US1327221A - Method of preparing pulp - Google Patents

Description

-- weight may be added to the mass, and paper tartan 's'ra'ras Parana err es.

cam. AoHE-WIIG. or PORTLAND, MAINE.

METHOD DEPREPARING PULP.

No hrawing.

This invention relates to the production oi pulp from cellulosic materials, including pine wood, white pine, Norway pine, and other woods which are rich in resinous sub stances, including turpentine, all of which" substances are herein expressly intended to be included in the general term, ligne'ous matter.

In my application #231,204, filed April 27th, 1918, a method of-preparing pulp is described whereby the ligneous matter for the most part is retained in order that its suitable for newsprint may be produced.

The method involves two treatments,

which are carried on successively. I

By the first treatmentthe' cellulosic material, composing the pulp is softened, that is to say, the ligneous matter is softened but not destroyed and the fibers are swollen and caused to separate.

By the second treatment the treated mass is cooked with a bisulfite pulp forming liq-'- u'or for a relatively shortperiod of time, the process being checked before the destruction of the ligneous matter occurs.

A solution of sodium chlorid, NaC-l, is employed, in the first treatment, and I find that this substance doesnot discolor the fiber but tends to whiten it. and when the treated mass is cooked with the bisullite pulp forming liquor thefibcr is not discolored and an unbleached pulp is produced which is suit-- able for newsprint paper but which may be bleached if desired for the finer grades. of paper.

The present invention is an improvement on the aforesaid method and has for its ob ject the production of unbleached pulp by a novel method involving the employment of a bisulfite pulp forming liquor or; in other words the sulfite process, whereiinthe lig-. neous matter is removed from the. fiber or substantially so, as contrasted to being saved and used as a. constituent of the pulp.

13y my present method a high grade of unbleached pulp may be made ofhigh grade cellulosic materials and a good unbleached pulp made of the low grades of cellulosic materials, such as the pinesabdve noted,

Specification of Letters Patent.

which is suitable for newsprint paper, which can not be made by the method of my said application.

My present invention involves two treatments which I have carried on successively, similar to the method of the aforesaid appli- 'ation, although the object sought to be attained is the destruction and removal of the ligneous matter. v The two successive treatment-sale or may be carried on at their maximum tempera,- tures and forlong periods of time, and particularly the first treatment Where the period of time is continued for a'great many hours and until the ultimate result has been obtained.

In carrying out my first treatment, I may proceed as follows The material or substance employed, in small pieces or chips, is placed in a tank or digester, which may be opened or closed,

' and. a softening agent, as a solution of sodium chlorid NaCl, isadded, as for instance,

Patented Jan. 6,1920.

Application filed. February 20,1919. Serial no. 2 78257.

I may add water containing from one-half of one to e per cent. of sodium chlorid, and

then heat the mass to a temperature from 70 C. to 110 Cmfor from 12 to T2 hours, the temperature and the time being more or less variable depending upon the material used and the strength thereof, yet' it will be understood that ordinarily the higher the temperature the shorter the time required and vice versa. I

During this first treatment the lign'eous' matter is variously affected and in different degrees, as for instance the dissolutionof some of the l gfnenes 1s hastened and of others is retarded; the vaporization of some of the lignencs is also hastened and of others is retarded; the softening of some of the lignenes is hastened and of others is retarded; and probably all are more or less prepared for reaction with the bisulfite pulp forming liquor-which is employed-in thesubsequent treatment.

' The cellulosicpieces or chips are saturated with the softening solution which is further utilized in the performance of ,the second treatment of the method. a

This solution is then drawn oft or removed.

The same solution may be used repeatedly I asa softening agent for, alarge number of times, 1f desired".

As anexaing e of the first treatment in case of thepm s above noted, some of the resinous substances are dissolved in the solution and others softened. and those of a volatilecharacter, such as turpentine are vapoi-med, and may be collected, if desired, and

all which remain are more /or less affected,

so that they'are better preparedfor reactio duringthe second treatment. The second treatment.-The mass having been thus treated is, then cooked with a bisulfite pulp forming agent, or a sodium chlo'rid solution depending upon that kind of paper the pulp is to be used, for instance, if during the'first treatment a sodium chlorid solution is employed then during the second treatment a bis'ulfite liquor will be employed and an unbleached pulp suitable .for newsprint paper (will be produced, or iuay be" bleached. for the finer grades of a er. A,

p he strength of the bisulfite solution may '20, be such together with the time and temperature' of cooking that the ligneous matter may practically be removed from the fiber.

The second treatment may continue for a period of time, say, from 10 to 24 hours at 25 temperature of from lIOdegre'es C. to 135 degrees C, but the longer the period of time and, the lowerthe temperature within rea sonable limits'the better the pulp.

, A reaction takes place between the sodium chlorid with which the mass is saturated and the bisulfite liquor employed during .the second treatment to which I attribute "at least in part some of. the advantages gained by this process.

I claim i 1. The method of preparing cellulosi -material which consists intreating the material withksodium chlorid and subsequently cooking the mass with a 40 bisulfite pulp forming liquor until substan? tially all the ligneous matter hasbeen freed from the fiber. 1

'2. The method of preparing pulp from cellulosic material which consists in two successive treatments, first, treating the' material with a sodium chlorid solution, and

second in cookin the treated mass with a bisulfite pulp forming liquor until substantially all ligneous matter has been .freed 60 from the fiber.

3. The method of preparing pulp from cellulosic material in' the form. of chips,

I which consists in adding a solution of sodium chlorid to the material, heating the mass for a period of time to dissolve some of the ligneous matter in the solution, and "aporize some and prepare the remainder for subsequent reactioin'then drawing off the solutionand then cooking the treated mass. 'with a bisulfite pulp forming liquor until substantially all-of theligneous matter is freed from the fiber.

' 4. The method of "preparing pulp from cellulosic material in the form of chips, which. consists in adding a solution of sopulp from I dium chlorid to the material, heating the mass for a period of time to soften the ligneous matter, and dissolve some in. the solution and prepare somefor subsequent reae; tion, then drawing off the solution and then cooking the treated mass witha 'bisulfite pulp forming liquor until substantially all of) the ligneous matter is freed from the fi er.

5, The method of preparing pulp from cellulosie material in 'the form of chips, which consists in adding a solution of sodium chlorid to the material, heating the mass for a period of time to soften the [ligneous matter and dissolve some in the solution and vaporize some, and prepare some for subsequent reaction, then drawing oil the solution, and then cooking the treated mass with a bisulfite pulp forming liquor until substantially all of the ligneous matter is 8 5 freed from'the' fiber. I v I 6. The method of preparing pulp from I cellulosic material in the form of chips, which consists in adding a solution of sodium 'chlorid to. the material, heating the mass for a period of time to soften the ligneous matter and dissolve some in the solutiou, and prepare some for subsequent re-' action, then drawing oil the solution, and then cooking the treated mass with a-bisuhv fite pulp forming liquor until some of the ligneous. matter has 'been dissolved by the liquor and substantially all is freed from the fiber.

7. The method of preparing pulp from cellulosic materialin the form ot'chips.' which consists in adding a solution of so-, dium chlorid to the :material, heating the mass for a period of timeto soften the'ligneous matter and dissolve some, in thesolu tion, and prepare some for subsequent ,reaction, then drawing off the solution, and then cooking the treated mass with bisulfite pulp forming liquor until some of the ligneous matter tially all is free'dfrom the filier.

8. The method'of preparing pulp from cellulosie material, which consists in treating the material in the form of chips with a Water solution of sodium chlorid for a period of time and at a temperature, substantially as specified, and subsequently cooking the mass with a bisulfite pulp forming liquor for a period of time and at a tenor-V perature, substantially as specified, whereby substantially all ligneous matter is freed from the fiber. v

In testimony whereof, I have signed my name to this specification, inlthe presence of two subscribing witnesses;

, GAR-L BAGHELWIIG. lVitnesses *Cnsnnns M. DRUMMOND, W'ADLEIGH'B. Dno Monn.

has been dissolved by the 116- liquor, some has been vaporized and substan