Functionalized cage-type oligomeric silsesquioxane-modified aluminum pigment for high-gloss silver ink and preparation method thereof

Abstract

The present invention provides a kind of high-gloss silver ink functionalized cage-type oligomeric silsesquioxane modified aluminum pigment and preparation method thereof, adopts bifunctional POSS to coat modified flaky aluminum pigment, and uses isophorone diisocyanate (IPDI) as bridge, grafts nitrocellulose (NC).On the one hand, hydroxyl-containing POSS is bonded with aluminum hydroxyl groups on the surface of flaky aluminum powder to form Al-O-Si bond, so that it forms a firm coating on the surface of aluminum pigment;On the other hand, utilizing the difference of the reactivity of two isocyanate groups in IPDI, NC is grafted onto amino-containing POSS molecular chain.The modified aluminum pigment prepared by the method provided by the present invention has the characteristics of strong corrosion resistance, good metallic luster, high brightness, good compatibility, and is very suitable for being added to the high-gloss silver ink system to enhance the bright effect of the printed surface.

Description

Technical Field

[0001] The invention relates to the technical field of printing materials, and in particular to a functionalized cage-type oligomeric silsesquioxane-modified aluminum pigment for high-gloss silver ink and a preparation method thereof. Background Art

[0002] Aluminum pigment is a type of aluminum powder or aluminum paste with a silver-gray metallic luster. It has an "angle-dependent color" effect, good light reflection ability, high hiding power and shielding properties, and is widely used in printing inks, industrial coatings, automotive metallic paints and other fields. Dispersing aluminum pigments in an organic system to prepare metallic silver ink can make the printed images more noble and gorgeous and improve the product grade. However, aluminum pigments are easy to react with water, oxygen, etc., which reduces or loses their excellent properties. They have poor compatibility with resins, are difficult to disperse in the medium, and are easy to agglomerate, which greatly affects their application performance in printing inks.

[0003] As consumers' requirements for product packaging continue to increase, the performance requirements for aluminum pigments are also getting higher and higher, which are mainly reflected in the corrosion resistance, glitter, dispersibility, compatibility, etc. At present, coating modification is one of the most effective methods to improve the stability of aluminum pigments in corrosive media, including inorganic coating method, organic coating method and hybrid coating method.

[0004] Inorganic coating is represented by SiO2 coated aluminum pigment, which has the advantages of good corrosion resistance and wear resistance, but poor dispersibility, easy agglomeration, poor compatibility with film-forming materials, and significantly reduced gloss. Chinese patent CN108410216B invented a method of assembling dense film-coated flaky aluminum powder by two-step acid-base catalysis. The aluminum powder modified by this method can exist stably under high temperature and low pH conditions, but the inorganic coating layer makes the aluminum pigment dispersible and compatible, and the inorganic particles generated on the surface of the aluminum powder will also reduce the gloss of the pigment.

[0005] Organic coating method mainly uses coating polymer, usually by in-situ copolymerization, free radical polymerization and other effects, and the coating layer is mainly a single layer of polyacrylate resin or polystyrene resin. Because the secondary bond between the polymer and the surface of the aluminum pigment is weak, it is easy to fall off under strong shear environment, and it cannot bring a very stable protection effect to the aluminum pigment.

[0006] The hybrid coating method has the advantages of both organic and inorganic coatings, and provides a new idea for achieving effective coating and stable dispersion of aluminum pigments. Usually, tetraethyl orthosilicate and other organosilicon compounds are used as precursors, and are synergistically hydrolyzed in an alcohol-water solution containing a catalyst to form an organic-inorganic double-layer coating on the surface of the aluminum pigment by a sol-gel method. Chinese patent CN101580653B discloses that an aluminum powder pigment is used as the core, and a carbon-carbon double-bond organic siloxane polymer is synergistically hydrolyzed with tetraethyl orthosilicate to coat the surface of the aluminum powder pigment with an organic-inorganic hybrid nanofilm. This method can form a sufficient barrier to protect the flaky aluminum pigment from the influence of corrosive media, and can also take into account good dispersibility and resin compatibility, but the protective layer is prone to cracking and the aluminum pigment has low gloss. Summary of the invention

[0007] The invention provides a functionalized cage-type oligomeric silsesquioxane-modified aluminum pigment for high-gloss silver ink and a preparation method thereof, and aims to solve the problems existing in the background technology.

[0008] In order to achieve the above object, an embodiment of the present invention provides a method for preparing a functionalized cage-type oligomeric silsesquioxane-modified aluminum pigment for high-gloss silver ink, comprising the following steps:

[0009] S1, vacuum filtration of aluminum silver paste, soaking in solvent, stirring, standing, desolvation and then dispersing in solvent 1 to obtain aluminum pigment dispersion;

[0010] The raw materials such as isophorone diisocyanate (IPDI), bifunctional cage oligomeric silsesquioxane (POSS), nitrocellulose (NC), and ethyl acetate were dried and dehydrated;

[0011] S2, take the aluminum pigment dispersion and add it to a reaction vessel, place the reaction vessel in a water bath and stir under an inert gas protection, dropwise add catalyst 1 and the bifunctional POSS dispersion, and then, through a condensation reaction, vacuum filtration, cleaning and drying, prepare a bifunctional POSS coated aluminum pigment;

[0012] S3, dispersing the bifunctional POSS coated aluminum pigment in ethyl acetate, adding catalyst 2, and sequentially adding IPDI and NC dispersion dropwise, and grafting NC on the surface of the bifunctional POSS coated aluminum pigment through stepwise polymerization reaction;

[0013] S4, the material obtained in step S3 is precipitated, centrifuged, washed and dried to obtain a functionalized POSS modified aluminum pigment.

[0014] The present invention innovatively uses bifunctional POSS hybrid modified flaky aluminum pigment, uses isophorone diisocyanate (IPDI) as a bridge, and adopts a stepwise polymerization method to graft nitrocellulose (NC) to prepare a functionalized POSS modified aluminum pigment; the modified aluminum pigment prepared by the present invention has the characteristics of strong corrosion resistance, good metallic luster, high brightness, good compatibility, etc.

[0015] Furthermore, the pretreatment conditions of the aluminum-silver paste in step S1 are: soaking in solvent for 10 to 15 minutes, magnetically stirring at room temperature for 0.5 to 1 hour, standing for 30 minutes, and removing the solvent by vacuum filtration.

[0016] Furthermore, the aluminum-silver paste in step S1 is a nano-flaky aluminum paste made by a special electroplating process, and the aluminum-silver paste has a solid content of 5-15%, a particle size (D50) of 5-20 μm, and a thickness of 10-50 nm;

[0017] The first solvent is an alcohol ester solvent, usually one or more of methyl acetate, ethyl acetate, propyl acetate, butyl acetate, ethanol, and isopropanol;

[0018] The bifunctional POSS is a typical inorganic-organic hybrid hexahedral cage-type three-dimensional structure, having two reactive groups, hydroxyl and amino, and six inert groups, wherein the inert groups are alkanes or cycloalkanes of methyl, isobutyl or isooctyl groups;

[0019] The nitrogen content of the nitrocellulose is 11.8-12.3wt%;

[0020] The ratio of the aluminum-silver paste to the solvent one is 1 g:1 mL to 1 g:2 mL.

[0021] Furthermore, the condensation reaction conditions in step S2 are: water bath temperature 40-50° C., reaction time 2-3 h.

[0022] Furthermore, after the reaction in step S2 is stopped, the solid product is collected, washed with ethyl acetate for 3 times, and dried at 40° C. under vacuum conditions for 5 h.

[0023] Furthermore, in step S2, the inert gas is nitrogen; the catalyst is triethylamine or ethylenediamine, and the amount of the catalyst added is 0.1-2% of the total solid content;

[0024] The dispersion of the bifunctional POSS is formed by dispersing the bifunctional POSS in solvent one;

[0025] The mass ratio of the aluminum pigment to the bifunctional POSS is 1:2 to 2:1;

[0026] The ratio of the bifunctional POSS to the solvent one is 1 g:1 mL to 1 g:2 mL.

[0027] Furthermore, the stepwise polymerization reaction conditions in step S3 are as follows: adding catalyst 2, adding IPDI dispersion dropwise, reacting at 45-55° C. and N2 atmosphere for 1.5-2.5 hours; adding NC dispersion dropwise, reacting at 65-75° C. and N2 atmosphere for 1.5-2.5 hours; the IPDI dispersion and NC dispersion are IPDI and NC dispersed in ethyl acetate, respectively.

[0028] Furthermore, in step S3, the catalyst is dibutyltin dilaurate or stannous 2-ethylhexanoate, and the amount of the catalyst added is 0.1 to 2% of the total solid content;

[0029] The mass fractions of the IPDI, NC and bifunctional POSS coated aluminum pigment are 1-10%, 40-75% and 15-35% respectively; the volume fraction of the ethyl acetate is 20-40%.

[0030] Furthermore, the post-treatment conditions in step S4 are: adding n-hexane, collecting the solid precipitate and washing it three times with solvent one, and drying it at 40° C. under vacuum conditions for 5 h;

[0031] The volume fraction of n-hexane is 10-30%.

[0032] Based on a general concept of the invention, the present invention also provides a modified aluminum pigment obtained by the preparation method of the above-mentioned functionalized cage-type oligomeric silsesquioxane-modified aluminum pigment for high-gloss silver ink.

[0033] NC is one of the earliest and most widely used cellulose derivatives. It can be used as a film-forming aid for printing inks and coatings to improve the directional arrangement of metal pigments, shorten drying time, improve leveling, reduce shrinkage pits, etc., but it has poor heat resistance and poor compatibility with film-forming resins. The present invention proposes to use isophorone diisocyanate (IPDI) as a bridge, adopt a step-by-step polymerization method, and utilize the different reactivity of two isocyanate groups in IPDI to graft NC onto an amino-containing POSS molecular chain to prepare a functionalized POSS-modified aluminum pigment. The introduction of NC can improve the directional arrangement of aluminum pigments and improve metallic luster; the amino-containing POSS graft-modified NC also improves the heat resistance of NC and its compatibility with the main resin.

[0034] The above scheme of the present invention has the following beneficial effects:

[0035] The above scheme of the present invention is innovative in that bifunctional POSS is hybridized and modified into a thin flaky aluminum pigment, and a layer of organic-inorganic hybrid nanofilm is coated on the surface thereof. Since POSS has two reactive groups and six inert groups, the hybrid nanofilm is interwoven into a network structure in three-dimensional space, which weakens the blocking effect of the coating layer on light, so that the coated aluminum pigment retains a good metallic luster; the silicon hydroxyl group on the surface of POSS is bonded with the aluminum hydroxyl group on the surface of the flaky pigment to form a Si-O-Al bond, so that a firm coating layer is formed on the surface of the aluminum pigment; the organic chain segment on the inert group can improve the compatibility of the hybrid film with the resin system in the printing ink, and improve the adhesion of the ink.

[0036] When the modified aluminum pigment prepared by the method of the present invention is added to the ink system, due to the good compatibility of the functionalized POSS modified aluminum pigment with the film-forming resin, it can be well coated by the main resin to form a stable dispersion system, which has obvious significance for improving the corrosion resistance, metallic gloss, printability and dispersion stability of the silver ink, and can be widely used in the field of high-end printing. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0038] Figure 1 It is a flow chart for preparing the functionalized cage-type oligomeric silsesquioxane-modified aluminum pigment for high-gloss silver ink according to an embodiment of the present invention. DETAILED DESCRIPTION

[0039] In order to make the technical problems, technical solutions and advantages to be solved by the present invention more clear, a detailed description will be given below with reference to the accompanying drawings and specific embodiments.

[0040] Unless otherwise defined, all professional terms used below have the same meanings as those generally understood by those skilled in the art. The professional terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the scope of protection of the present invention.

[0041] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in the present invention can be purchased from the market or prepared by existing methods.

[0042] In view of the existing problems, the present invention provides a functionalized cage-type oligomeric silsesquioxane-modified aluminum pigment for high-gloss silver ink and a preparation method thereof.

[0043] A method for preparing a functionalized cage-type oligomeric silsesquioxane-modified aluminum pigment for high-gloss silver ink comprises the following steps:

[0044] S1, vacuum filtration of aluminum silver paste, soaking in solvent, stirring, standing, desolvation and then dispersing in solvent 1 to obtain aluminum pigment dispersion;

[0045] The raw materials such as isophorone diisocyanate (IPDI), bifunctional cage oligomeric silsesquioxane (POSS), nitrocellulose (NC), and ethyl acetate were dried and dehydrated;

[0046] S2, take the aluminum pigment dispersion and add it to a reaction vessel, place the reaction vessel in a water bath and stir under an inert gas protection, dropwise add catalyst 1 and the bifunctional POSS dispersion, and then, through a condensation reaction, vacuum filtration, cleaning and drying, prepare a bifunctional POSS coated aluminum pigment;

[0047] S3, dispersing the bifunctional POSS coated aluminum pigment in ethyl acetate, adding catalyst 2, and sequentially adding IPDI and NC dispersion dropwise, and grafting NC on the surface of the bifunctional POSS coated aluminum pigment through stepwise polymerization reaction;

[0048] S4, the material obtained in step S3 is precipitated, centrifuged, washed and dried to obtain a functionalized POSS modified aluminum pigment.

[0049] The present invention innovatively uses bifunctional POSS hybrid modified flaky aluminum pigment, uses isophorone diisocyanate (IPDI) as a bridge, and adopts a stepwise polymerization method to graft nitrocellulose (NC) to prepare a functionalized POSS modified aluminum pigment; the modified aluminum pigment prepared by the present invention has the characteristics of strong corrosion resistance, good metallic luster, high brightness, good compatibility, etc.

[0050] Furthermore, the pretreatment conditions of the aluminum-silver paste in step S1 are: soaking in solvent for 10 to 15 minutes, magnetically stirring at room temperature for 0.5 to 1 hour, standing for 30 minutes, and removing the solvent by vacuum filtration.

[0051] Furthermore, the aluminum-silver paste in step S1 is a nano-flaky aluminum paste made by a special electroplating process, and the aluminum-silver paste has a solid content of 5-15%, a particle size (D50) of 5-20 μm, and a thickness of 10-50 nm;

[0052] The first solvent is an alcohol ester solvent, usually one or more of methyl acetate, ethyl acetate, propyl acetate, butyl acetate, ethanol, and isopropanol;

[0053] The bifunctional POSS is a typical inorganic-organic hybrid hexahedral cage-type three-dimensional structure, having two reactive groups, hydroxyl and amino, and six inert groups, wherein the inert groups are alkanes or cycloalkanes of methyl, isobutyl or isooctyl groups;

[0054] The nitrogen content of the nitrocellulose is 11.8-12.3wt%;

[0055] The ratio of the aluminum-silver paste to the solvent one is 1 g:1 mL to 1 g:2 mL.

[0056] Furthermore, the condensation reaction conditions in step S2 are: water bath temperature 40-50° C., reaction time 2-3 h.

[0057] Furthermore, after the reaction in step S2 is stopped, the solid product is collected, washed with ethyl acetate for 3 times, and dried at 40° C. under vacuum conditions for 5 h.

[0058] Furthermore, in step S2, the inert gas is nitrogen; the catalyst is triethylamine or ethylenediamine, and the amount of the catalyst added is 0.1-2% of the total solid content;

[0059] The dispersion of the bifunctional POSS is formed by dispersing the bifunctional POSS in solvent one;

[0060] The mass ratio of the aluminum pigment to the bifunctional POSS is 1:2 to 2:1;

[0061] The ratio of the bifunctional POSS to the solvent one is 1 g:1 mL to 1 g:2 mL.

[0062] Furthermore, the stepwise polymerization reaction conditions in step S3 are as follows: adding catalyst 2, adding IPDI dispersion dropwise, reacting at 45-55° C. and N2 atmosphere for 1.5-2.5 hours; adding NC dispersion dropwise, reacting at 65-75° C. and N2 atmosphere for 1.5-2.5 hours; the IPDI dispersion and NC dispersion are IPDI and NC dispersed in ethyl acetate, respectively.

[0063] Furthermore, in step S3, the catalyst is dibutyltin dilaurate or stannous 2-ethylhexanoate, and the amount of the catalyst added is 0.1 to 2% of the total solid content;

[0064] The mass fractions of the IPDI, NC and bifunctional POSS coated aluminum pigment are 1-10%, 40-75% and 15-35% respectively; the volume fraction of the ethyl acetate is 20-40%.

[0065] Furthermore, the post-treatment conditions in step S4 are: adding n-hexane, collecting the solid precipitate and washing it three times with solvent one, and drying it at 40° C. under vacuum conditions for 5 h;

[0066] The volume fraction of n-hexane is 10-30%.

[0067] The following is explained by specific embodiments; Figure 1 The following is a flow chart of the preparation of the functionalized cage-type oligomeric silsesquioxane-modified aluminum pigment for high-gloss silver ink in the following embodiments.

[0068] Example 1

[0069] This embodiment provides a method for preparing a functionalized cage-type oligomeric silsesquioxane-modified aluminum pigment for high-gloss silver ink, comprising the following steps:

[0070] S1: 30 parts of aluminum silver paste were vacuum filtered, immersed in 45 parts of ethyl acetate for 10 minutes, magnetically stirred at room temperature for 1 hour and then allowed to stand for 30 minutes, vacuum filtered to remove the solvent and then dispersed in 45 parts of ethyl acetate to obtain an aluminum pigment dispersion; raw materials such as isophorone diisocyanate (IPDI), bifunctional cage oligomeric silsesquioxane (POSS), nitrocellulose (NC), and ethyl acetate were dried and dehydrated;

[0071] Among them, the aluminum-silver paste is a nano-thin sheet aluminum paste made by a special electroplating process, the solid content of the aluminum-silver paste is 10%, the particle size (D50) is 5 to 20 μm, and the thickness is 10 to 50 nm; the bifunctional POSS is a typical inorganic-organic hybrid hexahedral cage-type three-dimensional structure, with 1 hydroxyl group and 1 amino group, 2 methyl groups and 4 isobutyl groups; the nitrogen content of the nitrocellulose is 12.0wt%.

[0072] S2: Take 6 parts of the bifunctional POSS in step S1 and disperse them in 9 parts of ethyl acetate to obtain a bifunctional POSS dispersion; add the aluminum pigment dispersion in step S1 to a reaction container, place the reaction container in a 45°C water bath and stir under nitrogen protection, then add 0.01 parts of triethylamine dropwise and condense the bifunctional POSS dispersion for 2.5 hours. After the reaction stops, collect the solid product, wash the product with ethyl acetate 3 times, and dry it at 40°C under vacuum for 5 hours to prepare a bifunctional POSS coated aluminum pigment;

[0073] S3: Take 7 parts of the bifunctional POSS-coated aluminum pigment in step S2 and disperse them in 30 parts of ethyl acetate, add 0.02 parts of dibutyltin dilaurate, add ethyl acetate dispersion containing 1 part of IPDI dropwise, and react at 50°C and N2 atmosphere for 2 hours; add ethyl acetate dispersion containing 12 parts of NC dropwise, and react at 70°C and N2 atmosphere for 2 hours. Through stepwise polymerization reaction, NC is grafted on the surface of the bifunctional POSS-coated aluminum pigment;

[0074] The volume fraction of ethyl acetate is 40%.

[0075] S4: adding n-hexane to the material obtained in step S3, collecting the solid precipitate and washing it with ethyl acetate for 3 times, and drying it at 40° C. under vacuum conditions for 5 h to obtain a functionalized POSS-modified aluminum pigment.

[0076] The volume fraction of n-hexane is 30%.

[0077] S5: Take 5 parts of the functionalized POSS modified aluminum pigment in step S4, 5 parts of NC resin, 15 parts of thermoplastic acrylic resin, 50 parts of propyl acetate and 25 parts of ethyl acetate, mix and stir evenly at room temperature to obtain silver ink, and then print it on imitation glass cardboard through a gravure suitability tester, and obtain a metallic glitter ink film after natural evaporation and drying.

[0078] Example 2

[0079] This embodiment provides a method for preparing a functionalized cage-type oligomeric silsesquioxane-modified aluminum pigment for high-gloss silver ink, comprising the following steps:

[0080] S1: 60 parts of aluminum silver paste are vacuum filtered, immersed in 60 parts of propyl acetate for 15 minutes, magnetically stirred at room temperature for 30 minutes, and then allowed to stand for 30 minutes, vacuum filtered to remove the solvent, and then dispersed in 60 parts of propyl acetate to obtain an aluminum pigment dispersion; raw materials such as isophorone diisocyanate (IPDI), bifunctional cage oligomeric silsesquioxane (POSS), nitrocellulose (NC), and ethyl acetate are dried and dehydrated;

[0081] Among them, the aluminum-silver paste is a nano-thin sheet aluminum paste made by a special electroplating process, the solid content of the aluminum-silver paste is 5%, the particle size (D50) is 5 to 20 μm, and the thickness is 10 to 50 nm; the bifunctional POSS is a typical inorganic-organic hybrid hexahedral cage-type three-dimensional structure, with 1 hydroxyl group and 1 amino group, 3 methyl groups and 3 isooctyl groups; the nitrogen content of the nitrocellulose is 11.8wt%.

[0082] S2: Take 3 parts of the bifunctional POSS in step S1 and disperse them in 3 parts of propyl acetate to obtain a bifunctional POSS dispersion; add the aluminum pigment dispersion in step S1 to a reaction container, place the reaction container in a 40°C water bath and stir under nitrogen protection, then add 0.12 parts of ethylenediamine dropwise and condense the bifunctional POSS dispersion for 3 hours. After the reaction stops, collect the solid product, wash the product with ethyl acetate 3 times, and dry it at 40°C under vacuum for 5 hours to prepare a bifunctional POSS coated aluminum pigment;

[0083] S3: Take 5 parts of the bifunctional POSS-coated aluminum pigment in step S2 and disperse them in 20 parts of ethyl acetate, add 0.46 parts of stannous 2-ethylhexanoate, add ethyl acetate dispersion containing 1.5 parts of IPDI dropwise, and react at 45°C and N2 atmosphere for 2.5 hours; add ethyl acetate dispersion containing 16.5 parts of NC dropwise, and react at 65°C and N2 atmosphere for 2.5 hours. Through stepwise polymerization reaction, NC is grafted on the surface of the bifunctional POSS-coated aluminum pigment;

[0084] The volume fraction of ethyl acetate is 30%.

[0085] S4: n-hexane is added to the material obtained in step S3, the solid precipitate is collected and washed with propyl acetate for 3 times, and dried at 40° C. under vacuum conditions for 5 h to obtain a functionalized POSS-modified aluminum pigment.

[0086] The volume fraction of n-hexane is 20%.

[0087] S5: Take 5 parts of the functionalized POSS modified aluminum pigment in step S4, 5 parts of NC resin, 15 parts of thermoplastic acrylic resin, 50 parts of propyl acetate and 25 parts of ethyl acetate, mix and stir evenly at room temperature to obtain silver ink, and then print it on imitation glass cardboard through a gravure suitability tester, and obtain a metallic glitter ink film after natural evaporation and drying.

[0088] Example 3

[0089] This embodiment provides a method for preparing a functionalized cage-type oligomeric silsesquioxane-modified aluminum pigment for high-gloss silver ink, comprising the following steps:

[0090] S1: Take 40 parts of aluminum silver paste and vacuum filter it, soak it in 80 parts of a mixed solvent of propyl acetate and isopropanol (V 醋酸丙酯 :V 异丙醇 =10:1) for 12 minutes, magnetically stirred at room temperature for 40 minutes and then allowed to stand for 30 minutes, vacuum filtered to remove the solvent and then dispersed in 80 parts of a mixed solvent to obtain an aluminum pigment dispersion; drying and dehydrating raw materials such as isophorone diisocyanate (IPDI), bifunctional cage oligomeric silsesquioxane (POSS), nitrocellulose (NC), and ethyl acetate;

[0091] Among them, the aluminum-silver paste is a nano-flake aluminum paste made by a special electroplating process, the solid content of the aluminum-silver paste is 15%, the particle size (D50) is 5 to 20 μm, and the thickness is 10 to 50 nm; the bifunctional POSS is a typical inorganic-organic hybrid hexahedral cage-type three-dimensional structure, with 1 hydroxyl group and 1 amino group, 5 methyl groups and 1 cyclopentyl group; the nitrogen content of the nitrocellulose is 12.3wt%.

[0092] S2: Disperse 3 parts of the bifunctional POSS in step S1 in 6 parts of a mixed solvent (V propyl acetate and isopropanol) 醋酸丙酯 :V 异丙醇 =10:1) to obtain a bifunctional POSS dispersion; add the aluminum pigment dispersion in step S1 to a reaction container, place the reaction container in a 50°C water bath and stir under nitrogen protection, then dropwise add 0.09 parts of triethylamine and the bifunctional POSS dispersion to condense for 2 hours. After the reaction stops, collect the solid product, wash the product 3 times with ethyl acetate, and dry it at 40°C under vacuum for 5 hours to prepare a bifunctional POSS coated aluminum pigment;

[0093] S3: Take 6 parts of the bifunctional POSS-coated aluminum pigment in step S2 and disperse them in 20 parts of ethyl acetate, add 0.4 parts of dibutyltin dilaurate, add ethyl acetate dispersion containing 4 parts of IPDI dropwise, and react at 75°C and N2 atmosphere for 1.5 hours; add ethyl acetate dispersion containing 30 parts of NC dropwise, and react at 55°C and N2 atmosphere for 1.5 hours. Through stepwise polymerization reaction, NC is grafted on the surface of the bifunctional POSS-coated aluminum pigment;

[0094] The volume fraction of ethyl acetate is 20%.

[0095] S4: adding n-hexane to the material obtained in step S3, collecting the solid precipitate and rinsing it with a mixed solvent of propyl acetate and isopropanol (V 醋酸丙酯 :V 异丙醇 =10:1) for three times, and dried at 40°C under vacuum conditions for 5 h to obtain a functionalized POSS modified aluminum pigment.

[0096] The volume fraction of n-hexane is 10%.

[0097] S5: Take 5 parts of the functionalized POSS modified aluminum pigment in step S4, 5 parts of NC resin, 15 parts of thermoplastic acrylic resin, 50 parts of propyl acetate and 25 parts of ethyl acetate, mix and stir evenly at room temperature to obtain silver ink, and then print it on imitation glass cardboard through a gravure suitability tester, and obtain a metallic glitter ink film after natural evaporation and drying.

[0098] The functionalized POSS modified aluminum pigment prepared in Examples 1-3 of the present invention was stored in an acid solution of pH=1 and an alkaline solution of pH=11 at room temperature for 2 months, respectively. No H2 was produced, and the apparent color of the aluminum pigment did not change significantly. However, commercially available aluminum powder pigment (such as Zuxing ZC905) produced a large amount of H2 when stored in an alkaline solution of pH=9 for 15 days at room temperature or in an acid solution of pH=1 for 5 days at room temperature, and the appearance color gradually turned to grayish white. Under microscopic observation, the surface of the prepared aluminum pigment particles was coated with a dense film, which further confirmed that the functionalized cage-type low-silicon siloxane-modified aluminum pigment for high-gloss silver ink of the present invention has good acid and alkali resistance and good storage stability.

[0099] Comparative Example 1

[0100] Take 50 parts of uncoated modified aluminum silver paste raw material (solid content = 10%), 5 parts of NC resin, 15 parts of thermoplastic acrylic resin, 5 parts of propyl acetate and 25 parts of ethyl acetate, mix and stir evenly at room temperature to obtain silver ink, and then print it on imitation glass cardboard through a gravure suitability tester, and obtain a metallic glitter ink film after natural evaporation and drying.

[0101] Comparative Example 2

[0102] Take 50 parts of commercially available electroplating silver paste (ZE8108, solid content = 10%), 5 parts of NC resin, 15 parts of thermoplastic acrylic resin, 50 parts of propyl acetate and 25 parts of ethyl acetate, mix and stir evenly at room temperature to obtain silver ink, and then print it on imitation glass cardboard through a gravure suitability tester, and obtain a metallic glitter ink film after natural evaporation and drying.

[0103] The silver ink and metallic flash ink films prepared in the above comparative examples 1 and 2 were respectively compared with those prepared in examples 1 to 3:

[0104] Storage stability test: Store the silver ink in a sealed container at room temperature for one month and observe whether there is visible stratification, agglomeration, or sinking to the bottom.

[0105] Gloss test: Use a gloss meter to test at an incident angle of 20°, and take the average value of three measurements. Use a polished black glass plate with a refractive index of 1.567 as a gloss standard.

[0106] Brightness test: Use an integrating sphere spectrophotometer to test the brightness of the ink film, that is, record the brightness value L under the mirror reflection mode, and take the average value of three measurements.

[0107] Adhesion fastness test: stick 3M tape on the ink film, flatten it with your fingers or rubber to avoid wrinkling the tape and substrate, then tear off the tape at 180 degrees. The adhesion fastness is expressed by the proportion of the ink falling area on the sample. Take the average value of three measurements.

[0108] Table 1 Performance test of different types of aluminum pigments used in inks

[0109]

[0110] The storage stability test results in Table 1 show that the functionalized cage-type oligomeric silsesquioxane-modified aluminum pigment silver ink of the present invention has no obvious change after storage for one month, indicating that the compatibility between the components of the ink system is better and the stability of the silver ink is better; the gloss and brightness test results show that the gloss and brightness of the ink film of the functionalized cage-type oligomeric silsesquioxane-modified aluminum pigment ink of the present invention are 95% to 100% and 96% to 100% of the uncoated modified aluminum pigment ink film, respectively, and are much higher than the commercially available electroplated silver paste ink film, indicating that the functionalized POSS modified aluminum pigment can well maintain the brightness of the original aluminum pigment; the adhesion fastness test results show that the adhesion fastness of the ink film of the functionalized cage-type oligomeric silsesquioxane-modified aluminum pigment ink of the present invention is significantly better than that of the uncoated modified aluminum pigment and the commercially available electroplated silver paste ink film.

[0111] The above is a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for preparing a functionalized cage-type oligomeric silsesquioxane-modified aluminum pigment for high-gloss silver ink, characterized in that: The steps include: S1: vacuum filtration of aluminum silver paste, soaking in solvent, stirring, standing, desolvation and then dispersing in solvent 1 to obtain aluminum pigment dispersion; The isophorone diisocyanate IPDI, the bifunctional cage-type oligomeric silsesquioxane POSS, the nitrocellulose NC and the ethyl acetate were dried and dehydrated; S2: adding the aluminum pigment dispersion into a reaction container, placing the reaction container in a water bath and stirring under the protection of an inert gas, adding the catalyst 1 and the dispersion of the bifunctional POSS dropwise, and performing a condensation reaction, vacuum filtering, washing, and drying to prepare a bifunctional POSS-coated aluminum pigment; S3: dispersing the bifunctional POSS-coated aluminum pigment in the ethyl acetate, adding catalyst 2, and sequentially adding IPDI dispersion and NC dispersion dropwise, and grafting NC on the surface of the bifunctional POSS-coated aluminum pigment through stepwise polymerization reaction; S4: The material obtained in step S3 is precipitated, centrifuged, washed and dried to obtain a functionalized POSS modified aluminum pigment; The first solvent is an alcohol ester solvent, and one or more of methyl acetate, ethyl acetate, propyl acetate, butyl acetate, ethanol, and isopropanol are selected; The bifunctional POSS is a typical inorganic-organic hybrid hexahedral cage-type three-dimensional structure, having two reactive groups, hydroxyl and amino, and six inert groups, wherein the inert groups are alkanes or cycloalkanes of methyl, isobutyl or isooctyl groups; The catalyst 1 is triethylamine or ethylenediamine; The second catalyst is dibutyltin dilaurate or stannous 2-ethylhexanoate; The dispersion of the bifunctional POSS is formed by dispersing the bifunctional POSS in a solvent 1; The condensation reaction conditions in step S2 are: water bath temperature 40-50° C., reaction time 2-3 h; The IPDI dispersion and the NC dispersion are IPDI and NC dispersed in ethyl acetate respectively; The stepwise polymerization reaction conditions in step S3 are: adding catalyst 2, adding IPDI dispersion dropwise, reacting at 45-55° C. and N2 atmosphere for 1.5-2.5 hours; adding NC dispersion dropwise, reacting at 65-75° C. and N2 atmosphere for 1.5-2.5 hours.

2. The preparation method according to claim 1, characterized in that: The pretreatment conditions of the aluminum-silver paste in step S1 are: soaking in solvent 1 for 10 to 15 minutes, magnetically stirring at room temperature for 0.5 to 1 hour, standing for 30 minutes, and removing the solvent by vacuum filtration.

3. The preparation method according to claim 1, characterized in that: The aluminum paste in step S1 is a nano-thin sheet aluminum paste made by a special electroplating process, the aluminum paste has a solid content of 5-15%, a particle size (D50) of 5-20 μm, and a thickness of 10-50 nm; the nitrogen content of the nitrocellulose is 11.8-12.3 wt%; The ratio of the aluminum-silver paste to the solvent one is 1 g:1 mL to 1 g:2 mL.

4. The preparation method according to claim 1, characterized in that: After the reaction in step S2 is stopped, the solid product is collected, washed with ethyl acetate three times, and dried at 40° C. under vacuum conditions for 5 h.

5. The preparation method according to claim 1, characterized in that: In step S2, the inert gas is nitrogen; the amount of the catalyst 1 added is 0.1-2% of the total solid content; the mass ratio of the aluminum pigment to the bifunctional POSS is 1:2-2:1; The ratio of the bifunctional POSS to the solvent one is 1 g:1 mL to 1 g:2 mL.

6. The preparation method according to claim 1, characterized in that: In step S3, the mass fractions of IPDI, NC, and bifunctional POSS coated aluminum pigment are 1-10%, 40-75%, and 15-35%, respectively; The volume fraction of the ethyl acetate is 20-40%.

7. The preparation method according to claim 1, characterized in that: The amount of catalyst 2 added in step S3 is 0.1% to 2% of the total solid content.

8. The preparation method according to claim 1, characterized in that: The specific steps of post-treatment in step S4 are: adding n-hexane, collecting the solid precipitate and washing it with solvent one three times, and drying it at 40° C. under vacuum conditions for 5 hours; The volume fraction of n-hexane is 10-30%.

9. A functionalized cage-type oligomeric silsesquioxane-modified aluminum pigment for high-gloss silver ink obtained by the preparation method according to any one of claims 1 to 8.

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