A new ink for decorative paper and a method for preparing and printing the same

Abstract

The present application belongs to the technical field of printing ink, and particularly relates to a novel ink for decorative paper, a preparation method thereof and a printing method. The present application is greatly improved on the basis of the prior art. The ink is modified by bio-based materials, a multiple cross-linking network is constructed, and a precise staged curing process is adopted, thereby breaking through the bottleneck of traditional decorative paper ink in environmental protection, mechanical property, functionalization and production efficiency, realizing the synergistic improvement of environmental protection, mechanical property and printability, and providing a new path for the high performance and greenization of the decorative paper ink.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of printing ink, and particularly relates to a novel ink for decorative paper and a preparation method and printing method thereof. BACKGROUND

[0002] Decorative paper is a rapidly developing special industrial paper, which is made of titanium dioxide, coniferous pulp and broadleaf pulp as main raw materials, and other additives, and then treated by a special process, and then printed by a machine, impregnated with resin (melamine type), etc., and used for decoration on artificial boards. The impregnated decorative base paper in the artificial board industry is also called melamine paper. With the development of national economy, the decoration industry also develops, and the demand for decorative paper increases year by year, so it is necessary to improve the quality of decorative paper.

[0003] As the core decorative material in the fields of furniture, floor, building materials, etc., the printing quality of decorative paper directly affects the aesthetics and functionality of the terminal product. The traditional decorative paper ink mainly uses petroleum-based resin as the main body, and adopts a single-stage hot air curing process, which has the following significant defects: (1) insufficient environmental protection: the petroleum-based resin contains a large amount of volatile organic compounds (VOCs), which does not meet the requirements of the European Union REACH regulation and the domestic GB 38507-2020 standard for the environmental protection of ink. (2) performance limitations: the adhesion, wear resistance and ultraviolet aging resistance of the traditional ink are difficult to meet the needs of the high-end market, especially in the high-temperature and high-pressure impregnation process, problems such as discoloration and film layer rupture are prone to occur. (3) single function: it cannot realize adjustable gloss, anti-slip and other functions, and the production energy consumption is high, which is difficult to adapt to the trend of individual customization and green manufacturing.

[0004] Therefore, it is urgent to develop and research a kind of green and environmentally friendly ink for decorative paper with high performance, which is used for printing of decorative paper, so as to improve the quality of decorative paper. SUMMARY

[0005] The purpose of the present application is to provide a novel ink for decorative paper and a preparation method and printing method thereof in view of the existing problems.

[0006] The present application is realized by the following technical scheme:

[0007] A novel ink for decorative paper comprises the following raw materials by mass:

[0008] 50-70 parts of water-based acrylic emulsion, 10-15 parts of chitosan modified casein graft copolymer, 5-10 parts of dopamine modified TiO2 / oxidized graphene (GO) composite material, 1-5 parts of fatty alcohol polyoxyethylene ether, 1-3 parts of nano-chitin whisker, 2-5 parts of heat-expandable microcapsule, 1-3 parts of photoinitiator 1173, 1-3 parts of acylhydrazone crosslinking agent, 1-2 parts of silane coupling agent KH550, and 20-40 parts of pure water.

[0009] Further, the preparation of the chitosan modified casein graft copolymer comprises the following steps:

[0010] (1) casein is added into NaOH solution, after stirring to completely dissolve, a 20% casein sodium solution is formed;

[0011] (2) chitosan is dissolved in 1% acetic acid, then added into the casein sodium solution, heated to 65~75℃, and then dropwise added with epoxy chloropropane, and reacted for 4~5h;

[0012] (3) after the reaction is completed, cooling is performed, then 3 times volume of anhydrous ethanol is added into the reaction solution, the precipitate is collected by centrifugation, washed with deionized water, and then vacuum freeze-dried to obtain the chitosan modified casein graft copolymer.

[0013] Further, the mass ratio of casein, chitosan and epoxy chloropropane is (5~6):(1.7~2):1;

[0014] The dropwise adding speed of epoxy chloropropane is 4~5mL / min.

[0015] Further, the preparation of the dopamine modified TiO2 / oxidized graphene (GO) composite material comprises the following steps:

[0016] 1) graphene oxide (GO) is added into Tris-HCl buffer solution, and ultrasonic treatment is performed for 30~40min to form a 0.25%~0.3% GO dispersion liquid;

[0017] 2) nano-TiO2 and dopamine hydrochloride are added into the GO dispersion liquid, and stirring treatment is performed at 50~60℃ and 200~300r / min for 1~2h, after the treatment is completed, centrifugation is performed, the precipitate is collected, washed with deionized water until neutral, and then vacuum dried at 60~70℃ for 10~12h to obtain the dopamine modified TiO2 / oxidized graphene (GO) composite material.

[0018] Further, the mass ratio of graphene oxide, nano-TiO2 and dopamine hydrochloride is 1:(20~25):(4~5).

[0019] A preparation method of a new type of ink for decorative paper comprises the following steps:

[0020] S1, weigh the corresponding weight parts of water-based acrylic emulsion 50-70 parts, chitosan modified casein graft copolymer 10-15 parts, dopamine modified TiO2 / oxidized graphene (GO) composite 5-10 parts, fatty alcohol polyoxyethylene ether 1-5 parts, nano-chitin whisker 1-3 parts, heat-expandable microcapsule 2-5 parts, photoinitiator 1173 1-3 parts, acylhydrazone crosslinking agent 1-3 parts, silane coupling agent KH550 1-2 parts, and pure water 20-40 parts for standby;

[0021] S2, inject the dispersed phase into the glass material T-shaped microfluidic chip at a flow rate of 8-12 mL / min, and inject pure water into the glass material T-shaped microfluidic chip at a flow rate of 16-24 mL / min, to form a stable laminar flow in the chip, and use the shear force to preliminarily break the pigment aggregates to submicron level, and collect the pre-dispersed liquid at the outlet section, and transfer the pre-dispersed liquid to a sand mill, and grind at a speed of 3000-4000 r / min for 20-30 min to obtain a pigment dispersion;

[0022] S3, chitosan modified casein graft copolymer and water-based acrylic emulsion are pre-mixed to form a homogeneous system under stirring at 60℃, then KH550 is added, then the temperature is raised to 70℃, and after reaction for 2-3h, the temperature is lowered to 50℃, acylhydrazone crosslinking agent is added, and stirring is carried out for 1-2h to obtain a bio-based hybrid emulsion;

[0023] S4, the bio-based hybrid emulsion is added to a high-speed dispersion kettle, the pigment dispersion is added, stirring is carried out at 1000-2000 r / min for 10-20 min, then dopamine modified TiO2 / oxidized graphene (GO) composite is added, stirring is continued for 5-10 min, then nano-chitin whisker is added, ultrasonic treatment is carried out for 10-15 min, then heat-expandable microcapsule is added, stirring is carried out at 500-600 r / min for 4-6 min, then photoinitiator 1173 is added, pure water is used to adjust the solid content to 55±2%, and finally filtration is carried out with a 300 mesh filter screen.

[0024] Further, the preparation method of the dispersed phase in step S1 is: the pigment and the fatty acid polyoxyethylene ether are mixed according to a mass ratio of (10-12):1, and then ultrasonic dispersion is carried out in pure water to prepare 20% pigment slurry as the dispersed phase.

[0025] Further, the pigment is one or more of carbon black, phthalocyanine blue, permanent red, and pigment yellow.

[0026] A printing method of a new type of ink for decorative paper, comprising: preparing a decorative base paper and a new type of ink for decorative paper, printing the new type of ink for decorative paper onto the surface of the decorative base paper using a micro-gravure printing machine, and then performing a three-stage curing treatment.

[0027] Further, the three-stage curing process is specifically: first, placed in a hot air circulating oven with infrared assistance, dried at 60~80℃, infrared power 5~8kW / m 2 , hot air speed 1~2m / s for 3~5min; then heated to 90~100℃ at a rate of 5~8℃ / min, constant temperature treatment for 8~12min, then placed in a UV curing device, irradiated for 1~3s under the condition of light power of 1000~1500mW / cm 2 , and then immediately cooled by a fan.

[0028] Compared with the prior art, the present application has the following advantages:

[0029] 1. The present application provides a new type of ink for decorative paper, which introduces chitosan-modified casein graft copolymer, nano-chitin whiskers and other bio-based materials into the formula, reduces the amount of petroleum-based resin, and the dopamine-modified TiO2 / GO composite material has antibacterial and light-resistant properties. The light shielding effect of TiO2 combined with the barrier property of GO can delay the yellowing of the ink and prolong its aging resistance life. The catechol structure of dopamine enhances the interface bonding between the filler and the resin, preventing the filler from falling off. The graphene oxide in the dopamine-modified TiO2 / GO composite material can effectively prevent the evaporation of organic solvents while imparting functionality to the ink. The synergistic effect of the acylhydrazone crosslinking agent and the silane coupling agent forms a composite network of "chemical covalent bond + physical entanglement" between the chitosan-casein copolymer and the water-based acrylic emulsion, thereby improving the cohesive force of the film layer and the wear resistance and rubbing fastness of the dried ink. After the uniform dispersion of nano-chitin whiskers, the pores of the film layer are filled, thereby improving the tensile strength and improving the tear resistance.

[0030] 2. The present application provides a preparation method of a new type of ink for decorative paper, which breaks the pigment aggregates to submicron level through the laminar shear force of a T-shaped microfluidic chip, and improves the fineness of the ink through fine grinding with a sand mill, making the ink clear in dot and uniform in color, suitable for high-precision pattern printing.

[0031] 3. The present application adopts a three-stage curing process, which first performs pre-drying, the synergistic effect of hot air and infrared radiation rapidly removes water in the ink through surface evaporation and internal diffusion, the residual water exists in the hydrogen bond network of chitosan in the form of "bound water", avoiding excessive expansion of paper fibers, then the medium temperature promotes the crosslinking of acylhydrazone and silane hydrolysis, greatly reducing the energy consumption compared with traditional full hot air curing, and finally performing UV curing, instantaneously inducing the polymerization of acrylic double bonds, shortening the total curing time and improving the production efficiency. DETAILED DESCRIPTION

[0032] In order to further explain the present application, the following specific embodiments are described.

[0033] Table 1 Reagents

[0034]

[0035] Note: Unless otherwise specified, the raw materials used in the present application are all from the market-purchased conventional products.

[0036] Example 1

[0037] A preparation method of a new type of ink for decorative paper, comprising the following steps:

[0038] S1, weigh the corresponding weight parts of water-based acrylic emulsion 50 parts, chitosan modified casein graft copolymer 10 parts, dopamine modified TiO2 / oxidized graphene (GO) composite material 5 parts, fatty alcohol polyoxyethylene ether 1 part, nanochitin whisker 1 part, heat-expandable microcapsule 2 parts, photoinitiator 1173 1 part, acylhydrazone crosslinking agent 1 part, silane coupling agent KH550 1 part, and 20 parts of pure water for standby;

[0039] The preparation of the chitosan modified casein graft copolymer comprises the following steps:

[0040] (1) The casein is added to the NaOH solution, and after stirring to completely dissolve, a casein sodium solution with a mass concentration of 20% is formed;

[0041] (2) The chitosan is dissolved with 1% acetic acid, then added to the casein sodium solution, and heated to 65℃, and the epoxy chloropropane is added dropwise at a speed of 4mL / min, and the reaction is carried out for 4h;

[0042] (3) After the reaction is completed, cooling is carried out, then 3 times the volume of anhydrous ethanol is added to the reaction solution, the precipitate is collected by centrifugation, and after washing with deionized water, vacuum freeze-drying is carried out to obtain the chitosan modified casein graft copolymer;

[0043] The mass ratio of the casein, chitosan and epoxy chloropropane is 5:1.7:1;

[0044] The preparation of the dopamine modified TiO2 / oxidized graphene (GO) composite material comprises the following steps:

[0045] 1) The graphene oxide (GO) is added to the Tris-HCl buffer solution, and ultrasonic treatment is carried out for 30min to form a 0.25% GO dispersion liquid;

[0046] 2) The nanometer TiO2 and dopamine hydrochloride are added to the GO dispersion liquid, and stirring treatment is carried out at 50℃ and 200r / min for 1h, and after completion, centrifugation is carried out, the precipitate is washed with deionized water until neutral, and vacuum drying is carried out at 60℃ for 10h to obtain the dopamine modified TiO2 / oxidized graphene (GO) composite material;

[0047] The mass ratio of the graphene oxide, nano TiO2 and dopamine hydrochloride is 1:20:4;

[0048] S2, inject the dispersed phase into the glass T-shaped microfluidic chip at a flow rate of 8 mL / min, and inject pure water into the glass T-shaped microfluidic chip at a flow rate of 16 mL / min, form a stable laminar flow in the chip, and use the shear force to preliminarily break the pigment aggregates to submicron level, collect the pre-dispersed liquid at the outlet section, transfer the pre-dispersed liquid to a sand mill, and grind at a speed of 3000 r / min for 20 min to obtain a pigment dispersion;

[0049] The preparation method of the dispersed phase is: mixing the pigment and the fatty acid polyoxyethylene ether according to a mass ratio of 10:1, and then ultrasonic dispersing into pure water to prepare 20% pigment slurry as the dispersed phase;

[0050] The pigment is a mixture obtained by mixing carbon black and phthalocyanine blue according to a mass ratio of 1:1;

[0051] S3, the chitosan modified casein graft copolymer and the water-based acrylic emulsion are pre-mixed to form a homogeneous system under stirring at 60 DEG C, then KH550 is added, then the temperature is increased to 70 DEG C, and after reaction for 2h, the temperature is decreased to 50 DEG C, and the acylhydrazone crosslinking agent is added, and stirred for 1h to obtain a bio-based hybrid emulsion;

[0052] S4, the bio-based hybrid emulsion is added into a high-speed dispersion kettle, the pigment dispersion is added, and after stirring at 1000 r / min for 10 min, the dopamine modified TiO2 / oxidized graphene (GO) composite material is added, and continues to stir for 5 min, then the nano-chitin whisker is added, and after ultrasonic treatment for 10 min, the heat-expandable microcapsule is added, and after stirring at 500 r / min for 4 min, the photoinitiator 1173 is added, the solid content is adjusted to 55±2% by pure water, and finally filtered through a 300 mesh filter.

[0053] A printing method of a new type of ink for decorative paper, comprising: preparing a decorative base paper and a new type of ink for decorative paper, printing the new type of ink for decorative paper onto the surface of the decorative base paper using a micro-gravure printing machine, and then performing a three-stage curing treatment, specifically: first, drying in an infrared-assisted hot air circulation oven at 60 DEG C, infrared power 5kW / m 2 , hot air speed 1m / s for 3min; then increasing the temperature to 90 DEG C at a rate of 5 DEG C / min, constant temperature treatment for 8min, then placing in a ultraviolet curing device, irradiating at a light power of 1000mW / cm 2 for 1s, and then immediately cooling by a fan.

[0054] Example 2

[0055] A preparation method of a new type of ink for decorative paper, comprising the following steps:

[0056] S1, weigh the corresponding weight parts of water-based acrylic emulsion 60 parts, chitosan modified casein graft copolymer 12 parts, dopamine modified TiO2 / oxidized graphene (GO) composite material 7 parts, fatty alcohol polyoxyethylene ether 3 parts, nano chitin whisker 2 parts, thermal expansion microcapsule 3.5 parts, photoinitiator 1173 2 parts, acylhydrazone crosslinking agent 2 parts, silane coupling agent KH550 1.5 parts, and 30 parts of pure water for standby;

[0057] The preparation of the chitosan modified casein graft copolymer comprises the following steps:

[0058] (1) The casein is added to the NaOH solution, and after stirring to completely dissolve, a casein sodium solution with a mass concentration of 20% is formed;

[0059] (2) The chitosan is dissolved with 1% acetic acid, then added to the casein sodium solution, and heated to 70℃, and the epoxy chloropropane is added dropwise at a speed of 4.5mL / min, and the reaction is carried out for 4.5h;

[0060] (3) After the reaction is completed, cooling is carried out, then 3 times the volume of anhydrous ethanol is added to the reaction solution, the precipitate is collected by centrifugation, and after washing with deionized water, vacuum freeze-drying is carried out to obtain the chitosan modified casein graft copolymer;

[0061] The mass ratio of the casein, chitosan and epoxy chloropropane is 5.5:1.8:1;

[0062] The preparation of the dopamine modified TiO2 / oxidized graphene (GO) composite material comprises the following steps:

[0063] 1) The graphene oxide (GO) is added to the Tris-HCl buffer solution, and ultrasonic treatment is carried out for 35min to form a 0.27% GO dispersion liquid;

[0064] 2) The nano TiO2 and dopamine hydrochloride are added to the GO dispersion liquid, and stirring treatment is carried out at 55℃ and 250r / min for 1.5h, and after completion, centrifugation is carried out, the precipitate is collected, washed with deionized water until neutral, and then vacuum dried at 65℃ for 11h to obtain the dopamine modified TiO2 / oxidized graphene (GO) composite material;

[0065] The mass ratio of the graphene oxide, nano TiO2 and dopamine hydrochloride is 1:22:4.5;

[0066] S2, inject the dispersed phase into the glass material T-shaped microfluidic chip at a flow rate of 10 mL / min, and inject pure water into the glass material T-shaped microfluidic chip at a flow rate of 20 mL / min, form a stable laminar flow in the chip, use the shear force to preliminarily break the pigment aggregate to submicron level, collect the pre-dispersion liquid at the outlet section, transfer the pre-dispersion liquid to a sand mill, grind at a speed of 3500 r / min for 25 min to obtain a pigment dispersion;

[0067] The preparation method of the dispersed phase is: mixing the pigment and the fatty acid polyoxyethylene ether according to a mass ratio of 11:1, and then ultrasonic dispersing into pure water to prepare a 20% pigment slurry as the dispersed phase;

[0068] The pigment is a mixture obtained by mixing carbon black and phthalocyanine blue according to a mass ratio of 1:1;

[0069] S3, the chitosan modified casein graft copolymer and the water-based acrylic emulsion are pre-mixed to form a homogeneous system under stirring at 60°C, then KH550 is added, then the temperature is increased to 70°C, and after reaction for 2.5 h, the temperature is decreased to 50°C, the acylhydrazone crosslinking agent is added, and stirring is performed for 1.5 h to obtain a bio-based hybrid emulsion;

[0070] S4, the bio-based hybrid emulsion is added into a high-speed dispersion kettle, the pigment dispersion is added, stirring is performed at 1500 r / min for 15 min, then the dopamine modified TiO2 / oxidized graphene (GO) composite material is added, stirring is continued for 7 min, then the nano-chitin whisker is added, ultrasonic treatment is performed for 12 min, then the heat-expandable microcapsule is added, stirring is performed at 550 r / min for 5 min, then the photoinitiator 1173 is added, the solid content is adjusted to 55±2% by pure water, and finally filtration is performed using a 300-mesh filter screen.

[0071] A printing method of a new type of ink for decorative paper, comprising: preparing a decorative base paper and a new type of ink for decorative paper, printing the new type of ink for decorative paper onto the surface of the decorative base paper using a micro-gravure printing machine, and then performing a three-stage curing treatment, specifically: first, drying in an infrared-assisted hot air circulation oven at 70°C, an infrared power of 6 kW / m 2 , and a hot air speed of 1.5 m / s for 4 min; then increasing the temperature to 95°C at a rate of 6°C / min, constant temperature treatment for 10 min, then irradiating in a ultraviolet curing device at a light power of 1200 mW / cm 2 for 2 s, and then immediately cooling by a fan.

[0072] Example 3

[0073] A preparation method of a new type of ink for decorative paper, comprising the following steps:

[0074] S1, weigh the corresponding weight parts of water-based acrylic emulsion 70 parts, chitosan modified casein graft copolymer 15 parts, dopamine modified TiO2 / oxidized graphene (GO) composite material 10 parts, fatty alcohol polyoxyethylene ether 5 parts, nano-chitin whisker 3 parts, heat-expandable microcapsule 5 parts, photoinitiator 1173 3 parts, acylhydrazone crosslinking agent 3 parts, silane coupling agent KH550 2 parts, and 40 parts of pure water for standby;

[0075] The preparation of the chitosan modified casein graft copolymer includes the following steps:

[0076] (1) The casein is added to the NaOH solution, and after stirring to completely dissolve, a casein sodium solution with a mass concentration of 20% is formed;

[0077] (2) The chitosan is dissolved with 1% acetic acid, and then added to the casein sodium solution, and heated to 75°C, and then the epoxy chloropropane is added dropwise at a speed of 5mL / min, and the reaction is carried out for 5h;

[0078] (3) After the reaction is completed, cooling is carried out, then 3 times the volume of anhydrous ethanol is added to the reaction solution, the precipitate is collected by centrifugation, and after washing with deionized water, vacuum freeze-drying is carried out to obtain the chitosan modified casein graft copolymer;

[0079] The mass ratio of the casein, chitosan and epoxy chloropropane is 6:2:1;

[0080] The preparation of the dopamine modified TiO2 / oxidized graphene (GO) composite material includes the following steps:

[0081] 1) The graphene oxide (GO) is added to the Tris-HCl buffer solution, and ultrasonic treatment is carried out for 40min to form a 0.3% GO dispersion;

[0082] 2) The nano-TiO2 and dopamine hydrochloride are added to the GO dispersion, and stirring treatment is carried out at 60°C and 300r / min for 2h, and after completion, centrifugation is carried out, the precipitate is washed with deionized water until neutral, and then vacuum drying is carried out at 70°C for 12h to obtain the dopamine modified TiO2 / oxidized graphene (GO) composite material;

[0083] The mass ratio of the graphene oxide, nano-TiO2 and dopamine hydrochloride is 1:25:5;

[0084] S2, the dispersion phase is injected into the glass T-shaped microfluidic chip at a flow rate of 12mL / min, and at the same time, the pure water is injected into the glass T-shaped microfluidic chip at a flow rate of 24mL / min, a stable laminar flow is formed in the chip, the shear force is used to preliminarily break the pigment aggregates to a submicron level, and the pre-dispersion liquid is collected at the outlet section, the pre-dispersion liquid is transferred to a sand mill, and grinding is carried out at a speed of 4000r / min for 30min to obtain the pigment dispersion;

[0085] The preparation method of the dispersion phase is: mixing the pigment and the fatty acid polyoxyethylene ether according to a mass ratio of 12:1, and then ultrasonic dispersing into pure water to prepare a 20% pigment slurry as the dispersion phase;

[0086] The pigment is a mixture obtained by mixing carbon black and phthalocyanine blue according to a mass ratio of 1:1;

[0087] S3, the chitosan-modified casein graft copolymer and the water-based acrylic emulsion are pre-mixed to form a homogeneous system under stirring at 60°C, then KH550 is added, then the temperature is increased to 70°C, and the reaction is carried out for 3h, then the temperature is decreased to 50°C, the acylhydrazone crosslinking agent is added, and stirring is carried out for 2h to obtain a bio-based hybrid emulsion;

[0088] S4, the bio-based hybrid emulsion is added into a high-speed dispersion kettle, the pigment dispersion is added, stirring is carried out at 2000r / min for 20min, then the dopamine-modified TiO2 / oxidized graphene (GO) composite material is added, stirring is continued for 10min, then the nano-chitin whisker is added, ultrasonic treatment is carried out for 15min, then the heat-expandable microcapsule is added, stirring is carried out at 600r / min for 6min, then the photoinitiator 1173 is added, the solid content is adjusted to 55±2% by pure water, and finally the filter screen with a mesh size of 300 is used for filtration.

[0089] A printing method of a new type of ink for decorative paper, comprising: preparing a decorative base paper and a new type of ink for decorative paper, printing the new type of ink for decorative paper onto the surface of the decorative base paper using a micro-gravure printing machine, and then performing three-stage curing treatment, specifically: first, drying in an infrared-assisted hot air circulation oven at 80°C, infrared power 8kW / m 2 , hot air speed 2m / s for 5min; then increasing the temperature to 100°C at a rate of 8°C / min, constant temperature treatment for 12min, then irradiating in a ultraviolet curing device at a light power of 1500mW / cm 2 for 3s, and then immediately cooling by a fan.

[0090] Comparative Example 1

[0091] Comparative Example 1 is compared with Example 2, in which the chitosan-modified casein graft copolymer is replaced by casein, and the other steps are the same as those in Example 2.

[0092] Comparative Example 2

[0093] Comparative Example 2 is compared with Example 2, in which the dopamine-modified TiO2 / oxidized graphene (GO) composite material is replaced by nano-TiO2, and the other steps are the same as those in Example 2.

[0094] Comparative Example 3

[0095] Comparative Example 3 is the same as Example 2 except that KH550 and acylhydrazone crosslinking agent are omitted.

[0096] Comparative Example 4

[0097] Comparative Example 4 is the same as Example 2 except that the three-stage curing process is replaced by a single-stage thermal solidification (curing at 100℃ for 20 min).

[0098] Performance test

[0099] The new inks for decorative paper were prepared by the methods of Examples 1-3 and Comparative Examples 1-4, respectively, and then printed by the corresponding printing methods, and then performance tests were performed.

[0100] Test method:

[0101] Adhesion: ISO 2409 grid method;

[0102] Wear resistance: GB / T 1768 wear resistance test;

[0103] UV aging resistance: GB / T 16422.3-1997;

[0104] VOCs content: GB 38507-2020.

[0105] The test results are shown in Table 2 below.

[0106] Table 2

[0107]

[0108] As can be seen from Table 2 above, the adhesion of the inks of Examples 1-3 is 5B, the weight loss rate is <2.5%, ΔE is <3, the VOCs content is low, the prepared ink has good mechanical properties and UV aging resistance, is green and environmentally friendly, and the various performances are better than those of the comparative examples, indicating that the raw material composition ratio and printing process of the ink of the present application are improved, which can well improve the quality and printing characteristics of the ink.

[0109] The above description is only a preferred specific embodiment of the present application, but the protection scope of the present application is not limited thereto, any skilled person in the art can make equivalent substitutions or changes within the technical scope disclosed by the present application and according to the technical solutions and inventive concept of the present application, which should be covered within the protection scope of the present application.

Claims

1. An ink for decorative paper, characterized in that, The raw materials include the following parts by weight: 50-70 parts of waterborne acrylic emulsion, 10-15 parts of chitosan-modified casein graft copolymer, 5-10 parts of dopamine-modified TiO2 / graphene oxide composite, 1-5 parts of fatty alcohol polyoxyethylene ether, 1-3 parts of nano-chitosan whiskers, 2-5 parts of thermally expandable microcapsules, 1-3 parts of photoinitiator 1173, 1-3 parts of acylhydrazone crosslinking agent, 1-2 parts of silane coupling agent KH550, and 20-40 parts of purified water; The preparation of the chitosan-modified casein graft copolymer includes the following steps: (1) Add casein to NaOH solution and stir until completely dissolved to form a 20% sodium casein solution; (2) Dissolve chitosan in 1% acetic acid, add it to sodium casein solution, heat to 65~75℃, add epichlorohydrin dropwise, and react for 4~5h; (3) After the reaction is completed, cool the mixture and then add 3 times the volume of anhydrous ethanol to the reaction solution. Centrifuge to collect the precipitate, wash with deionized water, and freeze-dry under vacuum to obtain chitosan-modified casein graft copolymer. The preparation of the dopamine-modified TiO2 / graphene oxide composite material includes the following steps: 1) Add graphene oxide to Tris-HCl buffer and sonicate for 30-40 min to form a 0.25-0.3% GO dispersion; 2) Add nano-TiO2 and dopamine hydrochloride to the GO dispersion, stir at 50~60℃ and 200~300r / min for 1~2h, centrifuge, collect the precipitate, wash with deionized water until neutral, and vacuum dry at 60~70℃ for 10~12h to obtain dopamine modified TiO2 / graphene oxide mixture.

2. The ink for decorative paper according to claim 1, characterized in that, The mass ratio of casein, chitosan, and epichlorohydrin is (5~6):(1.7~2):1; The dropping rate of epichlorohydrin is 4-5 mL / min.

3. The ink for decorative paper according to claim 2, characterized in that, The mass ratio of the graphene oxide, nano-TiO2, and dopamine hydrochloride is 1:(20~25):(4~5).

4. The method for preparing decorative paper ink according to any one of claims 1 to 3, characterized in that, Includes the following steps: S1. Weigh out the following ingredients in appropriate weight proportions: 50-70 parts of water-based acrylic emulsion, 10-15 parts of chitosan-modified casein graft copolymer, 5-10 parts of dopamine-modified TiO2 / graphene oxide composite, 1-5 parts of fatty alcohol polyoxyethylene ether, 1-3 parts of nano-chitosan whiskers, 2-5 parts of thermally expandable microcapsules, 1-3 parts of photoinitiator 1173, 1-3 parts of acylhydrazone crosslinking agent, 1-2 parts of silane coupling agent KH550, and 20-40 parts of purified water. S2. The dispersed phase is injected into a glass T-shaped microfluidic chip at a flow rate of 8-12 mL / min, and purified water is injected into the glass T-shaped microfluidic chip at a flow rate of 16-24 mL / min. A stable laminar flow is formed in the chip, and the pigment agglomerates are initially broken down to the submicron level by shear force. The pre-dispersion liquid is collected at the outlet section and transferred to a sand mill. The pre-dispersion liquid is ground at a speed of 3000-4000 r / min for 20-30 min to obtain the pigment dispersion. S3. Chitosan-modified casein graft copolymer and aqueous acrylic emulsion are stirred and premixed at 60°C to form a homogeneous system. Then KH550 is added, and the temperature is raised to 70°C. After reacting for 2-3 hours, the temperature is lowered to 50°C, an acylhydrazone crosslinking agent is added, and the mixture is stirred for 1-2 hours to obtain a bio-based hybrid emulsion. S4. Add the bio-based hybrid emulsion to a high-speed dispersion vessel, add the pigment dispersion, stir at 1000~2000 r / min for 10~20 min, then add the dopamine-modified TiO2 / graphene oxide composite material, continue stirring for 5~10 min, then add nano chitin whiskers, sonicate for 10~15 min, then add thermally expanded microcapsules, stir at 500~600 r / min for 4~6 min, then add photoinitiator 1173, adjust the solid content to 55±2% with purified water, and finally filter with a 300 mesh filter.

5. The method for preparing an ink for decorative paper according to claim 4, characterized in that, The method for preparing the dispersed phase in step S1 is as follows: the pigment and fatty acid polyoxyethylene ether are mixed at a mass ratio of (10~12):1, and then ultrasonically dispersed in pure water to prepare a 20% pigment slurry, which is the dispersed phase.

6. The method for preparing an ink for decorative paper according to claim 5, characterized in that, The pigment is one or more of carbon black, phthalocyanine blue, permanent red, and pigment yellow.

7. A printing method for the decorative paper ink prepared according to any one of claims 5-6, characterized in that, include: Prepare decorative base paper and new ink for decorative paper. Use a microgravure printing press to print the new ink for decorative paper onto the surface of the decorative base paper, and then perform a three-stage curing process.

8. The printing method for decorative paper ink according to claim 7, characterized in that, The three-stage curing process specifically involves: first, placing the product in a hot air circulating oven with infrared assistance at 60~80℃ and an infrared power of 5~8kW / m². 2 Dry under hot air velocity of 1-2 m / s for 3-5 min; then heat to 90-100℃ at a rate of 5-8℃ / min, hold at that temperature for 8-12 min, and then place in a UV curing device at 1000-1500 mW / cm². 2 Irradiate for 1-3 seconds under the specified light power, then immediately cool with a fan.

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