The paper is coated with a layer of starch on the surface of the paper. After drying, it forms a continuous film on the surface of the sheet, but because the starch is hydrophilic. So unlike other sizing agents can reduce the water absorption of the paper, but because of its small amount of sizing so the water value and not much impact.
The main effect of the surface of the paper on the surface of the paper is to improve the bonding strength between the fibers, to achieve the purpose of improving the surface strength of the paper; Surface Sizing Agent In particular, the current product market downturn, in order to reduce production costs Many paper companies want to improve the paper into the ash to achieve the purpose. But the ash is inevitable in the printing process appears hair loss powder. And the stiffness of the paper is bound to decline. So increase the surface of the paper surface sizing can effectively improve the paper surface strength and stiffness. Improve the printing performance and the use of results.
AKD sizing from the pulp to the surface (AKD surface sizing need to use its compatibility with the AKD synergist, otherwise it will be serious hydrolysis, slow) or part of the change to the surface, not only improve the degree of AKD, but also eliminates the AKD hydrolysis Product contamination of wet end systems.
AKD surface sizing is mainly AKD and cellulose covalent bond and fixed on the fiber. AKD has a reactive group, can be directly and cellulose hydroxyl reaction to form a covalent bond in the fiber surface to form a stable film. So that the fiber from hydrophilicity into hydrophobic.
But AKD and fiber role is slow. Surface Sizing Agent Need a certain drying temperature and curing time, so the use of AKD surface sizing, you must use a accelerated AKD curing additives to achieve AKD surface sizing.
Under normal circumstances, AKD synergist mainly polyamide polyamine epichlorohydrin resin (PAE), polyacrylamide (PAM), or PAE and PAM at the same time. For example, when PAE is used as the synergist for AKD, the epoxy groups in the PAE molecule will ring open during the heating and drying to cause secondary alkylation of the secondary amine. At this point the PAE resin becomes a nucleophile, Surface Sizing Agent to attack the AKD lactone ring, to open it, and fixed in the PAE resin macromolecular chain. PAE resin has a strong bridging ability, irreversibly fixed on the fiber surface, so that AKD through the middle of the reaction with the PAE resin and irreversibly bonded to the fiber surface.
Styrene-acrylic acid copolymer emulsion surface sizing agent and surface sizing starch with surface sizing, is coated with a layer of paper
Sizing agent. After drying, Surface Sizing Agent a continuous film is formed on the surface of the sheet to prevent liquid penetration and achieve better surface properties. As well as to improve the physical properties of the paper, while the surface of the liquid in the liquid phase dissociation, and the paper layer of anionic components interact and penetrate into the paper fiber gap, Surface Sizing Agent thereby increasing the bonding strength between the fiber Improve the surface strength of the purpose of the paper.
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