US1572478A - Process for reclaiming used paper - Google Patents

Description

Patented Feb. 9, I926.

UNITED STATES GRANT HAMMOND, on NEW HAVEN, comrncrxcur.

PROCESS RECLAIMING USED PAPER.

No Drawing.

To all whom it may concern:

' Be it known that I, -GRANT}HAMMOND, a citizen of the United States, residing in New Haven, county of New Haven, State of Con- 6 necticut, have invented pertain new and useful Improvements in Processes for Reclaiming Used Paper, of which the following is a full, clear, concise, and exact description. Thisinvention relates to a process forre- 10 claiming used paper, such as newspapers and other papers which have been printed or 4 combined with pigments in the form of printing ink or otherwise.

The principal object of the invention is to provide a simple process forreclaiming such papers which may be easily and inexpen- ,sively carried out in apparatus already in existence in'paper mills and which shall produce, particularly when waste newspaper stocks. are used, a resulting product having superior qualities to the newspaper from which it was made.

This application is a; continuation in part of my application, Serial No. 697,376, filed.

March 6, 1924. Broadly, the invention accordingly comprises a process for reclaiming paper having inks or pigments applied thereto, especially newspaper or similar printed paper having ment, which. includes beating .the paper,- treating it with a caustic alkali during beat- -'ing and'mixingan alkali acidfsulfite with the resulting pulp. W

In carrying out the process in its preferred form, I'treat used paper, such as newspapers, in a suitable beater of the type ordinarily employed in the manufacture of paper. The amount of water employed is substantially the same as that used for heating fresh pulp in paper manufacture, namely, approximately 2500 gallons per ton of paper. 'According to my process, this water is preferably luke Warm or is heated to about 110 F. and I preferv to avoid higher temperatures in most instances. I have obtained satisfactory results with temperatures as low as 80 F. The beater is started and ti) it is fed 6 shredded newspappr, or other pa erhavinga pigment thereon with a saponi able binder such as linseed oil. Preferably during the entire beating period a solution of caustic soda is run into the paper stock. The

asaponifiable binder containing the* pig-.

Application filed March 12, 1925. Serial No. 15,146.

amount of caustic soda varies from 30 to 70 pounds per ton of newspaper stock but I prefer touse about 50 pounds per ton of newspaper stock, representing approximately 2.5 per cent of caustic soda based on the Weight of the paper taken. This is pref- Q erably dissolved "in 30 gallons of water at room temperature F.) and thus 'is added in the form of an approximately 20 per cent solution.

l'V hen the stock has been thoroughly 5 pulped, it may be washed in the beater. For this purpose I replace the caustic soda solution with cold Water and continue beating. Thereafter the water is replacedby fresh cold water again, and such washing may be 70 repeated as desired. 7

In carrying out the whole of the reclamation process as I prefer in the beater, I next add to the washed stock, containing a fresh amount of wash water (below 110 F., preferably at room temperature) equal approximately to 2500 gallons, 20 to 50 pounds of sodium acid sulfite,- NaHSO This matei rial may be added in powdered form or dissolved in a small amount of water; The amount of sodium acid sulfite used will depend upon the alkalinity of the pulp, enough being employed preferably to neutralize the alkali. in the pulp and provide a. slight excess. acid sullite, further beating of the pulp is continued until the action of the sodium acid sulfite is complete. Where the pulp contains the quantity of water which- I have described above, the-action-of the sodium acid sulfite is 0 rapid. For onetonxof pulp of a mushy consi'stency approximately five to twenty minutes depending upon the efiiciency of the stirring apparatus employed, is sutficiei t to pro duce thorough neutralization and'whitening of the pulp. The same quantity of a thinner pulp that is, one containing considerably more water may be treated to produce the same results in one to two minutes. In other.

words, the action of the sodium acid sulfite for small quantities of pulp is substantially instantaneous and-the ti e required mentioned above represents that necessary for sodium acid sulfite to be brought into con- F'tact with" the fibers. 'Where smaller quantities of water are used, the pulp should be allowed, to stand in contact with sodium I aeid sulfite, in order that its action maybe After the addition of sodium 35 tassium acid sulfite.-

completed. The result of the actionis to bleach the pulp and at the same time neutralize the alkali.

" It will be understood that other" alkalis than caustic soda may be used, for example, I may use'caustic potash. In place of sodium acid sulphite I, also may employ pov Other .kinds of paper than newspaper, having a pigment printed/or otherwise applied thereon with a saponifiable or "like binder, may also be. treated by the process.

Although I have described the entire action as taking place in the beater, it is obvious that the process may be carried out in more than one vessel. For instance, I may wash the material in other beaters or stir-- ring machines or in a rotary washer attached to the (beating engine for the purpose, or the pulp may be washed in separate washing machines such as are well known in the art. Instead of beating the pulp upon addition of sodium acid shlfite, I may run the'pulp into storage tanks and allow the sodium'acid sulfite to stand in contact therewith. After treatment with the-sodium bisulfite the resulting pulp may be washed to free it from excess of this material as well as from sodiunl sulfite and other water soluble substances. e

The pulp so obtained may then be run out on the Foudrinier machine, formed into paper, dried, and passed through the usual finishing operations. The paper so resulting is superior to the newspaper from which it was made. For example, the average news print paper shows a Mullen test of 9. Such sheets when reclaimed by my process shows a Mullen test of 13.; The above figures have been obtained as a result of a practical mill test on ten tons of paper. The 1'8? claimed paper resultingfrom this test was not only stronger as indicated above, but was as bright in color as new unprinted news a 'igmen't applied thereto w .re ucing the paper to pulp and removing the pigment therefrom, and then mixingsaid pul, with an alkali acidsulfite at substa print, and had .as well, a better print surface as was demonstrated'when an edition of a newspaper was printed thereon.

What I claim and desire to protect by Letters Patent is 1. A process forvreclaimi ng paper having a pigment applied thereto which comprises beatm 110 l caustic alkali during beating and mixing an akali acid sulfite with the resulting pulp 66 at substantially rbom temperature.

the paper at a temperature below approximately, treating it with a 2. A process for reclaiming newspaper which comprises. beating the newspaper with water at a temperature below 110 F approximately; treating the newspaper withv 6p caustic soda during the, beating, thereby producing an alkaline pulp, washing the pulp so prepared and adding at room temperature approximately a slight eXcess of sodium acid sulfite above that necessary to neutralize the alkalinity of the pulp) 3. A process for reclaiming newspaper whichcomprises beating the newspaper with water at a temperature below 110 F. approximately, while running into the beater 70 a 20 per cent caustic soda sblution in an amount equal approximately 2. 5 per cent by weight of the newspaper taken, thereby rov duclng an alkaline pulp, washing the a kal ine pulp, adding to the washed pulp a slight 7 excess of sodium acid sulfite above that cessar pulp, w le maintaining the mass at a tem-' peraturebelow 110 F. approximately and washing the resulting ulp to free it from excess sodium acid sufiteto neutralize the alkalinity of the 4. ,A process-for reelaimi paper having ich comprises tial 37' room temperature.-

. GRANT HAMMOND.