The opinion of the court was delivered by: SMITH
This is a suit under the patent laws for the infringement of Patent No. 1,580,814, hereinafter referred to as '814, of which the plaintiff is admittedly the owner. This patent issued on April 13, 1926, on an application filed on June 7, 1924. The defendant denies infringement and challenges the validity of the patent.
The patent covers 'Improvements in Methods of Hydrating Cellulose Fibers' of which papers are made. Claims 1, 2 and 3 thereof cover a 'method of hydrating cellulose fibers,' and claim 4 thereof covers a 'pliable paper product made from cellulose fibers.' We deem it advisable to consider the process claims and the product claim separately.
The history of the art and its development were adequately summarized in the opinions filed in the related suit,
and it seems unnecessary to review that summary here. We briefly outline only that branch of the art to which the patent in suit relates. This outline follows substantially the language of our earlier opinions.
The many kinds of kraft paper, such as those manufactured by the defendant, are made of cellulose fibers extracted from wood. The wood, cleaned and suitably prepared, is digested in a solution of caustic alkali and reduced to pulp; its ligneous constituents are removed by this chemical treatment, leaving a slightly cohering mass of insoluble cellulose fibers. The cellulose fibers, thus extracted and prepared, are converted into paper in three successive operations, identified in the industry as 'beating,' 'refining,' and 'felting.'
The pulp, brought to a predetermined fluidity and consistency by the introduction of water, is milled in a beater; the fibers are thus isolated, shortened, and hydrated, and the pulp becomes gelatinous. The pulp, after having been thus treated and prepared, is then refined in a jordan; the fibers are thus refined, 'fibrillated,' and further hydrated. These successive operations, which are substantially similar, impart to the cellulose fibers the physical properties essential to the formation of the paper.
The invention of claim 1 is therein defined as follows: 'A method of hydrating cellulose fibers, which consists in beating them in both beater and Jordan while in an alkaline condition.' The invention of claim 2 is similar to that of claim 1, and is therein defined as follows: 'A method of hydrating cellulose fibers, which consists in passing them through a Jordan engine while in an alkaline condition.' (Emphasis by the Court.) The only difference is obvious.
The invention of claim 3 is therein defined as follows: 'A method of treating cellulose fibers for paper making, which consists in hydrating the fibers by beating and jordaning them in the presence of a soluble alkali until the fibers are made pliable by the penetration of the alkali, and then neutralizing the alkali that is on the surface of the fibers and in the solution surrounding the fibers, by means of sulphate of alumina.' (Emphasis by the Court.)
There is no better explanation of these inventions than that which is found in the specifications of the patent. It is therein stated:
'I have discovered that the hydration is most rapid while the stock is in an alkaline condition and that the hydration is the slowest when it takes place in the presence of a solution of sulphate of alumina which makes the fibers astringent, stiff and prevents them from absorbing the water of hydration and also makes the fibers more easily cut by the knives of the beating engine or the Jordan.
'In order to produce rapid hydration with the minimum of power and in order to produce the best quality of paper, I beat the stock while in a neutral or alkaline condition and discharge it from the beating engine without adding sulphate of alumina to produce an acid condition.
'The fibers are then treated in the Jordan while still in a neutral or alkaline condition where it undergoes further degrees of hydration and refinement and after this action is completed and the stock is ready for the paper machine, it is then mixed with sulphate of alumina to produce the acid condition necessary for the sizing, ...