Single ethanol solvent-based ink and method of making same

Abstract

The application discloses single ethanol solvent type ink and a preparation method thereof, and relates to the technical field of intaglio printing. The single ethanol solvent type ink comprises the following components: connecting material, polyethylene wax powder and fumed silica; the connecting material comprises the following components: special acrylic resin, anhydrous ethanol and phosphate adhesion promoter; the special acrylic resin is a quaternary copolymer of IBOMA, 2-EHA, HPMA and IA, has a core-shell structure, the core layer of the core-shell structure has a Tg of -15 to -5 DEG C, the shell layer has a Tg of 50 to 60 DEG C, and the temperature rising rate is 9.5 to 10.5 DEG C / min. The preparation method comprises the following steps: preparation of pre-dispersed slurry, preparation of sanding slurry, preparation of ink slurry and stirring and dispersing process. The single ethanol solvent type ink is environmentally friendly, has bright and beautiful color, high adhesion, good printing suitability and can meet the requirements of medium and high speed printing of 200 to 350 m / min.

Description

Technical Field

[0001] This invention relates to the field of solvent-based ink technology, specifically to single ethanol solvent-based inks and their preparation methods. Background Technology

[0002] Traditional gravure inks use a mixture of benzophenone solvents (toluene + methyl ethyl ketone). Toluene is a Group 1 carcinogen, and residual solvents can migrate to food packaging, causing benzene compounds to exceed the standard. The total solvent content is >300g / L, and the VOC concentration in the printing workshop is ≥120mg / m³. An incineration RTO unit is also required, with energy consumption >800kW·h / ton of ink, resulting in high costs.

[0003] The alcohol-ester composite ink (isopropanol + ethyl acetate) reduces VOC to 150-200 g / L, initially meeting environmental protection requirements. However, residual ethyl acetate in the solvent is ≥3.0 mg / m², resulting in insufficient adhesion. Adhesion to non-polar BOPP films (surface tension ≤32 mN / m) is only 70-80%, requiring pre-coating with a primer or the addition of chlorinated polypropylene (CPP), which increases VOC levels.

[0004] In summary, the existing technology's single ethanol solvent system is insufficient to dissolve highly polar resins and cannot form homogeneous bonding materials;

[0005] Low-boiling-point solvents evaporate too quickly, resulting in poor leveling and white spots / cracks on printed materials; non-polar plastic surfaces lack active groups, and traditional resins rely on CPP or primers. Summary of the Invention

[0006] The purpose of this invention is to provide a single ethanol solvent-based ink and its preparation method. By using a single ethanol solvent and grafting modification of acrylic resin, the prepared solvent-based ink can adapt to medium-high speed printing of 200-350m / min and can be directly adhered to BOPP / PET without a primer. This improves the problem in the prior art that the single ethanol solvent system is difficult to dissolve highly polar resins, cannot form homogeneous binders, and cannot be directly adhered to BOPP / PET.

[0007] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0008] Single ethanol solvent-based inks, by weight, comprise the following components:

[0009] 30-40 parts binder, 0.5-2 parts polyethylene wax powder, 0.3-1 part fumed silica, and 40-60 parts anhydrous ethanol;

[0010] The binder comprises the following components: 45-55 parts of special acrylic resin, 45-55 parts of anhydrous ethanol, and 1-3 parts of phosphate ester adhesion promoter; the special acrylic resin is a quaternary copolymer of IBOMA, 2-EHA, HPMA and IA, having a core-shell structure, wherein the core layer Tg=-15~-5℃, the shell layer Tg=50~60℃, and the heating rate is 9.5~10.5℃ / min.

[0011] Phosphate ester adhesion promoters can specifically include VISIOMER® HEMA-P 100 phosphate ester.

[0012] In existing technologies, pure ethanol cannot dissolve highly polar resins, and conventional acrylic resins require benzene / ketone solvents. This invention employs a special quaternary copolymer design of IBOMA, 2-EHA, HPMA, and IA, precisely matching the polarity gradient with ethanol to achieve hydrogen-bonded dominance for dissolution; and forming a core-shell structure: a core layer with low Tg (-15~-5℃) containing flexible daughter chains (2-EHA) to effectively increase solubility; and a shell layer with high Tg (50~60℃) containing rigid monomers, IBOMA, which can suppress excessive ethanol swelling. Conventional core-shell resins suffer from interfacial defects (Tg transition zone > 20℃) due to misaligned phase separation kinetics. This invention, by precisely controlling the heating rate of 9.5~10.5℃ / min, induces gradient copolymerization of the core-shell monomers, forming an interpenetrating polymer network (IPN) in the ≤5℃ transition zone. This IPN structure enables instantaneous glass transition of the shell layer (hardening within 0.5s after solvent evaporation), supporting high-speed printing ≥200m / min. Meanwhile, to address the issue of VOC increases of 80g / L caused by traditional chlorinated polypropylene (CPP) tackifiers, a phosphate ester accelerator was selected. Adding 3% of it only contributes VOC ≤0.5g / L. Its phosphate ester groups anchor BOPP through P=O dipoles and form P=O···HOC hydrogen bonds with the resin carboxyl groups (from IA monomers), synergistically achieving BOPP adhesion ≥94.2%, completely replacing the primer coating process.

[0013] During film formation, polyethylene wax powder migrates to the ink surface, forming a dense physical barrier that improves the abrasion resistance of printed materials by 3 times. Simultaneously, it significantly reduces the surface friction coefficient, effectively preventing film adhesion during high-speed printing (≥200m / min). Its partial crystallization properties regulate surface gloss through light refraction, achieving an adjustable matte / semi-gloss effect of 30~70 GU. Furthermore, it melts under high-speed printing shear conditions, instantly reducing ink viscosity and increasing dot transfer rate from 75% to 92%. After detaching from the printing plate, it rapidly recrystallizes, inhibiting dot diffusion (resolution improvement ≥20%).

[0014] Fumed silica forms a thixotropic system through an interparticle hydrogen bond network: high viscosity in a static state prevents pigment sedimentation; network disintegration under shearing action achieves low viscosity (50 mPa·s), ensuring printing leveling; and significantly improves anti-sagging performance on vertical surfaces. The silanol groups (≡Si-OH) on the surface of fumed silica form hydrogen bonds with ethanol, blocking resin aggregation and ensuring storage stability; the nanoscale particle size (7~40nm) generates a light scattering effect, synergistically controlling gloss with wax powder.

[0015] Furthermore, the sol portion of the special acrylic resin has a Mw value of 8000~12000.

[0016] Furthermore, it also includes 8 to 30 parts of pigment, including titanium dioxide, permanent yellow, or phthalocyanine blue.

[0017] Pigments can also be selected from surface-modified inorganic pigments, such as iron oxide red or cobalt blue; high-performance organic pigments, such as DPP red or benzimidazole yellow; and coating-type special effect pigments, such as aluminum silver paste.

[0018] A preparation method, applicable to the preparation of the single ethanol solvent-based ink, includes the following steps:

[0019] Under S100 protective atmosphere, after heating the binder, add polyethylene wax powder and disperse it at a step speed. After dispersion, immediately cool it to room temperature to obtain a pre-dispersed slurry.

[0020] S200. After adding the above pre-dispersed slurry and pigment to the sand mill, maintain the temperature ≤50℃ and perform two-stage sand milling until the particle size is ≤15μm to obtain the sand milled slurry.

[0021] S300. Transfer the above-mentioned sand-milled slurry to a vacuum dispersion kettle, first add fumed silica, then dilute with anhydrous ethanol in a gradient, adjust the viscosity to 20~40s, and obtain ink slurry;

[0022] S400: Disperse the ink slurry evenly and filter to obtain the target ink.

[0023] Traditional high-speed dispersion can lead to localized high temperatures, damaging the high Tg structure of the core and shell. In step S100, a stepped rotation speed is used to control the accumulation of shear heat; after dispersion, instantaneous cooling (25°C) locks the swollen state of the core layer; the core-shell integrity retention rate is >99%.

[0024] In step 200, a two-stage low-temperature sand mill is used. The coarse grinding stage breaks down pigment aggregates; the fine grinding stage encapsulates the pigment in the core layer, eliminates interface defects, and reduces the white spot rate by 90%. The sand mill selected is the Zeta® LMZ sand mill.

[0025] In step S300, fumed silica is added first, followed by anhydrous ethanol. This maximizes SiO2 dispersion efficiency by utilizing a high-viscosity environment; and phase separation is avoided by controlling solvation kinetics through fractional dilution.

[0026] The native particle size of gaseous SiO2 is only 7-40 nm, but the surface silanol groups (≡Si-OH) easily form hydrogen bonds and aggregate. The high viscosity of the undiluted slurry is conducive to the full extension of SiO2 particles to form a three-dimensional hydrogen bond network, laying the foundation for subsequent rheological control. If ethanol is added first, the viscosity of the system drops sharply, the Brownian motion of SiO2 particles intensifies, and the probability of collisional aggregation increases; ethanol molecules will competitively occupy the silanol groups on the SiO2 surface, resulting in a decrease in the hydrogen bond network density and loss of thixotropy.

[0027] The FLUKO FDV-50 vacuum dispersion vessel was selected.

[0028] In step S400, the ink slurry is dispersed evenly under stirring.

[0029] The stepped dispersion of S100 and the grinding of S200 at ≤50℃ effectively prevent premature glass formation of the shell layer; the hydrogen bond reconstruction of S300 and the uniform dispersion of S400 activate the synergistic anchoring of phosphate ester and IA carboxyl group. This four-step reaction achieves deep coupling between physical processes (temperature / vacuum / oscillation) and chemical design (core-shell / phosphate ester). The preparation method of this invention achieves a VOC residue of <3mg / m³ in a pure ethanol system through a three-stage process chain: low-temperature protection of the core-shell structure, precise vacuum rheological control, and stirring dispersion-induced interface anchoring. 2 Drying speed > 300 m / min, BOPP adhesion > 94.2%.

[0030] Further, in step S100, the temperature is raised to 40~45℃; the stepped speed dispersion includes the following: first, premix at 800~1000 rpm for 4~6 min to make the wax powder evenly wetted; then raise to 2500~2800 rpm for high-speed dispersion for 12~18 min; the protective atmosphere includes nitrogen or argon.

[0031] Furthermore, in step S200, the two-stage grinding includes the following:

[0032] First-stage grinding: Zirconium beads with a particle size of 1.2~1.4 mm are ground to a particle size D. 90 ≤35μm;

[0033] Secondary grinding: Zirconium beads with a particle size of 0.6~0.8 mm are ground to a particle size D. 90 ≤15μm.

[0034] Furthermore, in step S300, the conditions for adding fumed silica include: dispersion at 1300~1600 rpm for 8~12 min under a vacuum of -0.08~-0.1 MPa.

[0035] Furthermore, in step S300, the method for gradient dilution of anhydrous ethanol includes: adding anhydrous ethanol three times, with an interval of 5 to 10 minutes between each addition, and simultaneously adjusting the viscosity to 20 to 40 seconds.

[0036] Furthermore, the method of adding anhydrous ethanol three times includes:

[0037] For the first time, control the temperature at 15~25℃, the volume at 10~15% of the total ethanol volume, and the rotation speed at 800~1200 rpm;

[0038] The second time, the temperature is controlled at 25~35℃, the volume is 60~70% of the total ethanol volume, and the rotation speed is 1400~1600 rpm;

[0039] The third time, control the temperature at 20~25℃, the volume at 15~30% of the total ethanol volume, and the rotation speed at 1000~1200rpm.

[0040] A gradient dilution was achieved by adding anhydrous ethanol three times: the first addition swells the resin core layer, reducing the concentration difference between the resin phase and the SiO2 network; the second addition unwraps the shell layer and integrates SiO2, breaking down potential flocculation precursors with high shear force; the third addition allows -COOH (carboxyl) groups to bond with EtOH, reconstructing hydrogen bond equilibrium and suppressing the repulsive barrier between the resin and SiO2. These additions were spaced 5–10 minutes apart to ensure that the shear field reorganization reached equilibrium after each addition.

[0041] Further, in step S400, the ink slurry is dispersed at 25~35℃ and stirred at 1200~1500rpm for 15~20min, and then filtered through a 4~5μm filter bag to obtain the target ink.

[0042] Compared with the prior art, the beneficial effects of the present invention are:

[0043] The single-ethanol solvent ink of this invention achieves a VOC residue of <3mg / m³ in a pure ethanol system. 2 The drying speed is >300 m / min, and the BOPP adhesion is ≥94.2%. The preparation method of this invention, with its step-dispersion and rapid cooling processes, ensures a resin core-shell integrity rate >99%; the two-stage low-temperature milling effectively reduces the particle size D. 90 ≤15μm, while eliminating white spots; ethanol gradient dilution process to regulate solvation kinetics and avoid phase separation; stirring and dispersion process to induce molecular orientation assembly, improve storage stability, and ensure no stratification for >180 days.

[0044] IBOMA: Isobornyl methacrylate;

[0045] 2-EHA: 2-Ethylhexyl acrylate;

[0046] HPMA: Hydroxypropyl methacrylate;

[0047] IA: itaconic acid;

[0048] BOPP: Biaxially oriented polypropylene film;

[0049] PET: Polyethylene terephthalate;

[0050] CPP: Chlorinated polypropylene;

[0051] Tg: Glass transition temperature. Detailed Implementation

[0052] Example 1

[0053] The binder material includes the following components:

[0054] Special acrylic resin 500g, anhydrous ethanol 450g, phosphate ester adhesion promoter 20g;

[0055] Among them, the special acrylic resin is a quaternary copolymer of IBOMA, 2-EHA, HPMA and IA, with a core-shell structure, and the sol portion of the special acrylic resin has Mw=10000.

[0056] The core-shell structure has a core layer Tg of -10℃ and a shell layer Tg of 55℃, with a heating rate of 10℃ / min.

[0057] A preparation method, applicable to the preparation of the binder, includes the following steps:

[0058] The mass ratio of IBOMA, 2-EHA, HPMA and IA is 20:25:2.2:1.

[0059] Under D100 and argon protection, in a mixed solution of deionized water and sodium methacrylate sulfonate, the temperature was raised to 85°C, and a mixture of monomers of 2-EHA and IA was added dropwise, while ammonium persulfate was added dropwise simultaneously. The reaction was maintained at this temperature for 1.8 h to form a flexible core layer with a core-shell structure. The amount of deionized water added was 37% of the total mass of the system. The mass ratio of sodium methacrylate sulfonate, ammonium persulfate and IA was 0.6:0.15:1.

[0060] D200, cool to 70℃, add dropwise a mixture of monomers IBOMA, HPMA, and ethylene glycol dimethacrylate, and simultaneously add potassium persulfate, keep the reaction at this temperature for 1.8h to form a rigid shell, and obtain an aqueous core-shell emulsion with a solid content of 40%; the mass ratio of IBOMA, ethylene glycol dimethacrylate, and potassium persulfate is 1:0.018:0.008.

[0061] D300: After cooling the above aqueous core-shell emulsion to 39°C, slowly add anhydrous ethanol (32% of the total ethanol volume) dropwise at a rate ≤1 mL / min. Simultaneously, distill under reduced pressure at -0.075 MPa and 40°C to remove water until the system water content is 7%.

[0062] D400: Heat the system from step D300 to 65°C, add anhydrous ethanol accounting for 43% of the total ethanol volume, distill under normal pressure until the water content is 0.35%, cool to 37°C, add phosphate ester adhesion promoter, and continue stirring the reaction for 0.8h.

[0063] D500: Cool the D400 system to 22°C, stir at low speed (300 rpm) for 30 minutes, add the remaining anhydrous ethanol until the solid content of the solution reaches 47%, mix evenly, and obtain the target binder.

[0064] Example 2

[0065] The binder material includes the following components:

[0066] Special acrylic resin 450g, anhydrous ethanol 400g, phosphate ester adhesion promoter 10g;

[0067] Among them, the special acrylic resin is a quaternary copolymer of IBOMA, 2-EHA, HPMA and IA, with a core-shell structure, and the sol portion of the special acrylic resin has a Mw=8000.

[0068] The core-shell structure has a core layer Tg of -15℃ and a shell layer Tg of 50℃, with a heating rate of 9.5℃ / min.

[0069] A preparation method, applicable to the preparation of the binder, includes the following steps:

[0070] The mass ratio of IBOMA, 2-EHA, HPMA and IA is 18:22:2:1.

[0071] Under D100 and argon protection, in a mixed solution of deionized water and sodium methacrylate sulfonate, the temperature was raised to 82°C, and a mixture of monomers of 2-EHA and IA was added dropwise, while ammonium persulfate was added dropwise simultaneously. The reaction was maintained at this temperature for 1.5 h to form a flexible core layer with a core-shell structure. The amount of deionized water added was 35% of the total mass of the system. The mass ratio of sodium methacrylate sulfonate, ammonium persulfate and IA was 0.5:0.1:1.

[0072] D200, cooled to 68℃, added dropwise a mixture of IBOMA, HPMA, and ethylene glycol dimethacrylate monomers, simultaneously adding potassium persulfate, and kept at this temperature for 1.5h to form a rigid shell, yielding an aqueous core-shell emulsion with a solid content of 38%; the mass ratio of IBOMA, ethylene glycol dimethacrylate, and potassium persulfate was 1:0.015:0.006.

[0073] D300: After cooling the above aqueous core-shell emulsion to 36°C, slowly add anhydrous ethanol (30% of the total ethanol volume) dropwise at a rate ≤1 mL / min. Simultaneously, distill under reduced pressure at -0.08 MPa and 38°C to remove water until the water content of the system is 0.8%.

[0074] D400: Heat the system from step D300 to 63°C, add anhydrous ethanol accounting for 40% of the total ethanol volume, distill under normal pressure until the water content is 0.4%, cool to 35°C, add phosphate ester adhesion promoter, and continue stirring the reaction for 0.5 h.

[0075] D500: Cool the system from step D400 to 20°C, stir at low speed (280 rpm) for 25 minutes, add the remaining anhydrous ethanol until the solid content of the solution reaches 45%, mix evenly, and obtain the target binder.

[0076] Example 3

[0077] The binder material includes the following components:

[0078] Special acrylic resin 550g, anhydrous ethanol 500g, phosphate ester adhesion promoter 30g;

[0079] Among them, the special acrylic resin is a quaternary copolymer of IBOMA, 2-EHA, HPMA and IA, with a core-shell structure, and the sol portion of the special acrylic resin has a Mw=12000.

[0080] The core-shell structure has a core layer Tg of -5℃ and a shell layer Tg of 60℃, with a heating rate of 10.5℃ / min.

[0081] A preparation method, applicable to the preparation of the binder, includes the following steps:

[0082] The mass ratio of IBOMA, 2-EHA, HPMA and IA is 22:28:2.5:1.

[0083] Under D100 and argon protection, in a mixed solution of deionized water and sodium methacrylate sulfonate, the temperature was raised to 87°C, and a mixture of monomers of 2-EHA and IA was added dropwise, while ammonium persulfate was added dropwise simultaneously. The reaction was maintained at this temperature for 2 hours to form a flexible core layer with a core-shell structure. The amount of deionized water added was 40% of the total mass of the system. The mass ratio of sodium methacrylate sulfonate, ammonium persulfate and IA was 0.8:0.2:1.

[0084] D200, cool to 72℃, add dropwise a mixture of monomers IBOMA, HPMA, and ethylene glycol dimethacrylate, and simultaneously add potassium persulfate, keep the reaction at this temperature for 2 hours to form a rigid shell, and obtain an aqueous core-shell emulsion with a solid content of 42%; the mass ratio of IBOMA, ethylene glycol dimethacrylate, and potassium persulfate is 1:0.02:0.01.

[0085] D300: After cooling the above aqueous core-shell emulsion to 42°C, slowly add anhydrous ethanol (35% of the total ethanol volume) dropwise at a rate ≤1 mL / min. Simultaneously, distill under reduced pressure at -0.07 MPa and 42°C to remove water until the water content of the system is 6%.

[0086] D400: Heat the system from step D300 to 68°C, add anhydrous ethanol accounting for 45% of the total ethanol volume, distill under normal pressure until the water content is 0.3%, cool to 40°C, add phosphate ester adhesion promoter, and continue stirring the reaction for 1.0 h.

[0087] D500: Cool the system from step D400 to 25°C, stir at low speed (320 rpm) for 35 minutes, add the remaining anhydrous ethanol until the solid content of the solution reaches 49%, mix evenly, and obtain the target binder.

[0088] The performance parameters of the binders for gravure plastic printing prepared using the formulations and preparation methods of Examples 1-3 are shown in Table 1.

[0089] Table 1 Performance parameters of the binders for gravure plastic printing prepared using the formulations and preparation methods of Examples 1-3

[0090]

[0091] As shown in Table 1, the gravure plastic printing binder prepared by the formulation and preparation method of Examples 1-3 of this invention constructs a soft core-hard shell partitioned structure through quaternary copolymerization of 2-EHA / IA core layer and IBOMA / HPMA shell layer. The soft core (Tg=-10℃~-5℃) provides adhesion, and the hard shell (IBOMA crosslinking network, Tg=55~60℃) provides hardness. The BOPP adhesion reaches 93.1%, and the hardness reaches 2H, realizing that a single resin can simultaneously meet the requirements of high adhesion and high hardness.

[0092] It can withstand more than 50 methyl ethyl ketone (MEK) wiping cycles; using a three-step method of low-temperature decompression, atmospheric pressure azeotropic distillation, and room-temperature replenishment, it achieves a water removal rate of >99.6% and a core-shell integrity rate (TEM) of 97%, with a dehydration time of <4.5 hours. The emulsion particle size is stable at 82~88 nm, and it shows no gelation after 30 days of storage at 40℃, achieving high molecular weight miscibility with ethanol. VOC residue ≤2.1 mg / m³. 2 It meets environmental protection requirements.

[0093] Example 4

[0094] Single ethanol solvent-based inks include the following components:

[0095] Example 1 contains 350g of binder, 12g of polyethylene wax powder, 6g of fumed silica, 500g of anhydrous ethanol, and 200g of permanent yellow.

[0096] A preparation method, applicable to the preparation of the single ethanol solvent-based ink, includes the following steps:

[0097] Under S100 and nitrogen protection, the binder is heated to 42°C, polyethylene wax powder is added, and it is dispersed at a stepped speed. After dispersion, it is immediately cooled to 25°C to obtain a pre-dispersed slurry.

[0098] The stepped speed dispersion includes the following steps: first, premix at 900 rpm for 5 minutes to uniformly wet the wax powder; then increase to 2650 rpm for high-speed dispersion for 15 minutes; the protective atmosphere includes nitrogen or argon.

[0099] S200. After adding the above pre-dispersed slurry and pigment to the sand mill, maintain the temperature at 48°C and perform two-stage sand milling until the particle size is 14μm to obtain the sand milled slurry.

[0100] Two-stage sanding includes the following:

[0101] First-stage grinding: Zirconium beads with a particle size of 1.3 mm are ground to a particle size D. 90 =30μm;

[0102] Secondary grinding: Zirconium beads with a particle size of 0.7mm are ground to a particle size D. 90 =13μm.

[0103] S300. Transfer the above-mentioned sand-milled slurry to a vacuum dispersion kettle, first add fumed silica, then dilute with anhydrous ethanol in a gradient, adjust the viscosity to 30s, and obtain ink slurry.

[0104] The conditions for adding fumed silica include:

[0105] Disperse at 1450 rpm for 10 min under a vacuum of -0.09 MPa.

[0106] The gradient dilution method for anhydrous ethanol includes adding anhydrous ethanol three times, with an 8-minute interval between each addition, and simultaneously adjusting the viscosity to 30 seconds.

[0107] The method of adding anhydrous ethanol three times includes:

[0108] For the first time, the temperature was controlled at 20℃, the volume was 12% of the total ethanol volume, and the rotation speed was 1000 rpm.

[0109] The second time, the temperature was controlled at 30℃, the volume was 66% of the total ethanol volume, and the rotation speed was 1500 rpm.

[0110] The third time, the temperature was controlled at 23℃, the volume was 22% of the total ethanol volume, and the rotation speed was 1100 rpm.

[0111] S400. Stir the ink slurry at 30°C and 1350 rpm for 18 minutes, then filter it through a 4.5 μm filter bag to obtain the target ink.

[0112] Example 5

[0113] Single ethanol solvent-based inks include the following components:

[0114] Example 1 contains 300g of binder, 5g of polyethylene wax powder, 3g of fumed silica, 400g of anhydrous ethanol, and 80g of phthalocyanine blue.

[0115] A preparation method, applicable to the preparation of the single ethanol solvent-based ink, includes the following steps:

[0116] Under S100 and argon protection, the binder is heated to 40°C, then polyethylene wax powder is added and dispersed at a stepped speed. After dispersion, the temperature is immediately reduced to 27°C to obtain a pre-dispersed slurry.

[0117] The stepped speed dispersion includes the following steps: first, premix at 800 rpm for 4 minutes to uniformly wet the wax powder; then increase to 2500 rpm for high-speed dispersion for 12 minutes; the protective atmosphere includes nitrogen or argon.

[0118] S200. After adding the above pre-dispersed slurry and pigment to the sand mill, maintain the temperature at 50°C and perform two-stage sand milling until the particle size is 15μm to obtain the sand milled slurry.

[0119] Two-stage sanding includes the following:

[0120] First-stage grinding: Zirconium beads with a particle size of 1.4 mm are ground to a particle size D. 90 =35μm;

[0121] Secondary grinding: Zirconium beads with a particle size of 0.8 mm are ground to a particle size D. 90 =15μm.

[0122] S300. Transfer the above-mentioned sand-milled slurry to a vacuum dispersion kettle, first add fumed silica, then dilute with anhydrous ethanol in a gradient, adjust the viscosity to 20s, and obtain ink slurry;

[0123] The conditions for adding fumed silica include:

[0124] Disperse at 1300 rpm for 8 min under a vacuum of -0.1 MPa.

[0125] The gradient dilution method for anhydrous ethanol includes adding anhydrous ethanol three times, with an interval of 5 minutes between each addition, and simultaneously adjusting the viscosity to 20 seconds.

[0126] The method of adding anhydrous ethanol three times includes:

[0127] For the first time, the temperature was controlled at 15℃, the volume was 10% of the total ethanol volume, and the rotation speed was 800 rpm.

[0128] The second time, the temperature was controlled at 25℃, the volume was 60% of the total ethanol volume, and the rotation speed was 1400 rpm.

[0129] The third time, the temperature was controlled at 20℃, the volume was 30% of the total ethanol volume, and the rotation speed was 1000 rpm.

[0130] S400. The ink slurry is dispersed at 25°C and stirred at 1200 rpm for 15 minutes, then filtered through a 4μm filter bag to obtain the target ink.

[0131] Example 6

[0132] Single ethanol solvent-based inks include the following components:

[0133] Example 1 contains 400g of binder, 20g of polyethylene wax powder, 10g of fumed silica, 600g of anhydrous ethanol, and 300g of titanium dioxide.

[0134] A preparation method, applicable to the preparation of the single ethanol solvent-based ink, includes the following steps:

[0135] Under S100 and nitrogen protection, the binder is heated and polyethylene wax powder is added. It is dispersed at a step speed and then immediately cooled to room temperature to obtain a pre-dispersed slurry.

[0136] The stepped speed dispersion includes the following steps: first, premix at 1000 rpm for 6 minutes to uniformly wet the wax powder; then increase to 2800 rpm for high-speed dispersion for 18 minutes; the protective atmosphere includes nitrogen or argon.

[0137] S200. After adding the above pre-dispersed slurry and pigment to the sand mill, maintain the temperature at 45°C and perform two-stage sand milling until the particle size is 12μm to obtain the sand milled slurry.

[0138] Two-stage sanding includes the following:

[0139] First-stage grinding: Zirconium beads with a particle size of 1.2 mm are ground to a particle size D. 90 =26μm;

[0140] Secondary grinding: Zirconium beads with a particle size of 0.6 mm are ground to a particle size D. 90 =12μm.

[0141] S300. Transfer the above-mentioned sand-milled slurry to a vacuum dispersion kettle, first add fumed silica, then dilute with anhydrous ethanol in a gradient, adjust the viscosity to 40s, and obtain ink slurry.

[0142] The conditions for adding fumed silica include:

[0143] Disperse at 1600 rpm for 12 min under a vacuum of -0.08 MPa.

[0144] The gradient dilution method for anhydrous ethanol includes adding anhydrous ethanol three times, with an interval of 10 minutes between each addition, and simultaneously adjusting the viscosity to 40 seconds.

[0145] The method of adding anhydrous ethanol three times includes:

[0146] For the first time, the temperature was controlled at 25℃, the volume was 15% of the total ethanol volume, and the rotation speed was 1200 rpm.

[0147] The second time, the temperature was controlled at 35℃, the volume was 70% of the total ethanol volume, and the rotation speed was 1600 rpm.

[0148] The third time, the temperature was controlled at 25℃, the volume was 15% of the total ethanol volume, and the rotation speed was 1200 rpm.

[0149] S400. The ink slurry is dispersed at 35°C and stirred at 1500 rpm for 20 min, and then filtered through a 5μm filter bag to obtain the target ink.

[0150] The performance parameters of the single ethanol solvent-based inks prepared using the formulations and preparation methods of Examples 4-6 are shown in Table 2.

[0151] Table 2. Performance parameters of single ethanol solvent-based inks prepared using the formulations and preparation methods of Examples 4-6.

[0152]

[0153] As shown in Table 2, the printing drying speed of the single ethanol solvent-based inks prepared in Examples 4-6 is >300 m / min, the BOPP adhesion can reach 94.2%, and the VOC residue is <3 mg / m³. 2 The leveling defect rate is ≤2.5%, there is no delamination after 180 days of storage, the thixotropic index is between 3.6 and 3.9, and the printing sag rate is ≤1.5%.

[0154] Comparative Example 1

[0155] A printing binder comprises the following components:

[0156] Acrylic resin 350g, anhydrous ethanol 500g, phosphate ester adhesion promoter 20g;

[0157] The acrylic resin is a random copolymer (non-core-shell) of IBOMA, 2-EHA, HPMA and IA, and the acrylic resin Mw=10000.

[0158] A preparation method, applicable to the preparation of the printing binder, includes the following steps:

[0159] Synthesis of S100 random copolymer emulsion: Under N2 protection, 37% of the total system mass of deionized water was added to the reactor, followed by sodium methacrylate sulfonate. The temperature was raised to 85℃, and mixed monomers: IBOMA, 2-EHA 25, HPMA 2.2, IA 1, and ammonium persulfate were added dropwise at a rate of 2 mL / min. The reaction was maintained at this temperature for 1.8 h to obtain a random copolymer emulsion (solid content 40%, Tg≈35℃).

[0160] The mass ratio of IBOMA, 2-EHA, HPMA, and IA is 20:25:2.2:1. The mass ratio of sodium methacrylate sulfonate, ammonium persulfate, and IA is 0.6:0.15:1; the mass ratio of IBOMA, ethylene glycol dimethacrylate, and potassium persulfate is 1:0.018:0.008.

[0161] S200, Solvent Replacement: Cool the emulsion to 70°C, add all anhydrous ethanol at once, and stir vigorously at 500 rpm. Distill and dehydrate under reduced pressure of -0.075 MPa at 70°C until the water content is ≤0.4%.

[0162] S300, Additives and Adjustments: Maintain 65℃, add phosphate ester adhesion promoter, and stir for 0.5 h. Cool to 25℃, add deionized water to adjust the solid content to 47%, mix evenly, and obtain the target binder.

[0163] The binder prepared using the above method is used as a raw material to prepare a single ethanol solvent-based ink.

[0164] The components and preparation method of the single ethanol solvent-based ink are the same as those in Example 4.

[0165] Comparative Example 2

[0166] The phosphate ester adhesion promoter was replaced with chlorinated polypropylene; in the preparation method, anhydrous ethanol was first added for gradient dilution in S300, followed by the addition of fumed silica. All other components, parameters, and preparation methods were the same as in Example 4.

[0167] Comparative Example 3

[0168] The composition and parameters of the single ethanol solvent-based ink are the same as those in Example 4.

[0169] In the preparation method: the ink slurry is allowed to stand at 30°C for 18 minutes, then filtered through a 4.5μm filter bag to obtain the target ink. Steps S100 to S300 are the same as in Example 1.

[0170] Comparative Example 4

[0171] The binder was prepared using the same method as the binder in Comparative Example 1.

[0172] Replace phosphate ester adhesion promoters with chlorinated polypropylene.

[0173] In the preparation method, in step S300, anhydrous ethanol is first added for gradient dilution, and then fumed silica is added.

[0174] In step S400, stirring is replaced by standing.

[0175] The other components, parameters, and preparation methods are the same as in Example 4.

[0176] Comparative Example 5

[0177] The composition and parameters of the single ethanol solvent-based ink are the same as those in Example 4.

[0178] In the preparation method, the gradient dilution of anhydrous ethanol is replaced by the one-time addition of anhydrous ethanol, and the other steps and parameters are the same as in Example 4.

[0179] Comparative Example 6

[0180] The composition and parameters of the single ethanol solvent-based ink are the same as those in Example 4.

[0181] In the preparation method, the vacuum addition of fumed silica was replaced with the addition of fumed silica under normal pressure. Other steps and parameters were the same as in Example 4.

[0182] Comparative Example 7

[0183] The composition and parameters of the single ethanol solvent-based ink are the same as those in Example 4.

[0184] In the preparation method, the vacuum addition of fumed silica was replaced with the addition of fumed silica under normal pressure, and the gradient dilution of anhydrous ethanol was replaced with the one-time addition of anhydrous ethanol. Other steps and parameters were the same as in Example 4.

[0185] The performance parameters of the single ethanol solvent-based inks prepared by the methods of Examples 4 and Comparative Examples 1-7 are shown in Table 3.

[0186] Table 3 Performance parameters of single ethanol solvent-based inks prepared by the methods of Examples 4 and Comparative Examples 1-7

[0187]

[0188] As shown in Table 1, in Comparative Example 1, the acrylic resin randomly copolymerized from IBOMA, 2-EHA, HPMA and IA resulted in a double failure due to the lack of a core-shell structure: the absence of a low Tg core layer led to poor wettability of the BOPP surface, and the contact angle >85° resulted in decreased adhesion; the absence of a high Tg shell layer resulted in a slow glass transition speed, and the curing time after solvent evaporation was >3s, reducing the drying speed. Therefore, it was impossible to achieve both fast drying and flexibility, with a printing drying speed of 185m / min and an adhesion of 72%.

[0189] In Comparative Example 2, chlorinated polypropylene caused the VOC residue level to increase to 16.5 mg / m³. 2 First, anhydrous ethanol was added for gradient dilution, and then fumed silica was added. This caused the later-added fumed silica to agglomerate in the low-viscosity system, and the pigments also flocculated.

[0190] When ethanol is added first, the viscosity of the system drops sharply, which intensifies the Brownian motion of SiO2, causing collisions and agglomeration. The hydrogen bond network cannot be established, resulting in the loss of thixotropy, which is only 2.0. The leveling defect rate is 26%, and the printing sag rate is 42%.

[0191] In Comparative Example 3, stirring and dispersion were replaced by standing. During standing, the phosphate esters were randomly distributed, and only 30% of the P=O groups contacted the BOPP surface. The “P=O···HOC” hydrogen bonds were not activated, the interfacial bonding energy decreased, the adhesion was only 84%, and the viscosity increased or decreased by 15% during storage.

[0192] In Comparative Example 4, the use of random copolymerized acrylic resin resulted in slow drying; the use of chlorinated polypropylene led to an increase in VOC residue to 18.2 mg / m³. 2 Adding ethanol before silicon dioxide caused silicon dioxide to aggregate, and the aggregated particles blocked the printing plate, resulting in a decrease in transfer rate and a leveling defect rate of 31%.

[0193] In Comparative Example 5, the one-time addition of ethanol resulted in an excessively large local solvent concentration gradient in the system, triggering phase separation. The one-time addition of ethanol caused differences in the swelling rates of the core and shell resins, leading to excessive swelling of the core layer, microgel precipitation, and the appearance of leveling white spots. The leveling defect rate was 17.5%, and the storage precipitation rate was 8%.

[0194] In Comparative Example 6, SiO2 was added at atmospheric pressure. The air mixed in at atmospheric pressure caused the bubble-particle interface free energy to drive agglomeration under the shear energy transfer efficiency, resulting in a printing sag rate of 38%.

[0195] In Comparative Example 7, the addition of SiO2 at atmospheric pressure and the one-time addition of ethanol resulted in aggregate blockage and interfacial air gaps, leading to a decrease in adhesion to 74%. The dual interference of microgels and air bubbles resulted in a leveling defect rate of 31%.

[0196] The synergistic process of core-shell resin design, phosphate ester thickening, pre-vacuum dispersion of SiO2, subsequent gradient ethanol, and stirring dispersion in this invention enables high-speed printing of single-ethanol solvent-based inks at 200-350 m / min, achieving 94.2% adhesion and VOC residue <3 mg / m³. 2 .

Claims

1. A single ethanol solvent-based ink, characterized in that, By weight, it includes the following components: 30-40 parts binder, 0.5-2 parts polyethylene wax powder, 0.3-1 part fumed silica, and 40-60 parts anhydrous ethanol; The binder comprises the following components: 45-55 parts of special acrylic resin, 45-55 parts of anhydrous ethanol, and 1-3 parts of phosphate ester adhesion promoter; the special acrylic resin is a quaternary copolymer of IBOMA, 2-EHA, HPMA and IA, having a core-shell structure, wherein the core layer Tg=-15~-5℃, the shell layer Tg=50~60℃, and the heating rate is 9.5~10.5℃ / min; The method for preparing the binder includes the following steps: D100. Under argon protection, in a mixed solution of deionized water and sodium methyl propylene sulfonate, after heating, a mixed monomer of 2-EHA and IA is added dropwise, and ammonium persulfate is added dropwise simultaneously. The reaction is kept at the temperature to form a flexible core layer with a core-shell structure. After cooling, D200 is added dropwise with a mixture of monomers including IBOMA, HPMA, and ethylene glycol dimethacrylate, while potassium persulfate is added dropwise simultaneously. The reaction is kept at a constant temperature to form a rigid shell, resulting in an aqueous core-shell emulsion. D300: After cooling the above aqueous core-shell emulsion, slowly add anhydrous ethanol dropwise, and simultaneously remove water by vacuum distillation. D400: Heat the system from step D300, add anhydrous ethanol, remove water by atmospheric distillation, cool down and add phosphate ester adhesion promoter, and continue stirring the reaction. D500: Cool down the system from step D400, stir at low speed, add the remaining anhydrous ethanol, mix evenly, and obtain the target ink binder. The preparation method of the single ethanol solvent-based ink includes the following steps: Under S100 protective atmosphere, after heating the binder, add polyethylene wax powder and disperse it at a step speed. After dispersion, immediately cool it to room temperature to obtain a pre-dispersed slurry. S200. After adding the above pre-dispersed slurry and pigment to the sand mill, maintain the temperature ≤50℃ and perform two-stage sand milling until the particle size is ≤15μm to obtain the sand milled slurry. S300. Transfer the above-mentioned sand-milled slurry to a vacuum dispersion kettle, first add fumed silica, then dilute with anhydrous ethanol in a gradient, adjust the viscosity to 20~40s, and obtain ink slurry; S400: Disperse the ink slurry evenly and filter to obtain the target ink.

2. The single ethanol solvent-based ink according to claim 1, characterized in that, The sol portion of the special acrylic resin has a molecular weight of 8000~12000.

3. The single ethanol solvent-based ink according to claim 1, characterized in that, It also includes 8 to 30 parts of pigment, including titanium dioxide, permanent yellow or phthalocyanine blue.

4. The single ethanol solvent-based ink according to claim 1, characterized in that, In step S100, the temperature is raised to 40~45℃; the step-speed dispersion includes the following: first, premix at 800~1000 rpm for 4~6 min to make the wax powder evenly wetted; then raise to 2500~2800 rpm for high-speed dispersion for 12~18 min; the protective atmosphere includes nitrogen or argon.

5. The single ethanol solvent-based ink according to claim 1, characterized in that, In step S200, the two-stage grinding includes the following: First-stage grinding: Zirconium beads with a particle size of 1.2~1.4 mm are ground to a particle size D. 90 ≤35μm; Secondary grinding: Zirconium beads with a particle size of 0.6~0.8 mm are ground to a particle size D. 90 ≤15μm.

6. The single ethanol solvent-based ink according to claim 1, characterized in that, In step S300, the conditions for adding fumed silica include: dispersion at 1300~1600 rpm for 8~12 min under a vacuum of -0.08~-0.1 MPa.

7. The single ethanol solvent-based ink according to claim 1, characterized in that, In step S300, the method for gradient dilution of anhydrous ethanol includes: adding anhydrous ethanol three times, with an interval of 5 to 10 minutes between each addition, and simultaneously adjusting the viscosity to 20 to 40 seconds.

8. The single ethanol solvent-based ink according to claim 7, characterized in that, The method of adding anhydrous ethanol in three parts includes: For the first time, control the temperature at 15~25℃, the volume at 10~15% of the total ethanol volume, and the rotation speed at 800~1200 rpm; The second time, the temperature is controlled at 25~35℃, the volume is 60~70% of the total ethanol volume, and the rotation speed is 1400~1600 rpm; The third time, control the temperature at 20~25℃, the volume at 15~30% of the total ethanol volume, and the rotation speed at 1000~1200rpm.

9. The single ethanol solvent-based ink according to claim 1, characterized in that, In step S400, the ink slurry is dispersed at 25~35℃ and stirred at 1200~1500rpm for 15~20min, and then filtered through a 4~5μm filter bag to obtain the target ink.

Images