Dispersing agent for solvent type ceramic ink-jet ink and preparation method of dispersing agent

Abstract

The invention relates to the technical field of dispersing agents, and discloses a dispersing agent for solvent type ceramic ink-jet ink and a preparation method of the dispersing agent. A comb-shaped polymer in the comb-shaped dispersing agent is prepared by reacting polyamide which is synthesized by reacting polyethylene polyamine and binary acid and contains primary amine at the tail end with polyacrylate which is synthesized by reversible addition-fragmentation free radical polymerization and contains carboxylic acid at one end, and the comb-shaped dispersing agent can be prepared by diluting the comb-shaped polymer with a solvent. Amino groups in the dispersing agent can be firmly adsorbed on the surfaces of pigment particles, and the dispersing agent cannot fall off from the pigment particles due to heating and other reasons; polyalkyl acrylate in the dispersing agent is dissolved in the solvent and fully extends, a steric hindrance effect is provided, and pigment particles dispersed in the solvent are prevented from being agglomerated and precipitated. The solvent type ceramic ink prepared from the dispersing agent is free of precipitation of ceramic pigment after standing at room temperature for two months, shows excellent storage stability, has proper viscosity and density, and meets the technical requirements of ink-jet printing.

Description

Technical Field

[0001] The invention relates to the technical field of dispersants, in particular to a dispersant for solvent-based ceramic inkjet ink and a preparation method thereof. Background Art

[0002] Ceramic inkjet printing technology is the third generation of tile printing technology after screen printing and roller printing. It is known as the "third revolution in tile decoration technology". Compared with screen printing and roller printing, ceramic inkjet printing technology has the advantages of high degree of automation, simple process, low energy consumption, etc., which can effectively improve the work efficiency and decorative effect of the ceramic surface decoration industry. Ceramic inkjet printing is to prepare ceramic color powder into ink, spray it at high speed through the nozzle and deposit it on the carrier such as the blank and glaze. With the development and technological progress of ceramic inkjet printing technology, this technology has been basically popularized in ceramic enterprises and successfully replaced the traditional ceramic tile decoration process.

[0003] At present, most commercial ceramic inks are solvent-based inks, which are mainly composed of ceramic pigments, solvents, dispersants and other auxiliary materials to form a suspended slurry. The key to the preparation of ceramic inks is how to stably disperse micro-nano ceramic pigments in the dispersion medium, that is, to ensure that the powder is in a monodispersed state in the solvent without flocculation or precipitation. Dispersants are interfacial active substances that can keep the ink dispersion system stable. Dispersants added to inks can be adsorbed on the surface of micro-nano ceramic pigments to form an adsorption layer, generate charge repulsion and steric hindrance effects, prevent the dispersed pigment particles from flocculating again, and keep the system in a stable suspension state. Generally speaking, the larger the molecular weight of the dispersant, the thicker the adsorption layer can be formed. If the dispersant is used properly, it can not only prevent the precipitation of pigments and make the ceramic ink have good storage stability, but also reduce the viscosity of the color paste, increase the content of pigments in the grinding color paste, improve the grinding efficiency, and achieve the effect of saving manpower and energy. Therefore, in ceramic inks, dispersants play a vital role in the dispersion of ceramic pigments.

[0004] The density of pigments in ceramic inks is high. The pigments in currently commercialized ceramic inks will precipitate during storage and printing, which may clog the nozzles. Based on this, the present application proposes a dispersant for solvent-based ceramic inkjet inks and a preparation method thereof to solve the above problems. Summary of the invention

[0005] 1. Technical issues to be resolved

[0006] In view of the shortcomings of the prior art, the present invention provides a dispersant for a solvent-based ceramic inkjet ink and a preparation method thereof. The solvent-based ceramic ink prepared by using the comb-like dispersant for solvent-based ceramic inkjet ink has no precipitation of ceramic colorant after being left standing at room temperature for two months, showing excellent storage stability. The ceramic ink has appropriate viscosity and density and meets the technical requirements of inkjet printing.

[0007] (II) Technical solution

[0008] To achieve the above-mentioned purpose, the present invention provides the following technical solution: a dispersant for solvent-based ceramic inkjet ink, wherein the comb-like polymer in the comb-like dispersant is prepared by reacting a polyamide containing a primary amine at the end synthesized by reacting polyethylene polyamine and a dibasic acid with a polyacrylate containing a carboxylic acid at one end synthesized by reversible addition-fragmentation free radical polymerization, and the comb-like dispersant can be prepared by diluting the comb-like polymer with a solvent.

[0009] Preferably, the polyethylene polyamine is one or more of diethylenetriamine, triethylenetetramine, tetraethylenepentamine, preferably tetraethylenepentamine.

[0010] Preferably, the dibasic acid is one or more of oxalic acid, malonic acid, adipic acid, and terephthalic acid, preferably adipic acid.

[0011] Preferably, during the reaction of polyethylene polyamine and dibasic acid, the molar ratio of polyethylene polyamine to dibasic acid is 1.2-2:1, and the temperature is 150-200°C.

[0012] Preferably, when the polyacrylate containing carboxylic acid at one end is synthesized by reversible addition-fragmentation free radical polymerization, the chain transfer agent used is 2-(dodecylthiothiocarbonylthio)-2-methylpropionic acid.

[0013] Preferably, when the polyacrylate containing carboxylic acid at one end is synthesized by reversible addition-fragmentation free radical polymerization, the acrylate used has an alkyl carbon number of not less than 8 and is one or more of isooctyl acrylate, lauryl acrylate, and hexadecyl acrylate.

[0014] Preferably, the mass ratio of the 2-(dodecylthiothiocarbonylthio)-2-methylpropionic acid to the acrylic acid ester is 1:20-100.

[0015] Preferably, during the reaction of the polyacrylate containing carboxylic acid at one end and the polyamide containing amino group at the terminal, the molar ratio of the polyacrylate to the amine in the polyamide is 1:1, and the solvent is one or more of No. 6 white oil, No. 15 white oil, and methyl oleate.

[0016] A method for preparing a dispersant for a solvent-based ceramic inkjet ink comprises the following steps:

[0017] S1. Add polyethylene polyamine and dibasic acid into the reactor in proportion, pass nitrogen, stir mechanically, keep the material temperature at 150-200°C, and keep the temperature until the acid value of the material meets the requirements, to synthesize polyamide containing primary amine at the end;

[0018] S2, 2-(dodecylthiothiocarbonylthio)-2-methylpropionic acid, hexadecyl acrylate, and azobisisobutyronitrile are added into a reactor in proportion, nitrogen is passed through, mechanical stirring is performed, the material temperature is 75-85° C., and the temperature is kept for 3-5 hours to obtain a polyacrylate containing carboxylic acid at one end;

[0019] S3, adding a polyacrylate containing carboxylic acid at one end to a polyamide containing an amine group at the end, and keeping the temperature until the amine value of the material meets the requirements;

[0020] S4. Cool the material to 80°C-100°C, add a certain proportion of solvent, cool to room temperature, stop stirring, stop passing nitrogen, and obtain a dispersant for ceramic inkjet ink.

[0021] (III) Beneficial effects

[0022] Compared with the prior art, the present invention provides a solvent-based ceramic inkjet ink dispersant and a preparation method thereof, which has the following beneficial effects:

[0023] 1. The solvent-based dispersant of the present invention has a comb-like structure, a narrow molecular weight distribution, and a low viscosity, and has little effect on the viscosity of the ceramic inkjet ink;

[0024] 2. The amine groups in the dispersant of the present invention can be firmly adsorbed on the surface of the pigment particles, and the dispersant will not fall off from the pigment particles due to heat or other reasons; the polyalkyl acrylate in the dispersant is dissolved in the solvent and fully extended, providing a steric hindrance to prevent the pigment particles dispersed in the solvent from agglomerating and precipitating;

[0025] 3. The amine group of the dispersant of the present invention and the polyalkyl acrylate work simultaneously. The solvent-based ceramic ink prepared by using the dispersant of the present invention has no precipitation of ceramic pigments after standing at room temperature for two months, showing excellent storage stability. The ceramic ink has appropriate viscosity and density, meeting the technical requirements of inkjet printing. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 A schematic diagram of the performance test results of preparing a solvent-based ceramic inkjet ink using the dispersant of Example 1 of the present invention;

[0027] Figure 2 A schematic diagram of the performance test results of preparing a solvent-based ceramic inkjet ink using the dispersant of Example 2 of the present invention;

[0028] Figure 3 A schematic diagram of the performance test results of preparing a solvent-based ceramic inkjet ink using the dispersant of Example 3 of the present invention;

[0029] Figure 4 A schematic diagram of the performance test results of preparing a solvent-based ceramic inkjet ink using the dispersant of Example 4 of the present invention;

[0030] Figure 5 Schematic diagram of performance test results of solvent-based ceramic inkjet ink prepared using the dispersant of Example 5 of the present invention. DETAILED DESCRIPTION

[0031] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0032] Example 1

[0033] 568 g of tetraethylenepentamine and 292 g of adipic acid were added to a reactor, nitrogen was passed through, mechanical stirring was performed, the material temperature was 150° C., and the temperature was maintained until the acid value of the material reached 0.02 mg KOH / g, to obtain a polyamide containing terminal amino groups;

[0034] 40 g of 2-(dodecylthiothiocarbonylthio)-2-methylpropionic acid, 1000 g of lauryl acrylate and 5 g of azobisisobutyronitrile were introduced into a reactor, nitrogen was passed through, mechanical stirring was performed, the material temperature was 80°C, and the temperature was kept for 4 hours to obtain a polyacrylate containing carboxylic acid at one end;

[0035] Add a polyacrylate containing a carboxylic acid at one end to a polyamide containing an amine group at the end and keep the mixture warm for 2 hours;

[0036] The material temperature was lowered to 80° C., 1800 g of No. 6 white oil was added, and the mixture was cooled to room temperature. Stirring and nitrogen flow were stopped to obtain a dispersant for ceramic inkjet ink.

[0037] Example 2

[0038] 568 g of tetraethylenepentamine and 292 g of adipic acid were added to a reactor, nitrogen was passed through, mechanical stirring was performed, the material temperature was 180° C., and the temperature was maintained until the acid value of the material reached 0.01 mg KOH / g, to obtain a polyamide containing terminal amino groups;

[0039] 40 g of 2-(dodecylthiothiocarbonylthio)-2-methylpropionic acid, 1000 g of hexadecyl acrylate and 5 g of azobisisobutyronitrile were introduced into a reactor, nitrogen was passed through, mechanical stirring was performed, the material temperature was 80°C, and the temperature was kept for 4 hours to obtain a polyacrylate containing carboxylic acid at one end;

[0040] Add a polyacrylate containing a carboxylic acid at one end to a polyamide containing an amine group at the end and keep the mixture warm for 4 hours;

[0041] The material temperature was lowered to 80° C., 1800 g of No. 6 white oil was added, and the mixture was cooled to room temperature. Stirring and nitrogen flow were stopped to obtain a dispersant for ceramic inkjet ink.

[0042] Example 3

[0043] 568 g of tetraethylenepentamine and 292 g of adipic acid were added to a reactor, nitrogen was passed through, mechanical stirring was performed, the material temperature was 200° C., and the temperature was maintained until the acid value of the material reached 0.03 mg KOH / g, to obtain a polyamide containing terminal amino groups;

[0044] 40 g of 2-(dodecylthiothiocarbonylthio)-2-methylpropionic acid, 800 g of lauryl acrylate and 5 g of azobisisobutyronitrile were introduced into a reactor, nitrogen was passed through, mechanical stirring was performed, the material temperature was 80° C., and the temperature was kept at 4 hours to obtain a polyacrylate containing carboxylic acid at one end;

[0045] Add a polyacrylate containing a carboxylic acid at one end to a polyamide containing an amine group at the end and keep the mixture warm for 2 hours;

[0046] The material temperature was lowered to 80° C., 1600 g of No. 6 white oil was added, and the mixture was cooled to room temperature. Stirring and nitrogen flow were stopped to obtain a dispersant for ceramic inkjet ink.

[0047] Example 4

[0048] 568 g of tetraethylenepentamine and 292 g of adipic acid were added to a reactor, nitrogen was passed through, mechanical stirring was performed, the material temperature was 190° C., and the temperature was maintained until the acid value of the material reached 0.02 mg KOH / g, to obtain a polyamide containing terminal amino groups;

[0049] 40 g of 2-(dodecylthiothiocarbonylthio)-2-methylpropionic acid, 1600 g of lauryl acrylate and 10 g of azobisisobutyronitrile were introduced into a reactor, nitrogen was passed through, mechanical stirring was performed, the material temperature was 80°C, and the temperature was kept at 4 hours to obtain a polyacrylate containing carboxylic acid at one end;

[0050] Add a polyacrylate containing a carboxylic acid at one end to a polyamide containing an amine group at the end and keep the mixture warm for 2 hours;

[0051] The material temperature was lowered to 100° C., 2400 g of methyl oleate was added, and the mixture was cooled to room temperature. Stirring and nitrogen flow were stopped to obtain a dispersant for ceramic inkjet ink.

[0052] Example 5

[0053] 568 g of tetraethylenepentamine and 292 g of adipic acid were added to a reactor, nitrogen was passed through, mechanical stirring was performed, the material temperature was 160° C., and the temperature was maintained until the acid value of the material reached 0.04 mg KOH / g, to obtain a polyamide containing terminal amino groups;

[0054] 40 g of 2-(dodecylthiothiocarbonylthio)-2-methylpropionic acid, 1200 g of hexadecyl acrylate and 6 g of azobisisobutyronitrile were introduced into a reactor, nitrogen was passed through, mechanical stirring was performed, the material temperature was 80°C, and the temperature was kept at 4 hours to obtain a polyacrylate containing carboxylic acid at one end;

[0055] Add a polyacrylate containing a carboxylic acid at one end to a polyamide containing an amine group at the end and keep the mixture warm for 3 hours;

[0056] The material temperature was lowered to 90° C., 2000 g of methyl oleate was added, and the mixture was cooled to room temperature. Stirring and nitrogen flow were stopped to obtain a dispersant for ceramic inkjet ink.

[0057] The dispersant prepared in the above embodiment and the solvent-based ceramic inkjet ink prepared with the dispersant were subjected to relevant performance tests, wherein the process for preparing the solvent-based ceramic inkjet ink is as follows:

[0058] 500 g of No. 6 white oil and 100 g of the dispersant of the embodiment were stirred and mixed evenly, and then 400 g of wrapped red was added. After mixing evenly, the mixture was placed in a sand mill and ground at a speed of 2000 rpm until the particle size of the slurry was D90 = 0.3-0.5 μm. After filtering, an aqueous ceramic ink was obtained.

[0059] The relevant performance tests are as follows:

[0060] Molecular weight and molecular weight distribution index of dispersant: The number average molecular weight and molecular weight distribution index of dispersant are determined by gel permeation chromatography;

[0061] The particle size of the pigment in the ink: The D90 particle size of the ink is measured using the BeNano90 laser particle size analyzer produced by Dandong Better Instrument Co., Ltd.

[0062] Ink viscosity: The viscosity of the ink before aging and after aging at 60°C for 7 days was measured using a rotational viscometer, with the test temperature at 23°C and the rotor speed at 30 rpm. The viscosity change rate is the ratio of the viscosity difference before and after aging to the viscosity before aging;

[0063] Sedimentation rate: put 100g ink into a 100ml bottle, place it in a 60℃ oven for 7 days, pour out the ink in the bottle and turn the bottle upside down for 2 minutes, and measure the mass ratio of the residue in the bottle to the ink.

[0064] Related performance test results can be found in Figure 1-5 And Table 1:

[0065] Table 1: Performance test results of solvent-based ceramic inkjet inks prepared using the dispersants of Examples 1-5

[0066]

[0067] Depend on Figure 1-5 As can be seen from Table 1, when the dispersants of Examples 1-5 are used to prepare solvent-based ceramic inkjet inks, the D90 particle size of the inks reaches less than 0.5 μm, the viscosity change rate of the inks before and after aging is less than 2%, and the sedimentation rate is less than 0.3%. The dispersants have good anti-settling effects and the inks have good aging resistance.

[0068] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A dispersant for solvent-based ceramic inkjet ink, characterized in that: The comb polymer in the comb dispersant is prepared by reacting a polyamide containing primary amines at the end synthesized by reacting polyethylene polyamine and dibasic acid with a polyacrylate containing carboxylic acid at one end synthesized by reversible addition-fragmentation free radical polymerization. The comb dispersant can be prepared by diluting the comb polymer with a solvent.

2. A dispersant for solvent-based ceramic inkjet ink according to claim 1, characterized in that: The polyethylene polyamine is one or more of diethylenetriamine, triethylenetetramine and tetraethylenepentamine.

3. A dispersant for solvent-based ceramic inkjet ink according to claim 2, characterized in that: The dibasic acid is one or more of oxalic acid, malonic acid, adipic acid and terephthalic acid.

4. A dispersant for solvent-based ceramic inkjet ink according to claim 3, characterized in that: During the reaction of the polyethylene polyamine and the dibasic acid, the molar ratio of the polyethylene polyamine to the dibasic acid is 1.2-2:1, and the temperature is 150-200°C.

5. The dispersant for solvent-based ceramic inkjet ink according to claim 1, characterized in that: When the polyacrylate containing carboxylic acid at one end is synthesized by reversible addition-fragmentation free radical polymerization, the chain transfer agent used is 2-(dodecylthiothiocarbonylthio)-2-methylpropionic acid.

6. A dispersant for solvent-based ceramic inkjet ink according to claim 5, characterized in that: When the polyacrylate containing carboxylic acid at one end is synthesized by reversible addition-fragmentation free radical polymerization, the alkyl carbon number of the acrylic acid ester used is not less than 8, and it is one or more of isooctyl acrylate, lauryl acrylate, and hexadecyl acrylate.

7. A dispersant for solvent-based ceramic inkjet ink according to claim 6, characterized in that: The mass ratio of the 2-(dodecylthiothiocarbonylthio)-2-methylpropionic acid to the acrylic acid ester is 1:20-100.

8. The dispersant for solvent-based ceramic inkjet ink according to claim 1, characterized in that: During the reaction of the polyacrylate containing carboxylic acid at one end and the polyamide containing amine at the terminal, the molar ratio of the polyacrylate to the amine in the polyamide is 1:1, and the solvent is one or more of No. 6 white oil, No. 15 white oil, and methyl oleate.

9. A method for preparing the dispersant according to any one of claims 1 to 8, characterized in that: The following steps are involved: S1. Add polyethylene polyamine and dibasic acid into the reactor in proportion, pass nitrogen, stir mechanically, keep the material temperature at 150-200°C, and keep the temperature until the acid value of the material meets the requirements, to synthesize polyamide containing primary amine at the end; S2, 2-(dodecylthiothiocarbonylthio)-2-methylpropionic acid, hexadecyl acrylate, and azobisisobutyronitrile are added into a reactor in proportion, nitrogen is passed through, mechanical stirring is performed, the material temperature is 75-85° C., and the temperature is kept for 3-5 hours to obtain a polyacrylate containing carboxylic acid at one end; S3, adding a polyacrylate containing carboxylic acid at one end to a polyamide containing an amine group at the end, and keeping the temperature until the amine value of the material meets the requirements; S4. Cool the material to 80°C-100°C, add a certain proportion of solvent, cool to room temperature, stop stirring, stop passing nitrogen, and obtain a dispersant for ceramic inkjet ink.

10. Use of the dispersant according to any one of claims 1 to 8 in the preparation of solvent-based ceramic ink.

Images