Starch-based corrugating adhesive having cross-linked polyvinyl alcohol components
OwnerDonald C. Sistrunkinventor
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Abstract
Corrugating adhesives and premixes containing polyvinyl alcohol reacted with ketone-aldehyde resins are provided which exhibit stable viscosities and excellent adhesive properties. The premix formulations include PVA reacted with a selected resin, preferably in the absence of starch or borax, in order to yield pourable compositions which retain a stable viscosity over extended storage periods at ambient temperature. The premixes can be added to adhesive formulations including starch, alkali and borax to give corrugating adhesives which resist premature gelation and have good wet tack and adhesive properties.
Claims1
A premix composition for addition to a starch-based corrugating adhesive, said premix composition consisting essentially of water, polyvinyl alcohol and a resin selected from the group consisting of ketone-aldehyde resins and ureaformaldehyde resins and in the absence of borax and starch, said premix being formed by mixing said polyvinyl alcohol in water, heating the mixture to a temperature from about 125.degree.-210.degree. F., holding the mixture at said temperature for a period of about 15 minutes to 3 hours, allowing the mixture to cool to a temperature of about 100.degree. F. or less, and thereafter adding said resin thereto to effect reaction of the resin with the polyvinyl alcohol to disperse the polyvinyl alcohol and stabilize the viscosity of the composition, there being from about 10 to 25 weight percent of polyvinyl alcohol and from about 1 to 15 weight percent of said resin, said composition being pourable after a period of 7 days storage at ambient temperature.
Dependencies are inferred from the claim text.