Selvol PVOHs have many characteristics that make them useful in a wide range of applications.
By choosing from the many Selvol PVOH grades available, you can obtain the performance properties needed for your specific applications. These include properties such as water solubility, abrasion resistance, tensile strength, adhesive and bonding properties, grease or oil resistance and film-forming qualities.
Our highly skilled technical service group can help you select your ideal Selvol PVOH grade.
Changes Occurring in the Properties of PVOH as the Degree of Hydrolysis and Molecular Weight Change
Viscosity/Concentration Relationships of Aqueous Selvol PVOH Solutions at 20%
Selvol PVOH Molecular Weight
||Degree of Polymerization
||Average Molecular Weight Range
Selvol PVOH combines high tensile strength with ease of film formation. Additionally, Selvol PVOH resins show outstanding adhesive and bonding characteristics. Partially hydrolyzed grades adhere better to hydrophobic surfaces.
Furthermore, the degree of hydrolysis affects the water sensitivity of both the resin and film. Water resistance increases as hydrolysis increases. You should use the super-hydrolyzed grades when you need maximum water resistance and humidity resistance.
Greases, petroleum hydrocarbons and animal or vegetable oils generally do not affect Selvol PVOH resins. Resistance to organic solvents also increases with the degree of hydrolysis. When necessary, one can plasticize Selvol PVOH film with glycerol or lower molecular weight glycols. These materials usually act as humectants to hold water in the film.
Physical Properties of PVOH
||White-to-cream granular powder
||40 lbs per cu ft
|Specific Gravity — of solid — of 10 wt % solid at 25°C
||1.27 – 1.311.02
||Gradual discoloration at about 100°C, rapid darkening above 150°C and rapid decomposition above 200°C
|Thermal Conductivity, W/(m•K)3
|Electrical Resistivity, ohm•cm
||(3.1 – 3.8) x 107
|Specific Heat, J/(g•K)b
|Melting Point (unplasticized), °C
||230 for fully hydrolyzed grades and 180-190 for partially hydrolyzed grades
|Tg, °C (dry film)
|Storage Stability (solid)
||Indefinite when protected from moisture
||Burns similarly to paper
|Stability to Sunlight
a. To convert W/(m•K) to (Btu•in)/(h•ft2•F), divide by 0.1441.
b. To convert J to cal, divide by 4.184.
PVOH resins react in a manner similar to other secondary polyhydric alcohols. One can carry out PVOH’s esterification reactions with a number of compounds. A commercially important reaction is the formation of tackified PVOH using boric acid or borax to form cyclic esters. This reaction is very sensitive to pH, and an insoluble gel forms above 4.5-5.0.
Other esterification reactions include the following:
- Those with chloroformate esters to yield polyvinyl carbonate
- Those with urea to yield a polymeric carbamate ester
- Those with isocyanates to form substituted carbamate esters
Another commercially important reaction is acetalization with aldehydes. The reaction of PVOH with butyraldehyde produces polyvinyl butyral, which manufacturers use in the production of inner adhesive film for safety glass. One can use its reaction with dialdehydes, such as glyoxal or gluteraldehyde, to crosslink PVOH.
Other reactions include ethoxylation, propoxylation and cyanoethylation.
Packaging and Storage
Selvol PVOH products are available in multiple packages:
- Granular/powder product in 25 KG, 500 KG and 1000 KG
- Solutions product in 450-LB drums and 2250-LB tote
- Other potential packaging
For more information, please contact us.