Water-based dispersing agent, preparation method thereof and application of water-based dispersing agent in ink-jet printing

Abstract

The invention belongs to the technical field of ink, and provides a water-based dispersing agent, a preparation method thereof and application of the water-based dispersing agent in ink-jet printing. Amphiphilic resin, amino acid and water are used as main raw materials of the aqueous dispersant, wherein the amphiphilic resin contains a hydrophobic chain segment and a hydrophilic chain segment; the hydrophobic chain segment is a styrene chain segment; the hydrophilic chain segment is a maleic anhydride chain segment. Amino acid is used for modifying amphiphilic resin, amino groups in the amino acid can react with hydrophilic chain segments, other remaining amino groups can serve as anchoring groups to enhance the adsorption effect on pigment, carboxyl can increase charge repulsion among pigment particles, and therefore the water-based dispersing agent is high in dispersing performance, and the water-based dispersing agent can be used as a water-based dispersing agent. The ink can be further used for preparing stable pigment dispersions, ink and the like, and the prepared ink is good in printing performance. In addition, amino acid is low in price and easier to obtain, reaction conditions with amphiphilic resin are simple, and operation is easy.

Description

Technical Field

[0001] The present invention relates to the technical field of inks, and more particularly, to an aqueous dispersant, a preparation method thereof, and an application thereof in inkjet printing. Background Art

[0002] Inkjet printing is a type of digital printing method. Tiny ink droplets are precisely ejected from the printer nozzle onto the applied medium to form an image. The colorants in the ink are generally dyes or pigments. Since pigments have good weather resistance and stable colors, they are gradually replacing dyes in this application.

[0003] An aqueous pigment dispersion is a key material for formulating inkjet printing inks, usually composed of water, pigments, dispersants, a small amount of organic solvents, and additives, etc. Since inkjet printing forms an image by ejecting tiny ink droplets through a nozzle on the micron scale onto the substrate, and the other components in the dispersion are mainly water, or solvents, additives, or polymers that are miscible with water, the dispersed size of the pigment will greatly affect parameters such as the stability, viscosity, and surface tension of the dispersion, and thus affect the smoothness of the printer operation, the nozzle life, the working efficiency, the printing effect, etc.

[0004] Commercially available pigments are usually in powder or granular form, and a small part is supplied in the form of preparations or filter cakes. According to their chemical composition, they are divided into organic pigments and inorganic pigments. Organic pigments are roughly divided into azo pigments and polycyclic / heterocyclic pigments. The most important black pigment in inorganic pigments is carbon black. Due to the existence of crystal or particle aggregate structures, pigments are usually difficult to dissolve in the medium. Macroscopically, pigments can be regarded as a collection of many particles with the same chemical structure and different sizes. The aggregation size of commercially available organic pigments and carbon black powders ranges from a few microns to several hundred microns, while the particle size required for pigments in inkjet printing is in the range of dozens to hundreds of nanometers. This reduction in particle scale needs to be achieved through dispersion. The dispersion of pigments not only affects optical properties such as color, hue, concentration, covering power, and gloss, but may also affect the stability of the system, and other physical and chemical properties.

[0005] For the sake of easier description, the process of pigment dispersion is usually divided into three stages: wetting, dispersion, and stabilization. In fact, these three stages do not occur independently of each other. In the wetting stage, the pigment is sheared and mixed with components such as the carrier and additives into a uniform state, and the interface between the pigment powder particles and the air is replaced by the liquid components in the system. The dispersion stage is to use external energy input devices, such as sand mills, three-roll mills, high-pressure homogenizers, etc., to make the pigment particles in the slurry reach the required particle size range for application.

[0006] During the above dispersion process, as the size of pigment particles decreases, the surface area of the pigment increases, and the surface free energy of the particles also increases accordingly. Therefore, the attraction between pigment particles increases. During storage, the pigment particles are prone to re-aggregation, the viscosity of the system increases, resulting in system instability. Therefore, a dispersant is usually added during the dispersion of pigments to overcome the attraction between pigment particles. The dispersant can be a compound containing anionic, cationic or non-ionic structures. Regardless of which type, the principle of stabilizing pigments is that one end is anchored on the surface of the pigment, and the other end overcomes the repulsion between pigment particles through charge repulsion or steric hindrance to prevent the particles from aggregating again, thereby obtaining a stable dispersion system. This is particularly crucial in inkjet printing applications, as even minor changes can seriously affect the printing smoothness, print color, and even clog or damage the print head. However, the dispersion effect of commonly used dispersants is limited, and the stability of the pigments and inks prepared is not ideal enough.

[0007] Therefore, there is an urgent need to develop an aqueous dispersant for pigments and inks that can effectively improve the stability of pigments and inks. Summary of the Invention

[0008] The present invention aims to solve at least one of the technical problems existing in the above prior art. For this purpose, the present invention provides an aqueous dispersant, its preparation method, and its application in inkjet printing. The aqueous dispersant provided by the present invention can be further used to prepare pigments and inks, and can improve the stability of pigments and inks.

[0009] The first aspect of the present invention provides an aqueous dispersant.

[0010] Specifically, an aqueous dispersant comprises the following raw materials:

[0011] An amphiphilic resin, an amino acid, and water;

[0012] The amphiphilic resin contains a hydrophobic segment and a hydrophilic segment; the hydrophobic segment is a styrene segment; the hydrophilic segment is a maleic anhydride segment.

[0013] The amino acid in the present invention refers to a compound formed by substituting one or more hydrogen atoms on the hydrocarbon group in a carboxylic acid molecule with an amino group.

[0014] The present invention modifies the amphiphilic resin with an amino acid. Among them, the amino groups with the same molar amount in the amino acid can react with the hydrophilic segment (such as SMA anhydride), and the remaining amino groups can be used as anchoring groups to enhance the adsorption effect on pigments. The carboxyl group can increase the charge repulsion between pigment particles to form the required structure for application. Compared with the simple hydrolysis product of the amphiphilic resin (such as SMA), the aqueous dispersant of the present invention not only increases the number of hydrophilic groups but also increases the length of the side chain, thereby improving the dispersion performance of the dispersant.

[0015] Preferably, the amphiphilic resin is a styrene maleic anhydride resin.

[0016] Styrene maleic anhydride resin (SMA) is a thermoplastic resin copolymerized from styrene and maleic anhydride. The molecular structure of SMA contains both hydrophobic styrene segments and hydrophilic maleic anhydride segments. The benzene ring structure of the hydrophobic segments has excellent affinity with organic pigments and carbon black, and is easily adsorbed and anchored on the surface of the pigments. The hydrophilic anhydride segments are hydrolyzed and dissolved in water, which not only has a steric hindrance effect but also generates charge repulsion. Therefore, SMA resins are used as dispersants for pigment dispersion and show excellent performance especially in aqueous systems.

[0017] Preferably, the amino acid is at least one of arginine, lysine, glutamine, aspartic acid, cysteine, and homocysteine.

[0018] Preferably, by weight, the aqueous dispersant comprises the following raw materials:

[0019] 700 - 900 parts of styrene maleic anhydride resin, 30 - 70 parts of amino acid, and 1500 - 2500 parts of water.

[0020] Further preferably, by weight, the aqueous dispersant comprises the following raw materials:

[0021] 750 - 850 parts of styrene maleic anhydride resin, 35 - 68 parts of amino acid, and 2000 - 2500 parts of water.

[0022] Preferably, the number average molecular weight of the styrene maleic anhydride resin is 2000 - 3500.

[0023] Further preferably, the number average molecular weight of the styrene maleic anhydride resin is 2100 - 3000.

[0024] Preferably, the raw materials of the aqueous dispersant further include a pH regulator.

[0025] Preferably, the solid content of the aqueous dispersant is 20 - 40%.

[0026] Further preferably, the solid content of the aqueous dispersant is 25 - 35%.

[0027] The second aspect of the present invention provides a preparation method of an aqueous dispersant.

[0028] A preparation method of an aqueous dispersant comprises the following steps:

[0029] First, mix the amphiphilic resin and water, then add the amino acid, adjust the pH value to be greater than or equal to 10, and carry out the reaction to obtain the aqueous dispersant.

[0030] Preferably, the temperature of the reaction is 60 - 80 °C, and / or the time of the reaction is 5 - 15 h.

[0031] More preferably, the temperature of the reaction is 65 - 75 °C, and / or the time of the reaction is 8 - 12 h.

[0032] Preferably, during the reaction, the pH value is maintained at 10.0 - 10.5.

[0033] Preferably, after the reaction, it further includes a post-treatment step, and the post-treatment includes cooling to room temperature and then standing for defoaming.

[0034] The third aspect of the present invention provides an application of an aqueous dispersant.

[0035] An application of an aqueous dispersant in the preparation of pigments, inks or printing inks.

[0036] The fourth aspect of the present invention provides a pigment dispersion.

[0037] A pigment dispersion, comprising the following components:

[0038] The aqueous dispersant, pigment and water.

[0039] Preferably, by weight, the pigment dispersant comprises the following components:

[0040] 100 - 350 parts of aqueous dispersant, 100 - 200 parts of pigment and 200 - 1000 parts of water.

[0041] Preferably, the pigment dispersant further comprises the following components: humectant, cosolvent, dispersing aid, defoaming agent.

[0042] More preferably, by weight, the pigment dispersant comprises the following components:

[0043] 10 - 30 parts of humectant,

[0044] 5 - 20 parts of cosolvent,

[0045] 1 - 10 parts of dispersing aid,

[0046] 1 - 10 parts of defoaming agent.

[0047] Preferably, the humectant is at least one of glycerol, 1,2,6 - hexanetriol, tetraethylene glycol, 1,2 - hexanediol, polyethylene glycol 400, polyethylene glycol 600.

[0048] Preferably, the cosolvent is at least one of diethylene glycol butyl ether, diethylene glycol propyl ether, diethylene glycol butyl ether, propylene glycol butyl ether, dipropylene glycol butyl ether, 2 - pyrrolidone.

[0049] Preferably, the dispersant aid is 2-amino-2-methyl-1-propanol (AMP-95).

[0050] Preferably, the defoamer is of the Surfynol series produced by Evonik, of the Foamex series produced by Evonik, or the defoamer BYK-1770 produced by BYK Chemi.

[0051] The fifth aspect of the present invention provides a method for preparing a pigment dispersion.

[0052] A method for preparing a pigment dispersion includes the following steps:

[0053] Mix water and an aqueous dispersant, then add a pigment, grind, and filter to obtain the pigment dispersion.

[0054] Preferably, while mixing water and the aqueous dispersant, a solubilizer, an emulsifier, a dispersant aid, and a defoamer are added.

[0055] Preferably, the solid weight of the aqueous dispersant accounts for 40-60% of the total weight of the pigment dispersion.

[0056] The sixth aspect of the present invention provides an ink.

[0057] An ink includes the following components:

[0058] The pigment dispersant, a film-forming agent, a humectant, a co-solvent, a surfactant, a pH regulator, and water.

[0059] Preferably, by weight, the ink includes the following components:

[0060] 100-200 parts of a pigment dispersant, 50-90 parts of a film-forming agent, 50-95 parts of a humectant, 15-35 parts of a co-solvent, 1-5 parts of a surfactant, 1-5 parts of a pH regulator, and 100-250 parts of water.

[0061] Preferably, the film-forming agent is of the model Takelac W6110 produced by Mitsui Chemicals.

[0062] Preferably, the humectant is at least one of glycerol, 1,2,6-hexanetriol, tetraethylene glycol, 1,2-hexanediol, polyethylene glycol 400, and polyethylene glycol 600.

[0063] Preferably, the co-solvent is at least one of diethylene glycol butyl ether, diethylene glycol propyl ether, diethylene glycol butyl ether, propylene glycol butyl ether, dipropylene glycol butyl ether, and 2-pyrrolidone.

[0064] Preferably, the surfactant is an alkynol surfactant (such as Surfynol 465 produced by Air Products and Chemicals, Inc.).

[0065] Preferably, the pH regulator is triethanolamine.

[0066] The seventh aspect of the present invention provides a method for preparing an ink.

[0067] A method for preparing an ink, comprising the following steps:

[0068] Mixing each component, and after filtration, the ink is prepared.

[0069] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0070] The present invention uses an amphiphilic resin, an amino acid, and water as the main raw materials of an aqueous dispersant, wherein the amphiphilic resin contains a hydrophobic segment and a hydrophilic segment; the hydrophobic segment is a styrene segment; the hydrophilic segment is a maleic anhydride segment. The present invention modifies the amphiphilic resin with an amino acid, wherein the amino group in the amino acid can react with the hydrophilic segment (such as the reaction of the amino group and SMA anhydride), and the remaining amino groups can be used as anchoring groups to enhance the adsorption of the pigment, and the carboxyl group can increase the charge repulsion between pigment particles. Therefore, the aqueous dispersant of the present invention has strong dispersion performance and can be further used to prepare stable pigment dispersions, inks, etc., and the printing performance of the ink is good. In addition, amino acids are inexpensive and easier to obtain, and the reaction conditions with amphiphilic resins are simple and easy to operate. Detailed Embodiments

[0071] In order to make those skilled in the art more clearly understand the technical solutions of the present invention, the following examples are listed for illustration. It should be noted that the following examples do not limit the scope of protection required by the present invention.

[0072] Unless otherwise specified, the raw materials, reagents or devices used in the following examples can be obtained from conventional commercial channels or can be obtained by known existing methods.

[0073] The main raw materials used in the present invention are as follows:

[0074] Table 1 Main parameters of three different SMAs used in the present invention

[0075] Substance Acid value Number-average molecular weight (Mn) HLB value SMA1000 465-495 2100 24.1 SMA2000 335-375 2700 16.5 SMA3000 265-305 3000 16.2

[0076] Arginine: Guaranteed reagent, produced by Sinopharm Chemical Reagent Co., Ltd.

[0077] Glutamic acid: Guaranteed reagent, produced by Sinopharm Chemical Reagent Co., Ltd.

[0078] Example 1

[0079] An aqueous dispersant, comprising the raw materials shown in Table 2 below.

[0080] The preparation method of the above aqueous dispersant comprises the following steps:

[0081] (1) Add 2000 g of deionized water to a reaction kettle equipped with temperature control and high-speed stirring, stir at 500 revolutions per minute, and slowly add 800 g of SMA1000 to avoid resin caking;

[0082] (2) Then add 66.4 g of arginine and a sodium hydroxide solution with a solute mass fraction of 10%, adjust the pH value to be between 10.0 - 10.5, increase the stirring speed to 3000 revolutions per minute, set the reaction kettle temperature to 70 °C and react for 10 h. During this process, add the sodium hydroxide solution to keep the pH value in the reaction kettle between 10.0 - 10.5. After the reaction is completed, cool to room temperature, stand still to defoam, and obtain a slightly yellowish clear and transparent polymer solution with a solid content of about 30.2%.

[0083] Example 2

[0084] An aqueous dispersant, comprising the raw materials shown in Table 2 below.

[0085] The preparation method of the above aqueous dispersant comprises the following steps:

[0086] (1) Add 2000 g of deionized water to a reaction kettle equipped with temperature control and high-speed stirring, stir at 500 revolutions per minute, and slowly add 800 g of SMA2000 to avoid resin caking;

[0087] (2) Then add 51.6 g of arginine and a sodium hydroxide solution to adjust the pH value to be between 10.0 - 10.5, increase the stirring speed to 3000 revolutions per minute, set the reaction kettle temperature to 70 °C and react for 10 h. During this process, supplement the sodium hydroxide solution to keep the pH value in the reaction kettle between 10.0 - 10.5. After the reaction is completed, cool to room temperature, stand still to defoam, and obtain a slightly yellowish clear and transparent polymer solution with a solid content of about 29.9%.

[0088] Example 3

[0089] An aqueous dispersant, comprising the raw materials shown in Table 2 below.

[0090] The preparation method of the above aqueous dispersant comprises the following steps:

[0091] (1) Add 2000 g of deionized water to a reaction kettle equipped with temperature control and high-speed stirring, stir at 500 revolutions per minute, and slowly add 800 g of SMA3000 to avoid resin caking;

[0092] (2) Then add 46.5 g of arginine and sodium hydroxide solution to make the pH value between 10.0 - 10.5, increase the stirring speed to 3000 revolutions per minute, set the reaction kettle temperature at 70 °C and react for 10 h. During this process, add sodium hydroxide solution to keep the pH value in the reaction kettle between 10.0 - 10.5. After the reaction, cool to room temperature, stand still to defoam, and obtain a slightly yellowish clear and transparent polymer solution with a solid content of about 29.7%.

[0093] Example 4

[0094] An aqueous dispersant, including the raw materials shown in Table 2 below.

[0095] The preparation method of the above aqueous dispersant includes the following steps:

[0096] (1) Add 2000 g of deionized water to a reaction kettle equipped with temperature control and high-speed stirring, stir at 500 revolutions per minute, and slowly add 800 g of SMA1000 to avoid resin caking;

[0097] (2) Then add 56.0 g of glutamic acid and sodium hydroxide solution to make the pH value between 10.0 - 10.5, increase the stirring speed to 3000 revolutions per minute, set the reaction kettle temperature at 70 °C and react for 10 h. During this process, add sodium hydroxide solution to keep the pH value in the reaction kettle between 10.0 - 10.5. After the reaction, cool to room temperature, stand still to defoam, and obtain a slightly yellowish clear and transparent polymer solution with a solid content of about 30.0%.

[0098] Example 5

[0099] An aqueous dispersant, including the raw materials shown in Table 2 below.

[0100] The preparation method of the above aqueous dispersant includes the following steps:

[0101] (1) Add 2000 g of deionized water to a reaction kettle equipped with temperature control and high-speed stirring, stir at 500 revolutions per minute, and slowly add 800 g of SMA2000 to avoid resin caking;

[0102] (2) Then add 43.6 g of glutamic acid and sodium hydroxide solution to make the pH value between 10.0 - 10.5, increase the stirring speed to 3000 revolutions per minute, set the reaction kettle temperature at 70 °C and react for 10 h. During this process, add sodium hydroxide solution to keep the pH value in the reaction kettle between 10.0 - 10.5. After the reaction, cool to room temperature, stand still to defoam, and obtain a slightly yellowish clear and transparent polymer solution with a solid content of about 29.7%.

[0103] Example 6

[0104] An aqueous dispersant, including the raw materials shown in Table 2 below.

[0105] The preparation method of the above aqueous dispersant comprises the following steps:

[0106] (1) Add 2000 g of deionized water to a reaction kettle equipped with temperature control and high-speed stirring, stir at 500 revolutions per minute, and slowly add 800 g of SMA3000 to avoid resin caking;

[0107] (2) Then add 39.2 g of glutamic acid and sodium hydroxide solution to make the pH value between 10.0 - 10.5, increase the stirring speed to 3000 revolutions per minute, set the reaction kettle temperature at 70 °C and react for 10 h. During this process, add sodium hydroxide solution to keep the pH in the reaction kettle between 10.0 - 10.5. After the reaction is completed, cool to room temperature, stand still to defoam, and obtain a slightly yellowish clear and transparent polymer solution with a solid content of about 29.6%.

[0108] The main raw materials and their product situations used in Examples 1 - 6 are as shown in the following table:

[0109] Table 2 Main raw materials and their product situations used in Examples 1 - 6

[0110] Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 SMA1000 (g) 800 / / 800 / / SMA2000 (g) / 800 / / 800 / SMA3000 (g) / / 800 / / 800 Arginine (g) 66.4 51.6 46.5 / / / Glutamic acid (g) / / / 56.0 43.6 39.2 Solid content (%) 30.2 29.9 29.7 30.0 29.7 29.6

[0111] The products obtained in Examples 1 - 3 are respectively denoted as Products 1 - 3, and their structures are as follows:

[0112]

[0113] The products obtained in Examples 4 - 6 are respectively Products 4 - 6, and their structures are as follows:

[0114]

[0115] Comparative Example 1

[0116] A dispersant, different from Example 1 in that it does not contain arginine. The preparation method is the same as that of Example 1, and Product 7 is obtained.

[0117] Comparative Example 2

[0118] A dispersant, different from Example 2 in that it does not contain arginine. The preparation method is the same as that of Example 2, and Product 8 is obtained.

[0119] Comparative Example 3

[0120] A dispersant, different from Example 3 in that it does not contain arginine. The preparation method is the same as that of Example 3, and Product 9 is obtained.

[0121] The solid contents of Products 7 - 9 obtained in Comparative Examples 1 - 3 are all 28.6%, and their structures are respectively as follows:

[0122]

[0123] Application Example 1 (Pigment Dispersion)

[0124] Application Example 1 provides a pigment dispersion, and the preparation method is as follows: The products 1-6 obtained in Examples 1-6 are respectively used as aqueous dispersants to disperse Pigment Blue 15:4 (produced by Heubach, model: HOSTAPERM BLUE BT-617D), and then pigment dispersions A1-A6 are respectively prepared. Among them, the aqueous dispersants in the pigment dispersions A1-A6, the aqueous dispersant accounts for 50% of the pigment, and the addition amount of the aqueous dispersant is calculated according to the following formula:

[0125] (Weight of aqueous dispersant × Solids content of aqueous dispersant) ÷ Weight of pigment = 50%, which is abbreviated as the aqueous dispersant accounts for 50% of the pigment. Similarly, the addition amounts of the aqueous dispersants of the present invention are all calculated by the above formula.

[0126] The specific preparation method of the pigment dispersion is as follows:

[0127] Successively take deionized water, glycerol, diethylene glycol butyl ether, 2-amino-2-methyl-1-propanol (AMP-95), defoamer (BYK-1770), and aqueous dispersant (one of the products 1-6), add them to the dispersion cup, and start high-speed dispersion at a speed of 500 revolutions per minute. Then add pigment powder. After all the pigment is mixed into the liquid, increase the linear speed of the dispersion disk to 10 m / s. After dispersing for 60 minutes at this linear speed, pump the dispersion into a laboratory horizontal sand mill with a filling amount of 0.5 mm zirconia beads accounting for 85% of the volume of the grinding chamber, and circulate and grind the slurry at a speed of 3000 revolutions per minute for 8 h. After grinding, the dispersions are respectively filtered and purified by using 1.0 μm and 0.5 μm fiberglass filter membranes in sequence, and the solids content is adjusted to 15%.

[0128] The raw materials and their dosages of the pigment dispersions A1-A6 are shown in the following table.

[0129] Table 3 Raw Materials and Their Dosages of Pigment Dispersions A1-A6 (Unit: g)

[0130]

[0131] Application Example 2 (Pigment Dispersion)

[0132] A kind of pigment dispersion, the preparation method is the same as that of Application Example 1, the difference is that Pigment Blue is replaced by Pigment Red 122 (produced by Heubach, model: INKJETMAGENTAE02). Pigment dispersions B1-B6 are respectively obtained.

[0133] Application Example 3 (Pigment Dispersion)

[0134] A pigment dispersion, the preparation method is the same as that of Application Example 1, except that Pigment Blue is replaced with Pigment Yellow 74 (produced by Heubach, model number INKJETYELLOW5GX-W). Pigment dispersions C1-C6 are obtained respectively.

[0135] Application Example 4 (Pigment Dispersion)

[0136] A pigment dispersion, the preparation method is the same as that of Application Example 1, except that Pigment Blue is replaced with Pigment Black 7 (produced by Birla Carbon, model number Raven3500). Pigment dispersions D1-D6 are obtained respectively.

[0137] Application Example 5 (Pigment Dispersion)

[0138] A pigment dispersion, the preparation method is the same as that of Application Example 1, except that Pigment Blue is replaced with Pigment Orange 43 (produced by Heubach, model number PVFASTORANGEGRL). Pigment dispersions E1-E6 are obtained respectively.

[0139] Application Example 6 (Pigment Dispersion)

[0140] A pigment dispersion, the preparation method is the same as that of Application Example 1, except that Pigment Blue is replaced with Pigment Green 7 (produced by Heubach, model number HOSTAPERM GREEN GNX). Pigment dispersions F1-F6 are obtained respectively.

[0141] Application Examples 7-12 (Pigment Dispersion)

[0142] Application Examples 7-12 provide pigment dispersions, all of which are prepared using Pigment Black 7 (produced by Birla Carbon, model number Raven3500), and the raw materials and their dosages are shown in the following table. The preparation method is the same as that of Application Example 1.

[0143] Table 4 Raw Materials and Dosages of Pigment Dispersions in Application Examples 7-12 (Unit: g)

[0144]

[0145] Application Examples 13-18 (Pigment Dispersion)

[0146] Application Examples 13-18 provide pigment dispersions, all of which are prepared using Pigment Black 7 (produced by Birla Carbon, model number Raven3500), and the raw materials and their dosages are shown in the following table. The preparation method is the same as that of Application Example 1.

[0147] Table 5 Raw Materials and Dosages of Pigment Dispersions in Application Examples 13-18 (Unit: g)

[0148]

[0149]

[0150] Application Examples 19-22 (Pigment dispersion using a mixture of two aqueous dispersants)

[0151] Application Examples 19-22 provide pigment dispersions, all of which are prepared using Pigment Black 7 (produced by Birla Carbon Black, model Raven 3500), and the raw materials and amounts thereof are shown in the following table. The preparation method is the same as that of Application Example 1. In Application Example 19, the pigment addition amount of Product 2 and Product 5 is 25% each, and Application Examples 20-22 use similar combinations.

[0152] Table 6 Raw materials and amounts of pigment dispersions of Application Examples 19-22 (unit: g)

[0153]

[0154] Application Example 23-28 (Ink)

[0155] The pigment dispersions of the above-mentioned application examples 1-6 are selected, and the pigment dispersions prepared by using the aqueous dispersant of product 2, namely A2, B2, C2, D2, E2, and F2, are used to prepare inks with a pigment weight content of 5%. The preparation method is as follows: weigh each component and add it to a 1000mL beaker, use magnetic stirring to mix at a speed of 600 rpm for 30 minutes, and then filter through 1μm and 0.5μm filter membranes in turn for printing tests. The remaining components except deionized water are commercially available. The components and their amounts of application examples 23-28 are shown in the following table:

[0156] Table 7 Raw materials and amounts of inks in Application Examples 23-28 (unit: g)

[0157]

[0158] Application Example 29-34 (Ink containing two aqueous dispersants)

[0159] According to the formula of the pigment dispersion of Application Example 19 (using Product 2 and Product 5 as mixed aqueous dispersants), different pigments are then matched to prepare inks, wherein Product 2 and Product 5 each add 25% of the pigment. The ink preparation method is the same as that of Application Example 23. The only difference between the pigment dispersion ① (Pigment Red 122) and Application Example 19 is that Pigment Black 7 is replaced with an equal amount of Pigment Blue 15:4. The same applies to other pigment dispersions ②-⑥. Pigment dispersion ④ is Application Example 19. The components and contents of the ink are shown in the following table.

[0160] Table 8 Raw materials and amounts of inks of Application Examples 29-34 (unit: g)

[0161]

[0162]

[0163] Comparative Application Example 1

[0164] A pigment dispersion, the preparation method is the same as that of Application Example 1, except that Products 1-3 are respectively replaced with Products 7-9 to obtain pigment dispersions G1-G3.

[0165] Table 9 Components and Dosages of the Pigment Dispersions in Comparative Application Example 1 (Unit: g)

[0166] G1 G2 G3 Pigment 150 150 150 Deionized water 547.8 547.8 547.8 Glycerol 20 20 20 Diethylene glycol butyl ether 10 10 10 AMP-95 5 5 5 BYK-1770 5 5 5 Product 7 262.2 / / Product 8 / 262.2 / Product 9 / / 262.2

[0167] Comparative Application Example 2

[0168] A pigment dispersion, the preparation method is the same as that of Comparative Application Example 1, except that Pigment Blue is replaced with Pigment Red 122 (produced by Heubach, model INKJETMAGENTAE02). Pigment dispersions H1-H3 are respectively obtained.

[0169] Comparative Application Example 3

[0170] A pigment dispersion, the preparation method is the same as that of Comparative Application Example 1, except that Pigment Blue is replaced with Pigment Yellow 74 (produced by Heubach, model INKJET YELLOW 5GX-W). Pigment dispersions I1-I3 are respectively obtained.

[0171] Comparative Application Example 4

[0172] A pigment dispersion, the preparation method is the same as that of Comparative Application Example 1, except that Pigment Blue is replaced with Pigment Black 7 (produced by Birla Carbon Black, model Raven3500). Pigment dispersions J1-J3 are respectively obtained.

[0173] Comparative Application Example 5

[0174] A pigment dispersion, the preparation method is the same as that of Comparative Application Example 1, except that Pigment Blue is replaced with Pigment Orange 43 (produced by Heubach, model PVFASTORANGEGRL). Pigment dispersions K1-K3 are respectively obtained.

[0175] Comparative Application Example 6

[0176] A pigment dispersion, the preparation method is the same as that of Comparative Application Example 1, except that Pigment Blue is replaced with Pigment Green 7 (produced by Heubach, model HOSTAPERM GREEN GNX). Pigment dispersions L1-L3 are respectively obtained.

[0177] Product Effect Test

[0178] 1. Stability of Pigment Dispersion before and after Aging

[0179] (1) Test Method

[0180] Viscosity: Use a Brookfield viscometer to measure the viscosity of the pigment dispersion at 20°C and 10 revolutions per minute.

[0181] Particle Size: Use a Mastersizer 2000 laser particle size analyzer to measure the Dn of the pigment dispersion 50 particle size.

[0182] Surface Tension: Use a Kruss surface tension meter to measure the surface tension of the pigment dispersion.

[0183] Filtration Performance: Use a Buchner funnel, a suction flask, and a vacuum pump, together with a 0.5μm polypropylene filter membrane, to measure the time required for vacuum filtration of 500g of the dispersion, and evaluate its filtration performance.

[0184] Use the above methods to measure the viscosity, particle size, surface tension, and filtration time of the pigment dispersion before aging. Then place the pigment dispersion in an oven at 60°C for 7 days, and then use the above methods to measure the viscosity, particle size, surface tension, and filtration time of the pigment dispersion after aging. Generally, a change of ±5% in the viscosity, D 50 particle size, surface tension, and filtration time of the dispersion before and after aging is acceptable.

[0185] (2) Test Results

[0186] The above test results are shown in the following table:

[0187] Table 10 Viscosity, Dn of the Pigment Dispersion of Each Application Example 50 Particle Size

[0188]

[0189]

[0190] Table 11 Filtration Performance, Surface Tension of the Pigment Dispersion of Each Application Example

[0191]

[0192] As can be seen from the above table, for the pigment dispersions dispersed by Products 2, 3, 5, and 6, the change in viscosity before and after aging is small, all within 5%, and the performance is good, which can meet the requirements of inkjet printing applications. However, when Products 1 and 4 are used to disperse pigments, the change in viscosity of the obtained pigment dispersions before and after aging exceeds 5%, the particle size of some colors increases, and the filtration performance deteriorates, resulting in slightly worse performance.

[0193] Table 12 Viscosity, Dn of the Pigment Dispersion of Application Examples 7 - 1250 Particle size, surface tension

[0194]

[0195]

[0196] As can be seen from the above table, when the addition amounts of Products 2 and 3 are 30% of the pigment, the stability of the viscosity and particle size of the dispersion is poor. When the addition amounts of Products 2 and 3 are 40% and 60% of the pigment, a dispersion with stable viscosity, particle size and surface tension can be obtained, which can be better used for inkjet printing. In Examples 7-12, stable dispersions can also be obtained when the addition amount of Products 2 and 3 to the pigment is 50%. Therefore, in practical applications, the addition amount of Products 2 and 3 to the pigment is preferably 40%-60%.

[0197] Table 13 Viscosity and Dn of the pigment dispersions in Application Examples 13-18 50 Particle size, surface tension

[0198]

[0199] As can be seen from the above table, when the addition amounts of Products 5 and 6 are 30% of the pigment, the viscosity and particle size of the dispersion are poor. When the addition amounts of Products 5 and 6 are 40% and 60% of the pigment, a dispersion with stable viscosity, particle size and surface tension can be obtained, which can be better used for inkjet printing. In Examples 7-12, stable dispersions can also be obtained when the addition amount of Products 2 and 3 to the pigment is 50%. Therefore, in practical applications, the addition amount of Products 5 and 6 to the pigment is preferably 40%-60%.

[0200] Table 14 Viscosity and Dn of the pigment dispersions in Application Examples 19-22 50 Particle size, surface tension

[0201]

[0202]

[0203] As can be seen from the above table, for the system using two kinds of aqueous dispersants, a stable pigment dispersion that can be used for inkjet printing can be prepared when the total addition amount of the aqueous dispersants is 50%. This result is similar to that of using a single aqueous dispersant.

[0204] Table 15 Viscosity and Dn of the pigment dispersions in each comparative application example 50 Particle size, filterability, surface tension

[0205]

[0206] As can be seen from the above table, compared with Application Example 1, in Comparative Application Examples 1-6, only SMA was hydrolyzed, and the hydrolyzate obtained was used to disperse the pigment. The viscosity change range of the obtained dispersion before and after aging exceeded 5%, and the filterability and stability deteriorated, and none of them could meet the requirements for inkjet printing.

[0207] 2. Printing Test of Ink

[0208] The printing performance of the inks prepared in each application example was tested respectively. The method is as follows: After the pure cotton white cloth was dip-coated with the pretreatment solution, it was placed in an oven at 130 °C and dried for later use. Use an EPSON 3200 printer to print solid color blocks on the above white cloth, set the ink volume to 100%, and use an X-Rite SpectroEye color densitometer to measure the color density of the color blocks. Use a DataColor 500 spectrophotometer of Datacolor to measure the L*, a*, and b* values of the color blocks. These values represent the coordinates of each color in the color space defined by the International Commission on Illumination in 1976. Continue to set the ink output to 100% and continuously print on uncoated A4 paper to observe the printing smoothness and whether there are printing defects.

[0209] The test results are shown in the following table:

[0210] Table 16 Printing Test Results of Inks in Application Examples 23-28

[0211]

[0212] The results show that the inks in Application Examples 23-28 can all be smoothly printed by the printer for 500 mL without any situation of ink breakage or nozzle clogging, and have good printing performance. The color density and color saturation of the printed products can meet the requirements of textile digital printing.

[0213] Table 17 Printing Test Results of Inks in Application Examples 29-34

[0214]

[0215] As can be seen from the above table, the inks in Application Examples 29-34 can all be smoothly printed by the printer for 500 mL without any situation of ink breakage or nozzle clogging, and have good printing performance. The color density and color saturation of the printed products can meet the requirements of textile digital printing.

[0216] In summary, the aqueous dispersant provided by the present invention not only has good dispersion effect on various pigments by using amino acids to modify SMA, the inks prepared have good printing performance and great application potential, but also the raw materials are easily available and the preparation process is simple.

Claims

1. An aqueous dispersant, characterized in that Including the following raw materials: Amphiphilic resin, amino acid and water; The amphiphilic resin contains a hydrophobic segment and a hydrophilic segment; the hydrophobic segment is a styrene segment; and the hydrophilic segment is a maleic anhydride segment.

2. The aqueous dispersant according to claim 1, characterized in that The amphiphilic resin is styrene maleic anhydride resin, and / or the amino acid is at least one of arginine, lysine, glutamine, aspartic acid, cysteine ​​and homocysteine.

3. The aqueous dispersant according to claim 1, characterized in that The aqueous dispersant comprises the following raw materials in parts by weight: 700-900 parts of amphiphilic resin, 30-70 parts of amino acid, 1500-2500 parts of water.

4. The method for preparing the aqueous dispersant according to any one of claims 1 to 3, characterized in that: The steps include: The amphiphilic resin and water are first mixed, and then amino acids are added, and the pH value is adjusted to be greater than or equal to 10, and a reaction is carried out to prepare the aqueous dispersant.

5. The preparation method according to claim 4, characterized in that: The reaction temperature is 60-80° C., and / or the reaction time is 5-15 h.

6. Use of the aqueous dispersant according to any one of claims 1 to 3 in the preparation of pigments, inks or printing inks.

7. A pigment dispersion, characterized in that: The components include: The aqueous dispersant according to any one of claims 1 to 3, a pigment and water.

8. The method for preparing the pigment dispersion according to claim 7, characterized in that: The steps include: The pigment dispersion is prepared by mixing water and an aqueous dispersant, then adding a pigment, grinding, and filtering.

9. An ink, characterized in that: The components include: The pigment dispersant, film former, humectant, cosolvent, surfactant, pH regulator and water as described in claim 7.

10. The method for preparing the ink according to claim 9, comprising the following steps: The ink is prepared by mixing the components and filtering them.

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