16 



PRODUCTS FROM WASTE RESINOUS WOODS. 

 TABLE 2. Cooking data Continued. 



The wood as received, approximately 30 per cent of which would 

 pass a one-fourth-inch screen and 25 per cent which would not pass 

 an inch screen, could of course not be cooked to produce a uniform 

 pulp. The fine material was overcooked and weak, while the large 

 pieces were cooked only superficially, often remaining hard in the 

 centers. These facts are shown by the results of cooks 1 to 3. 



The cooking data show a low consumption of alkali and a high 

 yield of fiber. This is due partly to the fact that the cook was made 

 for the production of a strong wrapping paper, for which the wood 

 employed was suitable only, because of the charcoal which is almost 

 invariably present in light wood. The pulp after milling was very 

 firm and strong and the fiber long and well separated, in every way 

 suitable for making strong wrapping papers. The average air-dry 

 unbleached pulp approximated 45 to 50 per cent from wood which 

 contained about 18 per cent of rosin. The total time of cooking was 

 somewhat under the usual time required for cooking wood by the 

 soda process. Probably the time required in the mill to steam off 

 turpentine and to cook for a strong wrapping paper is slightly longer 

 than that required in these small-scale experiments. This time will 

 naturally differ considerably with mill conditions. In no case do the 

 results indicate more than a normal loss of fiber through the action of 

 the alkali. It is true that the yields of fiber from the finest material 

 were lower than those from larger chips, though not differing greatly 

 from the yields from chips larger than one-fourth and smaller than 

 one inch. As previously stated, however, the pulp from the finer 

 chips was quite weak and overcooked. 



It has been established in paper mills and on a commercial scale 

 that a very good grade of wrapping paper is made from long-leaf pine. 

 Samples have been tested in the Bureau of Chemistry which show a 

 strength factor of from 0.7 to 1. This is practically equal to similar 

 paper made by chemical processes from spruce. 



