MOWITAL B75H - KURARAY

• The Mowital® grades are thermoplastic polyvinyl butyral resins. The properties of the grades are mainly determined by molecular weight and degree of acetalisation. Mowital® can be processed thermoplastically or in solution of organic solvents. Mowital® grades are soluble in a broad variety of organic solvents.
• They show good compatibility with plasticisers and other resins. The grades are able to cross-link with other resins such as phenolic, epoxy and melamine resins. The network density may be adjusted depending on the degree of residual OH-groups which is determined by the degree of acetalisation (see stoving enamels).
• Mowital® films are resistant to light and heat-sealable at temperatures above 120 °C. Toughness and elasticity are influenced by their molecular weight. Water resistance and solubility in non-polar solvents mainly depend on the degree of acetalisation. Mowital® HH grades show the highest water resistance and best solubility in non-polar solvents such as toluene. Guided recipes can be provided on demand for different applications.

Temporary binder for ceramics

• Mowital® is an excellent binder for the production of ceramics and ceramic tape cast materials. It shows remarkably good strength and flexibility of the ceramic tapes. Mowital® provides good dimensional stability and decomposes cleanly during sintering.

Stoving enamels

• Due to their medium to high content of hydroxyl groups Mowital® grades are particularly suitable for cross- linking with phenol formaldehyde, epoxy and melamine resins, respectively. In stoving enamels the Mowital® content should be between 10 and 40 % based on total binder content. Generally, stoving conditions are temperatures between 160 and 200 °C for 10 to 20 minutes.
• In the case of multi-layer coatings the first layer should not be fully stoved before application of the second layer in order to avoid adhesion faults of the succeeding coating. Mowital® H grades provide better plasticising properties in above mentioned binder combinations. However, they are less cross-linkable then T grades due to the lower number of non-acetalised OH-groups.

Shop and wash primers

• In combination with orthophosphoric acid Mowital® H and HH grades are generally used to manufacture shop and wash primers (1K and 2K primers). The films adhere extremely well to steel, iron, zinc, aluminum and other metals.
• To achieve further improvement in anti-corrosion protection as well as adhesion Mowital® can be combined with low-molecular weight phenolic, epoxy or melamine resins as well as corrosion protection pigments. The good anchorage of the primer on metal is caused by a binder/pigment/orthophosphoric acid/metal complex. In 1K primers the orthophosphoric acid is added to the primer during its manufacture.
• The acid amount used should not exceed 5%. In the case of 2K primers the acid is supplied in a second container separately. 2K primers contain higher acid amounts. However, if the level exceeds 10 % the coating becomes less water resistant. Upon mixing the pot life of the 2K primer is limited to a few hours.

Printing inks

• Low-viscosity grades are suitable binders for flexographic and gravure printing inks. They exhibit very good adhesion to substrates like polyolefins, metals, cellulose acetate, polyester, cellophane, polyamide, and polystyrene films. If necessary, the adhesion to problematic substrates like OPP foil can be improved by way of coronal discharge and chemical adhesion promoters. Mowital® show an excellent pigment wetting property.
• These grades are suitable for the manufacture of pigment concentrates and preparations. Printing inks based on Mowital® exhibit low solvent retention, and good flow, as well as good resistance to water. Mowital® can be used as a sole binder or in combination with alcohol-soluble nitro-cellulose or other resins, like ketone condensation resins, alkyds, maleic resins, and some natural polymers.

Strippable lacquers

• Although Mowital® H grades exhibit very good adhesion properties they may also be used successfully as strippable lacquers. Strippability has to be adjusted using common additives and will retain for several months.

Adhesives and hotmelts

• Owing to the excellent adhesion of Mowital® to glass and metals, it is used to bond or laminate these materials. It may also be employed for binding other polar substrates.
• Mowital® can be applied in solution or as a part of hotmelt. For hotmelts Mowital® is compounded in heated kneaders or extruders with plasticisers and adequate additives. These compounds are applied by heated rollers, nozzles or spray guns on to one of the substrates and subsequently submitted applying heat and pressure.

Preparation of solutions

• Mowital® can be dissolved in single solvents. To obtain low solution viscosities it is recommended to dissolve Mowital® in solvent mixtures (e.g. 1:1 mixture of ethanol and toluene). Mowital® is not soluble in water. However, a water content of up to 10 % in the solvent mixture is possible and can be used to influence solution viscosity. The viscosity depends on the solvent (e.g. increase in ethanolic solution) and must be tested in advance.
• To dissolve Mowital® , while low to medium stirring speed of the solvent, Mowital® is added in portions at ambient temperature. This ensures good dispersion of Mowital® powder in the solvent and avoid dusting. Later the the stirring speed can be increased. Sometimes heat may be necessary for dissolving Mowital® . In this case do not apply heat until Mowital® is wetted to avoid agglomeration.
• For preparation of a solution with mixed solvents first add Mowital® to the solvent which does not dissolve Mowital® alone (e.g. aromatic solvent) in order to form a slurry. Then add the alcoholic solvent which normally dissolves Mowital® best. The final solution viscosity as well as the speed of dissolution depend on the used solvent, the temperature and the stirring speed.

Overpaintability

• Virtually all commonly used paints adhere to hardened coatings of Mowital® based primers. Problems may be encountered using some special nitro-cellulose or 2-component epoxy resin paints.

• MOWITAL B75H - KURARAY can be stored in its original packaging under dry and cool conditions for at least 12 months after delivery date.
• Static electricity has to be avoided applying the appropriate safety measures while handling Mowital® as well as organic solvents.