Date of Award

4-1967

Degree Name

Bachelor of Science

Department

Pulp and Paper Technology

Abstract

The purpose of this paper has been to examine what properties of sheet strength may be stabilized by the use of kelgin in a size press application and after a subsequent heating period.

A softwood kraft pulp was used because of the strength properties which it possesses. Alkaline sizing with Aquapel and Kymene was felt to be the best because of the alkaline p.H. range which was desired. The sheets were sized with solutions of Kelgin (M .V.) of varying concentrations and treated at 150 and 175 °C. The effects were studied using the M.I .T. Fold Test, the Instron Tensile (kg to rupture), and the Instron Elongation.

The results showed that as the concentrations of the kelgin size solutions increased, some protection was afforded the fiber against prolonged heating. The strength loss was appreciable in the samples which were treated at the different temperatures. The room temperature samples showed higher strength properties than either of the samples heated at 150 or 175°C. which was as expected.

It was shown that the high viscosity of the kelgin solutions at the concentrations of 1.00 and 1.25 percent tended to . give a tapering off of the protection which was expected. A viscosity reducer (Azite 900 Liquifier) was used in conjunction with the kelgin solutions to study the effects of a reduced viscosity on strength maintenance. It was shown that the liquefier did indeed increase the penetration of the kelgin into the sheet and provide a better protection.

The experimental findings demonstrate that the use of kelgin in the form of a sizing solution can give beneficial results against loss of strength upon prolonged heating. It was also shown that the magnitude of this effect was not as great as had been expected from previous findings.

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