阅读说明：本技术 一种改性海藻酸衍生物糊料及其制备方法 (Modified alginic acid derivative paste and preparation method thereof ) 是由 章天寅 章建木 于 2021-09-17 设计创作，主要内容包括：公开了一种改性海藻酸衍生物,由海藻酸钠在酸性条件和活化剂存在下与具有活性氢原子的亲水性聚合物反应得到,后者选自单端氨基的亲水性聚合物。此外,还公开了其制备方法以及包括改性海藻酸衍生物和水的糊料。与未改性的海藻酸钠相比,改性海藻酸衍生物糊料粘度、流变性和抱水性更好。(Disclosed is a modified alginic acid derivative obtained by reacting sodium alginate with a hydrophilic polymer having an active hydrogen atom selected from single-terminal amino group-containing hydrophilic polymers under acidic conditions in the presence of an activating agent. In addition, a method for the preparation thereof and a paste comprising the modified alginic acid derivative and water are disclosed. Compared with unmodified sodium alginate, the modified alginic acid derivative paste has better viscosity, rheological property and water holding capacity.)

1. A modified alginic acid derivative obtained by reacting sodium alginate with a hydrophilic polymer having active hydrogen atoms under acidic conditions in the presence of an activating agent, wherein the hydrophilic polymer having active hydrogen atoms is selected from the group consisting of single-terminal amino group hydrophilic polymers.

2. The derivative according to claim 1, wherein the single-terminal amino hydrophilic polymer is selected from monoethylene diamine substituted polyethylene glycol monomethyl ether.

3. A derivative according to claim 2 wherein the monoethylene diamine substituted polyethylene glycol monomethyl ether is obtained by reacting polyethylene glycol monomethyl ether with ethylene diamine.

4. The derivative as claimed in claim 3, wherein the polyethylene glycol monomethyl ether has a number average molecular weight Mn of 400-600 g/mol; preferably 200-800 g/mol.

5. The derivative as claimed in claim 1, wherein the number average molecular weight Mn of sodium alginate is 40,000-120,000 g/mol; polydispersity index PDI = 1.4-2.2.

6. The derivative according to claim 1, wherein the acidic condition has a pH value of 4.0-5.0; and/or the activator is selected from EDC · HCl.

7. The derivative of claim 1, wherein the molar ratio of sodium alginate to the activator is 1: (1.05-1.4); and/or the molar ratio of sodium alginate to the hydrophilic polymer with active hydrogen atoms is 1: (5-15).

8. A process for the preparation of a modified alginic acid derivative according to any one of claims 1 to 7, comprising:

obtaining a hydrophilic polymer having active hydrogen atoms;

under the acidic condition and the existence of an activating agent, sodium alginate reacts with a hydrophilic polymer with active hydrogen atoms to obtain the modified alginic acid derivative.

9. The method of claim 8, further comprising the step of purifying using 12000g/mol to 14000g/mol dialysis bags.

10. A modified alginic acid derivative paste comprising the modified alginic acid derivative according to any one of claims 1 to 7 and water.

Technical Field

The invention belongs to the technical field of textile printing and dyeing, and particularly relates to a modified alginic acid derivative paste and a preparation method thereof.

Background

The rotary screen printing is a printing mode of printing color paste on a fabric by adopting a rotary screen printing machine. It uses a continuously revolving seamless rotary screen stencil, and in the relative movement of the rotary screen and the scraper, the color paste in the rotary screen is printed on the fabric through the hollow screen to form the pattern. According to the arrangement mode of the circular screen, the circular screen printing machine has three types of vertical type, radial type and horizontal type. The circular screen printing machine is a horizontal circular screen printing machine. The printing machine can print 3, 6, 8, 12, 16, 20 and 24 chromatic colors, the printing amplitude has the specifications of 1280mm, 1620mm, 1850mm, 2400mm and the like, and the circumference of the circular screen has the specifications of 480mm, 640mm, 913mm, 1826mm and the like.

The printing part of the horizontal rotary screen printing machine mainly comprises a rotary screen, a rotary screen driving device, a printing guide belt, a color paste scraper, a paste scraping and aligning device, a guide belt washing device, a water scraping device and a fabric pasting and paste supplying system. In the working process of the rotary screen printing machine, the consumed main material is printing paste. The printing paste is prepared by adding dye, thickener and other additives. The rotary screen printing has high requirements on the performances of the paste, and not only is the paste required to have good rheological property and thixotropy, but also the performances directly influence the definition of printed patterns, and meanwhile, the paste is required to have good water holding capacity, otherwise, the paste has serious seepage phenomenon. The thickener is also an important factor for determining printing quality, and determines printing running performance, apparent color yield, pattern contour smoothness and the like.

Sodium alginate paste is the most widely used printing paste at present, and due to the limitations of the sodium alginate paste in terms of rheology and permeability, the printing quality is unsatisfactory when the sodium alginate paste is applied to fine printing and large-area printing.

Chinese patent application CN102634999A discloses a sodium alginate printing paste, which comprises the following components in percentage by weight: 60% -90% of sodium alginate; 5% -15% of sodium hexametaphosphate; 5 to 25 percent of anhydrous sodium sulfate. The preparation process of the sodium alginate printing paste comprises the following steps: (1) weighing sodium alginate, sodium hexametaphosphate and anhydrous sodium sulfate according to the proportion of the formula; (2) pulverizing sodium alginate to 30-40 mesh; (3) placing the crushed sodium alginate, sodium hexametaphosphate and anhydrous sodium sulfate into a mixing tank and stirring; (4) stirring the mixture until the mixture is completely uniform to obtain a finished product of the sodium alginate printing paste. The printing paste removes sodium carboxymethyl starch which has adverse effect on coloring, and adopts anhydrous sodium sulfate which can activate active groups in dye and has high coloring rate; the sodium hexametaphosphate can make calcium ions or magnesium ions in water enter sodium hexametaphosphate molecules to become stable soluble complex, so that the permeability of the printing paste is improved, the color fastness is improved, and the dye can be saved.

Chinese patent application CN108193526A discloses a printing paste and a preparation method thereof. The printing paste comprises the following components in percentage by mass: 20-70% of low-viscosity sodium alginate, 20-70% of modified sodium alginate, 1-8% of complexing agent, 0.2-1% of preservative and 0.2-1% of anti-migration agent; the low-viscosity sodium alginate is a sodium alginate aqueous solution with the mass concentration of 1%, the viscosity of the sodium alginate aqueous solution is 20-60mPa.s, the modified sodium alginate is modified by adopting epichlorohydrin, and the viscosity of the modified sodium alginate aqueous solution with the mass concentration of 1% is 30-80 mPa.s; the printing paste has high paste removal and good hand feeling, meets the market demand of active digital printing paste, and improves the definition of printed patterns.

However, the viscosity, rheology and water holding capacity of some prior art sodium alginate pastes are still unsatisfactory, and it is still desirable to obtain a modified alginic acid derivative paste and a preparation method thereof with better performances.

Disclosure of Invention

The invention aims to provide a modified alginic acid derivative paste and a preparation method thereof. Compared with the prior art, the modified alginic acid derivative paste has better viscosity, rheological property and water holding capacity.

In order to solve the technical problem, on one hand, the invention adopts the following technical scheme: a modified alginic acid derivative obtained by reacting sodium alginate with a hydrophilic polymer having active hydrogen atoms under acidic conditions in the presence of an activating agent, wherein the hydrophilic polymer having active hydrogen atoms is selected from the group consisting of single-terminal amino group hydrophilic polymers.

The derivative according to the invention, wherein the hydrophilic polymer with a single amino group is selected from polyethylene glycol monomethyl ether substituted by monoethylene diamine.

The derivative is prepared by reacting polyethylene glycol monomethyl ether substituted by monoethylene diamine and ethylene diamine.

The derivative according to the invention, wherein the number average molecular weight Mn of polyethylene glycol monomethyl ether is 400-600 g/mol; preferably 200-800 g/mol.

The derivative provided by the invention is characterized in that the number average molecular weight Mn of the sodium alginate is 40,000-120,000 g/mol; polydispersity index PDI = 1.4-2.2.

Preferably, the sodium alginate has a number average molecular weight Mn of 60,000-100,000 g/mol; polydispersity index PDI = 1.6-2.0.

The derivative according to the present invention, wherein the pH value of the acidic condition is 4.0 to 5.0.

Preferably, the pH of the acidic conditions is 3.5-5.5.

The derivative according to the invention, wherein the activator is selected from EDC-HCl.

The derivative provided by the invention is characterized in that the molar ratio of sodium alginate to the activating agent is 1: (1.05-1.4).

Preferably, the molar ratio of sodium alginate to the activating agent is 1: (1.1-1.3).

The derivative provided by the invention is characterized in that the molar ratio of sodium alginate to the hydrophilic polymer with active hydrogen atoms is 1: (5-15).

Preferably, the molar ratio of sodium alginate to the hydrophilic polymer having active hydrogen atoms is 1: (8-12).

In another aspect, the present invention provides a method for preparing a modified alginic acid derivative according to the present invention, comprising:

obtaining a hydrophilic polymer having active hydrogen atoms;

under the acidic condition and the existence of an activating agent, sodium alginate reacts with a hydrophilic polymer with active hydrogen atoms to obtain the modified alginic acid derivative.

The preparation method of the invention further comprises the step of purifying by using 12000g/mol-14000g/mol dialysis bags.

In yet another aspect, the present invention further provides a modified alginic acid derivative paste comprising the modified alginic acid derivative according to the present invention and water.

Compared with the sodium alginate paste before modification, the rising height of the modified alginic acid derivative paste water along the filter paper is reduced, which shows that the water holding capacity of the paste is better. The water holding capacity and the structural viscosity are in positive correlation, so that the sodium alginate has low structural viscosity and poor water holding capacity; the modified alginic acid derivative paste introduces polyethylene glycol monomethyl ether substituted by ethylenediamine, forms amido bonds, is favorable for forming a stable network structure among molecules, has high structural viscosity and improves the water holding capacity.

The PVI value is one of the important indicators reflecting the rheology of the paste. The PVI value of the modified alginic acid derivative is smaller than that of sodium alginate, the pseudoplasticity is more obvious, and the modified alginic acid derivative is more suitable for fine printing.

When the modified alginic acid derivative paste is stored for 7 days at the temperature of 30 ℃, the viscosity of the modified alginic acid derivative paste and the viscosity of the sodium alginate paste before modification both show a descending trend, but the viscosity change rate of the modified alginic acid derivative paste is only about that of the sodium alginate paste before modification, which indicates that the storage stability of the modified alginic acid derivative paste is superior to that of the sodium alginate paste. Meanwhile, no skinning, mildewing, smelling and the like of the two pastes are observed.

Detailed Description

The invention will be further illustrated with reference to specific embodiments.

It should be understood that the detailed description of the invention is merely illustrative of the spirit and principles of the invention and is not intended to limit the scope of the invention. Furthermore, it should be understood that various changes, substitutions, deletions, modifications or adjustments may be made by those skilled in the art after reading the disclosure of the present invention, and such equivalents are also within the scope of the invention as defined in the appended claims.

In the present invention, all percentages are by weight, as otherwise indicated.

Example 1

1g of polyethylene glycol monomethyl ether (CAS: 9004-74-4; number average molecular weight Mn =516.6 g/mol) was dissolved in 5mL of dichloromethane, 2mL of triethylamine was added, and a solution of 1.9g of p-toluenesulfonyl chloride in 20mL of dichloromethane was added dropwise with stirring and reacted at room temperature for 12 hours. After the reaction, the organic phase was washed with 1M hydrochloric acid solution, deionized water, saturated sodium bicarbonate solution and saturated sodium chloride solution in this order, dried over anhydrous sodium sulfate and filtered. And concentrating the solution under reduced pressure, dropwise adding the concentrated solution into 150mL of cold ether, separating out a white precipitate, and drying in vacuum to obtain an intermediate product, namely the p-toluenesulfonyl substituted polyethylene glycol monomethyl ether.

0.65g of the intermediate product was dissolved in 10mL of DMF, and 1.5mL of ethylenediamine was added dropwise, followed by reaction at 80 ℃ for 24 hours under a nitrogen atmosphere. After the reaction, the same volume of water was added, mixed well by shaking, and then the organic phase was extracted with dichloromethane, washed with saturated sodium chloride solution, dried over anhydrous sodium sulfate, and filtered. And (3) concentrating the solution under reduced pressure, dropwise adding the concentrated solution into 80mL of cold ether to separate out a white precipitate, and drying the white precipitate in vacuum to obtain a white solid product, namely the monoethylene diamine substituted polyethylene glycol monomethyl ether.

4.1g of sodium alginate (number average molecular weight Mn =82000 g/mol; polydispersity index PDI = 1.78) was dissolved in 160mL of water and pH =4.5 was adjusted using 0.1M hydrochloric acid solution. To this solution, 0.06mmol of 1-ethyl- (3-dimethylaminopropyl) carbodiimide hydrochloride (EDC. HCl) was added, and 0.5mmol of monoethylene diamine-substituted polyethylene glycol monomethyl ether was added, followed by reaction at 90 ℃ for 8 hours under a nitrogen atmosphere. Adding water with the same volume after the reaction is finished, oscillating to uniformly mix the water with the same volume after the reaction is finished, and oscillating to uniformly mix the water with the same volume; dialyzing for 3 days by using a dialysis bag with the molecular weight cut-off of 12000g/mol-14000g/mol, and then freezing and drying the obtained solution to obtain the modified alginic acid derivative.

Compared with the modified alginic acid derivative, the modified alginic acid derivative has increased 2876cm^-1、1473cm^-1、856cm^-1Isocratic absorption peak and 1108cm^-1The absorption peak of (1) corresponds to the characteristic absorption peak of methylene and ether bond in the structure of polyethylene glycol monomethyl ether, respectively, 1714cm^-1、1648cm^-1And 1557cm^-1The absorption peaks at equal positions respectively correspond to the characteristic absorption peaks of bending vibration of amide bonds, N-H bonds and C-N bonds.

Performance testing

Water holding capacity: and adding the modified alginic acid derivative and sodium alginate before modification into deionized water to respectively prepare 5wt% of paste. A10 cm × 1cm filter paper with a line marker was inserted into the paste at 1cm (to the marker line), and the rise height was recorded after 30 min.

PVI values: the viscosities eta of the 5% modified alginic acid derivative paste and the 5% sodium alginate paste before modification were measured at 60rpm and 6rpm, respectively, using a rotational viscometer₆₀And η₆According to PVI value = η₆₀/η₆The viscosity index of both pastes was calculated.

Storage stability: storing 1% modified alginic acid derivative paste and 1% sodium alginate paste before modification at 30 deg.C for 7 days, measuring viscosity of paste per day, and determining viscosity change rate = (eta) =_1-η₇)/η₇100% the paste viscosity change rate was calculated for 7 days for both pastes. The smaller the viscosity change rate, the better the storage stability.

See table 1 for results.

TABLE 1

	Modified alginic acid derivatives	Sodium alginate
			Water holding capacity/mm	1.6	2.3
PVI value	0.46	0.61
			Storage stability/%)	19	35

As can be seen from table 1, the height of the rise of the water of the modified alginic acid derivative paste along the filter paper was reduced as compared with the sodium alginate paste before modification, indicating that the water holding capacity of the paste was superior. The PVI value of the modified alginic acid derivative is smaller than that of sodium alginate, the pseudoplasticity is more obvious, and the modified alginic acid derivative is more suitable for fine printing. When the modified alginic acid derivative paste is stored for 7 days at the temperature of 30 ℃, the viscosity of the modified alginic acid derivative paste and the viscosity of the sodium alginate paste before modification both show a descending trend, but the viscosity change rate of the modified alginic acid derivative paste is only about that of the sodium alginate paste before modification, which indicates that the storage stability of the modified alginic acid derivative paste is superior to that of the sodium alginate paste.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention shall fall within the protection scope of the present invention.