Polyvinyl alcohol (PVA) is used more in papermaking, and the main effect is to make binder. Specific applications can be divided into:
1. Paper products inside glue: With the micro-powder level, add in the pulp, mixed with paper fiber when doing the papermaking, in the slurry has been fully absorbent swelling, papermaking finished the drying stage, the swelling of the good PVA melts the paper fiber bonding together. Mainly in the manufacture of raw paper used, and pulp added together, increase the moisture of paper, the added account is 4-8%.
2. Paper Binder: Mainly used for bonding paper, such as a paper tube, paper tube, corrugated cardboard, kraft bag, paperboard and so on. Added to the paper, the amount of uncertainty, depending on the specific formula and different, bonding effect.
3. Wet bonding: wallpaper, stamp paper, label paper, paper tape and so on, paper products on the back, mainly used for wet bonding, add the amount of concrete formula, and then wet binder.
4. Paper Surface plastic: paper surface, increase paper surface strength and tension and flatness, improve printing adaptability; most of the paper that needs to be printed can be added.
Usage: Polyvinyl alcohol resin series products can be dissolved in hot water under 95 ℃, but because of the difference of polymerization degree and alcoholysis degree, an alcohol solution is different in dissolution time and temperature, so the dissolution method and time need to be groped when using different brands of polyvinyl alcohol resin. Dissolve, can be stirred side will slowly add this product 20 ℃ around the cold water in full swelling, disperse and volatile material escape (do not add the product directly to the water in the 40 ℃ above to dissolve, in order to avoid the appearance of wrapping and skin-soluble endogenous phenomenon), and then heat up to 95 ℃ or so accelerated dissolution, and heat preservation 2-2.5 hours until the solution no longer contains small particles, and then after 28 mesh stainless steel filter impurities, you can spare. Stirring speed 70-100/min, heating, can be used jacket, water bath, such as indirect heating, can also use steam direct heating; however, do not use open flame directly heating, in order to avoid partial overheating and decomposition, if there is no mixer, can be used to tangential direction of steam blowing method, to dissolve.