are in the following proportions by mass: 10-20 parts of waste residue from the modified ammonia-soda process for preparing soda ash, 20-40 parts of diisocyanate, 60-80 parts of polymer polyol, 0.5-2 parts of chain extender, 0.2-0.6 parts of catalyst, 10-15 parts of pigment, and 100-130 parts of water.

3. The green, environmentally friendly, waste-reducing printing process with excellent finished product quality according to claim 2, characterized in that, The preparation of the waste residue from the modified ammonia-soda process for producing soda ash includes the following steps: mixing the waste residue from the ammonia-soda process for producing soda ash, polymerizing monomers, initiators, surfactants, and water for emulsion polymerization to obtain the waste residue from the modified ammonia-soda process for producing soda ash.

4. The green, environmentally friendly, waste-reducing printing process with excellent finished product quality according to claim 3, characterized in that, The polymeric monomers include viscous monomers, cohesive monomers, and functional monomers; the viscous monomers are ethyl acrylate and / or isooctyl acrylate; the cohesive monomers are one or more of styrene, acrylonitrile, and vinyl acetate; the functional monomers are one or more of methacrylic acid, maleic anhydride, and hydroxyethyl acrylate; the mass ratio of viscous monomers, cohesive monomers, and functional monomers is 20-30:20-30:2-5.

5. The green, environmentally friendly, waste-reducing printing process with excellent finished product quality according to claim 3 or 4, characterized in that, The initiator is ammonium persulfate; the surfactant is sodium dodecyl sulfonate and OP-10; the mass ratio of sodium dodecyl sulfonate and OP-10 is 1-1.5:0.5-1; the mass ratio of waste residue from the ammonia-soda process for preparing soda ash, polymer monomer, initiator, surfactant and water is 40-60:40-50:0.2-0.5:2-3:30-60.

6. The green, environmentally friendly, waste-reducing printing process with excellent finished product quality according to claim 5, characterized in that, The emulsion polymerization temperature is 40–50°C, and the emulsion polymerization time is 2–3 hours.

7. The green, environmentally friendly, waste-reducing printing process with excellent finished product quality according to claim 1 or 2, characterized in that, The diisocyanate is one or more selected from toluene diisocyanate, isophorone diisocyanate, diphenylmethane 4,4-diisocyanate, and tetramethylphenyldimethyl diisocyanate; the polymer polyol is polycaprolactone and / or polycarbonate; the chain extender is 2,2,4-trimethyl-1,3-pentanediol and / or neopentanediol or 1,6-hexanediol; the catalyst is an organobismuth catalyst; and the pigment is carbon black.

8. The green, environmentally friendly, waste-reducing printing process with excellent finished product quality according to claim 7, characterized in that, Before printing, the printing substrate is washed and dried sequentially.

9. The green, environmentally friendly, waste-reducing printing process with excellent finished product quality according to claim 8, characterized in that, The mixing is carried out under stirring conditions, with a stirring rate of 1000–2000 r / min; the mixing temperature is 80–100℃, and the mixing time is 2–3 h; the emulsification temperature is 40–60℃.

10. The green, environmentally friendly, waste-reducing printing process with excellent finished product quality according to claim 9, characterized in that, The curing temperature is 60–80°C, and the curing time is 10–20 minutes.

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