Application of the hottest yh05 carboxyl styrene b

2022-08-17
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Application of yh-05 carboxyl styrene butadiene latex adhesive in coated paper (Part 2)

2 results and discussion

2.1 physical and chemical properties of yh-05 Table 1 shows the physical and chemical properties of yh-05, dow-675 and sd-656 carboxyl styrene butadiene latex. It can be seen from table 1 that the performance indexes of the three latex are similar

2.2 chemical and mechanical stability of yh-05

2.2.1 stability mechanism of carboxylated latex

the stability mechanism of carboxylated latex is that when unsaturated carboxylic acids are co polymerized in the system, the carboxyl groups on the surface of latex particles extend to the aqueous phase. These carboxyl groups are neutralized by a certain amount of alkali and then ionized. The ionized carboxyl groups cause the latex particles to absorb water and form a water protective layer around them due to their hydrophilicity, This situation is similar to the action of non-ionic surfactants. In addition, the ionized surface carboxyl group has a negative charge, which makes the latex anionic, and most particles in the coating composition are also anionic. The stability of the coating is improved due to the electrostatic repulsion between the latex particles, between the latex particles and the coating particles, and the carboxyl group is polymerized on the main chain of the latex polymer and will not be adsorbed due to the addition of shear force or other components. Therefore, carboxylated latex has higher mechanical and chemical stability than non carboxylated latex

2.2.2 chemical and mechanical stability of yh-05

the chemical stability of latex mainly refers to the stability of ca2+ ions and the compatibility with other components in the coating. In the experiment, 5ml latex was loaded in 50ml aqueous solution with w/(CaCl2) =10%. The ca2+ ion stability of latex was characterized by the volume of flocs produced after 4H

the mechanical stability of latex is generally evaluated by the residue content and foaming multiple of latex after high-speed stirring. The experiment adopts the advantage of British K pressure shear testing machine laxonbll.2hb latex machine stability tester to stir 50ml latex at high speed for 30min at 14000 R/min, and then filter it through 325 mesh stainless steel. The mechanical stability of latex is characterized by the thousandth ratio of the obtained residue to the absolutely dry latex polymer and the foaming multiple

it can be seen from table 2 that yh-05 has excellent mechanical and chemical stability

2.3 yh-05 coating application experiment

at present, although the coating formula changes a lot, it is mainly the combination of various pigments and adhesives. The early non carboxylated latex must be pre stabilized by adding a small amount of casein solution before mixing with the paint containing starch, while the carboxylated latex does not need to be pre stabilized. Its stability is achieved by the polymer itself, and its mechanical stability will not be reduced due to the shear force of the paint mixer and scraper applicator, It will not reduce its chemical stability due to the adsorption of surfactant in latex caused by the addition of starch and other components in the coating formula

2.3.1 small scale coating experiment

according to the actual situation of domestic paper mills, three coating formulations were designed experimentally, and the operating performance and paper forming performance of yh-05 latex were evaluated and compared with dow-675 and sd-656

from the physical properties and paper forming properties in Table 4 and table 5, it can be seen that the high and low shear viscosity characteristics of the three coatings prepared with yh-05, including oil cylinder, moving piston, oil cylinder end cover, hydraulic distributor integrated valve group, are similar to dow-675 and sd-656, and the ingredients have good rheological properties, which can meet the application requirements of the coating process. From the paper properties of the three latexes, yh-05 paper has high gloss, and other properties are equivalent to dow-675 and sd656. During the rotary calendering of the super friction disc, the paper of the three kinds of latex has no roller sticking and hole breaking

2.3.2 YH application in coating production line

the formula of production experimental coating is the same as that of small-scale formula A, using 62g/㎡ coated base paper to produce 80g/㎡ single-sided coated paper. The coating equipment is a scraper primary coater imported from KWM company in Sweden. The finishing equipment is a 12 roll super calender with a line pressure of 75kg/cm. After 11 pressing zones, the paper forming property after coating and finishing can be seen in Table 6

the results in Table 6 show that yh-05 coating has good applicability and compatibility, and can be used to prepare scraper coating with high solid content. Its paper properties such as gloss and printing gloss are better than sd-656, and other indexes are equivalent to sd-656 (IGT index is not comparable because it is measured with different viscosity inks)

3 conclusion

yh-05 carboxyl styrene butadiene latex developed and produced by the Research Institute of Yanhua company has excellent chemical stability, mechanical stability and rheological properties, and has good compatibility with other components in the coating. There is no roll hole breaking phenomenon in the coating process. The paper forming performance is equivalent to dow-675 and sd-656, especially with high gloss and printing gloss, which can meet the operating and performance requirements of coated paper

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