CN111574682B

CN111574682B - Waterborne polyurethane dispersant and color paste containing same for textile digital printing

Info

Publication number: CN111574682B
Application number: CN202010305300.6A
Authority: CN
Inventors: 刘明辉; 梁文龙; 杨飞虎
Original assignee: Zhuhai Zhongmo Technology Co ltd
Current assignee: Zhuhai Chuanmeixun New Materials Co ltd
Priority date: 2020-04-17
Filing date: 2020-04-17
Publication date: 2021-06-18
Anticipated expiration: 2040-04-17
Also published as: CN111574682A

Abstract

The invention belongs to the field of materials, and particularly discloses a water-based polyurethane dispersant which is mainly prepared from a hydrophobic monomer, an anchoring monomer, a hydrophilic monomer, a catalyst, a capping agent and a solvent; the hydrophobic monomer is at least one of polytetrahydrofuran diol, polycarbonate diol and polycaprolactone diol; the anchoring monomer is a benzene ring-containing and nitrogen-based derivative monomer; the hydrophilic monomer is polyethylene glycol and/or a chain extender. The prepared main chain of the dispersant has an anchoring structure which is strongly adsorbed with the surface of the dye, can carry out high-compatibility strong adsorption on the surface of the dye, and can effectively reduce the surface energy of the disperse dye; meanwhile, the hydrophilic structure has good compatibility with water, the hydrophilic structure can be smoothly unfolded to form three-dimensional space obstacle or electrostatic repulsion, and the dispersing ability is strong and the stability is good. The color paste for textile digital printing prepared by the waterborne polyurethane dispersant has high dispersibility and stability.

Description

Waterborne polyurethane dispersant and color paste containing same for textile digital printing

Technical Field

The invention belongs to the field of materials, and particularly relates to a waterborne polyurethane dispersant and a color paste containing the same for textile digital printing.

Background

The traditional textile printing needs to use a large amount of water to clean sizing agent and uncolored pigment, and the generated waste water is considerable and has great influence on the environment; when the printed and dyed cloth is dried, a large amount of heat energy needs to be consumed, so that the cost is high; and the color paste coating required by the traditional screen printing is far higher than the ink amount required by ink-jet digital printing, the ink amount required by the ink-jet digital printing is low, and the resolution and the precision are also higher than those of the screen printing. Because the ink consumption of the ink-jet digital printing ink is low, the energy required for transfer printing and drying is obviously lower than that of the traditional textile printing, even drying is not needed, and the method has great advantages for the high-speed textile printing and dyeing industry. In addition, the ink-jet digital printing process of printing as required can reduce or eliminate cloth pulp washing process, greatly reduce the generation of sewage, and is a clean and environment-friendly green process.

Although the ink-jet digital printing has many advantages, the problems of broken holes, oblique jetting or no ink discharge are caused by the blockage of the nozzle due to the uneven and unstable dye dispersion. Therefore, how to ensure stable dispersion of the dye particles in the ink becomes a problem to be solved urgently.

Non-structured dispersants, such as conventional small molecule dispersants or polymeric dispersants, have been conventionally used, in which the anchor group has too few or too weak adsorption sites for the disperse dye, and the hydrophilic chain is too short or too long, and affinity for water is too poor to generate sufficient steric hindrance or electrostatic repulsion. Therefore, the water-based textile digital printing paste with strong dispersion and high stability cannot be obtained, and the disperse dye is easy to separate out, settle and block the spray head.

Therefore, it is desirable to provide a strongly dispersible, highly stable aqueous dispersant.

Disclosure of Invention

The present invention is directed to solving at least one of the problems of the prior art described above. Therefore, the invention provides the waterborne polyurethane dispersant which has strong dispersibility and high stability and can solve the problems of uneven and unstable dye dispersion.

A water-based polyurethane dispersant is mainly prepared from a hydrophobic monomer, an anchoring monomer, a hydrophilic monomer, a catalyst, a capping agent and a solvent; the hydrophobic monomer is at least one of polytetrahydrofuran diol, polycarbonate diol or polycaprolactone diol; the anchoring monomer is a benzene ring-containing and nitrogen-based derivative monomer; the hydrophilic monomer is polyethylene glycol and/or a chain extender.

The anchoring monomer has the function of increasing the anchoring group of the structure of the disperse dye in the dispersant, and helps the dispersant to be adsorbed to the surface of the disperse dye more strongly and stably. The hydrophilic monomer has the function of increasing the compatibility of the dispersing agent to water, and the molecular chain length and electrostatic force of the hydrophilic monomer are utilized to generate steric hindrance and electrostatic repulsion, so that the disperse dye is stably dispersed.

The dispersing agent is mainly prepared from the following raw materials in parts by weight:

preferably, the molecular weight of the hydrophobic monomer is 100-2000; further preferably, the molecular weight of the hydrophobic monomer is 200-1000. Too large weight average molecular weight of the hydrophobic monomer can cause too far spacing of anchoring groups and weakening adsorption force on pigment particles; the molecular weight is too small, the anchoring groups are too closely spaced to be effectively adsorbed.

Preferably, the anchoring monomer is at least one of diphenylmethane diisocyanate, dimethylbiphenyl diisocyanate, or naphthalene diisocyanate.

Preferably, the hydrophilic monomer is polyethylene glycol and/or a chain extender;

preferably, the molecular weight of the polyethylene glycol monomer is 500-15000; further preferably, the molecular weight of the polyethylene glycol monomer is 1000-10000. Too large weight average molecular weight of the hydrophilic monomer can cause too long molecular chains to generate winding flocculation, and the dispersion of pigment particles is poor; the molecular weight is too small, the chain length of the molecules is too short, effective steric hindrance cannot be formed, and the particles are easy to aggregate and have coarse particle size.

Preferably, the chain extender is one or more of tartaric acid, dimethylolpropionic acid, dimethylolbutyric acid, diaminobenzoic acid, diaminopentanoic acid, diaminocaproic acid, diethanolamine, 1, 2-propanediol-3-sulfonate or 1, 4-butanediol-2-sulfonate. The chain extender has the functions of increasing the water solubility of the dispersing agent and generating electrostatic repulsion, and promotes the dispersion stability of the disperse dye.

Preferably, the catalyst is at least one of organic tin, organic zinc or organic titanium; further preferably, the catalyst is at least one of dibutyltin dilaurate, dioctyltin dilaurate, stannous octoate, dibutyltin diacetate, dibutyltin dioleate, zinc isooctanoate, or tetrabutyl titanate. The catalyst functions to activate the anchoring monomer to enable it to undergo polymerization with other monomers.

Preferably, the end-capping agent is one or more of dimethylethanolamine, taurine, sodium bisulfite, sodium hydroxymethylsulfonate, sodium isethionate, sodium polypropyleneglycol diamine propylsulfonate, sodium sulfamate, and the like. The end capping agent is used for deactivating the terminal reactive group of the synthesized dispersant, so that the dispersant is prevented from continuously reacting during storage or use.

Preferably, the solvent is at least one of acetone, dimethyl sulfoxide, sulfolane, dimethylformamide, methylpyrrolidone or pyrrolidone; the solvent serves to dissolve the monomers, catalyst, and dispersant upon completion of the polymerization, allowing for rapid reaction in a homogeneous phase.

A preparation method of the water-based polyurethane dispersant comprises the following steps:

(1) under the state of protective atmosphere, adding the hydrophilic monomer, the hydrophobic monomer and the catalyst into the solvent, and mixing to obtain a mixture A;

(2) heating the mixture A, and adding the anchoring monomer to obtain a mixture B;

(3) and heating the mixture B, reacting, and adding an end-capping reagent to obtain the waterborne polyurethane dispersant.

Preferably, the heating step in the step (2) is heating to 40-80 ℃; further preferably, the heating step in the step (2) is heating to 50-70 ℃.

Preferably, the heating step in step (3) is heating to 80-130 ℃; further preferably, the heating step in step (3) is heating to 90-110 ℃.

Specifically, the preparation method of the waterborne polyurethane dispersant comprises the following steps:

(2) heating the mixture A to 40-80 ℃, and adding the anchoring monomer to obtain a mixture B;

(3) and heating the mixture B to 80-130 ℃, reacting until the concentration of isocyanate groups (% NCO) is lower than 5%, adding a blocking agent, and reacting for 1-5 hours to obtain the waterborne polyurethane dispersant.

The color paste for textile digital printing comprises water, dye and the aqueous polyurethane dispersant.

Preferably, the color paste for textile digital printing comprises the following components in parts by weight: 50-90 parts of water, 10-50 parts of dye and 5-25 parts of the waterborne polyurethane dispersant.

Preferably, the dye includes red disperse dye 1, 11, 22, 50, 60, 65, 74, 92, 146, 239; yellow disperse dyes 7, 23, 42, 51, 54, 60, 65, 82, 98, 114, 160, 211; brown disperse dyes 1, 5, 19, 21, 27, 30; orange disperse dyes 25, 37, 119; blue disperse dye 14, 26, 56, 60, 72, 91, 165, 359, 360, 366; or mixtures of the above colorants, and the like.

Preferably, the color paste also comprises 0-25 parts of cosolvent and/or 0-5 parts of wetting agent.

Preferably, the cosolvent is at least one of alcohol, ether and alcohol ether, such as isopropanol, ethanol, methyl ether, ethyl ether, ethylene glycol, propylene glycol, and the like.

Preferably, the wetting agent is one or more of BYK154/190/306/333/346/378, DYNFET 800N, Evonik SURFYNOL104E/420/465, DYNOL 604/607.

A preparation method of color paste for textile digital printing comprises the following steps:

(1) dissolving the waterborne polyurethane dispersant and the rest components in water to obtain a pre-dispersion liquid;

(2) and (2) grinding and filtering the pre-dispersion liquid obtained in the step (1), and taking filtrate to obtain the color paste.

Compared with the prior art, the invention has the following beneficial effects:

the waterborne polyurethane dispersant is mainly prepared from a hydrophobic monomer, an anchoring monomer and a hydrophilic monomer; the hydrophobic monomer is at least one of polytetrahydrofuran diol, polycarbonate diol and polycaprolactone diol; the anchoring monomer is a benzene ring-containing and nitrogen-based derivative monomer; the hydrophilic monomer is polyethylene glycol. The main chain of the prepared dispersing agent has an anchoring structure which is strongly adsorbed with the surface of the disperse dye, can simultaneously carry out high-compatibility strong adsorption on the surface of the disperse dye, is not easy to fall off and replace, and can effectively reduce the surface energy of the disperse dye; meanwhile, the hydrophilic structure has good compatibility with water, the hydrophilic structure can be smoothly unfolded to form three-dimensional space obstacle or electrostatic repulsion, and the dispersing ability is strong and the stability is good. The color paste for textile digital printing prepared by the waterborne polyurethane dispersant has high dispersibility and stability.

Detailed Description

In order to make the technical solutions of the present invention more apparent to those skilled in the art, the following examples are given for illustration. It should be noted that the following examples are not intended to limit the scope of the claimed invention.

Example 1

Introducing nitrogen into a reaction bottle provided with a condensing reflux device, and adding 408.5g of methyl pyrrolidone as a solvent at normal temperature; then 37g of polytetrahydrofuran diol (Mw: 250), 6g of tartaric acid, 0.3g of dibutyltin dilaurate and 486g of polyethylene glycol (Mw: 5000) were mixed and heated to 60 ℃ with stirring; then adding 42g of naphthalene diisocyanate into a reaction bottle, heating to 100 ℃ to accelerate the reaction until the concentration of isocyanate group (NCO) is lower than 5%, and finally adding 2.2g of sodium sulfamate to react for at least 1 hour to obtain 59.15% of waterborne polyurethane dispersant with effective components; 690g of the solution were then added

Na⁺SO₃ ^--NH-capping agent

Aminosulfonic acid sodium salt

Water was added to the reaction solution, and the system pH was adjusted to 9 to obtain an aqueous solution SA1 of an aqueous polyurethane dispersant containing 35% of an active ingredient. SA1 includes compounds with molecular structures of structure A, structure B and structure C.

Example 2

Introducing nitrogen into a reaction bottle provided with a condensation reflux device, and adding a solvent 409.2g of dimethyl sulfoxide at normal temperature; then 52g of polycaprolactone diol (Mw 500), 4g of diaminopentanoic acid, 0.3g of tetrabutyltitanate and 480g of polyethylene glycol (Mw 7000) were mixed and heated to 60 ℃ with stirring; adding 53g of diphenylmethane diisocyanate into a reaction bottle, heating to 90 ℃ to accelerate the reaction until the concentration of isocyanate groups (NCO) is lower than 5%, and finally adding 1.5g of sodium bisulfite to react for at least 1 hour to obtain 59.08% of waterborne polyurethane dispersant with active ingredients; then, 714g of water was added thereto, and the system pH was adjusted to 9, to obtain an aqueous solution SA2 of an aqueous polyurethane dispersant containing 35% of an active ingredient. SA2 includes compounds having the molecular structures Structure D, Structure E, and Structure F.

Example 3

Introducing nitrogen into a reaction bottle provided with a condensing reflux device, and adding 406.6g of sulfolane as a solvent at normal temperature; then 110g of polycarbonate diol (Mw ═ 500), 6g of dimethylolbutyric acid, 0.3g of dibutyltin diacetate and 350g of polyethylene glycol (Mw ═ 2000) were mixed and heated to 70 ℃ with stirring; adding 121g of dimethyl biphenyl diisocyanate into a reaction bottle, heating to 100 ℃ to accelerate the reaction until the concentration of isocyanate (NCO) is lower than 5%, and finally adding 4.1g of sodium hydroxymethyl sulfonate to react for at least 1 hour to obtain a waterborne polyurethane dispersant with 59.34% of effective components; 695.4g of water was added thereto, and the pH of the system was adjusted to 9 to obtain an aqueous solution SA3 of an aqueous polyurethane dispersant containing 35% of an active ingredient.

Example 4

Mixing 508g of aqueous polyurethane dispersant solution SA1 (equivalent to 8.89 percent of active ingredient) with 1092g of deionized water, and stirring until the aqueous polyurethane dispersant solution is completely dissolved to obtain an aqueous pre-solution; then 400g of blue 359 disperse dye is mixed with the aqueous pre-solution, and the mixture is stirred to ensure that the disperse dye is completely wetted to obtain an aqueous pre-dispersion liquid; introducing the aqueous pre-dispersion liquid into a sand mill for grinding until the average particle size is 100-150 nm; filtering to remove the colloid and large particle size, and obtaining the color paste for textile digital printing with stable dispersion.

Example 5

602g of aqueous polyurethane dispersant aqueous solution SA2 (equivalent to 10.54 percent of active ingredient) is mixed with 998g of deionized water, and the mixture is stirred until the aqueous polyurethane dispersant aqueous solution SA2 and the deionized water are completely dissolved to obtain an aqueous pre-solution; then mixing 400g of red 60 disperse dye with the aqueous pre-solution, and stirring to completely wet the disperse dye to obtain an aqueous pre-dispersion solution; introducing the aqueous pre-dispersion liquid into a sand mill for grinding until the average particle size is 100-150 nm; filtering to remove the colloid and large particle size, and obtaining the color paste for textile digital printing with stable dispersion.

Example 6

618g of the aqueous solution SA3 (equivalent to 10.82 percent of the active ingredient) of the aqueous polyurethane dispersant is mixed with 982g of deionized water, and the mixture is stirred until the mixture is completely dissolved to obtain an aqueous pre-solution; then mixing 400g of yellow 54 disperse dye with the aqueous pre-solution, and stirring to completely wet the disperse dye to obtain an aqueous pre-dispersion liquid; introducing the aqueous pre-dispersion liquid into a sand mill for grinding until the average particle size is 100-150 nm; filtering to remove the colloid and large particle size, and obtaining the color paste for textile digital printing with stable dispersion.

Example 7

1150g of the aqueous solution SA3 (equivalent to 20.13 percent of the active ingredient) of the aqueous polyurethane dispersant is mixed with 450g of deionized water, and the mixture is stirred until the mixture is completely dissolved to obtain an aqueous pre-solution; then mixing 400g of brown 27 disperse dye with the aqueous pre-solution, and stirring to completely wet the disperse dye to obtain an aqueous pre-dispersion liquid; introducing the aqueous pre-dispersion liquid into a sand mill for grinding until the average particle size is 100-150 nm; filtering to remove the colloid and large particle size, and obtaining the color paste for textile digital printing with stable dispersion.

Comparative example 1

Introducing nitrogen into a reaction bottle provided with a condensing reflux device, and adding 408g of methyl pyrrolidone serving as a solvent at normal temperature; then 39g of polytetrahydrofuran diol (Mw 250), 8g of tartaric acid, 0.3g of dibutyltin dilaurate and 500g of polycaprolactone diol (Mw 5000) were mixed and heated to 60 ℃ with stirring; then adding 42g of naphthalene diisocyanate into a reaction bottle, heating to 100 ℃ to accelerate the reaction until the concentration of isocyanate group (NCO) is lower than 5%, and finally adding 2.7g of sodium sulfamate to react for at least 1 hour to obtain a dispersant solution with 60% of effective components; then, 691g of water was added thereto, and the system pH was adjusted to 9, to obtain an aqueous solution SA4 of a dispersant containing 35% of the active ingredient.

Comparative example 2

Mixing 200g of Lubozun W100 dispersant (equivalent to 10 percent of effective component) with 1400g of deionized water, and stirring until the dispersant is completely dissolved to obtain an aqueous pre-solution; then mixing 400g of red 60 disperse dye with the aqueous pre-solution, and stirring to completely wet the disperse dye to obtain an aqueous pre-dispersion solution; and (3) introducing the aqueous pre-dispersion liquid into a sand mill for grinding, and filtering to remove colloid and large particle size to obtain the contrast color paste.

Comparative example 3

Mixing 508g of multi-element structure dispersant aqueous solution SA4 (equivalent to 8.89 percent of active ingredient) with 1092g of deionized water, and stirring until the mixture is completely dissolved to obtain an aqueous pre-solution; then 400g of blue 359 disperse dye is mixed with the aqueous pre-solution, and the mixture is stirred to ensure that the disperse dye is completely wetted to obtain an aqueous pre-dispersion liquid; and (3) introducing the aqueous pre-dispersion liquid into a sand mill for grinding, and filtering to remove colloid and large particle size to obtain the contrast color paste.

Stability test

Firstly, preparing an ink combined liquid sample for stability test. The preparation method of the ink composition liquid is to dilute the color paste by 5 times by using 15% glycerol aqueous solution. And then, carrying out particle size, viscosity, surface tension, filterability and aging tests on the ink composition liquid. Particle size was measured using a Marvin (Malvern) Nano S90 nanosize particle sizer in British. Viscosity was measured using a Wells cone and plate viscometer, Bohler fly (Brookfield). Surface tension test, Japan synergy (KYOWA) CBVP type surface tensiometer. And (4) testing the filterability, namely filtering by adopting a glass fiber filter membrane with the aperture of 1.0 mu m and a PP filter membrane with the aperture of 0.45 mu m. And (3) testing the stability, namely aging for 7 days at the high temperature of 60 ℃, and testing the particle size, viscosity, surface tension and filterability after aging. The test results are shown in table 1, wherein the QC evaluation criteria: the average particle size is 100-200nm, the viscosity is 3-6cp, the surface tension is 35-45dyn/cm, and the filtering property is less than 15 min/kg; and (3) testing the stability, aging at the high temperature of 60 ℃ for 7 days, wherein the particle size change is less than 10%, the surface tension change is less than 5%, the viscosity change is less than 10%, the filterability is less than 15min/kg, the product is qualified OK, and otherwise, the product is NG.

TABLE 1 stability of inks obtained in examples 1 to 4 and comparative example 1

As can be seen from the test results in Table 1: the color paste for textile digital printing provided by the invention has good stability, and the prepared ink has good stability after aging for 7 days, and the particle size, viscosity, surface tension and filterability are still good.

Claims

1. The waterborne polyurethane dispersant is characterized by being mainly prepared from the following raw materials in parts by weight:

3-20 parts of hydrophobic monomer

5-20 parts of anchoring monomer

30-60 parts of hydrophilic monomer

0.01 to 0.5 portion of catalyst

0.1 to 1 portion of end capping agent

30-50 parts of a solvent;

the hydrophobic monomer is at least one of polytetrahydrofuran diol, polycarbonate diol or polycaprolactone diol; the hydrophilic monomer is polyethylene glycol and a chain extender;

the anchoring monomer is at least one of diphenylmethane diisocyanate, dimethylbiphenyl diisocyanate or naphthalene diisocyanate;

the chain extender is one or more of tartaric acid, dimethylolpropionic acid, dimethylolbutyric acid, diaminobenzoic acid, diaminopentanoic acid, diaminohexanoic acid, 1, 2-propanediol-3-sulfonate or 1, 4-butanediol-2-sulfonate;

the molecular weight of the polyethylene glycol monomer is 1000-10000.

2. The aqueous polyurethane dispersant of claim 1, wherein the molecular weight of said hydrophobic monomer is 100-.

3. The method for preparing the aqueous polyurethane dispersant of any one of claims 1 to 2, characterized by comprising the steps of:

(3) and heating the mixture B, reacting, and adding an end-capping reagent to react to obtain the waterborne polyurethane dispersant.

4. The color paste for textile digital printing is characterized by comprising the following components in parts by weight: 50-90 parts of water, 10-50 parts of dye and 5-25 parts of the aqueous polyurethane dispersant as defined in any one of claims 1-2.

5. The color paste according to claim 4, further comprising 0-25 parts of a cosolvent and/or 0-5 parts of a wetting agent.

6. An ink comprising the color paste according to claim 4 or 5.