Application Of Ionic Acrylate Copolymer Macromolecular Surfactant In Paper Sizing

Except for individual sanitary paper,other paper grades need to be glued to enhance the paper's water resistance and physical strength in the paper industry.The internal sizing of paper pulp is to add a paper additive to the pulp of papermaking to enhance the water resistance and physical strength of the paper.High dispersion rosin and other neutral sizing agents are commonly used in pulp sizing.At present,most domestic manufacturers often mix small-molecule emulsifiers or cationic starches to obtain rosin gum for the stability of the emulsion,which has many problems such as complicated production process.And the small molecular emulsifier will reduce the binding force between sizing agent and fiber,resulting in low sizing degree of papermaking and other problems.Although there are not many large paper mills,the stability and sizing of rosin emulsion are greatly affected by the quality of the water in the northwestern region of China.Therefore,it is necessary to further improve the highly dispersive emulsion rosin gum,which is of great importance in the preparation of high polymer dispersive emulsifiersSurface sizing refers to adding a layer of water-resistant thin layer adhesive to paper or cardboard that has already been moulded.It is mainly used for high-grade paper such as RMB and advanced writing paper.The surface sizing and sizing can enhance the physical strength and writing performance of the paper.The alkyl ketene dimer?AKD?is currently the most commonly used surface sizing agent and the effective reaction of sizing was esterification.However,AKD is prone to hydrolysis reaction with water,which will reduce emulsion stability and effectiveness.Therefore,AKD is not suitable as a surfac e sizing agent for long-term storage,which severely limits the development of AKD as a surface sizing agent.It is another important aspect of the research to develop an AKD neutral sizing agent with high solid content and long stay activity.The main work and results of this paper are as follows:?1?According to the actual application requirements,the synthesis method of cationic?anionic?acrylic acid dispersion emulsifier was designed.The cation separation monomer was dimethylaminoethyl methacrylate?DM?and the anionic monomer was acrylic acid?AA?.The best reaction conditions were as follows.The stirring rate was175r/min,the initiator amount was 0.5%,the reaction temperature was95°C,the reaction time was 4h,the neutralization degree was 0.8,the average conversion rate of the obtained cationic polymer was 78.8%,and the average conversion rate of anionic polymer was 81.3%.According to the infrared spectrum and NMR spectrum,the main functional groups and structural characteristics of the cat ionic?anion?acrylate copolymers were in accordance with the expected design of structural molecular formula,and the products obtained from the experiments were determined as the target products.The molecular weight distribution of the product was also n arrow,and the thermogravimetric analysis of the product was in line with the expected target product.The cation?anionic?ion rosin latex emulsion with a solid content of 30%was obtained by a reversal method.The changes of emulsion particle size,static stability,centrifugal stability,surface tension and emulsion viscosity under different ratios were studied to determine the optimum ratio of emulsifier and rosin to 1:1.The cationic?anionic?rosin emulsion under the best condition was tested.It was found that the solid content of the emulsion was 30%.The fluidity of the emulsion was about 100nm³00nm,the viscosity of the emulsion was about 440cp,and the stability of the emulsion was good.There will be no stratification in the greenhouse for half a year.?2?The influence factors of the sizing process were explored and optimized,such as the type of slurry,the optimal mix of rosin and emulsifier,the amount of rosin size,the amount of Al₂?SO₄?₃,and the amount of cationic polyamide polyamine epic hlorohydrin?PAE?,p H range,positive and negative sizing ect.The self-made cationic rosin sizing agent had its own cationic cation,which can be combined with electrostatic adsorption of fibers.The optimum technological conditions of cationic rosin sizi ng agent were as follows:1%for rubber compound,4%for Al₂?SO₄?₃,0.025%for PAE.The optimum technological conditions of anionic rosin sizing agent were as follows:1%for rubber compound,4%for Al₂?SO₄?₃,0.05%for PAE,5.5⁷ for p H.The sizing degree and physical properties of different pulps were tested.It was concluded that the degree of sizing and physical properties of the cotton pulp papers were the most improved and it also had a good improvement effect on hardwood pulp papers with promising future.By comparing the positive and negative sizing of pulp,paper SEM and physical properties of paper,it was concluded that reverse sizing was better than positive sizing and it can also solve low sizing and foaming effects in hard wate r.The final anionic rosin gum had a maximum sizing degree of 50.9 sec,a cation maximum degree of sizing of 48.7 sec,and the sizing performance was better than that of the marketed neutral rosin.The cationic AKD emulsion was prepared by the reversal meth od in this paper.The emulsion itself has a positive charge,which enhance d the retention of AKD on the surface of the paper fibers and reduce d the amount of filler.By studying the effect of AKD emulsion concentration on the hydrolysis rate of AKD,the pro blem of difficult storage in the AKD industry can be effectively solved when the solid content was increased to 60%,When using,the AKD emulsion was diluted with water to add dilution range:the light sizing concentration was 0.05%,the heavy sizing was 0.1%.By testing the physical properties of paper,it was known that AKD sizing agent could effectively improve the physical properties of paper and enhanced the water resistance of paper.The distribution of the gum in the paper was observed by SEM.It was known that the coverage of the gum on the surface of the paper-like fibers was high,the distribution of the gum was relatively uniform,and the pore filling of the fibers was better.