UV ink jet composition and preparation method thereof

Abstract

The invention relates to the technical field of photocuring color paste, in particular to the field of IPC C09D17, and more specifically relates to a UV ink jet composition and a preparation method thereof. The composition comprises the following components: polyester acrylate resin, an acrylate monomer, an amine compound, an initiator, toner and a dispersing agent, and the dispersing agent comprises a maleimide-styrene copolymer with an ammonium salt structure. The UV ink jet composition contains the maleimide-styrene copolymer dispersing agent with an ammonium salt structure, and is matched with the specific resin monomer, so that the amine compatibility is excellent, the long-acting storage stability can be obtained, and the viscosity change is avoided. The pigment particles are provided with the same electric charge, so that co-flocculation caused by different electric charges is prevented. And due to excellent deflocculation, the particles are smaller, and the particle size distribution is narrower.

Description

Technical Field

[0001] The present invention relates to the technical field of photocurable color paste, in particular to the field of IPC C09D17, and more specifically to a UV inkjet composition and a preparation method thereof. Background Art

[0002] UV inkjet refers to ultraviolet curing digital inkjet, which is developed on the basis of ultraviolet curing printing ink. It has a history of more than 50 years and is an ancient printing ink variety that has been widely used in the printing industry. Among them, the most important thing in the ultraviolet curing digital inkjet process is the UV digital ink used. The biggest feature of ultraviolet curing digital inkjet is the viscosity and rheology. The viscosity of printing ink is relatively high, and the rheology belongs to pseudoplastic fluid, while inkjet requires low viscosity and high tension, and the rheology is as close to Newtonian fluid as possible, requiring good fluidity. Therefore, the stability, compatibility and leveling of the pigment dispersion are particularly important.

[0003] Chinese invention patent CN113736316B discloses a UV-curable inkjet ink, which contains one or more photoinitiators, organic color pigments and a polymerizable composition containing at least one monofunctional polymerizable compound and at least one multifunctional polymerizable compound, wherein the organic color pigment is present in an amount of 6.0 to 13.0 wt% based on the total weight of the liquid UV-curable inkjet ink; the at least one multifunctional polymerizable compound is present in an amount of at least 20.0 wt% based on the total weight of the polymerizable composition; and the UV-curable inkjet ink is heated to 45°C and 10 s. -1 The viscosity at a shear rate of at least 16.0 mPa.s. However, the ink of the invention does not investigate stability. Summary of the invention

[0004] The first aspect of the present invention provides a UV inkjet composition, the components of which include: polyester acrylate resin, acrylate monomer, amine compound, initiator, toner and dispersant, wherein the dispersant includes a maleimide-styrene copolymer having an ammonium salt structure.

[0005] The number average molecular weight of the dispersant is 1,000 to 50,000, accounting for 0.1 to 5% of the total mass of the UV inkjet composition.

[0006] Optionally, the general structural formula of the dispersant is shown in at least one of the following formulae:

[0007]

[0008] Where R 1 represents an alkylene group, R 2 s independently represents a hydrogen atom or a methyl group, R 3represents a hydrogen atom or an alkyl group, R 4 represents an alkylene group, X+ represents a quaternary ammonium group, Z represents a counter anion, and n1, n2 and n3 independently represent the molar ratio of their respective constituent units, satisfying (n1): (n2+n3) = 1:99 to 99:1, and satisfying n2:n3 = 1:99 to 99:1.

[0009] Optionally, the ammonium salt structure is located in a component unit derived from a maleamide compound, as shown in Formula 2 below:

[0010]

[0011] Optional R a1 To R a3 independently represent a hydrogen atom, an alkyl group or an aryl group, Z 4 - indicates the counter anion, and the average line portion indicates the position of binding to another structure.

[0012] Where R a1 To R a3 Z is preferably independently an alkyl group or an aryl group, more preferably an alkyl group having 1 to 20 carbons or an aryl group having 6 to 10 carbons, still more preferably an alkyl group having 1 to 20 carbons, particularly preferably an alkyl group having 1 to 8 carbons, and most preferably a methyl group. 4 - preferably one selected from the following: anions of halide ion, sulfate anion, hydrogen sulfate anion, sulfonate anion, carboxylate anion, nitrate anion, phosphate anion, calcium hydrogen phosphate anion, dihydrogen phosphate anion, phosphonate anion and borate anion, more preferably one selected from the following: anions of halide ion, sulfonate ion, carboxylate ion, PF6- and BF4-.

[0013] The synthesis method of the dispersant is not particularly limited, and for example, a method can be preferably cited, wherein after copolymerization of styrene and maleic anhydride, the maleic anhydride structure is reacted with a compound having at least a primary amino group and a tertiary amino group to convert the maleic anhydride structure into a maleimide structure, thereby converting the tertiary amino group into a quaternary ammonium structure.

[0014] The dispersant includes an ethylene oxide structure or a propylene oxide structure.

[0015] The dispersant includes at least one of the following models: BYK-161, BYK-162, BYK-163, BYK-164, BYK-166, BYK-167, BYK-168, EFKA-4010, EFKA-4046, EFKA-4080, and EFKA-5010.

[0016] Optionally, the functionality of the polyester acrylate resin is 2-4.

[0017] The components of the UV inkjet composition also include at least one of a co-initiator, a light stabilizer and a leveling agent.

[0018] The acrylate monomers include phenoxyethyl acrylate (PHEA), hexanediol diacrylate (HDDA) and tetrahydrofurfuryl acrylate (THFA), and the weight ratio of PHEA, HDDA and THFA is (1.5-5): (1-2.5): (7-12).

[0019] Optionally, the weight ratio of PHEA, HDDA and THFA is (2-4):(1-2):(7-10).

[0020] The weight ratio of the polyester acrylate resin, the acrylate monomer and the dispersant is 1:(25-40):(0.2-1.5).

[0021] The applicant has found that the weight ratio of acrylate monomers PHEA, HDDA and THFA is (1.5-5): (1-2.5): (7-12), which can control the viscosity at 45°C to 10mPa·s and has excellent wet friction performance. It is possible that the above-mentioned acrylic monomers act as diluents to reduce the viscosity of the system while increasing the cohesion of the ink molecular system and improving the smoothness of the ink film surface, thereby reducing the dynamic friction coefficient, ensuring wear resistance and making it have good water resistance to prevent the ink from dissolving or falling off in a humid environment. Further research has found that the use of a specific maleimide-styrene copolymer dispersant with an ammonium salt structure can achieve long-term storage stability and improve the compatibility of amines. It is possible that it promotes the dispersion of the polymer system, approaches a Newtonian fluid, and makes the pigment particles carry the same charge, thereby preventing co-flocculation due to different charges.

[0022] Optionally, the weight ratio of the polyester acrylate resin, the acrylate monomer and the dispersant is 1:(25-40):(0.2-1.5).

[0023] The amine compound includes at least one of N-acryloylmorpholine (ACMO), N-vinylcaprolactam (NVC), N-hydroxyethylacrylamide (HEAA), dimethylacrylamide (DMAA), and N,N-dimethylacrylamide (DMAM).

[0024] The initiator includes TPO (trimethylbenzoyl-diphenylphosphine oxide), DETX (2,4-diethylthioxanthone) and 819 (diacylphosphine oxide 819), and the weight ratio of TPO, DETX and 819 is 5:(0.5-3):(1-4).

[0025] Optionally, the weight ratio of TPO, DETX and 819 is 5:(1-2):(1-3).

[0026] Optionally, the toner includes at least one of the following models: DIC RG, Cabot 250R, BASF 7110F, and BASF 1085J SQ.

[0027] A second aspect of the present invention provides a method for preparing a UV inkjet composition, comprising the following steps:

[0028] S1, grinding a dispersant, a color powder and 10-30 wt% of THFA to obtain a base material;

[0029] S2, mixing the remaining components with the base material, stirring evenly, and obtaining the product.

[0030] The grinding comprises the following steps:

[0031] Step 1: Using a disperser, stir THFA and a dispersant accounting for 10-30 wt% of the total THFA, and then add the color powder and continue stirring;

[0032] Step 2: Use a grinder without a separator to grind coarsely first;

[0033] Step 3: Filter with PP filter paper and grind finely with a separator grinder.

[0034] Optionally, the grinding comprises the following steps:

[0035] Step 1: THFA and dispersant accounting for 7 wt% of the total THFA are stirred for 30 min at 300 rpm using a disperser, and then color powder is added and stirred at 450 rpm for about 1 h;

[0036] Step 2: First use a separator-free grinder for coarse grinding, preferably with rotor material: zirconia, rotor structure: turbine pin + inner rotor pin, screen-free separation vertical grinder, zirconium bead filling amount: 85wt%, zirconium bead model: 0.3mm, air humidity: 60RH%, temperature: 28℃, grinding speed: 1500rpm, grinding flow: 1.2kg / min, grinding time: 1.5h.

[0037] Step 3: Use 1-micron PP filter paper to filter and then use a separator grinder for fine grinding. A ceramic rod-pin bedroom grinder is preferred. Its advantages are that the shorter and larger diameter grinding chamber can reduce the flow inertia force, and the longer and larger diameter separation system can make the particle size dispersed evenly and concentrated. Zirconium bead filling amount: 85wt%, zirconium bead model: 0.1mmm, sand mill separator gap: 0.05mm, air humidity: 60RH%, temperature: 28℃, grinding speed: 1500rpm, grinding flow: 1.2kg / min, grinding time: 2h.

[0038] Beneficial Effects

[0039] 1. The present application selects a dispersant of a maleimide-styrene copolymer having a specific ammonium salt structure to achieve long-term storage stability and improve the compatibility with amines.

[0040] 2. The dispersant includes an ethylene oxide structure or a propylene oxide structure, which can solve the particle size distribution and agglomeration phenomenon during the dispersion process of ink particles.

[0041] 3. The weight ratio of acrylate monomers PHEA, HDDA and THFA is (1.5-5): (1-2.5): (7-12), which can control the viscosity at 45°C to 10mPa·s and has excellent wet friction performance.

[0042] 4. The weight ratio of polyester acrylate resin, acrylate monomer and dispersant is 1:(25-40):(0.2-1.5), which can improve the standby performance of ink for printing on the machine.

[0043] 5. Through a specific three-step grinding process, the filterability and smoothness of the ink on the machine printing can be improved. DETAILED DESCRIPTION

[0044] Examples 1-4, Comparative Examples 1-3

[0045] A UV inkjet composition, calculated by weight, has a formula as shown in Table 1:

[0046] Table 1

[0047]

[0048] A method for preparing a UV inkjet composition comprises the following steps:

[0049] S1, grinding a dispersant, a color powder and THFA accounting for 7 wt% of the total amount of THFA to obtain a base material;

[0050] S2, mix the remaining components with the base material, and stir at 1500 rpm for 30 min.

[0051] The grinding is specifically the following steps:

[0052] Step 1: Use a disperser to stir 10-30wt% THFA and dispersant at 300rpm for 30min, then add color powder and continue stirring at 450rpm for about 1h;

[0053] Step 2: First, use a separator-free grinder for rough grinding, preferably a rotor material of zirconium oxide, a rotor structure of turbine pin + inner rotor pin, a screen-free separation vertical grinder, a zirconium bead filling amount of 85wt%, a zirconium bead model of 0.3mm, an air humidity of 60RH%, a temperature of 28°C, a grinding speed of 1500rpm, a grinding flow rate of 1.2kg / min, and a grinding time of 1.5h;

[0054] Step 3: Use 1-micron PP filter paper to filter and then use a separator grinder for fine grinding. A ceramic rod-pin bedroom grinder is preferred. Its advantages are that the shorter and larger diameter grinding chamber can reduce the flow inertia force, and the longer and larger diameter separation system can make the particle size dispersed evenly and concentrated. Zirconium bead filling amount: 85wt%, zirconium bead model: 0.1mmm, sand mill separator gap: 0.05mm, air humidity: 60RH%, temperature: 28℃, grinding speed: 1500rpm, grinding flow: 1.2kg / min, grinding time: 2h.

[0055] Performance testing methods and data

[0056] 1. The inks prepared in the examples and comparative examples were subjected to performance tests at room temperature (25° C.), and the test data are listed in Table 2.

[0057] 2. The inks prepared in the examples and comparative examples were put on a machine to test their readiness, filterability and fluidity. The test data are listed in Table 2.

[0058] 3. The inks prepared in the examples and comparative examples were subjected to an amine compatibility test (replacing any one of the amine compounds in Table 1 and conducting the same test), and the test data are listed in Table 2.

[0059] 4. The inks prepared in the examples and comparative examples were aged (60° C., 21 days) and then subjected to performance tests. The test data are listed in Table 2.

[0060] “\” indicates that no test was performed.

[0061] Table 2

[0062]

[0063]

Claims

1. A UV inkjet composition, characterized in that: Components include: Polyester acrylate resin, acrylate monomer, amine compound, initiator, color powder and dispersant, wherein the dispersant comprises maleimide-styrene copolymer with ammonium salt structure.

2. The UV inkjet composition according to claim 1, characterized in that The number average molecular weight of the dispersant is 1,000 to 50,000, accounting for 0.1 to 5% of the total mass of the UV inkjet composition.

3. The UV inkjet composition according to claim 2, characterized in that The dispersant includes an ethylene oxide structure or a propylene oxide structure.

4. The UV inkjet composition according to claim 3, characterized in that The dispersant includes at least one of the following models: BYK-161, BYK-162, BYK-163, BYK-164, BYK-166, BYK-167, BYK-168, EFKA-4010, EFKA-4046, EFKA-4080, and EFKA-5010.

5. The UV inkjet composition according to claim 4, characterized in that: The components of the UV inkjet composition also include at least one of a co-initiator, a light stabilizer and a leveling agent.

6. The UV inkjet composition according to claim 5, characterized in that The acrylate monomers include PHEA, HDDA and THFA, and the weight ratio of PHEA, HDDA and THFA is (1.5-5): (1-2.5)：(7-12)。 7. The UV inkjet composition according to claim 6, characterized in that The weight ratio of the polyester acrylate resin, the acrylate monomer and the dispersant is 1:(25-40):(0.2-1.5).

8. The UV inkjet composition according to claim 7, characterized in that: The amine compound includes at least one of ACMO, NVC, HEAA, DMAA and DMAM.

9. A method for preparing the UV inkjet composition according to any one of claims 6 to 8, characterized in that: The following steps are involved: S1, grinding a dispersant, a color powder and 10-30 wt% of THFA to obtain a base material; S2, mixing the remaining components with the base material, stirring evenly, and obtaining the product.

10. The method for preparing the UV inkjet composition according to claim 9, characterized in that: The grinding comprises the following steps: Step 1: Use a disperser to mix THFA and a dispersant accounting for 10-30wt% of the total THFA, and then add the color powder and continue to mix evenly; Step 2: Use a grinder without a separator to grind coarsely; Step 3: Use PP filter paper to filter and then grind it into fine powder using a separator grinder to obtain the base material.

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