US875315A - Process of making paper-pulp from straw. - Google Patents

Description

. general UNITED STATES PATENT OFFICE.

LUDWIG KARL B6HM, OF'JERSEY CITY, NEW JERSEY.

IBOOESS 01 me PAPER-PULP FROM STRAW.

No. s70,s1s.

Specification of Letters Patent.

Patented Dec. 31, 1907.

To all whom it maflfconcerm 'Be it known that I, Lunwro KARL Bonn,

a citizen of the United States of America,

fication.

This invention has reference. to certain new and useful improvements in rocess of making paper pulpfrom straw. t pertains particularly to an improvement in a novel process of making aper pulp from straw in which a new bleac ling process is em loyed whereby straw pulp is obtained which, as well as the paper made therefrom, remains always white without becoming slightly yellow, as is the case with certain pulps and papers heretofore made.

he increasing importance of making paper pul from straw at the present time is recognized. The trees from which the wel known sulfite (pulp is made, grow eath in 30-40 years an consequently cease to be in the future such a great resource of aper material as it has been in the past. t ier materials for pa er pulp such as sugar cane com stalk, and eaves of exotic plants yield a variable percentage of pulp because when cut, some are over ri e whileothers have not yet fully develope Particularly the latter are not yieldin a commercial percentage of fiber because t ey are still fleshy. Paper manufactured wholl or partly from straw ulp possesses a big degree of snap and e asticity. Cards made of same are highly elastic, when bent they issue an a seab 0 cracklin sound and return uic y to their origins position. If suitab y colored the cards resemble the well known elastic ivory cards which are very expensive.

It is a daily observance that white paper from various makes ets yellowish in the course of time. This is due to the resence of alkaline substances adhering to t e fiber. In order to be useful for hi h grades of paper, straw pulp must not only 0 fine and white, but the paper made of same must remain white in the course of time.

To obtain fine and white straw pulp from which paper may be made which does not get yel owish in the course of time, I substantially proceed as follows: Half stuff of straw is first produced in accordance to the process described in my Letters Patent #659,784 of October 16, 1900. When the required fineness for half stuff has been reached the liquid is drawn off and 3% solution of oxalid acid introduced into the hollander and the same set. to work again.. By this treatment the entire fiber is im regnated with oxalid acid. The purpose 0 this treatment will be a parent further on. The half stuff is now bleached in the bleaching tanks or the excess of liquid may be drawn off and the bleaching 'done directly in the hollander. The bleaching is ell'ected by a freshly prepared solution of hypochlorite of magnesia. The fiber impregnated with oxalic acid is attacked by the bleaching solution. When the bleaching agent enters the fiber it is directly decomposed by the oxalic acid and the chlorine acts energetically in the 'nascent state on the fiber without ractically any loss whereby a nick and ef ective bleaching takes place. perfectly white. Should some oxala te oi magnesium be forme an remain in the fib'r's'mdoes'notdoany harm because it is an indifferent white powder and acts as a filler, however durin the subsequent breaking and washing of t is fiber most of it settles and is washed out as it is sli htl soluble in water. The saturation of t e iber with a weak solution of oxalic acid brings about a white product which looks shin At the same time all the traces of free a ali adhering to the fiber are transformed into oxalate of sodium for instance which is ver easily solubleand quickl washed out. This is important because t e traces of alkali sticking to the fiber produce the yellowish appearance of the aper in the course of time. In glace of oxa 1c acid tartaric acid may be used.

xalic acid, however, is preferable because it is composed of two carboxyl grou s. The half stufi is now transferred into tie T e resulting fiber is r fiber breaker and disintegrated to fine pulp magnesia, producing thereby oxalate of mag- "half stuff by a solution of hypochlorite of meant and producing the fine pulp by d.isinte-' magnesia, producing thereby oxalate of maggratin the half stuff. nesla, disinte 'rating'the half -stuff to fine 2. T e improvement in the process of makpup, and w'orlzing the fine pulp up into paper. ing paper pulp from straw consistingin proigned at New York, N. Y., this 11th day 1 (lucing haf stuff from straw by means of of March, 1907. fixed alkalies, treating. the half stuff with an LUDWIG KARL BOHM.

oxalic acid solution, agitating the half stuff in Witnesses: the oxalic acid solution so as to com letely FRANK JORDAN, 10 impregnate the fiber therewith, bleachmg the LOUISE M. BOERLAGE.