Chapter 15.3.2 - Polyvinyl Acetate

Polyvinyl acetate (PVAc) is one of the most versatile of the vinyl adhesives. Polyvinyl
acetate adhesives are available as solvent solutions or emulsions. This polymer is perhaps
best noted as an emulsion stabilized with a few percent of polyvinyl alcohol. Such a
polyvinyl acetate latex is the basis for the common household white glue.

PVAc’s are normally not suitable for use as an adhesive in their basic unmodified state
since they form very brittle films and have limited adhesion capabilities. They are, however,
compatible with a wide range of modifiers. Plasticizers (e.g., dibutyl phthalate) and
thickeners (methyl cellulose) are two additives commonly used in PVAc-based adhesives.
PVAc resins are often copolymerized with polyethylene or blended with polyvinyl alcohol.
Their formulations may contain fillers and pigments, depending on the application. The
adhesives should be applied at 15 to 32°C. The latex can be ruined by repeated freeze-thaw
cycles and shelf life is generally limited.

The fully formulated PVAc adhesives can be relatively flexible especially at low temperatures.
Resistance to most solvents and moisture is poor although these adhesives will
withstand contact with grease, oils, and petroleum fluids. The cured films tend to soften at
temperatures approaching 45°C. Polyvinyl acetates tend to creep under substantial load.
With proper formulation, these can be low cost adhesives with high initial tack properties
and good gap-filling properties.

The low viscosity of the PVAc water emulsion and its fast setting capability provide an
excellent adhesive for woodworking. The adhesive also allows for a certain degree of
rework if the substrates are not assembled correctly. The PVAc bonded substrates can be
disassembled and then reactivated by solvent. Table 15.14 provides a formulation for a
polyvinyl acetate adhesive that is used to apply parquet wood flooring.

For wood bonding, 10 min to 3 h at 20°C and contact to moderate pressure (100 to 150
psi) is recommended. One to seven days’ conditioning is recommended before handling
bonded assemblies. In the furniture industry, microwave heating is sometimes employed to
speed the drying. These adhesive-bonded substrates can be disassembled and then reactivated
by solvent.

Products of this type are good adhesives for applications where at least one substrate is
porous. Paper, plastics, metal foil, leather, and cloth are bonded well with polyvinyl acetate
emulsions. The major use is in packaging. Polyvinyl acetates are also used in hot melt adhesive
formulations. In this form they are used for bookbinding and lamination of foils.
Organic solvent solutions are also used, although not as much as the latex form.

In the tapes and labels industry, PVAc’s are commonly used for remoistenable labels
(Table 15.15) and gummed tapes. They are also widely used as additives to other adhesives.
The use of polyvinyl acetate emulsions for PSA applications includes remoistenable
adhesives on envelopes, postage stamps, sealing tapes, permanent labels, and decorative
ribbons.

Polyvinyl acetate (PVAc) is one of the most versatile of the vinyl adhesives. Polyvinyl
acetate adhesives are available as solvent solutions or emulsions. This polymer is perhaps
best noted as an emulsion stabilized with a few percent of polyvinyl alcohol. Such a
polyvinyl acetate latex is the basis for the common household white glue.

PVAc’s are normally not suitable for use as an adhesive in their basic unmodified state
since they form very brittle films and have limited adhesion capabilities. They are, however,
compatible with a wide range of modifiers. Plasticizers (e.g., dibutyl phthalate) and
thickeners (methyl cellulose) are two additives commonly used in PVAc-based adhesives.
PVAc resins are often copolymerized with polyethylene or blended with polyvinyl alcohol.
Their formulations may contain fillers and pigments, depending on the application. The
adhesives should be applied at 15 to 32°C. The latex can be ruined by repeated freeze-thaw
cycles and shelf life is generally limited.

The fully formulated PVAc adhesives can be relatively flexible especially at low temperatures.
Resistance to most solvents and moisture is poor...