US1578405A - Process of hydration in paper making using friction - Google Patents

Description

Patented Mar. 30, 1926.

JUDSON A. DE LCEW, OF MOUNT VERNON, NEW YORK.

PROCESS OF HYDRATION IN PAPER MAKING USING FRICTION.

No Drawing.

To all whom it may concern: a

Be it known that I, JUnsoN A. DE Cnw, a subject of the King of Great Britain, and

resident of Mount Vernon, in the county of Westchester and State of New York, have invented certain new and useful Improvements in Processes of Hydration in Paper Making Using Friction, of which the following is a specification.

The following invention relates to a method for increasing the strength of paper fabric by altering the character of the surface of the fibres from which the paper is made, during the process of beating the paper stock. v

I have discovered that the chief factors effecting the strength of the paper fabric is the character of the surface of the fibres from which the paper is made.

It has been generally considered that the effect on the cellulose fibres in beating them into a condition for paper making is one of the hydration of the entire fibre itself, due to the bruising action resultingfrom the treatment received in beaters andv jordans.

It has been conceived that by chemical treatment of the fibres they may be swollen and made to absorb water, but I have discovered that the principal advantage in certain chemical treatments is the fact that certain surface phenomena occur of the nature of adsorption that will bring about a-condition on the surface of cellulose fibres which will make these fibres adhere to each other more firmly when formed into a sheet .of paper.

The basis of my discovery is that the method of obtaining the desired result is to agitate or beat the fibres in cold water in whichis dissolved a causticalkali such as caustic soda or caustic potash which will have a softening action upon the surface of the fibres while they are being rubbed against each other.

It has long been known that caustic alkali will have a swelling effect upon cellulose when the solution is concentrated and cellulose may be actually dissolved by' caustic at high temperatures, but for purposes of paper making by means ofmy process, it is only desired to produce aneffect upon the surface of the fibre and it is not necessary to use strong solutions which will penetrate to the interior of the cell walls or to heat the solutions.

My discovery applies to the treatment of any cellulose fibre for paper making, but

: Application filed January 20, 1925. Serial No. 3,597.

particularly in the preparation of sulphate cellulose which is used in the manufacture of wrapping paper. One method of operation is to carry out the beating of the fibres either in the beating engine or the jordan, or similar iachine, while the water surrounding the bres is made slightly alkaline with a solution of caustic soda or caustic potash. The result of this beating action under these conditions is that the surface of the fibres becomes slippery because the rapid movement of the fibres in the presence of the dilute caustic alkali accelerates the reactions on the surface of the fibres which produces a distinctive result as compared with any method of treatment in which the fibres are not being rubber against each other, or when the cellulose is heated with alkalis or in stronger solution than required for surface phenomena In fact the fibres may have a prolonged alkaline treatment without friction and then if agitated in the beater in the presence of the solutions used for sizing the fibres will not'make as strong a paper as when they are beaten within the. alkaline solution at a consistency in which the fibres will have some friction against each other. I also find that the only alkaline solution that is at all effective is a caustic alkali which has a'solvent action on the surface of the' fibre that is not obtained by a carbonate alkali, evenvof greater strength.

In the ordinary paper mill there are two stages in which the fibres are made soft and pliable, one being a treatment ina beater betweena revolving roll and bedplate, and

the later treatment'whereby the fibres pass I continuously through an apparatus containing a revolving cone with knives, called jordan engines, in which the fibres are again further rubbed against each other by the moving knives. In carrying out my process,

I prefer to' keep the amount of water surrounding the fibres as low as possible so thatduoe the surface phenomenawhich takes place when the fibres are agitated in this x I solution. 0

The action whlch takes place 1n. this processis just as beneficial to a cellulose if desired.

which has been produced by an alkaline At the present time both the beating and jordaning actions are carried out in the presence of a weak solution of sulphate of alumina and as a result the-fibres are astrin-.

gent through surface adsorption of basic aluminum sulphate. Under theseconditions With-adsorbed acidity, they do not readily produce surface hydration by fibre friction, and require harder mechanical treatment.

At a concentration of fibres up to about 5%, the fibresare floating in the. water surrounding them, and consequently there is little friction between ,them, but at-a consistency of from 5% to,12% the fibres are resting against each other and when moved about the surfaces actually rub against each other. It is under this condition that sur-' ravages face hydrationcan be obtained and the less water surrounding the fibres the greater the surface hydration obtainable.

Fibres that are hydrated in this manner have different physical characteristics than I those that are hydrated by bruising action, and will give a paper of both pliability and strength.

' In my' process any treatment requiring the useof sulphate of alumina is carried out after the surface treatment of the fibres. is

complete.

Having thus described my invention, What Y t A method of preparing cellulose fibres for erations in which the alkalinity is neutral-t ized; I In testimony whereof, I ture.

JUDSON A. DE CEW.

aflix my signa-