The Retention And Immobilization Of Waterborne Pigment In Color Paper Yarn Base Paper And Its Mechanism

The "Bicarbon" strategy advocates a green and low-carbon lifestyle.Color paper yarn is made from natural lignocellulosic raw materials by a series of special papermaking processes,and finally by twisting spinning paper yarn.It is a new type of health and environmental protection multifunctional textile material.In recent years,the product demand and performance requirements are constantly rising,and the development prospect is broad.But when the base paper is colored,there is a lack of chemical or hydrogen bonding between green-water-based organic pigments and plant fibers.It is difficult to retain and fix pigments in the base paper,resulting in poor dyeing effect and easy peeling of pigments.Therefore,this topic first starts from the wet part chemistry,by using different kinds of cellulose nanofibers(CNF)to form a three-dimensional network structure envelope pigment particles to form the envelope.The retention and immobilization of organic pigments were improved by enhancing the hydrogen bond between the envelope structure and paper fiber.In addition,through the base paper surface coating,using CNF and carboxymethyl cellulose(CMC)to construct a multi-dimensional gradient network structure,coating load fixed organic pigment particles.Then a network protective layer is coated on the surface to enhance the immobilization effect of pigment particles.Finally,bright and strong color paper yarn base paper was prepared.The details are as follows:First,a blending method was used to add negatively charged CNF,TEMPO oxidized cellulose nanofibers(TOCNF)with carboxyl group and rich negative charge on the surface,and cationic modified cellulose nanofibers(C-CNF)with positive charge.The three dimensional network structure formed by different electrostatic CNF adsorbs and intercepts the fixed organic pigments.The results showed that the addition of three kinds of nanocellulose significantly improved the retention of organic pigment phthalocyanine blue particles,which helped to fix the structure of the base paper.Among them,C-CNF had better retention and fixation effect on organic pigments than CNF and TOCNF.When the amount of C-CNF was 1.2wt%,the pigment retention rate was 46.58%,which was 33.43%higher than that without C-CNF addition.The rubbing color fastness of base paper is improved from 2 to 4.2,which is close to the top 5.At the same time,the paper yarn base paper tensile index also increased by 32.14%to 31.74 N·m/g.Secondly,in order to further improve the retention and immobilization effect of pigments,positively charged polyamide polyamine epichlorohydrin(PAE)molecules were introduced into the system.Through the synergistic effect of charge adsorption and the three-dimensional network structure of CNF interweaving,pigment@CNF pre-envelope was formed first,and then the retention and fixation effect of the three-dimensional network structure of nanocellulost on pigment particles was enhanced.The results showed that the premixed envelope of TOCNF/C-CNF and organic pigment increased the interaction between the modified nanocellulose and organic pigment particles,and significantly improved the retention of pigment and the rubbing color fastness of the base paper.Under the condition of TOCNF-OP-0.25%PAE,the pigment retention rate reached 77.05%,the color fastness to friction 3.8 and the tensile index 35.34 N·m/g.Compared with the direct mixing condition,the retention rate increased by 67.9%,the color fastness decreased by 0.4,and the tensile index increased by 27.95%.Finally,a multi-stage gradient network was constructed using nanocellulost as a first-order skeleton network and CMC molecules as a second-order reinforcement network.By first coating the surface of the base paper,and then coating the network protective layer to cover the fixed pigment particles to achieve full retention and strong fixation.The results show that the coatings prepared by TOCNF have the best effect,and the repulsion of a large number of negative charges on the surface promotes the uniform dispersion of the coatings.The composite properties of protective layer(CNF:CMC=3:2)and coloring layer(pigment:TOCNF:CMC=2:2:1)are the best,and their viscosities under low shear are 27.33 Pa·s and 14.66 Pa·s,respectively.When the total coating amount is 1.00±0.04 g/m~2,the L value of color paper yarn base paper is 48.29,b value is41.87,the color fastness is up to 4.5±0.1,and the tensile index is 132.78 N·m/g,which is 38.82%higher than the base paper provided by the enterprise.In this paper,two methods to improve the retention and immobilization of water-based organic pigments are developed to prepare and issue color paper yarn base paper with excellent color fastness,which has a positive promoting effect on the progress of high performance paper yarn preparation technology.