Selvol polyvinyl alcohols (PVOHs) have numerous characteristics that make them useful in an array of applications. By choosing from the many available Selvol PVOH grades, you can obtain the performance properties needed for your specific applications. These properties include the following:

• Water solubility
• Abrasion resistance
• Tensile strength
• Adhesive and bonding properties
• Grease or oil resistance
• Film-forming qualities

Plus, our highly skilled technical service group can help you select your required Selvol Premiol PVOH grade.

Changes Occurring in the Properties of PVOH as the Degree of Hydrolysis and Molecular Weight Change

Viscosity/Concentration Relationships of Aqueous Selvol Premiol PVOH Solutions at 20%

Selvol Premiol PVOH Molecular Weight

Physical Properties

Selvol PVOH combines high tensile strength with easy film formation. Additionally, Selvol PVOH resins show excellent adhesive and bonding characteristics. Partially hydrolyzed grades adhere better to hydrophobic surfaces.

The degree of hydrolysis affects the water sensitivity of both the resin and the film. Moreover, water resistance increases as hydrolysis increases. You should use the super-hydrolyzed grades when you need maximum water resistance and humidity resistance.

Generally, greases, petroleum hydrocarbons and animal or vegetable oils do not affect Selvol™ PVOH resins. Resistance to organic solvents increases with the degree of hydrolysis.

Manufacturers can plasticize Selvol PVOH film with glycerol or lower molecular weight glycols. These materials usually act as humectants that hold water in the film.

Physical Properties of PVOH

Notes
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.

Chemical Reactions

PVOH resins react in a manner similar to other secondary polyhydric alcohols. You can carry out PVOH esterification reactions with a number of compounds.

Importantly, a commercially significant reaction is the formation of tackified PVOH using boric acid or borax to form cyclicesters. 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 industries use to produce the inner adhesive film for safety glass. Industries 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 Premiol PVOH products are available in several packages:

• Granular/powder product in 25 KG, 500 KG and 1000 KG
• Solutions product in 450-LB drums and 2250-LB totes
• Other packaging types, depending on the product

For more information, please contact us.

Application and End Use Table for Textiles, Adhesives, Paper, Building Products and Specialty Products

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Typical Properties of Selvol Premiol PVOH Products

For most applications, you must dissolve Selvol PVOHs in water before use. Under the right conditions, S-grades may be more cold water processable, but you must cook all other grades.

We recommend the following procedure:

• Disperse Selvol PVOHs in cold or room-temperature water, using sufficient agitation to wet out all particles with water.
• Ensure the surface of the water is moving vigorously, as a general rule.

Addition rates, solids and cook-out temperatures vary by PVOH grade, as illustrated below. For the best results, do not exceed maximum solids. Elevate the solution temperature to the recommended levels (185-205°F/85-96°C). Then, hold for 30 minutes.

Selvol PVOHs are in solution after cooking, and you can use them at any temperature.

Although the cooking process is straightforward, please be aware of these pitfalls:

• All tanks and lines must be free of borax to avoid coagulation.
• Tanks should have baffles and flush bottom valves to avoid dead spots where PVOH can agglomerate.
• Not reaching the minimum temperature results in undissolved PVOH, no matter how long you cook it.
• You cannot overcook Selvol PVOHs. However, boiling induces foam.
• Avoid high-speed, small-diameter mixers. These agitators do not provide adequate mixing and tend to entrain air.
• If you use a defoamer, it is best to add the defoamer before adding the PVOH to the water. You do not need a defoamer with Selvol PVOHs 805, 823 and 840.
• If you keep solutions for longer than 24 hours, we recommend adding a biocide.
• You can jet-cook Selvol PVOHs. Unlike starch, which explodes in a steam jet, Selvol PVOHs dissolve by shedding layers. Maximizing time in the jet and providing a holding tank for the PVOH solution after the jet (where you can hold solutions for a minimum of 15 minutes) ensure complete solubility.

*Note: You should verify the FDA compliance status of a recommended additive with its respective manufacturer.

Please refer to your Material Safety Data Sheet (MSDS) for information on the safe use and handling of Selvol PVOHs, including toxicity, fire and explosion hazards and environmental effects. You can obtain an MSDS online here: MSDS.

SEKISUI Specialty Chemicals has an Intimate Human Contact (IHC) policy in effect. This policy restricts the use of Selvol PVOH in applications involving ingestion or contact with human mucous membranes.

Please contact us for more information.

FDA Compliance

Industries use PVOH in many food contact applications, including food packaging adhesives and paper and paperboard coatings. For more specific information on the FDA status of any of our PVOH grades, please contact our Technical Services.

Selvol™ PVOH Right to Know Information