Selvol polyvinyl alcohol (PVOH/PVA) is a water-soluble polymer. For that reason, manufacturers often perceive it as having little or no water resistance. However, Selvol polymers are tailorable to provide either water retention or water resistance, depending on the grade.
SEKISUI’s polymer range includes both hydrophilic and hydrophobic grades of PVOH, giving formulators options for coatings, films and adhesives.
Hydrophilic Properties and Water Retention
As a hydrophilic polymer, Selvol exhibits excellent water retention properties. Low-viscosity grades such as Selvol 103, 107, 502, 203 and 205 are preferable for these applications because they provide optimum coating rheology.
The figure below compares Selvol PVOH 203 with other hydrocolloids using the dynamic ABO AKADEMI methodology. Selvol performed very well in this comparison, offering much higher binder strength along with the ability to boost optical brightener performance.
These attributes make Selvol a strong water-soluble film former, delivering consistent performance in coating and packaging systems.
Hydrophobic Properties and Water Resistance
Proper Selvol grade selection and the use of crosslinkers open up an entire range of insolubilities. Hydrolysis primarily determines the water resistance of a specific Selvol grade. Super-hydrolyzed grades, such as Selvol PVOH 125 and 165, yield maximum water resistance, as shown in the figure below.
This balance of solubility options allows Selvol to serve as the foundation for polyvinyl alcohol water-soluble films. It also enables grades suited to high-resistance coatings and laminates.
Applications in Paper and Packaging
Surface applications of PVOH and alkyl ketene dimer (AKD) blends demonstrate outstanding improvements in Cobb and Hercules Sizing (HST) values on both acid and alkaline papers, with little or no loss in size values upon aging. Unlike starch, a PVOH surface application does not degrade the internal sizing effect of wet-end additives like AKD or ASA.
Selvol’s excellent resistance to oils, greases, waxes and solvents further demonstrates its hydrophobicity. Manufacturers can u se it alone or with starch to meet Vanceometer, Turpentine, K&N ink holdout and other specifications.
As a PVA/PVOH film material, Selvol also functions as an effective carrier for fluorochemicals. Blends of Selvol and fluorochemicals achieve high 3M Kit Ratings at lower cost than fluorochemicals alone. This versatility makes Selvol valuable in both cold water-soluble film applications and advanced paper coatings.
Contact SEKISUI for Selvol PVOH
SEKISUI Specialty Chemicals manufactures the largest range of polyvinyl alcohol polymers and copolymers worldwide, serving diverse industries including paper, packaging, coatings, adhesives and films.
Please see the brochure on Selvol for paper and paperboard applications for more information.
Contact SEKISUI or request a sample today to discover which grade best enhances a specific product or process.
Download the Selvol PVOH brochure to learn more about its composition and capabilities.
Reach the SEKISUI Technical Services Team for a consultation on the ideal Selvol grade.