US1457915A - Method of making paper pulp - Google Patents

Description

Making Paper Pulp,

Patented June 5, 1923.,

nnn'raanns. surnames, or roar Horton,

Ito Drawing.

TBS kTlENT @FFTQ MICHTGAN.

METHQD 03F MAKING PAPER YULP.

Application filed May 26,

To all whom it may concern:

Be it known that l runes, a citizen of ing at Port Huron, 5 State of Michigan,

BERTRAND S. Sunthe nited States, residcounty of St. Clair, and

have invented certain new and useful Improvements in Methods of is a specification.

of which the following My invention relates to methods of making paper pulp and especially to a method of. treating cereal straws so as to produce therefrom a pulp suit-able for the making of high grade paper free from spots and weaknesses, and

to the preliminary reduc of such straws to prepare special reference tlon or boiling of uniform quality and them for final reduction prior to the introduction of the treated material into the beating machine.

Generally speak ing, the cereal straws are composed of difierent parts varying In their chemical composition.

They are usually characterized by a thin covering or cuticle and a fibrousportion'and ]OlntS of more woody nature. containing a pecto ous tissue in the Flax has a waxy outer skin s fiber surroundin ligneform of a woo y tube.

These straws, therefore, contain different portions which a agents.

In the to practiced it ha ject the straw to an alkaline re-agent, after the straw has been subjected to reduction process straw to the line treatment, h

lightly the woody beating machine.

ct differently toward retreatment of such straws as hither- 5 been customary to sub a preliminary boiling in which boiling a further transferring the This alkaowever, effects but very tissue making necessary prior to a very severe subsequent treatment to complete the reduction.

If a bi-sulphite of calcium solution of the strength usually used in reducing the wood pulp is used, the bust fiber is very considerably weakened'and at the stage when the bast fiber is so weakened the woody portion is imperfectly reduced. It will be action of chemical re-agents on t pectos fiber is notably different than or is the effect upon I have discovered so treat the flax straw as duce the woody p portion without injury uniform and cleanerprodproducing a more uct, making possi seen, therefore, that the he bast woody or ligneous tissue. that it is possible to to successively reortion and then the bust to the latter, thus ble the production of a has ' nature.

addition is not necessary.

1920. Serial in. 384,361.,

high grade sheet of paper fnee from spots and of uniform strength.

In practicing my invention I treat the the ratio of about one-half gallon of said liquor to one pound of straw, suflicient Water being added to cover the straws After this cook is completed Wash, although the washing operation 18 not necessary but desirable, and I then subject the straw thus cooked to an alkali for from 3 to 4: hours at d0 to 50 pounds. I usually use a 5% solution of commercial caustic soda, proportionate to the original weight of dry straw. However, other alkali may be used such as alkaline carbonate, alkaline earth hydrates, in fact, any soluble chemical of an alkaline To this alkali may be added a slight amount of oxidizing agent such as lei-oxides or hypo-chlorites,

After the straw has been cooked in this alkaline bath it is thoroughly washed. At this stage the wood is quite soft and easily disintegrated, and the best fiber has been considerably dechlorized without decreasin its strength from a paper point.

T preferably the action of 1 of calcium is although this '7 makers stan The composite nature of these straws to alternate this treatment, though usually one treatment of an acid followed by the alkali is suflicient. It should be also noted that the first treatment is enhanced by the reducing nature of the acid, it being well known that the bi-sulphite of calcium is a strong reducing agent.

I have also discovered that if other diluted acids are used instead of the bi-sulphite calcium solution in the presence of reducing agents, good effects are obtained and when such treatment is followedby alkaline treatment the straw is reduced to ,an excellent condition for the final reducmake it necessary tion.

suitable vesseband treated with hypo-chloritecalcium solution which has been recipitated out by bicarbonate of soda. sually is dpreferably mixed with bicarbonate of so a in dry condition, and water added and thoroughly agitated when the precipitated carbonate of lime-is settled and the supernatent liquor is drawn off and introduced on to the mass of straw pulp previously prepared. The 111 is preferably continuously agitated whi e t is final reduction is taking place, which-is usually from four to six hours. When the pulp thus prepared is properlv obtained, the mass will be found to be of uniform white color and the different com ositions making up the straw will be found? to have been reduced to practically pure cellulose and all parts so thoroughly reduced that when the mass is introduced to the paper makers beating engine it is readily reduced to a pulp from-which a good grade of paper is readily obtained.

aving now described my invention, what I claim, anddesire to secure by Letters Patent is:

1. The herein described process of reducing vegetable straw, which consists in first cooking the straw in a reducing agent havmg ing it in an oxidizing agent having an alkaline re-action substantially as described.

2. The herein described process of reducan acid re-action and subsequentlycooking vegetable straw, which consists in first subjecting the said straw toa reducing agent with an acid reaction and subsequently subjecting the said straw to an oxidizing re-agent in an alkaline bath substantially as described.

BERTRAND S. SUMMERS.-