Preparation method of paper for colored yarns

Abstract

The invention belongs to the technical field of papermaking and spinning, and provides a preparation method of paper for colored yarns. The preparation method comprises the following steps: mixing carboxylated nanocellulose, dopamine hydrochloride, a catalytic oxidation system and an alkaline buffer solution, and carrying out polymerization reaction to obtain a polydopamine composite nanocellulose system; and mixing the polydopamine composite nano cellulose system, paper pulp, dye and a dyeing assistant, and sequentially carrying out dyeing and wet forming to obtain the paper for the colored yarn, the catalytic oxidation system comprises silver nitrate and sodium iodate. The invention provides a green, safe and convenient preparation method for preparing the yarn paper with high color fastness, high dyeing uniformity and high strength.

Description

TECHNICAL FIELD

[0001] The present application relates to the papermaking and textile technical field, and particularly relates to a preparation method of colored paper for yarn. BACKGROUND

[0002] In the field of papermaking and textile, the colored paper for yarn has always been a research hotspot. The traditional dyeing method of the colored paper for yarn is mainly to add dyes directly into pulp for dyeing. However, this method has many defects, for example, the combination of the dyes and the pulp fibers is weak, the color fastness is not high, and the color fading phenomenon is prone to occur in the subsequent use process, which affects the quality and service life of the colored paper for yarn. At the same time, the dyeing uniformity is difficult to guarantee, which reduces the product quality. SUMMARY

[0003] In view of this, the purpose of the present application is to provide a preparation method of colored paper for yarn. The preparation method provided by the present application can obtain colored paper for yarn with high color fastness and uniform dyeing.

[0004] In order to achieve the above-mentioned purpose of the application, the present application provides the following technical scheme:

[0005] The present application provides a preparation method of colored paper for yarn, comprising the following steps:

[0006] Mixing carboxylated nanocellulose, dopamine hydrochloride, a catalytic oxidation system and an alkaline buffer solution to perform a polymerization reaction, so as to obtain a polydopamine composite nanocellulose system;

[0007] Mixing the polydopamine composite nanocellulose system, pulp, dyes and a dyeing auxiliary agent, and sequentially performing dyeing and wet forming, so as to obtain the colored paper for yarn.

[0008] The catalytic oxidation system comprises silver nitrate and sodium iodate.

[0009] Preferably, the content of carboxyl groups in the carboxylated nanocellulose is 0.5-2 mmol / g, and the aspect ratio is 100-200.

[0010] Preferably, the mass ratio of the dopamine hydrochloride to the carboxylated nanocellulose is 1:1.25-20.

[0011] Preferably, the amount ratio of the dopamine hydrochloride to the silver nitrate is 1-4 g:4-15 mmol, and the amount ratio of the dopamine hydrochloride to the sodium iodate is 1-4 g:5-30 mmol.

[0012] Preferably, the temperature of the polymerization reaction is 20-40℃, and the time is 30-120 min.

[0013] Preferably, the mass ratio of the polydopamine composite nanocellulose system and the pulp is 10:90 to 0.5:99.5, calculated on the basis of dry weight; and the beating degree of the pulp is 35 to 65°SR.

[0014] Preferably, the dye is used in an amount of 2 to 10% owf.

[0015] Preferably, the dyeing agent includes sodium sulfate and sodium carbonate, the sodium sulfate is used in an amount of 20 to 60 g / L, and the sodium carbonate is used in an amount of 10 to 30 g / L.

[0016] Preferably, the dyeing temperature is 40 to 80°C, and the time is 30 to 120 min.

[0017] Preferably, the basis weight of the colored yarn paper is 12 to 20 g / m 2 .

[0018] The application provides a preparation method of colored yarn paper.

[0019] In the application, dopamine hydrochloride is used as a monomer, and a polydopamine is formed on the surface of carboxylated nanocellulose through a polymerization reaction of an AgNO3 / NaIO3 catalytic oxidation system. Since the carboxylated nanocellulose is homologous to the pulp fiber, and the carboxylated nanocellulose has an ultrahigh specific surface area, an ultrahigh length-diameter ratio and a uniform micro-nano size, the polydopamine composite nanocellulose system can be uniformly dispersed in the pulp, that is, the polydopamine can be uniformly dispersed in the pulp. The polydopamine is a high-molecular polymer with strong adhesion, and contains a large number of active groups such as phenolic hydroxyl groups and amino groups in the molecular structure. These active groups promote the polydopamine to form a covalent adsorption with the dye, and this covalent adsorption stably and firmly fixes the dye on the pulp fiber, thereby improving the color fastness of the colored yarn paper. Moreover, the polydopamine is loaded on the carboxylated nanocellulose, thereby improving the dispersibility of the polydopamine in the pulp and improving the dyeing uniformity. The catalytic oxidation system is added in the polymerization reaction system, and the catalytic oxidation system can promote the polydopamine to form micro-nano particles and be uniformly distributed on the surface of the pulp fiber, thereby making the dye connected to the pulp fiber by the polydopamine also be uniformly distributed, and finally improving the dyeing uniformity of the colored yarn paper. In addition, the carboxylated nanocellulose is in the form of a thin filament, and it is homologous to the pulp fiber. Therefore, the addition of the carboxylated nanocellulose can promote the interweaving between the pulp fibers, strengthen the hydrogen bond network between the pulp fibers, and thereby improve the tensile strength of the colored yarn paper.

[0020] Further, the content of carboxyl groups in the carboxylated nanocellulose is 0.5-2 mmol / g, and the aspect ratio is 100-200; the addition of the carboxylated nanocellulose with a high aspect ratio can promote the interweaving between pulp fibers, enhance the hydrogen bond network between pulp fibers, and thus improve the tensile strength of the colored yarn paper.

[0021] The data of the examples show that the prepared colored yarn paper of the application has high color fastness: the color fastness to washing is ≥4.5 grade, the color fastness to rubbing is ≥4 grade; the color depth K / S value is ≥15; the process is green: the amount of dyeing auxiliary is reduced, the wastewater COD is low, and urea or high-temperature fixing is not needed; the colored yarn paper has high strength: the tensile strength is increased by 20%-30%; and the antibacterial property is good: the inhibition rate of common pathogenic bacteria such as Escherichia coli and Staphylococcus aureus is ≥90%. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 SEM image of the colored yarn paper obtained in Comparative Example 2;

[0023] Figure 2 SEM image of the colored yarn paper obtained in Example 2. DETAILED DESCRIPTION

[0024] The application provides a preparation method of colored yarn paper, which comprises the following steps:

[0025] The carboxylated nanocellulose, dopamine hydrochloride, a catalytic oxidation system and an alkaline buffer solution are mixed to perform a polymerization reaction, so that a polydopamine composite nanocellulose system is obtained.

[0026] The polydopamine composite nanocellulose system, pulp, dye and dyeing auxiliary are mixed to perform dyeing and wet forming in sequence, so that the colored yarn paper is obtained.

[0027] The catalytic oxidation system comprises silver nitrate and sodium iodate.

[0028] Unless otherwise specified, the raw materials used in the application are preferably commercially available products.

[0029] In the application, the carboxylated nanocellulose (carboxylated CNF) is mixed with dopamine hydrochloride, a catalytic oxidation system and an alkaline buffer solution to perform a polymerization reaction, so that a polydopamine composite nanocellulose system (CNF@PDA system) is obtained.

[0030] In the application, the content of carboxyl groups in the carboxylated nanocellulose (carboxylated CNF) is preferably 0.5-2 mmol / g, and more preferably 0.5 mmol / g, 1 mmol / g, 1.5 mmol / g, 1.8 mmol / g or 2 mmol / g; and the aspect ratio is preferably 100-200, and more preferably 100, 120, 140, 150, 160, 180 or 200.

[0031] In the present application, the mass ratio of dopamine hydrochloride and carboxylated nanocellulose is preferably 1:1.25-20, and more preferably 1:1.25, 1:2.5, 1:5, 1:7.5, 1:10, 1:12.5, 1:15, 1:17.5 or 1:20.

[0032] In the present application, the catalytic oxidation system comprises silver nitrate and sodium iodate. In the present application, the ratio of the amount of dopamine hydrochloride to silver nitrate is preferably 1-4 g:4-15 mmol, and more preferably 1 g:4-15 mmol, and more preferably 1 g:2 mmol, 1 g:4 mmol, 1 g:5 mmol; and the ratio of the amount of dopamine hydrochloride to sodium iodate is preferably 1-4 g:5-30 mmol, and more preferably 1 g:5-30 mmol, and more preferably 1 g:10 mmol, 1 g:15 mmol. In the present application, AgNO3 and NaIO3 are used as the oxidation system, which greatly improves the polymerization rate of dopamine hydrochloride (DA) and effectively reduces the particle size of polydopamine (PDA) particles. Ag + The phenolic hydroxyl group and the amino group of the dopamine quinone intermediate form a complex (such as Ag-O or Ag-N coordination bond) with the functional groups, forming a charge layer (ζ potential increases) on the surface of the PDA particles, which inhibits the aggregation of the PDA particles through electrostatic repulsion, reduces the particle size of the PDA particles from microns (1-5 μm) to microns (50-200 nm), and the micron-sized PDA particles can be more uniformly distributed on the surface of the pulp fibers, further improving the binding effect of polydopamine and pulp fibers and the dyeing uniformity; on the other hand, the reducing intermediate (such as semiquinone free radical) produced in the dopamine oxidation process can reduce part of the Ag + to nanoscale Ag elements, which are uniformly adsorbed on the surface of the polydopamine composite nanocellulose. These Ag elements can impart long-acting antibacterial properties to the colored yarn paper by damaging the bacterial cell membrane, inhibiting enzyme activity and other ways.

[0033] In the present application, the pH value of the alkaline buffer is preferably 8-9, and further preferably 8.5. In the present application, the alkaline buffer is particularly preferably Tris buffer. In a specific embodiment of the present application, the preparation method of the Tris buffer particularly comprises the following steps: mixing Tris-HCl and a first portion of deionized water, then adjusting the pH to alkaline by using concentrated hydrochloric acid, and adding deionized water to a certain amount to obtain the Tris buffer. In the present application, the ratio of the amount of Tris-HCl to the first portion of deionized water is preferably 15.76 g:800 mL; the mass concentration of the concentrated hydrochloric acid is preferably 36-38%; the pH value of the alkaline is preferably consistent with the above technical solution, which will not be repeated here; and the volume of the certain amount is preferably 1000 mL.

[0034] In the present application, the mixing of the carboxylated nanocellulose, dopamine hydrochloride, catalytic oxidation system and alkaline buffer preferably comprises the following steps: dispersing the carboxylated nanocellulose in the alkaline buffer to obtain a carboxylated nanocellulose dispersion; and sequentially adding dopamine hydrochloride and a catalytic oxidation system to the carboxylated nanocellulose dispersion.

[0035] In the present application, the temperature of the polymerization reaction is preferably 20-40℃, and is particularly preferably 20℃, 25℃, 30℃, 35℃ or 40℃; and the time is preferably 30-120 min, and is particularly preferably 30 min, 60 min, 90 min or 120 min.

[0036] After the polymerization reaction, the present application preferably further comprises ultrasonic dispersion to obtain a polydopamine composite nanocellulose system. In the present application, the time of the ultrasonic dispersion is preferably 10-30 min, and is further preferably 20 min.

[0037] After obtaining the polydopamine composite nanocellulose system, the present application mixes the polydopamine composite nanocellulose system, pulp, dye and dyeing assistant, and sequentially performs dyeing and wet forming to obtain the colored paper for yarn.

[0038] In the present application, the pulp is preferably bleached pulp. In the present application, the pulp is particularly preferably softwood pulp. In the present application, the beating degree of the pulp is preferably 35-65°SR, and is particularly preferably 35°SR, 40°SR, 45°SR, 50°SR, 55°SR, 60°SR or 65°SR. The present application does not make specific limitations on the preparation method of the pulp, and the preparation method known to those skilled in the art can be used for preparation.

[0039] In the present application, the mass ratio of the polydopamine composite nanocellulose system and the pulp, calculated on the basis of dry weight, is preferably 10:90 to 0.5:99.5, and particularly preferably 10:90, 9:91, 8:92, 7:93, 6:94, 5:95, 4:96, 3:97, 2:98, 1:99 or 0.5:99.5.

[0040] In the present application, the amount of the dye is preferably 2 to 10% owf, and particularly preferably 2% owf, 3% owf, 4% owf, 5% owf, 6% owf, 7% owf, 8% owf, 9% owf or 10% owf. In the present application, the dye is preferably a dark dye, and particularly preferably a brown dye, a black dye or a navy blue dye. In a particular embodiment of the present application, the dye is particularly preferably an anthraquinone series dye, an azo dye or a phthalocyanine dye; the anthraquinone series dye is particularly preferably reactive blue 19KN-R; the azo dye is particularly preferably direct fast black G, reactive black 5 or sulfur black; and the phthalocyanine dye is particularly preferably copper phthalocyanine blue.

[0041] In the present application, the dyeing aid preferably includes sodium sulfate and sodium carbonate, the amount of the sodium sulfate is preferably 20 to 60 g / L, and particularly preferably 20 g / L, 30 g / L, 40 g / L, 50 g / L or 60 g / L; and the amount of the sodium carbonate is preferably 10 to 30 g / L, and particularly preferably 10 g / L, 15 g / L, 20 g / L, 25 g / L or 30 g / L.

[0042] In the present application, mixing the polydopamine composite nanocellulose system, the pulp, the dye and the dyeing aid preferably includes the following steps: after the polydopamine composite nanocellulose system and the pulp are first mixed, the dye and the dyeing aid are sequentially added. In the present application, the first mixing is preferably shear dispersion, the rotation speed of the shear dispersion is preferably 200 to 600 rpm, and particularly preferably 200 rpm, 300 rpm, 400 rpm, 500 rpm or 600 rpm; and the time is preferably 20 to 40 min, and further preferably 30 min.

[0043] In the present application, the dyeing temperature is preferably 40 to 80°C, and particularly preferably 40°C, 50°C, 60°C, 70°C or 80°C; and the time is preferably 30 to 120 min, and particularly preferably 30 min, 60 min, 90 min or 120 min.

[0044] After the dyeing, the present application preferably further includes washing. In the present application, the washing agent is preferably water, and the number of washing and the amount of the washing agent are not particularly limited as long as the fiber is washed to be neutral.

[0045] In the present application, the basis weight of the colored paper for yarn is preferably 12-20 g / m 2 , more preferably 12 g / m 2 , 13 g / m 2 , 14 g / m 2 , 15 g / m 2 , 16 g / m 2 , 17 g / m 2 , 18 g / m 2 , 19 g / m 2 or 20 g / m 2 . The present application does not make specific limitation to the wet forming method, as long as the corresponding basis weight of the colored paper for yarn can be obtained.

[0046] In the present application, the polydopamine has a large number of active groups such as phenolic hydroxyl and amino groups in the molecular structure, which can covalently bond with the dye or form hydrogen bond, firmly fixing the dye on the wood pulp fibers, thereby improving the color fastness of the colored paper for yarn. Meanwhile, polydopamine is a high molecular polymer with strong adhesion, which can form stable adhesion on the surface of carboxylated nanocellulose. The introduction of carboxylated nanocellulose can promote the uniform dispersion of polydopamine in the pulp, thereby improving the dyeing uniformity. In addition, the introduction of the catalytic oxidation system can promote the formation of micro-nano particles of polydopamine, which are uniformly distributed on the surface of the wood pulp fibers, thereby making the dye connected to the pulp fibers by polydopamine also uniformly distributed, and finally improving the dyeing uniformity of the colored paper for yarn.

[0047] The preparation method of the colored paper for yarn provided by the present application will be described in detail below in combination with examples, but they should not be understood as limiting the scope of protection of the present application.

[0048] Example 1

[0049] (1) Preparation method of alkaline buffer solution: 15.76 g of Tris-HCl (157.6 g / mol) was added to 800 mL of deionized water, and concentrated hydrochloric acid (36-38%) was used to adjust the pH to 8.5, and deionized water was added to 1 L, thus obtaining an alkaline buffer solution with a mass concentration of 1% and a pH value of 8.5.

[0050] (2) Carboxylated CNF (carboxyl content 1.5 mmol / g, aspect ratio 150) was dispersed in 1 L of basic buffer solution to obtain a carboxylated CNF dispersion with a concentration of 5 g / L; according to a mass ratio of dopamine hydrochloride to carboxylated CNF of 1:5, dopamine hydrochloride (DA) was added to the obtained carboxylated CNF dispersion, followed by the addition of AgNO3 (4 mmol) and NaIO3 (10 mmol), and then stirring at 30 °C for 60 min, followed by ultrasonic dispersion for 20 min to obtain a CNF@PDA system.

[0051] (3) According to a mass ratio of bleached softwood pulp (beating degree 40°SR) to CNF@PDA system of 90:10, the bleached softwood pulp (beating degree 40°SR) and the CNF@PDA system were mixed, and sheared and dispersed at 300 rpm for 30 min; reactive black 5 (2% owf), Na2SO420 g / L and Na2CO310 g / L were added, and the system was dyed at 60 °C for 120 min, followed by washing the fibers in the system with water to neutral; finally, wet forming was performed to obtain colored yarn paper with a basis weight of 14 g / m2.

[0052] The tensile strength of the obtained colored yarn paper was determined by GB / T 12914-2018 Determination of tensile strength of paper and paperboard - Constant rate of extension method (20 mm / min), the absorbance at the maximum absorption wavelength (540 nm) was determined by UV-Vis spectrophotometer, and thus the dye uptake of the obtained colored yarn paper was calculated. The color fastness of the obtained colored yarn paper was determined by GB / T 3922-2013 method, the K / S value of the obtained colored yarn paper was determined by Colori7 type computer colorimeter, and the antibacterial performance of the obtained colored yarn paper was determined by GB / T 20944.3-2008 method.

[0053] The results are: tensile strength: 117 N·m / g; dye uptake: 70.5%; color fastness: water washing resistance 4.5 grade, rubbing resistance 4.3 grade; K / S value: 19.7 (visible light full waveband integral); antibacterial rate against Staphylococcus aureus: 94.5%, antibacterial rate against Escherichia coli: 95.2%.

[0054] Example 2

[0055] (1) The preparation of the basic buffer solution was the same as in Example 1.

[0056] (2) The difference from (2) in Example 1 is that the carboxyl content of the carboxylated CNF is 1.8 mmol / g, the aspect ratio is 200, the amount of AgNO3 added is 5 mmol, and the amount of NaIO3 added is 15 mmol.

[0057] (3) The difference from (3) in Example 1 is that the dye is sulfur black, and the amount used is 7% owf, and the dyeing is carried out at 70°C for 60 min.

[0058] The properties of the obtained colored yarn paper are tested by the method of Example 1, and the results are: tensile strength: 124 N·m / g; dye uptake: 76.4%; color depth K / S value: 22.5 (better than reactive black), color fastness to washing 4.7 grade; color fastness to rubbing 4.5 grade; antibacterial rate against Staphylococcus aureus: 95.8%, antibacterial rate against Escherichia coli: 96.4%.

[0059] Example 3

[0060] (1) The alkaline buffer solution is prepared as in Example 1.

[0061] (2) The difference from (2) in Example 1 is that the amount of AgNO3 added is 2 mmol, and the amount of NaIO3 added is 10 mmol, and the polymerization is carried out at 25°C for 120 min.

[0062] (3) The difference from (3) in Example 1 is that the mass ratio of CNF@PDA system to bleached coniferous pulp is 5:95 on a dry basis, and the amount of dye used is 3% owf.

[0063] The properties of the obtained colored yarn paper are tested by the method of Example 1, and the results are: tensile strength: 104.4 N·m / g; dye uptake: 71.5%; K / S value: 16.3, color fastness to rubbing 4.0 grade; color fastness to washing 4.5 grade; antibacterial rate against Staphylococcus aureus: 94%, antibacterial rate against Escherichia coli: 95.2%.

[0064] Comparative Example 1

[0065] (1) The alkaline buffer solution is prepared as in Example 1.

[0066] (2) The difference from (2) in Example 2 is that silver nitrate is replaced by copper sulfate, and sodium iodate is replaced by hydrogen peroxide, and the others are the same as in Example 1.

[0067] (3) The same as Example 2.

[0068] The properties of the obtained colored yarn paper are tested by the method of Example 1, and the results are: tensile strength: 110.8 N·m / g; dye uptake: 69.5%; color depth K / S value: 16.1, color fastness to washing 3.5 grade; color fastness to rubbing 4 grade; antibacterial rate against Staphylococcus aureus: 90.2%, antibacterial rate against Escherichia coli: 91.3%.

[0069] Comparative Example 2

[0070] Similar to Example 2, except that: no CNF@PDA system was used, the bleached softwood pulp was directly dyed according to (3) to obtain the colored paper for yarn.

[0071] The performance of the obtained colored paper for yarn was tested by the method of Example 1, and the results were: tensile strength: 88.4 N·m / g; dye uptake: 20.8%; K / S value: 5.4, rubbing fastness 1.0 grade; washing fastness 1.5 grade; antibacterial rate against Staphylococcus aureus: 0%, antibacterial rate against Escherichia coli 0%.

[0072] Comparative Example 3

[0073] Similar to Example 2, except that: no silver nitrate and sodium iodate were added.

[0074] The performance of the obtained colored paper for yarn was tested by the method of Example 1, and the results were: tensile strength: 106.6 N·m / g; dye uptake: 65.2%; K / S value: 15.5, rubbing fastness 4.0 grade; washing fastness 3.5 grade; antibacterial rate against Staphylococcus aureus: 0%, antibacterial rate against Escherichia coli 0%.

[0075] Comparative Example 4

[0076] Carboxylated CNF (carboxyl content 1.8 mmol / g, aspect ratio 200) was dispersed in 1 L of an alkaline buffer solution to obtain a carboxylated CNF dispersion with a concentration of 5 g / L; dopamine hydrochloride (DA) was added to the obtained carboxylated CNF dispersion according to a mass ratio of dopamine hydrochloride to carboxylated CNF of 1:5 to obtain a mixed system.

[0077] According to a mass ratio of bleached softwood pulp (beating degree 40°SR) to mixed system of 90:10, the bleached softwood pulp (beating degree 40°SR) and the mixed system were mixed and sheared at 300 rpm for 30 min; sulfur black (7% owf), Na2SO420 g / L and Na2CO310 g / L were added, and the system was dyed at 70°C for 60 min, then the fibers in the system were washed to neutral with water; finally, wet forming was performed to obtain a colored paper for yarn with a basis weight of 14 g / m 2 .

[0078] The performance of the obtained colored paper for yarn was tested by the method of Example 1, and the results were: tensile strength: 108.6 N·m / g; dye uptake: 68.7%; K / S value: 17.8, rubbing fastness 3.0 grade; washing fastness 3.0 grade; antibacterial rate against Staphylococcus aureus: 0%, antibacterial rate against Escherichia coli 0%.

[0079] Comparative Example 5

[0080] The difference from Example 2 is that the carboxylated CNF, dopamine hydrochloride, AgNO3 and NaIO3 are directly added into the mixed softwood pulp (beating degree 40°SR), specifically:

[0081] The carboxylated CNF (carboxyl content 1.8 mmol / g, aspect ratio 200) is dispersed in 1 L of alkaline buffer solution to obtain a carboxylated CNF dispersion with a concentration of 5 g / L; according to the mass ratio of dopamine hydrochloride to carboxylated CNF of 1:5, dopamine hydrochloride (DA) is added into the obtained carboxylated CNF dispersion, and then AgNO3 (5 mmol) and NaIO3 (15 mmol) are added to obtain a mixed system;

[0082] According to the mass ratio of bleached softwood pulp (beating degree 40°SR) to mixed system of 90:10, the bleached softwood pulp (beating degree 40°SR) and the mixed system are mixed, and sheared at 300 rpm for 30 min; sulfur black (7% owf), Na2SO420 g / L and Na2CO310 g / L are added, and the system is dyed at 70°C for 60 min, and then the fibers in the system are washed to neutral with water; finally, wet forming is carried out to obtain a colored yarn paper with a basis weight of 14 g / m 2 .

[0083] The performance of the obtained colored yarn paper is tested by the method of Example 1, and the results are as follows: tensile strength: 115.7 N·m / g; dye uptake: 70%; K / S value: 18.8, rubbing fastness 3.0 grade; washing fastness 3.5 grade; antibacterial rate against Staphylococcus aureus: 87%, and antibacterial rate against Escherichia coli: 90%.

[0084] Figure 1 SEM image of the colored yarn paper obtained in Comparative Example 2; Figure 2 SEM image of the colored yarn paper obtained in Example 2.

[0085] Comparison Figure 1 and Figure 2 It can be seen that after the yarn paper treated by the CNF@PDA system, PDA particles and interwoven CNF networks are uniformly grown inside and on the surface of the yarn paper after dyeing.

[0086] The above only describes the preferred embodiments of the present application, and it should be noted that for ordinary skilled persons in the art, without departing from the principles of the present application, a number of improvements and refinements can be made, and these improvements and refinements should also be considered as the protection scope of the present application.

Claims

1. A method for preparing colored yarn paper, characterized in that, Includes the following steps: Carboxylated nanocellulose, dopamine hydrochloride, a catalytic oxidation system, and an alkaline buffer solution were mixed and polymerized to obtain a polydopamine composite nanocellulose system. The polydopamine composite nanocellulose system, pulp, dye and dyeing aid are mixed and dyed and wet-formed sequentially to obtain the colored yarn paper. The catalytic oxidation system includes silver nitrate and sodium iodate.

2. The preparation method according to claim 1, characterized in that, The carboxylated nanocellulose contains 0.5–2 mmol / g of carboxyl groups and has an aspect ratio of 100–200.

3. The preparation method according to claim 1, characterized in that, The mass ratio of dopamine hydrochloride to carboxylated nanocellulose is 1:1.25 to 20.

4. The preparation method according to claim 1, characterized in that, The ratio of dopamine hydrochloride to silver nitrate is 1-4 g: 4-15 mmol, and the ratio of dopamine hydrochloride to sodium iodate is 1-4 g: 5-30 mmol.

5. The preparation method according to any one of claims 1 to 4, characterized in that, The polymerization reaction is carried out at a temperature of 20–40°C for a time of 30–120 min.

6. The preparation method according to claim 1, characterized in that, On an oven-dry basis, the mass ratio of the polydopamine composite nanocellulose system to the pulp is 10:90 to 0.5:99.5; the freeness of the pulp is 35 to 65°SR.

7. The preparation method according to claim 1, characterized in that, The amount of dye used is 2-10% owf; the dye is a dark-colored dye.

8. The preparation method according to claim 1, characterized in that, The dyeing aid includes sodium sulfate and sodium carbonate, wherein the amount of sodium sulfate used is 20-60 g / L and the amount of sodium carbonate used is 10-30 g / L.

9. The preparation method according to claim 1, 6, 7, or 8, characterized in that, The staining temperature is 40–80℃, and the time is 30–120 min.

10. The preparation method according to claim 1, characterized in that, The basis weight of the colored yarn paper is 12-20 g / m². 2 .

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