CN116285432A - Functionalized cage-type oligomeric silsesquioxane modified aluminum pigment for high-brightness silver ink and preparation method thereof - Google Patents

Abstract

The invention provides a functionalized cage-type oligomeric silsesquioxane modified aluminum pigment for high-brightness silver ink and a preparation method thereof. The modified flake-shaped aluminum pigment is coated with bifunctional POSS, and isophorone Diisocyanate (IPDI) is the bridge, grafted with nitrocellulose (NC). On the one hand, the hydroxyl-containing POSS bonds with the aluminum hydroxyl groups on the surface of the flake aluminum powder to form an Al-O-Si bond, making it form a firm coating on the surface of the aluminum pigment; on the other hand, using two isocyanate groups in IPDI Based on the difference in group reactivity, NC was grafted onto the amino group-containing POSS molecular chain. The modified aluminum pigment prepared by the method provided by the invention has the characteristics of strong corrosion resistance, good metallic luster, high brightness, and good compatibility, and is very suitable for adding it to the high-gloss silver ink system to enhance the surface of printed products bright effect.

Description

A kind of functionalized cage type oligomeric silsesquioxane modified aluminum pigment for high brightness silver ink and its preparation method

technical field

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

Background technique

Aluminum pigment is a kind of metal aluminum powder or aluminum paste with silver-gray metallic luster. It has "angle-dependent" effect, good light reflection ability, high hiding and shielding properties, etc. It is widely used in printing inks and industrial coatings , automotive metal paint and other fields. Dispersing aluminum pigments in an organic system to prepare metallic silver ink can make the printed graphics more noble and gorgeous and improve the product grade. However, aluminum pigments are easy to react with water and oxygen, resulting in the reduction or loss of their excellent properties, poor compatibility with resins, difficulty in dispersing in media, and easy agglomeration, which also greatly affect their application performance in printing inks.

With the continuous improvement of consumers' requirements for commodity packaging, the performance requirements of aluminum pigments are also getting higher and higher, which is mainly reflected in the corrosion resistance, sparkle, dispersibility, and compatibility of aluminum pigments. At present, coating modification is one of the most effective methods to improve the stability of aluminum pigments in corrosive media, including inorganic coating, organic coating and hybrid coating.

Inorganic substance coating is represented by SiO ₂ coated aluminum pigment, which has the advantages of good corrosion resistance and wear resistance, but its dispersion is poor, easy to agglomerate, poor compatibility with film-forming substances, and gloss is significantly reduced. Chinese patent CN108410216B invented a method of assembling a dense film-coated flake aluminum powder by an acid-base two-step catalysis method. The aluminum powder modified by this method can exist stably at higher temperature and lower pH conditions, but the inorganic The coating layer makes the dispersibility and compatibility of the aluminum pigment poor, and the inorganic particles generated on the surface of the aluminum powder will also reduce the gloss of the pigment.

The organic coating method is mainly based on coating polymers, usually by in-situ copolymerization, free radical polymerization, etc., and the coating layer is mainly single-layer polyacrylate resin or polystyrene resin. Since the secondary bonding force between the polymer and the surface of the aluminum pigment is weak, it is easy to fall off in a strong shear environment, and cannot bring a very stable protective effect to the aluminum pigment.

The hybrid coating method has both the advantages of organic/inorganic coating, which provides a new idea for the effective coating and stable dispersion of aluminum pigments. Usually, tetraethyl orthosilicate and other organosilicon compounds are used as precursors, hydrolyzed in an aqueous alcohol solution containing a catalyst, and an organic-inorganic double-layer coating is formed on the surface of the aluminum pigment by a sol-gel method. Chinese patent CN101580653B discloses that the aluminum powder pigment is used as the core, and the carbon-carbon double bond organosiloxane polymer is hydrolyzed synergistically with ethyl orthosilicate, and a layer of organic-inorganic hybrid nano film is coated on the surface of the aluminum powder pigment. 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 dispersion and resin compatibility, but the protective layer is easy to crack and the gloss of the aluminum pigment is low.

Contents of the invention

The invention provides a functionalized cage-type oligosilsesquioxane-modified aluminum pigment for high-brightness silver ink and a preparation method thereof, aiming at solving the problems existing in the background technology.

In order to achieve the above object, the embodiments of the present invention provide a method for preparing a functionalized cage-type oligomeric silsesquioxane-modified aluminum pigment for high-brightness silver ink, comprising the following steps:

S1. Take the aluminum-silver paste and vacuum filter it, and disperse it in solvent one after soaking in a solvent, stirring, standing, and desolventizing to obtain an aluminum pigment dispersion;

Dry and remove water from raw materials such as isophorone diisocyanate (IPDI), difunctional cage oligomeric silsesquioxane (POSS), nitrocellulose (NC), and ethyl acetate;

S2. Take the aluminum pigment dispersion and add it to a reaction container, place the reaction container in a water bath and stir under the protection of an inert gas, add the catalyst one and the bifunctional POSS dispersion liquid dropwise, and conduct a condensation reaction , after vacuum filtration, cleaning and drying, the bifunctional POSS-coated aluminum pigment is prepared;

S3. Disperse the bifunctional POSS-coated aluminum pigment in ethyl acetate, add catalyst 2, add IPDI and NC dispersion solution drop by drop in turn, through gradual polymerization, contact the surface of the bifunctional POSS-coated aluminum pigment Branch NC;

S4. Precipitate, centrifuge, wash and dry the material obtained in step S3 to obtain a functionalized POSS modified aluminum pigment.

In the present invention, a difunctional POSS hybrid modified flake-shaped aluminum pigment is pioneered, and using isophorone diisocyanate (IPDI) as a bridge, a stepwise polymerization method is adopted to graft nitrocellulose (NC) to prepare a functionalized POSS modification. permanent 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 and the like.

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

Further, the aluminum-silver paste in the step S1 is a nano-flake aluminum paste made by a special electroplating process, the solid content of the aluminum-silver paste is 5-15%, and the particle size (D50) is 5-20 μm. The thickness is 10-50nm;

Described solvent one is alcohol ester solvent, usually selects one or more in methyl acetate, ethyl acetate, propyl acetate, butyl acetate, ethanol, isopropanol;

The bifunctional POSS is a typical inorganic-organic hybrid hexahedral cage three-dimensional structure, with two reactive groups of hydroxyl and amino groups, and six inert groups, the inert groups are methyl, isobutyl or isooctyl alkanes or naphthenes;

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

The ratio of the aluminum-silver paste to the solvent 1 is 1g:1mL˜1g:2mL.

Further, the condensation reaction conditions in the step S2 are: the temperature of the water bath is 40-50° C., and the reaction time is 2-3 hours.

Further, 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 for 5 h.

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

The dispersion of the bifunctional POSS is formed by dispersing the bifunctional POSS in a solvent;

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

The ratio of the bifunctional POSS to solvent 1 is 1g:1mL˜1g:2mL.

Further, the stepwise polymerization reaction conditions in the step S3 are: add catalyst 2, add IPDI dispersion liquid dropwise, react at 45-55°C under _N2 atmosphere for 1.5-2.5h; add NC dispersion liquid dropwise, at 65 ~75°C and N ₂ atmosphere for 1.5~2.5h; the IPDI dispersion and NC dispersion are respectively IPDI and NC dispersed in ethyl acetate.

Further, the catalyst in the step S3 is dibutyl tin dilaurate or 2-ethyl stannous hexanoate, and the amount of the catalyst added is 0.1-2% of the total solid content;

The mass fractions of the IPDI, NC, and bifunctional POSS-coated aluminum pigments are 1-10%, 40-75%, and 15-35% in sequence; the volume fraction of the ethyl acetate is 20-40%.

Further, the post-treatment conditions in step S4 are as follows: add n-hexane, collect the solid precipitate and wash it with a solvent for 3 times, and dry it at 40° C. under vacuum for 5 hours;

The volume fraction of the n-hexane is 10-30%.

Based on a general idea 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-brightness silver ink.

NC is the earliest and most widely used cellulose derivative. It can be used as a film-forming aid for printing inks and coatings to improve the alignment of metallic pigments, shorten drying time, improve leveling, and reduce shrinkage pits. However, it has poor heat resistance and poor compatibility with film-forming resins. The present invention proposes to use isophorone diisocyanate (IPDI) as a bridge, adopts a stepwise polymerization method, utilizes the difference in reactivity of two isocyanate groups in IPDI, and grafts NC onto POSS molecular chains containing amino groups to prepare functionalized POSS modified aluminum pigment. The introduction of NC can improve the alignment of aluminum pigments and enhance the metallic luster; the amino group-containing POSS graft modified NC also improves the heat resistance of NC and the compatibility with the host resin.

Said scheme of the present invention has following beneficial effect:

The above scheme of the present invention innovatively uses bifunctional POSS hybrid modified flaky aluminum pigment, and coats a layer of organic-inorganic hybrid nano film on its surface. Because POSS has 2 reactive groups and 6 inert groups, the hybrid nano-membrane interweaves into a network structure in three-dimensional space, which weakens the blocking effect of the coating layer on light and makes the coated aluminum pigment better retained. metallic luster; the silicon hydroxyl groups on the surface of POSS bond with the aluminum hydroxyl groups on the surface of flake pigments to form Si-O-Al bonds, making it form a firm coating on the surface of aluminum pigments; the organic segments on the inert groups can improve The compatibility of the hybrid film with the resin system in the printing ink improves the adhesion of the ink.

When the modified aluminum pigment prepared by the method of the present invention is added to the ink system, due to the good compatibility between the functionalized POSS modified aluminum pigment and the film-forming resin, it can be better covered by the main resin to form a stable dispersion The system has obvious significance for improving the corrosion resistance, metallic luster, printability and dispersion stability of silver ink, and can be widely used in high-end printing fields.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the accompanying drawings required in the embodiments. Obviously, the accompanying drawings in the following description are only some of the present invention. Embodiments, for those of ordinary skill in the art, other drawings can also be obtained based on these drawings without any creative effort.

Fig. 1 is a flow chart of the preparation of functionalized cage-type oligomeric silsesquioxane-modified aluminum pigments for high-brightness silver ink according to an embodiment of the present invention.

Detailed ways

In order to make the technical problems, technical solutions and advantages to be solved by the present invention clearer, the following will describe in detail with reference to the drawings and specific embodiments.

Unless otherwise defined, all technical terms used hereinafter have the same meanings as commonly understood by those skilled in the art. The terminology used herein is only for the purpose of describing specific embodiments, and is not intended to limit the protection scope of the present invention.

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.

Aiming at the existing problems, the invention provides a functionalized cage-type oligomeric silsesquioxane-modified aluminum pigment for high-brightness silver ink and a preparation method thereof.

A kind of preparation method of functionalized cage type oligomeric silsesquioxane modified aluminum pigment for high brightness silver ink, comprises the following steps:

S1. Take the aluminum-silver paste and vacuum filter it, and disperse it in solvent one after soaking in a solvent, stirring, standing, and desolventizing to obtain an aluminum pigment dispersion;

Dry and remove water from raw materials such as isophorone diisocyanate (IPDI), difunctional cage oligomeric silsesquioxane (POSS), nitrocellulose (NC), and ethyl acetate;

S2. Take the aluminum pigment dispersion and add it to a reaction container, place the reaction container in a water bath and stir under the protection of an inert gas, add the catalyst one and the bifunctional POSS dispersion liquid dropwise, and conduct a condensation reaction , after vacuum filtration, cleaning and drying, the bifunctional POSS-coated aluminum pigment is prepared;

S3. Disperse the bifunctional POSS-coated aluminum pigment in ethyl acetate, add catalyst 2, add IPDI and NC dispersion solution drop by drop in turn, through gradual polymerization, contact the surface of the bifunctional POSS-coated aluminum pigment Branch NC;

S4. Precipitate, centrifuge, wash and dry the material obtained in step S3 to obtain a functionalized POSS modified aluminum pigment.

In the present invention, a difunctional POSS hybrid modified flake-shaped aluminum pigment is pioneered, and using isophorone diisocyanate (IPDI) as a bridge, a stepwise polymerization method is adopted to graft nitrocellulose (NC) to prepare a functionalized POSS modification. permanent 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 and the like.

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

Further, the aluminum-silver paste in the step S1 is a nano-flake aluminum paste made by a special electroplating process, the solid content of the aluminum-silver paste is 5-15%, and the particle size (D50) is 5-20 μm. The thickness is 10-50nm;

Described solvent one is alcohol ester solvent, usually selects one or more in methyl acetate, ethyl acetate, propyl acetate, butyl acetate, ethanol, isopropanol;

The bifunctional POSS is a typical inorganic-organic hybrid hexahedral cage three-dimensional structure, with two reactive groups of hydroxyl and amino groups, and six inert groups, the inert groups are methyl, isobutyl or isooctyl alkanes or naphthenes;

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

The ratio of the aluminum-silver paste to the solvent 1 is 1g:1mL˜1g:2mL.

Further, the condensation reaction conditions in the step S2 are: the temperature of the water bath is 40-50° C., and the reaction time is 2-3 hours.

Further, 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 for 5 h.

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

The dispersion of the bifunctional POSS is formed by dispersing the bifunctional POSS in a solvent;

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

The ratio of the bifunctional POSS to solvent 1 is 1g:1mL˜1g:2mL.

Further, the stepwise polymerization reaction conditions in the step S3 are: add catalyst 2, add IPDI dispersion liquid dropwise, react at 45-55°C under _N2 atmosphere for 1.5-2.5h; add NC dispersion liquid dropwise, at 65 ~75°C and N ₂ atmosphere for 1.5~2.5h; the IPDI dispersion and NC dispersion are respectively IPDI and NC dispersed in ethyl acetate.

Further, the catalyst in the step S3 is dibutyl tin dilaurate or 2-ethyl stannous hexanoate, and the amount of the catalyst added is 0.1-2% of the total solid content;

The mass fractions of the IPDI, NC, and bifunctional POSS-coated aluminum pigments are 1-10%, 40-75%, and 15-35% in sequence; the volume fraction of the ethyl acetate is 20-40%.

Further, the post-treatment conditions in step S4 are as follows: add n-hexane, collect the solid precipitate and wash it with a solvent for 3 times, and dry it at 40° C. under vacuum for 5 hours;

The volume fraction of the n-hexane is 10-30%.

The following is explained by specific examples; FIG. 1 is a flow chart of preparation of functionalized cage-type oligomeric silsesquioxane-modified aluminum pigments for high-brightness silver ink in the following examples.

Example 1

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

S1: Take 30 parts of aluminum-silver slurry for vacuum filtration, soak in 45 parts of ethyl acetate for 10 minutes, stir magnetically at room temperature for 1 hour and then let it stand for 30 minutes, vacuum filter and remove the solvent, then disperse in 45 parts of ethyl acetate, Obtain an aluminum pigment dispersion; dry and remove water from raw materials such as isophorone diisocyanate (IPDI), bifunctional cage oligomeric silsesquioxane (POSS), nitrocellulose (NC), and ethyl acetate;

Wherein, 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 10%, the particle size (D50) is 5-20 μm, and the thickness is 10-50 nm; The bifunctional POSS is a typical inorganic-organic hybrid hexahedral cage 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 12.0 wt%.

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 the reaction vessel, and place the reaction vessel at 45°C Stir in a water bath under the protection of nitrogen, then add 0.01 part of triethylamine dropwise and condense with the bifunctional POSS dispersion for 2.5 hours. After the reaction was stopped, the solid product was collected, washed with ethyl acetate for 3 times, and dried at 40° C. under vacuum for 5 hours to prepare a bifunctional POSS-coated aluminum pigment;

S3: Take 7 parts of the bifunctional POSS-coated aluminum pigment in step S2 and disperse it in 30 parts of ethyl acetate, add 0.02 parts of dibutyltin dilaurate, add dropwise the ethyl acetate dispersion containing 1 part of IPDI, React for 2 hours at 50°C under N ₂ atmosphere; add dropwise an ethyl acetate dispersion containing 12 parts of NC, and react for 2 hours at 70°C under N ₂ atmosphere. Grafting NC on the surface of bifunctional POSS-coated aluminum pigments through stepwise polymerization;

Wherein, the volume fraction of ethyl acetate is 40%.

S4: Add n-hexane to the material obtained in step S3, collect the solid precipitate, wash it with ethyl acetate three times, and dry it at 40°C for 5 hours under vacuum to obtain a functionalized POSS modified aluminum pigment.

Wherein the volume fraction of n-hexane is 30%.

S5: Take 5 parts of functionalized POSS modified aluminum pigments 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 at room temperature to obtain silver ink , and then printed on imitation glass cardboard through the gravure suitability tester, and obtained the metallic glitter ink film after natural volatilization and drying.

Example 2

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

S1: Take 60 parts of aluminum-silver paste for vacuum filtration, soak in 60 parts of propyl acetate for 15 minutes, stir magnetically at room temperature for 30 minutes, then let it stand for 30 minutes, vacuum filter and remove the solvent, and disperse in 60 parts of propyl acetate, Obtain an aluminum pigment dispersion; dry and remove water from raw materials such as isophorone diisocyanate (IPDI), bifunctional cage oligomeric silsesquioxane (POSS), nitrocellulose (NC), and ethyl acetate;

Wherein, 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 5%, the particle size (D50) is 5-20 μm, and the thickness is 10-50 nm; The bifunctional POSS is a typical inorganic-organic hybrid hexahedral cage 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 11.8 wt%.

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 the reaction vessel, and place the reaction vessel at 40°C Stir in a water bath under the protection of nitrogen, and then add 0.12 parts of ethylenediamine and the bifunctional POSS dispersion dropwise for condensation reaction for 3 hours. After the reaction was stopped, the solid product was collected, washed with ethyl acetate for 3 times, and dried at 40° C. under vacuum for 5 hours to prepare a bifunctional POSS-coated aluminum pigment;

S3: Take 5 parts of the bifunctional POSS-coated aluminum pigment in step S2 and disperse it in 20 parts of ethyl acetate, add 0.46 parts of 2-ethyl stannous hexanoate, and add dropwise the ethyl acetate dispersion containing 1.5 parts of IPDI , reacted at 45°C under N ₂ atmosphere for 2.5h; added dropwise an ethyl acetate dispersion containing 16.5 parts of NC, and reacted at 65°C under N ₂ atmosphere for 2.5h. Grafting NC on the surface of bifunctional POSS-coated aluminum pigments through stepwise polymerization;

Wherein, the volume fraction of ethyl acetate is 30%.

S4: Add n-hexane to the material obtained in step S3, collect the solid precipitate and wash it with propyl acetate for 3 times, and dry it at 40° C. for 5 hours under vacuum to obtain the functionalized POSS modified aluminum pigment.

Wherein the volume fraction of n-hexane is 20%.

S5: Take 5 parts of functionalized POSS modified aluminum pigments 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 at room temperature to obtain silver ink , and then printed on imitation glass cardboard through the gravure suitability tester, and obtained the metallic glitter ink film after natural volatilization and drying.

Example 3

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

S1: Take 40 parts of aluminum silver slurry for vacuum filtration, soak in 80 parts of a mixed solvent of propyl acetate and isopropanol (V _{propyl acetate} : V _isopropanol = 10:1) for 12 minutes, and magnetically stir at room temperature for 40 Stand still for 30 minutes after 30 minutes, be dispersed in 80 parts of mixed solvents after vacuum filtration desolvation, obtain aluminum pigment dispersion; POSS), nitrocellulose (NC), ethyl acetate and other raw materials are dried and dewatered;

Wherein, 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 5-20 μm, and the thickness is 10-50 nm; The bifunctional POSS is a typical inorganic-organic hybrid hexahedral cage 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 12.3 wt%.

S2: Take 3 parts of the bifunctional POSS in step S1 and disperse them in 6 parts of a mixed solvent of propyl acetate and isopropanol (V _{propyl acetate} :V _isopropanol =10:1) to obtain a bifunctional POSS dispersion; Add the aluminum pigment dispersion in step S1 into the reaction vessel, place the reaction vessel in a water bath at 50°C and stir under the protection of nitrogen, then add 0.09 parts of triethylamine and the difunctional POSS dispersion solution dropwise for condensation reaction for 2 hours . After the reaction stopped, the solid product was collected, washed with ethyl acetate for 3 times, and dried at 40°C under vacuum for 5 hours to prepare a bifunctional POSS-coated aluminum pigment;

S3: Take 6 parts of the bifunctional POSS-coated aluminum pigment in step S2 and disperse it in 20 parts of ethyl acetate, add 0.4 parts of dibutyltin dilaurate, and add dropwise the ethyl acetate dispersion containing 4 parts of IPDI , reacted at 75°C under N ₂ atmosphere for 1.5h; added dropwise an ethyl acetate dispersion containing 30 parts of NC, and reacted at 55°C under N ₂ atmosphere for 1.5h. Grafting NC on the surface of bifunctional POSS-coated aluminum pigments through stepwise polymerization;

Wherein, the volume fraction of ethyl acetate is 20%.

S4: Add n-hexane to the material obtained in step S3, collect the solid precipitate and wash it 3 times with a mixed solvent of propyl acetate and isopropanol (V _{propyl acetate} :V _isopropanol =10:1), at 40°C, After drying for 5 hours under vacuum condition, the functionalized POSS modified aluminum pigment was obtained.

Wherein the volume fraction of n-hexane is 10%.

S5: Take 5 parts of functionalized POSS modified aluminum pigments 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 at room temperature to obtain silver ink , and then printed on imitation glass cardboard through the gravure suitability tester, and obtained the metallic glitter ink film after natural volatilization and drying.

The functionalized POSS modified aluminum pigments prepared in Examples 1-3 were respectively stored in an acid solution of pH=1 and an alkaline solution of pH=11, and after being stored at room temperature for 2 months, no _H2 was produced, and the apparent appearance of the aluminum pigment There is no obvious change in color, and commercially available aluminum powder pigments (such as Zuxing ZC905) have a large amount of H ₂ when they are stored at room temperature for 15 days in an alkaline solution with pH = 9 or at room temperature for 5 days in an acid solution with pH = 1. produced, and the appearance color gradually becomes off-white; under microscope observation, there is a dense coating film on the surface of the prepared aluminum pigment particles, further confirming that the high-gloss silver ink of the present invention uses functionalized cage-type low silsesquioxane The modified aluminum pigment has better acid and alkali resistance and better storage stability.

Comparative example 1

Get 50 parts of uncoated modified aluminum silver paste raw materials (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 The silver ink was prepared, and then printed on the imitation glass cardboard through the gravure suitability tester, and the metallic glitter ink film was obtained after natural volatilization and drying.

Comparative example 2

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 at room temperature to prepare The silver ink is then printed on the imitation glass cardboard through the gravure suitability tester, and the metallic glitter ink film is obtained after natural volatilization and drying.

The above Comparative Examples 1 and 2 were compared with the silver ink and metallic flash ink film prepared in Examples 1 to 3 respectively:

Storage stability test: Store the silver ink in a sealed container at room temperature for one month, and observe whether there is any phenomenon of delamination, agglomeration, and sinking that are visible to the naked eye.

Gloss test: use a gloss meter to test at an incident angle of 20°, and take the average of three measurements. A polished black glass plate with a refractive index of 1.567 was used as a gloss standard.

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

Adhesion fastness test: paste 3M tape on the ink film, flatten it with fingers or rubber to avoid wrinkling of the tape and the substrate, then tear off the tape at 180°, and use the proportion of the ink peeling area on the sample to indicate the adhesion Fastness, the average value of three measurements.

Table 1 Performance test of different types of aluminum pigments applied in ink

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 , the stability of the silver ink is better; the gloss and brightness test results show that the gloss and brightness of the functionalized cage type oligomeric silsesquioxane modified aluminum pigment ink ink film of the present invention are respectively 100% than that of the uncoated modified aluminum 95% to 100% and 96% to 100% of the pigment ink film, and much higher than the commercially available electroplated silver paste ink 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 functionalized cage oligomeric silsesquioxane modified aluminum pigment ink ink film of the present invention is significantly better than that of uncoated modified aluminum pigment and commercially available electroplated silver paste ink ink membrane.

The above description is a preferred embodiment of the present invention, it should be pointed out that for those of ordinary skill in the art, without departing from the principle of the present invention, some improvements and modifications can also be made, and these improvements and modifications can also be made. It should be regarded as the protection scope of the present invention.

Claims (10)

1. The preparation method of the functionalized cage-type oligomeric silsesquioxane modified aluminum pigment for the high-brightness silver ink is characterized by comprising the following steps of:

s1: vacuum filtering aluminum silver paste, soaking in a solvent, stirring, standing, desolventizing, and dispersing in a solvent I to obtain an aluminum pigment dispersion;

drying isophorone diisocyanate, difunctional cage-type oligomeric silsesquioxane, nitrocellulose (NC) and ethyl acetate for water removal;

s2: adding the aluminum pigment dispersion into a reaction vessel, placing the reaction vessel into a water bath kettle, stirring under the protection of inert gas, dropwise adding a catalyst I and a dispersion liquid of the difunctional POSS, performing condensation reaction, and performing vacuum filtration, cleaning and drying to obtain the difunctional POSS coated aluminum pigment;

s3: dispersing the difunctional POSS coated aluminum pigment in the ethyl acetate, adding a catalyst II, sequentially and dropwise adding IPDI and NC dispersion liquid, and grafting NC on the surface of the difunctional POSS coated aluminum pigment through gradual polymerization reaction;

s4: and (3) precipitating, centrifuging, cleaning and drying the material obtained in the step (S3) to obtain the functional POSS modified aluminum pigment.

2. The preparation method according to claim 1, wherein the pretreatment conditions of the aluminum paste in step S1 are as follows: soaking in solvent one for 10-15 min, magnetically stirring at normal temperature for 0.5-1 hr, standing for 30 min, and vacuum filtering to eliminate solvent.

3. The preparation method according to claim 1, wherein the aluminum paste in the step S1 is a nano lamellar aluminum paste prepared by a special electroplating process, the solid content of the aluminum paste is 5-15%, the particle size (D50) is 5-20 μm, and the thickness is 10-50 nm;

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

the difunctional POSS is a typical inorganic-organic hybrid hexahedral cage three-dimensional structure, has 2 reactive groups of hydroxyl and amino, and 6 inert groups, and the inert groups are methyl, isobutyl or isooctyl alkane or cycloalkane;

the nitrogen content of the nitrocellulose is 11.8-12.3wt%;

the ratio of the aluminum silver paste to the solvent I is 1g:1 mL-1 g:2mL.

4. The method according to claim 1, wherein the condensation reaction conditions in step S2 are: the water bath temperature is 40-50 ℃ and the reaction time is 2-3 h.

5. The preparation method according to claim 1, wherein after the reaction in the step S2 is stopped, the solid product is collected, washed 3 times with ethyl acetate, and dried under vacuum at 40 ℃ for 5 hours.

6. The method according to claim 1, wherein the inert gas in the step S2 is nitrogen; the catalyst is triethylamine or ethylenediamine, and the addition amount of the catalyst is 0.1-2% of the total solid content;

the dispersion liquid of the difunctional POSS is formed by dispersing the difunctional POSS in a solvent I;

the mass ratio of the aluminum pigment to the difunctional POSS is 1: 2-2: 1, a step of;

the ratio of the difunctional POSS to solvent one was 1g:1 mL-1 g:2mL.

7. The method according to claim 1, wherein the step S3 comprises the following polymerization conditions: adding a catalyst II, dropwise adding an IPDI dispersion liquid, and adding N at 45-55 DEG C ₂ Reacting for 1.5-2.5 h under atmosphere; adding NC dispersion liquid dropwise at 65-75deg.C with N ₂ Reacting for 1.5-2.5 h under atmosphere; the IPDI dispersion liquid and the NC dispersion liquid are respectively formed by dispersing IPDI and NC in ethyl acetate;

the mass fractions of the IPDI, NC and difunctional POSS coated aluminum pigment are sequentially 1-10%, 40-75% and 15-35%;

the volume fraction of the ethyl acetate is 20-40%.

8. The preparation method according to claim 1, wherein the catalyst in the step S3 is dibutyl tin dilaurate or stannous 2-ethylhexanoate, and the addition amount of the catalyst is 0.1% -2% of the total solid content.

9. The preparation method according to claim 1, wherein the specific steps of the post-treatment in step S4 are: adding n-hexane, collecting solid precipitate, washing with solvent for 3 times, and drying at 40deg.C under vacuum for 5 hr;

the volume fraction of the n-hexane is 10-30%.

10. A functionalized cage-type oligomeric silsesquioxane modified aluminum pigment for highlight silver ink obtained by the preparation method as claimed in any one of claims 1 to 9.

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