Aq. diketene paper size emulsion - contains polyvinyl lactam and high diketene content and has long storage life

摘要

An improved aq. emulsion of ketene dimers for sizing paper contains 1-30 wt. % polyvinyl lactam, pref. compising polyvinyl pyrrolidone and/or polyvinyl caprolactam. Pref. the emulsion also contains an emulsifier, 5-40 wt. % w.r.t. ketene dimers of organic solvent, and as emulsion aid, a water-soluble organic acid providing a pH of 2-4.5. Pref. organic acid is used in amt. so that carboxyl gps. are equiv. to vinyl lactam monomer units in the polyvinyl lactam. Known diketene-based sizes could only contain a low amt. of diketene (3-8 wt. %), and had a high viscosity and poor sizing properties compared with the new emulsion. Emulsions are simple to prepare and have very high storage stability. Suitable for mass sizing if diluted to 0.1-1 wt. % diketene content and used with polyaminoamide-epichlorhydrin fixative.