Polyvinyl Alcohol-PVA as an adhesive
a. The aqueous solution of polyvinyl alcohol has strong adhesion to materials containing cellulose (such as paper, cloth, wood, etc.). It has the advantages of being safe and non-toxic. It can be used for cardboard lamination, corrugated cardboard bonding and office glue, etc. Kraft paper bags for packaging heavy objects such as cement, fertilizers, grains, etc. also use PVA as an adhesive.
b. Urea-formaldehyde resin and phenolic resin modified with polyvinyl alcohol can be used as adhesives for laminates and wood-based panels.
c. Polyvinyl alcohol aqueous solution (by adding appropriate fillers and additives) is also widely used to prepare adhesives required for printing and binding, paper tubes, cartons and other paper products.
d. Polyvinyl alcohol is condensed with formaldehyde, butyraldehyde, glyoxal or other aldehydes under acid catalysis. It can generate polyvinyl acetal (such as PVAF, PVB) with stronger water resistance, adhesive force and mechanical strength. Widely used in construction, coatings, adhesives, safety glass interlayer and other fields. As the degree of polymerization of PVA increases, the viscosity of acetal increases.
e. Polyvinyl alcohol is an excellent protective colloid and dispersant for the homopolymerization of vinyl acetate or copolymerization with other monomers to produce emulsion (white glue), which is very important in the production of white glue. Generally, as the degree of polymerization of polyvinyl alcohol increases, the viscosity of the produced emulsion increases. Partial alcoholysis polyvinyl alcohol (17-88) and complete alcoholysis polyvinyl alcohol (such as 17-99, 19-99, etc.) are mostly used together. The use of partially alcoholyzed polyvinyl alcohol can increase the stability of the emulsion, and the use of fully alcoholyzed polyvinyl alcohol can increase the water resistance of the emulsion.
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