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Mowiol® & Kuraray Poval®Mowiol® and Kuraray Poval® are the trade name of the polyvinyl alcohols marketed by Kuraray. These are manufactured from polyvinyl acetate by alcoholysis using a continuous process. By varying the degree of polymerization of the polyvinyl acetate and its degree of hydrolysis (saponification), a number of different grades can be supplied. Our PVOH types are offered in a high standard purity showing especially “low ash and VOC contents”.
Polyvinyl alcohols are commonly divided into “fully hydrolyzed” and “partially hydrolyzed” types, depending on how many mol-% of residual acetate groups remain in the molecule. Polyvinyl alcohol is characterized by the presence of polar OH-groups, responsible not only for the polymer molecules' water solubility, but also giving rise to numerous reactions. For example, cross-linking may be performed by adding (di-) isocyanates, urea-/ phenolic- or melamine-resins, epoxies, as well as solely by adding (poly-) aldehydes. The resulting products (films) show water-resistance after being applied out of aqueous solutions.
The combination of hydroxyl groups and residual acetate groups renders polyvinyl alcohol as a water-soluble thickener as well as a high performance protective colloid: Mowiol® / Kuraray Poval® is the most important protective colloid stabilizing aqueous emulsions for adhesives, paints and rendering formulations.
Due to their high purity, Mowiol® / Kuraray Poval® grades are used as raw materials for the production of polyvinyl butyral. Mowiol® / Kuraray Poval® have a superb solubility in water, good Film-forming properties, excellent wetting properties on polar substances, good pigmentability, physiological safety and biodegradability, which all mean that these polymers are of great interest for many applications.
PVOH low ash
Polyvinyl alcohol with extremely low ash content, less than 0.1%, can be offered (Mowiol® low ash). Polyvinyl alcohol is well known temporary binder because of excellent binder strength. The low ash (ion) content can prevent some trouble of residual sodium and redox reaction during the sintering process.
PVOH fine powder
As an additive for building material (mortar/cement), sometimes polyvinyl alcohol should be easily soluble into water at ambient temperature. Usually Mowiol® / Kuraray Poval® grade are delivered as a granule form, but “fine powder grade, Mowiol® G2/ Kuraray Poval® S-grade”, easily soluble grades, can be offered also. Especially in oil well cementing application, “fine powder grade, Mowiol® G2 / Kuraray Poval® S-grade” is well used as a fluid loss control additive.
PVOH with functional groups
Adding full line up polyvinyl alcohol, Kuraray offers polyvinyl alcohol with some functional groups to meet various needs of customers.
• Kuraray Poval® K-grade; cationic PVOH
• Kuraray Poval® C-grade; anionic PVOH
• Kuraray Poval® R-grade; PVOH with silanol
Especially Kuraray Poval® R-grade, PVOH with silanol is well used in the IJ media, ink absorbing layer as a binder of silica based on the excellent binder strength with silica.
PVOH for melt molding
It has been said that melt molding (extrusion) of polyvinyl alcohol is difficult because melting point and degradation temperature are very close. Based on the developed special technologies, Kuraray offers pelletized polyvinyl alcohol, which can be processed with conventional plastic technology, such as blown and flat film extrusion as well as injection molding.
• Adhesives
• Papers
• Building Materials (additive for mortar, cement, oil well cementing, etc.)
• Polymerization (Emulsion / Suspension)
• Temporary Binders for Ceramics
• Gas barrier coating
• Films / Foils
• Textiles sizing
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