Preparation method of high color fastness and wet rubbing resistance colored tissue paper

Abstract

This invention relates to a method for preparing a high-colorfastness, wet-rub resistant colored paper yarn base paper, belonging to the interdisciplinary fields of papermaking and textile technology. The invention includes the following steps: mixing bleached softwood sulfate pulp and Manila abaca pulp in a specific ratio, adding nanocellulose dispersion, and then performing descaling and beating treatments; sequentially adding water-based dyes, composite fixing agents, environmentally friendly wet-strength agents, and release agents to the pulp, controlling temperature and stirring parameters for dyeing and auxiliary combination; forming the treated pulp onto a wire mesh, and then pressing, segmented drying, and surface sizing treatment to obtain the colored paper yarn base paper; the paper yarn base paper prepared by this invention exhibits high wet-rub resistant colorfastness, low bleaching index, and significantly improved colorfastness; the base paper also has high tear strength, can withstand the composite stress during the paper yarn cutting and twisting process, and possesses excellent mechanical properties.

Description

Technical Field

[0001] This invention relates to the field of papermaking and textile technology, and in particular to a method for preparing a base paper for colored paper yarn with high color fastness and wet rubbing resistance. Background Technology

[0002] Paper yarn base paper, as the core raw material for paper yarn production, is made from plant fibers as the base material. After being formed, slit, and twisted into yarn, it is widely used in the weaving of sun hats, fashion bags, decorative fabrics, and disposable environmentally friendly products. With the upgrading of the high-end woven product market, the performance requirements for colored paper yarn base paper are becoming increasingly stringent. It not only needs to have mechanical properties such as low basis weight, high strength, and suitable elongation, but also needs to meet the requirements of high color fastness, wet rubbing resistance, and uniform color performance to cope with the stretching, twisting, friction, and humid environment during subsequent weaving processing and use.

[0003] Chinese Patent CN121344973A discloses a method for preparing high-colorfastness woven base paper and the high-colorfastness woven base paper itself, relating to the field of papermaking technology. The method for preparing high-colorfastness woven base paper includes the steps of preparing a composite dyeing agent and preparing the woven base paper. The composite dyeing agent is obtained by mixing cationic microcrystalline cellulose, sodium carboxymethyl cellulose, triethanolamine myricetate, dextran hydroxypropyltrimethylammonium chloride, aqueous polycarbodiimide crosslinking agent, and deionized water. This composite dyeing agent is then added to the pulp, along with an aqueous dye, and a papermaking process is performed to obtain the woven base paper.

[0004] Chinese Patent CN107419577A: Provides a method for preparing high-strength paper yarn base paper. The method involves placing softwood pulp in a pulper, adding dye, achieving a pulping concentration of 3-5% and a freeness of 40-45°SR, then feeding it into a mixing tank. A fixing agent, wet strength agent, and ion-exchange stripping agent are added and thoroughly mixed. The pulp is then fed into a wire mesh box, along with a PVC fiber dispersion. After dewatering and forming into paper sheets, the PVC fibers are uniformly adhered to the paper sheet surface. The paper is then pressed and dewatered, and heated at 90-100℃ for 5-15 hours to obtain the paper yarn base paper.

[0005] In existing technologies, the dyeing of colored paper yarn base paper mostly employs in-slurry dyeing or surface dyeing processes. While in-slurry dyeing can achieve uniform color penetration, it suffers from low dye retention and insufficient color fastness; surface dyeing, on the other hand, is prone to uneven color and rubbing-induced peeling. Furthermore, to enhance the strength of the base paper, a large amount of wet strength agent is often added, leading to overly dense fiber bonding, reduced dye adsorption sites, and decreased color performance. Conversely, pursuing high dyeing effects sacrifices inter-fiber bonding strength, reducing the tensile and tear strength of the base paper, making it difficult to balance mechanical properties and color stability. Summary of the Invention

[0006] To address the above problems, this invention provides a method for preparing high color fastness and wet-rub resistant colored paper yarn base paper, the operation steps of which are as follows, according to parts by weight: S1: Mix 9-19 parts of bleached softwood sulfate pulp with a beating degree of 35-45°SR and 2-6 parts of Manila abaca pulp with a beating degree of 25-30°SR, add 0.1-0.4 parts of 1wt% nanocellulose dispersion CNC-C10, decompose using a standard pulp decomposer, and then beat the pulp with a double disc mill to a total beating degree of 40-45°SR; S2: Heat the slurry prepared in S1 to 40-50℃, add 0.05-0.075 parts of water-based dye, and stir at 300-500 r / min for 20-30 min; then add 0.1-0.3 parts of composite fixing agent, and continue stirring for 10-20 min; then add 0.1-0.4 parts of environmentally friendly wet strength agent epichlorohydrin modified polyamide resin PAE-100 and 0.004-0.008 parts of release agent allyl polyether modified dihydroxypropane mercaptan PE-80 in sequence, and soak at room temperature; S3: Dilute the pulp treated in S2 to a web-connected concentration of 0.6-0.8 wt%, and form it on a wire paper machine. Dewater the wire section to a dryness of 24-26%. Press it through press rolls, and then perform segmented drying. Finally, apply surface sizing at a rate of 1.5-2.0 g / m². The sizing solution is a 0.5-1.0 wt% sodium carboxymethyl cellulose solution with 0.1-0.2 wt% of a waterborne polyurethane dispersion PU-618, a wet rubbing resistance enhancer. Dry to constant weight to obtain colored paper yarn base paper.

[0007] Optionally, the rotation speed of the S1 standard slurry disintegrating machine is 2000-3000 r / min, and the disintegration time is 5-15 min.

[0008] Optionally, the preparation method of the composite color-fixing agent is as follows: A1: Mix 100-200 parts by weight of dextran and 800-1600 parts by weight of deionized water, and stir at 40-50℃ for 30-60 min until completely dissolved to obtain a homogeneous dextran solution; slowly add 10-30 parts by weight of sodium hydroxide, stir at room temperature for 15-30 min for alkalization and activation, then add 10-20 parts by weight of α-amino-ω-glycidyl polyethylene glycol and 0.1-0.5 parts by weight of 1,1'-diepoxyethylene ethyl sulfide, and heat to 35-45℃ for pre-reaction for 1-3 h; continue to slowly add 50-120 parts by weight of 3-chloro-2-hydroxypropyltrimethylammonium chloride to the system at a rate of 1-5 drops / second, heat to 55-65℃, and stir at a constant temperature for 3-6 h; A2: After the reaction is complete, neutralize to pH 6.5-7.5 with 10wt% hydrochloric acid solution, add 3-5 times the volume of isopropanol to the system, stir to precipitate for 1-3 hours, filter to collect the precipitate, and dry to constant weight at 60-70℃ to obtain the composite color-fixing agent.

[0009] Optionally, the aqueous dye of S2 is one of Direct Sunlight Blue GL, Direct Sunlight Yellow RS, and Direct Sunlight Black G.

[0010] Optionally, the S2 soaking time at room temperature is 2-4 hours, during which it is stirred at 100-200 r / min for 5 minutes every 30 minutes.

[0011] Optionally, the pressure of the S3 pressing roller is 0.3-0.5 MPa, and the pressing is to a dryness of 40-42%.

[0012] Optionally, the S3 segmented drying step is as follows: the first stage is dried at a temperature of 100-110℃ to a dryness of 60-70%, and the second stage is dried at a temperature of 130-135℃ to a dryness of 90-92%.

[0013] Reaction mechanism: Dextran is first fully dissolved in deionized water to form a homogeneous system. Upon addition of sodium hydroxide, the hydroxyl groups in the dextran molecules undergo alkalization and activation, generating more reactive sodium alkoxide groups, providing reaction sites for subsequent grafting reactions. α-amino-ω-glycidyl polyethylene glycol (NH2-PEG-GGE) is added, and 1,1'-diglycidyl thioether is introduced as a crosslinking aid. Under medium-temperature conditions, the epoxy groups of polyethylene glycol undergo ring-opening addition and pre-crosslinking reactions with the activated sodium alkoxide groups and their own amino groups of the dextran, achieving the grafting of polyethylene glycol segments onto the dextran backbone and constructing a dextran pre-linked structure containing polyether segments. The polymer was then added dropwise; 3-chloro-2-hydroxypropyltrimethylammonium chloride (CHPTAC) was added, and its active chlorine atoms underwent a nucleophilic substitution reaction with the hydroxyl groups in the dextran prepolymer, introducing quaternary ammonium salt cationic groups. Under high temperature and constant temperature, the reaction of each functional group was further promoted to form a structurally stable cationic dextran-based PEG copolymer. After the reaction, the alkalinity of the system was eliminated by neutralization with hydrochloric acid, and the product was separated and purified by the precipitation effect of isopropanol. Finally, the product was dried to obtain the finished product. The whole process, through stepwise grafting, crosslinking and cationization, endowed the product with a three-dimensional molecular structure that combines hydrophilicity, cationicity and steric hindrance.

[0014] Technical effects: The present invention provides a method for preparing a high color fastness and wet-rub resistant colored paper yarn base paper. Compared with the prior art, the present invention has the following significant advantages: 1. This fixing agent molecule has the multi-hydroxyl structure of dextran, the flexible chain segment of polyethylene glycol, and the quaternary ammonium salt cationic group. It can form hydrogen bonds with the hydroxyl groups of pulp fibers. At the same time, it can electrostatically adsorb anionic aqueous dyes through the cationic group. Combined with the steric hindrance effect of polyethylene glycol chain segment, it can achieve multiple anchoring of dye molecules, which can significantly improve the color fastness and wet rubbing resistance of paper yarn base paper.

[0015] 2. The flexible polyethylene glycol segments of the fixing agent molecules can form flexible connections between fibers and dyes, which not only does not destroy the bonding force between fibers, but also works synergistically with nanocellulose and environmentally friendly wet strength agents to help improve the mechanical strength of paper yarn and base paper, thus balancing the color fixing effect and the physical properties of the base paper.

[0016] 3. This color-fixing agent uses natural dextran as the base material. No harmful by-products are generated during the preparation process. It has excellent compatibility with pulp fibers and various papermaking additives, and is easy to disperse evenly in the pulp. No additional harmful additives are needed during the dyeing and color-fixing process, which meets the process requirements of environmentally friendly papermaking.

[0017] 4. The cationic modification of the fixing agent molecules results in a high retention rate in the pulp system, which can reduce dye loss, improve dye utilization, and avoid process pollution caused by dye residue, thereby reducing the raw material and environmental costs of papermaking. Detailed Implementation

[0018] To further illustrate the technical means and effects adopted by the present invention to achieve the intended purpose, the following detailed description is provided in conjunction with embodiments and comparative examples: 1. Colorfastness to wet rubbing: Referring to GB / T3920-2008 "Textiles - Tests for colorfastness to rubbing - Colorfastness to rubbing", a colorfastness to rubbing tester was used. The sample was rubbed 100 times with a wet rubbing cloth, the rubbing pressure was 9N, and the diameter of the rubbing head was 16mm. After rubbing, the staining grade was assessed using a gray scale. The higher the grade, the better the colorfastness to wet rubbing.

[0019] 2. Colorfastness index: The colorfastness of paper and paperboard is evaluated according to GB / T46184-2025, and is tested using a spectrophotometer. The lower the colorfastness index, the better the colorfastness.

[0020] 3. Longitudinal tear strength: Refer to GB / T455-2002 "Determination of tear strength of paper and paperboard" and use a tear tester to test the longitudinal tear strength. Example 1

[0021] A method for preparing a high color fastness and wet-rub resistant colored paper yarn base paper, the operation steps of which are as follows: S1: Mix 9 kg of bleached softwood sulfate pulp with a knockout degree of 35°SR and 2 kg of Manila abaca pulp with a knockout degree of 25°SR, add 0.1 kg of 1 wt% nanocellulose dispersion CNC-C10, knock out the pulp using a standard pulp de-kneading machine, and then beat the pulp with a double disc mill to a total knockout degree of 40°SR. S2: Heat the slurry prepared in S1 to 40℃, add 0.05kg of water-based dye, and stir at 300r / min for 200min; then add 0.1kg of composite fixing agent and continue stirring for 10min; then add 0.1kg of environmentally friendly wet strength agent epichlorohydrin modified polyamide resin PAE-100 and 0.004kg of release agent allyl polyether modified dihydroxypropane mercaptan PE-80 in sequence, and soak at room temperature; S3: The pulp treated in S2 is diluted to a web-connected concentration of 0.6wt%, and then formed on a wire paper machine. The wire section is dewatered to a dryness of 24%. It is then pressed by press rolls and subsequently dried in sections. Finally, surface sizing is performed using a sizing solution of 0.5wt% sodium carboxymethyl cellulose solution and 0.1wt% of waterborne polyurethane dispersion PU-618, a wet rubbing resistance enhancer. The sizing amount is 1.5g / m², and the paper is dried to constant weight to obtain colored paper yarn base paper.

[0022] The S1 standard slurry disintegration machine has a rotation speed of 2000 r / min and a disintegration time of 5 min.

[0023] The preparation method of the composite color-fixing agent is as follows: A1: Mix 100 kg of dextran and 800 kg of deionized water, and stir at 40 °C for 30 min until completely dissolved to obtain a homogeneous dextran solution; slowly add 10 kg of sodium hydroxide to the solution, stir at room temperature for 15 min for alkalization and activation, then add 10 kg of α-amino-ω-glycidyl polyethylene glycol (number average molecular weight 1000 Da), add 0.1 kg of 1,1'-diepoxyethylene ethyl sulfide (CAS: 14974-71-1), and heat to 35 °C for pre-reaction for 1 h; continue to slowly add 50 kg of 3-chloro-2-hydroxypropyltrimethylammonium chloride to the system at a rate of 1 drop / second, heat to 55 °C, and stir at a constant temperature for 3 h; A2: After the reaction is complete, neutralize to pH 6.5 with 10wt% hydrochloric acid solution, add 3 times the volume of isopropanol to the system, stir to precipitate for 1 hour, filter to collect the precipitate, and dry to constant weight at 60℃ to obtain the composite color fixing agent.

[0024] The aqueous dye of S2 is Direct Lightfast Turquoise Blue GL.

[0025] The S2 soaking time at room temperature is 2 hours, during which it is stirred at 100 r / min for 5 minutes every 30 minutes.

[0026] The pressure of the S3 press roller is 0.3 MPa, and the dryness is 40%.

[0027] The S3 segmented drying step is as follows: the first stage is dried at 100℃ to a dryness of 60%, and the second stage is dried at 130℃ to a dryness of 90%. Example 2

[0028] A method for preparing a high color fastness and wet-rub resistant colored paper yarn base paper, the operation steps of which are as follows: S1: Mix 11kg of bleached softwood sulfate pulp with a knockout degree of 40°SR and 3kg of Manila abaca pulp with a knockout degree of 25°SR. Add 0.2kg of 1wt% nanocellulose dispersion CNC-C10. After knocking with a standard pulp descrambling machine, the pulp is then beaten with a double disc mill to a total knockout degree of 40°SR. S2: Heat the slurry prepared in S1 to 45℃, add 0.06kg of water-based dye, and stir at 350r / min for 25min; then add 0.2kg of composite fixing agent and continue stirring for 15min; then add 0.2kg of environmentally friendly wet strength agent epichlorohydrin modified polyamide resin PAE-100 and 0.005kg of release agent allyl polyether modified dihydroxypropane mercaptan PE-80 in sequence, and soak at room temperature; S3: The pulp treated in S2 is diluted to a web-connected concentration of 0.7wt%, and formed on a wire paper machine. The wire section is dehydrated to a dryness of 25%. It is then pressed by press rolls and subsequently dried in sections. Finally, surface sizing is performed using a sizing solution of 0.6wt% sodium carboxymethyl cellulose solution and 0.15wt% of waterborne polyurethane dispersion PU-618, a wet rubbing resistance enhancer. The sizing amount is 1.6g / m², and the paper is dried to constant weight to obtain colored paper yarn base paper.

[0029] The S1 standard slurry disintegration machine has a rotation speed of 2500 r / min and a disintegration time of 10 min.

[0030] The preparation method of the composite color-fixing agent is as follows: A1: Mix 140 kg of dextran and 1000 kg of deionized water, and stir at 45 °C for 40 min until completely dissolved to obtain a homogeneous dextran solution; slowly add 15 kg of sodium hydroxide to the solution, stir at room temperature for 20 min for alkalization and activation, then add 14 kg of α-amino-ω-glycidyl polyethylene glycol (number average molecular weight 100 Da), add 0.2 kg of 1,1'-diepoxyethylene ethyl sulfide (CAS: 14974-71-1), and heat to 40 °C for pre-reaction for 2 h; continue to slowly add 70 kg of 3-chloro-2-hydroxypropyltrimethylammonium chloride to the system at a rate of 2 drops / second, heat to 60 °C, and stir at a constant temperature for 4 h; A2: After the reaction is complete, neutralize to pH 7 with 10wt% hydrochloric acid solution, add 4 times the volume of isopropanol to the system, stir to precipitate for 2 hours, filter to collect the precipitate, and dry to constant weight at 65℃ to obtain the composite color-fixing agent.

[0031] The aqueous dye of S2 is Direct Fast Yellow RS.

[0032] The S2 soaking time at room temperature is 3 hours, during which it is stirred at 150 r / min for 5 minutes every 30 minutes.

[0033] The pressure of the S3 pressing roller is 0.4 MPa, and the pressing is completed to a dryness of 41%.

[0034] The S3 segmented drying step is as follows: the first stage is dried at 105℃ to a dryness of 65%, and the second stage is dried at 130℃ to a dryness of 91%. Example 3

[0035] A method for preparing a high color fastness and wet-rub resistant colored paper yarn base paper, the operation steps of which are as follows: S1: Mix 17kg of bleached softwood sulfate pulp with a freeness of 40°SR and 5kg of Manila abaca pulp with a freeness of 30°SR, add 0.3kg of 1wt% nanocellulose dispersion CNC-C10, decompose using a standard pulp decomposer, and then beat the pulp with a double disc mill to a total freeness of 45°SR. S2: Heat the slurry prepared in S1 to 45℃, add 0.07kg of water-based dye, and stir at 450r / min for 25min; then add 0.2kg of composite fixing agent and continue stirring for 15min; then add 0.3kg of environmentally friendly wet strength agent epichlorohydrin modified polyamide resin PAE-100 and 0.007kg of release agent allyl polyether modified dihydroxypropane mercaptan PE-80 in sequence, and soak at room temperature; S3: The pulp treated in S2 is diluted to a web-connected concentration of 0.7wt%, and then formed on a wire paper machine. The wire section is dehydrated to a dryness of 25%. It is then pressed by press rolls and subsequently dried in sections. Finally, surface sizing is performed using a sizing solution of 0.8wt% sodium carboxymethyl cellulose solution and 0.15wt% waterborne polyurethane dispersion PU-618 (a wet rubbing resistance enhancer). The sizing amount is 1.8g / m², and the paper is dried to constant weight to obtain colored paper yarn base paper.

[0036] The S1 standard slurry disintegration machine has a rotation speed of 2500 r / min and a disintegration time of 10 min.

[0037] The preparation method of the composite color-fixing agent is as follows: A1: Mix 180 kg of dextran and 1400 kg of deionized water, and stir at 45 °C for 50 min until completely dissolved to obtain a homogeneous dextran solution; slowly add 25 kg of sodium hydroxide to it, stir at room temperature for 25 min for alkalization and activation, then add 18 kg of α-amino-ω-glycidyl polyethylene glycol (number average molecular weight 2000 Da), add 0.4 kg of 1,1'-diepoxy ethylene ethyl sulfide (CAS: 14974-71-1), and heat to 40 °C for pre-reaction for 2 h; continue to slowly add 100 kg of 3-chloro-2-hydroxypropyltrimethylammonium chloride to the system at a rate of 4 drops / second, heat to 60 °C, and stir at a constant temperature for 5 h; A2: After the reaction is complete, neutralize to pH 7 with 10wt% hydrochloric acid solution, add 4 times the volume of isopropanol to the system, stir to precipitate for 2 hours, filter to collect the precipitate, and dry to constant weight at 65℃ to obtain the composite color-fixing agent.

[0038] The aqueous dye of S2 is Direct Sunlight Black G.

[0039] The S2 soaking time at room temperature is 3 hours, during which it is stirred at 150 r / min for 5 minutes every 30 minutes.

[0040] The pressure of the S3 pressing roller is 0.4 MPa, and the pressing is completed to a dryness of 41%.

[0041] The S3 segmented drying step is as follows: the first stage is dried at 105℃ to a dryness of 65%, and the second stage is dried at 135℃ to a dryness of 91%. Example 4

[0042] A method for preparing a high color fastness and wet-rub resistant colored paper yarn base paper, the operation steps of which are as follows: S1: Mix 19kg of bleached softwood sulfate pulp with a freeness of 45°SR and 6kg of Manila abaca pulp with a freeness of 30°SR, add 0.4kg of 1wt% nanocellulose dispersion CNC-C10, decompose using a standard pulp decomposer, and then beat the pulp to a total freeness of 45°SR using a double disc mill. S2: Heat the slurry prepared in S1 to 50℃, add 0.075kg of water-based dye, and stir at 500r / min for 30min; then add 0.3kg of composite fixing agent and continue stirring for 20min; then add 0.4kg of environmentally friendly wet strength agent epichlorohydrin modified polyamide resin PAE-100 and 0.008kg of release agent allyl polyether modified dihydroxypropane mercaptan PE-80 in sequence, and soak at room temperature; S3: The pulp treated in S2 is diluted to a web-connected concentration of 0.8wt%, and formed on a wire paper machine. The wire section is dehydrated to a dryness of 26%. It is then pressed by press rolls and subsequently dried in sections. Finally, surface sizing is performed using a 1.0wt% sodium carboxymethyl cellulose solution with 0.2wt% waterborne polyurethane dispersion PU-618 added as a wet rubbing resistance enhancer. The sizing amount is 2.0g / m², and the paper is dried to constant weight to obtain colored paper yarn base paper.

[0043] The S1 standard slurry disintegration machine has a rotation speed of 3000 r / min and a disintegration time of 15 min.

[0044] The preparation method of the composite color-fixing agent is as follows: A1: Mix 200 kg of dextran and 1600 kg of deionized water, and stir at 50 °C for 60 min until completely dissolved to obtain a homogeneous dextran solution; slowly add 30 kg of sodium hydroxide to the solution, stir at room temperature for 30 min for alkalization and activation, then add 20 kg of α-amino-ω-glycidyl polyethylene glycol (number average molecular weight 2000 Da), add 0.5 kg of 1,1'-diepoxy ethylene ethyl sulfide (CAS: 14974-71-1), and heat to 45 °C for pre-reaction for 3 h; continue to slowly add 120 kg of 3-chloro-2-hydroxypropyltrimethylammonium chloride to the system at a rate of 5 drops / second, heat to 65 °C, and stir at a constant temperature for 6 h; A2: After the reaction is complete, neutralize to pH 7.5 with 10wt% hydrochloric acid solution, add 5 times the volume of isopropanol to the system, stir to precipitate for 3 hours, filter to collect the precipitate, and dry to constant weight at 70℃ to obtain the composite color fixing agent.

[0045] The aqueous dye of S2 is Direct Sunlight Black G.

[0046] The S2 soaking time at room temperature is 4 hours, during which it is stirred at 200 r / min for 5 minutes every 30 minutes.

[0047] The pressure of the S3 pressing roller is 0.5 MPa, and the dryness is 42%.

[0048] The S3 segmented drying step is as follows: the first stage is dried at 110℃ to a dryness of 70%, and the second stage is dried at 135℃ to a dryness of 92%.

[0049] Comparative Example 1 A method for preparing a high color fastness and wet-rub resistant colored paper yarn base paper, the operation steps of which are as follows: S1: Mix 9 kg of bleached softwood sulfate pulp with a knockout degree of 35°SR and 2 kg of Manila abaca pulp with a knockout degree of 25°SR, add 0.1 kg of 1 wt% nanocellulose dispersion CNC-C10, knock out the pulp using a standard pulp de-kneading machine, and then beat the pulp with a double disc mill to a total knockout degree of 40°SR. S2: Heat the slurry prepared in S1 to 40℃, add 0.05kg of water-based dye, and stir at 300r / min for 200min; then add 0.1kg of environmentally friendly wet strength agent epichlorohydrin modified polyamide resin PAE-100 and 0.004kg of release agent allyl polyether modified dihydroxypropane mercaptan PE-80 in sequence, and soak at room temperature; S3: The pulp treated in S2 is diluted to a web-connected concentration of 0.6wt%, and then formed on a wire paper machine. The wire section is dewatered to a dryness of 24%. It is then pressed by press rolls and subsequently dried in sections. Finally, surface sizing is performed using a sizing solution of 0.5wt% sodium carboxymethyl cellulose solution and 0.1wt% of waterborne polyurethane dispersion PU-618, a wet rubbing resistance enhancer. The sizing amount is 1.5g / m², and the paper is dried to constant weight to obtain colored paper yarn base paper.

[0050] The S1 standard slurry disintegration machine has a rotation speed of 2000 r / min and a disintegration time of 5 min.

[0051] The aqueous dye of S2 is Direct Lightfast Turquoise Blue GL.

[0052] The S2 soaking time at room temperature is 2 hours, during which it is stirred at 100 r / min for 5 minutes every 30 minutes.

[0053] The pressure of the S3 press roller is 0.3 MPa, and the dryness is 40%.

[0054] The S3 segmented drying step is as follows: the first stage is dried at 100℃ to a dryness of 60%, and the second stage is dried at 130℃ to a dryness of 90%.

[0055] Comparative Example 2 A method for preparing a high color fastness and wet-rub resistant colored paper yarn base paper, the operation steps of which are as follows: S1: Mix 9 kg of bleached softwood sulfate pulp with a knockout degree of 35°SR and 2 kg of Manila abaca pulp with a knockout degree of 25°SR, add 0.1 kg of 1 wt% nanocellulose dispersion CNC-C10, knock out the pulp using a standard pulp de-kneading machine, and then beat the pulp with a double disc mill to a total knockout degree of 40°SR. S2: Heat the slurry prepared in S1 to 40℃, add 0.05kg of water-based dye, and stir at 300r / min for 200min; then add 0.1kg of composite fixing agent and continue stirring for 10min; then add 0.1kg of environmentally friendly wet strength agent epichlorohydrin modified polyamide resin PAE-100 and 0.004kg of release agent allyl polyether modified dihydroxypropane mercaptan PE-80 in sequence, and soak at room temperature; S3: The pulp treated in S2 is diluted to a web-connected concentration of 0.6wt%, and then formed on a wire paper machine. The wire section is dewatered to a dryness of 24%. It is then pressed by press rolls and subsequently dried in sections. Finally, surface sizing is performed using a sizing solution of 0.5wt% sodium carboxymethyl cellulose solution and 0.1wt% of waterborne polyurethane dispersion PU-618, a wet rubbing resistance enhancer. The sizing amount is 1.5g / m², and the paper is dried to constant weight to obtain colored paper yarn base paper.

[0056] The S1 standard slurry disintegration machine has a rotation speed of 2000 r / min and a disintegration time of 5 min.

[0057] The preparation method of the composite color-fixing agent is as follows: A1: Mix 100 kg of dextran and 800 kg of deionized water, and stir at 40 °C for 30 min until completely dissolved to obtain a homogeneous dextran solution; slowly add 10 kg of sodium hydroxide to the solution, stir at room temperature for 15 min for alkalization and activation, then add 0.1 kg of 1,1'-diepoxyethylene ethyl sulfide (CAS: 14974-71-1), and heat to 35 °C for pre-reaction for 1 h; continue to slowly add 50 kg of 3-chloro-2-hydroxypropyltrimethylammonium chloride to the system at a rate of 1 drop / second, heat to 55 °C, and stir at a constant temperature for 3 h; A2: After the reaction is complete, neutralize to pH 6.5 with 10wt% hydrochloric acid solution, add 3 times the volume of isopropanol to the system, stir to precipitate for 1 hour, filter to collect the precipitate, and dry to constant weight at 60℃ to obtain the composite color fixing agent.

[0058] The aqueous dye of S2 is Direct Lightfast Turquoise Blue GL.

[0059] The S2 soaking time at room temperature is 2 hours, during which it is stirred at 100 r / min for 5 minutes every 30 minutes.

[0060] The pressure of the S3 press roller is 0.3 MPa, and the dryness is 40%.

[0061] The S3 segmented drying step is as follows: the first stage is dried at 100℃ to a dryness of 60%, and the second stage is dried at 130℃ to a dryness of 90%.

[0062] Comparative Example 3 A method for preparing a high color fastness and wet-rub resistant colored paper yarn base paper, the operation steps of which are as follows: S1: Mix 9 kg of bleached softwood sulfate pulp with a knockout degree of 35°SR and 2 kg of Manila abaca pulp with a knockout degree of 25°SR, add 0.1 kg of 1 wt% nanocellulose dispersion CNC-C10, knock out the pulp using a standard pulp de-kneading machine, and then beat the pulp with a double disc mill to a total knockout degree of 40°SR. S2: Heat the slurry prepared in S1 to 40℃, add 0.05kg of water-based dye, and stir at 300r / min for 200min; then add 0.1kg of composite fixing agent and continue stirring for 10min; then add 0.1kg of environmentally friendly wet strength agent epichlorohydrin modified polyamide resin PAE-100 and 0.004kg of release agent allyl polyether modified dihydroxypropane mercaptan PE-80 in sequence, and soak at room temperature; S3: The pulp treated in S2 is diluted to a web-connected concentration of 0.6wt%, and then formed on a wire paper machine. The wire section is dewatered to a dryness of 24%. It is then pressed by press rolls and subsequently dried in sections. Finally, surface sizing is performed using a sizing solution of 0.5wt% sodium carboxymethyl cellulose solution and 0.1wt% of waterborne polyurethane dispersion PU-618, a wet rubbing resistance enhancer. The sizing amount is 1.5g / m², and the paper is dried to constant weight to obtain colored paper yarn base paper.

[0063] The S1 standard slurry disintegration machine has a rotation speed of 2000 r / min and a disintegration time of 5 min.

[0064] The preparation method of the composite color-fixing agent is as follows: A1: Mix 100 kg of dextran and 800 kg of deionized water, and stir at 40 °C for 30 min until completely dissolved to obtain a homogeneous dextran solution; slowly add 10 kg of sodium hydroxide to it, stir at room temperature for 15 min for alkalization and activation, then add 10 kg of α-amino-ω-glycidyl polyethylene glycol (number average molecular weight 1000 Da), add 0.1 kg of 1,1'-diepoxy ethylene ethyl sulfide (CAS: 14974-71-1), and heat to 35 °C to react for 1 h; A2: After the reaction is complete, neutralize to pH 6.5 with 10wt% hydrochloric acid solution, add 3 times the volume of isopropanol to the system, stir to precipitate for 1 hour, filter to collect the precipitate, and dry to constant weight at 60℃ to obtain the composite color fixing agent.

[0065] The aqueous dye of S2 is Direct Lightfast Turquoise Blue GL.

[0066] The S2 soaking time at room temperature is 2 hours, during which it is stirred at 100 r / min for 5 minutes every 30 minutes.

[0067] The pressure of the S3 press roller is 0.3 MPa, and the dryness is 40%.

[0068] The S3 segmented drying step is as follows: the first stage is dried at 100℃ to a dryness of 60%, and the second stage is dried at 130℃ to a dryness of 90%.

[0069] Table 1. Test results of wet rubbing fastness, colorfastness index, and longitudinal tear strength of the paper yarn base paper in the specific implementation plan. Color fastness to wet rubbing (grade) Decolorization index (%) Longitudinal tear strength (mN) Example 1 5 5.7 810 Example 2 5 5.5 815 Example 3 5 5.0 823 Example 4 5 4.8 828 Comparative Example 1 2 18.5 485 Comparative Example 2 4 9.1 754 Comparative Example 3 4 8.6 766 A dextran-based PEG fixing agent was successfully prepared through a stepwise process of alkalization activation, pre-crosslinking grafting, and cationic modification. This process successfully grafted flexible polyethylene glycol segments and quaternary ammonium salt cationic groups onto the dextran backbone, constructing a uniquely structured cationic polymer fixing agent. The precise introduction of 1,1'-diepoxyethylene ethyl sulfide is key to improving the efficiency of the pre-crosslinking reaction and optimizing the molecular structure, while the grafting of quaternary ammonium salt groups endows the product with core cationic fixing properties. This preparation process is characterized by mild conditions, controllable steps, stable product structure, and excellent environmental friendliness. Compared with traditional fixing agents, it possesses multiple fixing effects, including hydrogen bonding, electrostatic adsorption, and steric hindrance. When applied to the internal dyeing of paper yarn base pulp, it can synergistically work with nanocellulose to achieve efficient anchoring of dye molecules, significantly improving the wet rubbing fastness of the base paper and reducing the fading index. Simultaneously, its flexible molecular segments can cooperate with environmentally friendly wet strength agents to strengthen the inter-fiber bonding force and help improve the tear strength of the base paper. This fundamentally solves the technical problem of balancing color stability and mechanical properties in the preparation of traditional paper yarn base paper. It can also improve dye utilization and reduce production pollution, providing a core environmentally friendly auxiliary agent solution for the preparation of high-fastness, wet-rubbing resistant colored paper yarn base paper, and meeting the high-end product production needs of the paper and textile cross-industry.

[0070] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A method for preparing a high-colorfastness, wet-rub resistant colored paper yarn base paper, the operation steps of which are as follows, by weight parts: S1: Mix 9-19 parts of bleached softwood sulfate pulp with a beating degree of 35-45°SR and 2-6 parts of Manila abaca pulp with a beating degree of 25-30°SR, add 0.1-0.4 parts of 1wt% nanocellulose dispersion CNC-C10, decompose using a standard pulp decomposer, and then beat the pulp with a double disc mill to a total beating degree of 40-45°SR; S2: Heat the slurry prepared in S1 to 40-50℃, add 0.05-0.075 parts of water-based dye, and stir at 300-500 r / min for 20-30 min; then add 0.1-0.3 parts of composite fixing agent and continue stirring for 10-20 min; Then add 0.1-0.4 parts of environmentally friendly wet-strength agent epichlorohydrin modified polyamide resin PAE-100 and 0.004-0.008 parts of release agent allyl polyether modified dihydroxypropane mercaptan PE-80 in sequence, and soak at room temperature; S3: Dilute the pulp treated by S2 to a web-forming concentration of 0.6-0.8 wt%, and form it on a fourdrinier paper machine. Dewater the web section to a dryness of 24-26%. After being pressed by press rollers, it is then dried in sections; finally, surface sizing is applied, with a sizing amount of 1.5-2.0 g / m², and the sizing solution is 0.5-1.0 wt% sodium carboxymethyl cellulose solution and 0.1-0.2 wt% waterborne polyurethane dispersion PU-618 for wet rubbing resistance enhancement. It is dried to constant weight to obtain colored paper yarn base paper. The composite color-fixing agent is prepared by reacting dextran, sodium hydroxide, α-amino-ω-glycidyl polyethylene glycol, 1,1'-diepoxyethylene ethyl sulfide, and 3-chloro-2-hydroxypropyltrimethylammonium chloride.

2. The method for preparing a high color fastness and wet-rub resistant colored paper yarn base paper according to claim 1, characterized in that: The speed of the S1 standard slurry disintegrating machine is 2000-3000 r / min, and the disintegration time is 5-15 min.

3. The method for preparing a high color fastness and wet-rub resistant colored paper yarn base paper according to claim 1, characterized in that: The preparation method of the composite color-fixing agent is as follows: A1: Mix 100-200 parts by weight of dextran and 800-1600 parts by weight of deionized water, and stir at 40-50℃ for 30-60 min until completely dissolved to obtain a homogeneous dextran solution; slowly add 10-30 parts by weight of sodium hydroxide, stir at room temperature for 15-30 min for alkalization and activation, then add 10-20 parts by weight of α-amino-ω-glycidyl polyethylene glycol and 0.1-0.5 parts by weight of 1,1'-diepoxyethylene ethyl sulfide, and heat to 35-45℃ for pre-reaction for 1-3 h; continue to slowly add 50-120 parts by weight of 3-chloro-2-hydroxypropyltrimethylammonium chloride to the system at a rate of 1-5 drops / second, heat to 55-65℃, and stir at a constant temperature for 3-6 h; A2: After the reaction is complete, neutralize to pH 6.5-7.5 with 10wt% hydrochloric acid solution, add 3-5 times the volume of isopropanol to the system, stir to precipitate for 1-3 hours, filter to collect the precipitate, and dry to constant weight at 60-70℃ to obtain the composite color-fixing agent.

4. The method for preparing a high color fastness and wet-rub resistant colored paper yarn base paper according to claim 1, characterized in that: The aqueous dye of S2 is one of Direct Sunlight Blue GL, Direct Sunlight Yellow RS, and Direct Sunlight Black G.

5. The method for preparing a high color fastness and wet-rub resistant colored paper yarn base paper according to claim 1, characterized in that: The S2 soaking time at room temperature is 2-4 hours, during which it is stirred at 100-200 r / min for 5 minutes every 30 minutes.

6. The method for preparing a high color fastness and wet-rub resistant colored paper yarn base paper according to claim 1, characterized in that: The pressure of the S3 pressing roller is 0.3-0.5 MPa, and the pressing is completed to a dryness of 40-42%.

7. The method for preparing a high color fastness and wet-rub resistant colored paper yarn base paper according to claim 1, characterized in that: The S3 segmented drying step is as follows: the first stage is dried at a temperature of 100-110℃ to a dryness of 60-70%, and the second stage is dried at a temperature of 130-135℃ to a dryness of 90-92%.