US1624492A - Paper manufacture - Google Patents

Description

Patented- A r. 12, 1927.

- UNITED I STATES! 1,624,492 PATENT OFFICE.)

ARTHUR D. LITTLE, F BROOKLINE, AND CARROLL E. CARPENTER, OF MELROSE, MAS- SACHUSETTS, ASSIGNORS TO ARTHUR D. LITTLE, IN 0., OF BOSTON, MASSACHUSETTS,

A CORPORATION OF MASSACHUSETTS.

' PAPER MANUFACTURE.

No Drawing.

Our present invention relates to the art of making paper from wood pulp, and particularly to the manufacture of newsprint papeiz, Its objectis to make available for the uses of that manufacture, and for analogous. uses, certain woods, particularly the southern pines of various species and southern hard woods of the class known as gumwood, which have heretofore been found ununworkable wood fiber mixture or furnishcomposed of the aforesaid ingredients into a furnish that is workable on the paper machine, by the incorporation in the unworkable furnish ofaflocculent agglutinant, preferably colloidal cellulose, conveniently, but not necessarily, produced by hydrating a part of one of the ingredients of the unwork- 8 able furnish. Our invention also embraces.

the method or steps .involved in so transforming sucha furnish,-and the resulting products, including the finished product, newsprint paper made from southern pine and gumwood; as will more fully appear from the following detailed description.

Preliminary to a description of the invenp tion, a brief discussion of the qualities required in newsprint paper, and of the characteristics, .with reference to the making of paper, of the woods above named and those heretofore used for making newsprint paper, will be helpful. Newsprint paper must have strength enoughpto carry it 'through the printingvpress at high speed, proper body and hardness, and an absorptive quality suf- -ficient to absorb quickly the liquid vehicle of the newspaper printing inks. Itmust also be light'in color, as nearly white as practicable. These conditions'have been'met heretofore by making such paper of a mixture of chemical wood pulp, the relatively long fibers of which give the required tensile strength, and ground wood pulp to give the Application filedMarch' 30, 1925. Serial No. 19,283.

required body and absorptive qualities and reduce the ,cost. commercial output of such paper is now, and long has been, made from the woods of the northern conifers, namely, spruce, fir, hemlock, larch, etc.; chemical pulp being made from these woods by the sulphite process. The ground wood pulp always predominates largely over the chemical pulp, and a very common proportion is seventy-five percent of the "former to twenty-five percent of the latter.

The southern pine woods have fibers much longer than thosev of the northern conifers,

but they also have a high content of resin,

many times that of the northern conifers. On account of this high resin content, the southern pines cannot be advantageously made into pulp by the s'ulphite process or by grinding. A long fibered stock may be readily prepared from thesouthern pines by the sulphate process, but the pulp so made;

Substantially the entire have relatively short fibers and a low resin content, wherefore they are well adapted to be made into pulp by grinding and the mechanical pulp so made from gumwood has the color and absorptive qualities required of the ground wood component of newsprint paper.

But when mechanical pulp is produced from gumwood by methods of grinding at resent ordinarily practiced, the separate particles of the wood thus obtained are so short in average length, and have such inferior felting qualities, that such pulp cannot be handled by the paper machine and made into satisfactory newsprint paper either alone or in admixture with permissible proportions of long fibered chemical pulp.

For the reasons above indicated no newsprint paper is now made in the South or from southern woods, notwithstanding that the consumption of such paper inthe Southern. States is in the neighborhood of fifteen hundred tons per day, and that vast quantities bf gumwoods and southern pines are found in the Southern States in convenient access to the markets in those States; and in spite of the fact, also, that the prices of The proportion o these woods ha ve for many years been much lower than the prices of pulp wood in the North.

The primary problem involved in attaining our object of making available to the paper industry, for the purposes above stated, the great supplies of southern pines and gumwoods, was to find a means by which gumwood ground pulp, in admixture with permissible proportions of long 'fibered chemical pulp, could be made into a workable paper furnish. In the search for a solution of this problem we have carried out a long and costly series of experiments, 1n the course of which we have attempted to obtain, by grinding gumwood with a wood pulp grinder of the type now commercially used, mechanical pulp which, in admixture with permissible proportions of long-fibered chemical pulp would pass over the paper machine. Although we made many such attempts, with various adjustments of the wood pulp grinder and with various modlfications in the dressing of the stones, the

fibers of the wood were so generally broken into short lengths by the grinder, that we were not able to obtain from gumwood by such means, mechanical pulp of the felting qualities and other characteristics required of the ground wood component of newsprint paper.

We succeeded, and were the first to succeed, in bleaching southern pine sulphate pulp, by careful control of the bleaching process, to a color which permits of its use (in white paper, with conservation at the same time of the necessary strength of the fibers, thus solving the secondary problem of making this pulp usable as the longfibered feltable component. of such paper. But paper made entirely of such bleached sulphate fiber or with a major component thereof in admixture with gumwood ground pul is not suitable for newsprint paper, while fiber mixtures containing permissible pro ortions of such sulphate pulp and the qua ity of gumwood pulp which we were able to obtain by grinding, are unworkable.

The primary problem was solved by our discovery that the addition of a. small proportional content of a suitable fiocculent agglutinant to the furnish or pulp mixture of sulphate fiber and mechanical gumwood pulp, so changed the working properties of the furnish that a web of good formation was readily securedwhich would run well over the paper machine, presented no unusual difiiculties in manufacture and made finished paper possessing the requisite strength and printing qualities for use on high speed news aper printing presses. agglutinant which we have found suitable is from five to ten erent by weight of the dry fiber contained in the total furnish; although a somewhat larger or smaller proportion may be used within the protection of our claims.

The agglutinant material causes the otherwise unfeltable fibers to mat and interlock into a firm web, and to adhere together. It also retards the draining away of water from the pulp on the wire of the paper machine, so that more time is given for the fibers to thus interlock and felt together, before the water is drawn out by the suction boxes at the delivery end of the wire.

The water which is pulled out by the suction boxes carries with it part of the agglutinant, to wit, all that does not remain adhering to and in mesh with the fibers lying on the wire. This water is used, in part at least, over and over again, being continuously returned to the stuff chest of the paper machine, and there added to the stock which is delivered from the beater.

.Hence the water is a carrier or vehicle for the agglutinant, and continually supplies the agglutinant to the paper stock in the machine. Whatever the exact action of the agglutinant may be, its effect is a treatment of the gumwood to make the fibers thereof feltable with one another and with the long fibers of the pine pulp, into a firm and strong web. It transforms an otherwise unworkable pulp mixture into a furnish which can be satisfactorily handled by a paper machine and made thereby into suitable newsprint paper. After extraction of the water, enough of the agglutinant remains in the web to serve as a binder adhering to the fibers and cementing them together, thus making thefinished paper hard and strong enough to meet the requirements of commercial newsprint paper. The agglutinant preferably used is colloidal cellulose made by. beatin chemical wood pulp, or otherwise abra ing it in water, until it is hydrated to the colloidal state. Cellulose so prepared is flocculent in condition, and is pure cellulose, free from any compounds or ingredients liable to produce objectionable results in the paper. It may be made from any chemically prepared or cooked wood fiber, including chemical pulp of southern pine or southern gumwood, or from other suitable cellulose material,

but preferably is made from the same.

bleached sulphate fiber as is used in the pulp furnish. Proper transformation of wood fiber to the colloidal state may be offected by beating in a standard beater, for a period of from twelve to fifteen hours; but it may be more quickly efi'cted, in about three hours, by treatment continuously and in rotation by a beater and a J ordan engine connected in series.

As more particularly illustrating the nature and characteristics of our invention, we give as follows a description of the No.1 quality. .southern pine sulphate used in making a certain run of paper ac cording to the invention, withouthowever implying any limitation of our protection to the exact steps, ingredients, or proportions so. described. The furnish was coinposed of:

Per cent.

pulp, bleached;

Ground black gumwood; '70. Colloidal I cellulose To the above total fiber furnish there was added,;for the usual purpose of sizing, 1 70 of rosin size and 1% of alum. The sulphate pulp was-made from North Carolina pine and was bleached by standard chlorine bleaching equipment. The ground pulp was made from black gumwood obta ned from the swamps of the Pearl River. M ssissippi, by the operation of a standard wood pulp grinder with a stone commonly used-for the production er pulp for newsprint use. buried "with a four-cut straight burr and operated with a grinding pressure of thirty pounds per square inch on a fourteen inch cylinder. The colloidal cellulose was made from chemical wood pulp by hydration in a standard beater and Jordan, connected in a series and operated in repeated rotation on the stock. v The furnish thus constituted was made into paper on a standard Fourdrinier paper machine, which was run in the usual way for making newsprint paper.

Paper -made as thus particularly described has been used with entire satisfaction in printing the regular editions of daily newspapers on high speedrotary perfecting newspaper presses of types which make exacting demands on the paper web.

While'the specific proportions of the in gredients illustratively described above are preferred at present to others, nevertheless considerable variations in such proportions may be made, and equivalent ingredients may be substituted, within the protection herein claimed. For instance, the southern pine sulphate fiber and gumwood fibers may be used in other proportions, although always with a substantial preponderance of the ground fiber; and other flocculent agglutinants having the functions hereinbefore ascribed to the agglutinant may be used in place of colloidal cellulose; while colloidal cellulose otherwise made in any suitable manner may be used.

Our invention has thus made possible the manufacture of commercial newsprint paper from southern pine and southern gumwood and has thereby rendered available to the industry great quantities of wood heretofore unavailable for this use.

While we have made this result possible by modifying the fiber furnish, consisting The stone was of medium gritchiefly of mechanical gumwood pulp, by

adding thereto an ingredient or agent, namely colloidal cellulose, which has the capacity of making an otherwise unworkable fiber mixture feltable into strong pa per in a paper machinel,nevertheless the protection which we claim is not limited to the use of an added felting agent or to paper containing such felting agent. we are the first to have produced a workable furnish composed wholly of southern pine chemical pulp and gumwood mechanical pulp, and are the first to make merchantable newsprint paper of these ingredients, we claim protection generically for means and methods of making such workable furnish, and for our products, commensurate with the novelty of our invention;

, The woods designated by the words southern pine as used in this specification include the following: short leaf yellow (Pin'us e-chinata'), long leaf-yellow, and Georgia long leaf (Pi'lmspalustris), Cuban pine ,(Pz'nus hezfcrophylla), loblolly pine (Pin-us swam or Pz'mes" taeda), and, in

Since general, all pines found in the southern United States and characterized by'a resin content substantially greater than that of the northern conifers. The term guinwood as here used, includes black gum (Ng ssa, syloatica), cotton gum (Ng ssa aguatz'ca), sweet or red gum (Liguidambar stg mciflua), and the like.

What we claim and desire to secure by Letters Patent is:

1. The method of making newsprint paper froma fiber furnish consisting of southern gumwood ground pulp and southern pine sulphate pulp, which consists in modifying said furnish by incorporating colloidal cellulose therewith, in substantially the proportions specified, and then forming said modified furnish into a paper web.

2. The method of making newsprint paper which embraces supplying to the paper machine a fiber furnish having as one component a chemical pulp, as another and major component southern gumwood pulp of such character that it would not so felt with the chemical component that the furnish could be carried over the paper machine, and a flocculent agglutinant to modify the felting capacity of the furnish to enable it to be carried over the paper machine.

3. The method of making newsprint paper which embraces supplying to the paper making machine a furnish consisting of southern pine sulphate pulp, southern gumwood ground pulp, and material to effect a felting action between the two components, and forming said furnish into a paper web on the machine.

4. The method of making newsprint paper from southern pine and ground gumwood 80% ground gumwood and 80% to 20% southern pine sulphate pulp to provide a sufliciently felting furnish to pass over the paper making machine, and forming the furnish into a paper web.

5. The method of making newsprint paper from southern pine and gumwood Which comprises preparing a fiber furnish of southern pine sulphate pulp and mechanically disintegrated gumwood, with treatment of the gumwood to make its fibers sufficiently feltable to enable the furnish to pass over the paper making machine, and forming said furnish into a paper We 6. The method of making a paper furnish from southern pine sulphate pulp andgumwood ground pulp which consists in incorporating with said gumwood pulp chemical wood fiber colloidal cellulose in substantially the proportions specified.

7. The method of transforming an unworkable paper furnish consisting chiefly of mechanical gumwood pulp of such character that it would not be carried over the paper machine which comprises incorporating colloidal cellulose in said furnish in substantially the proportions specified and thereby causing the fibers to become feltable into a suitable paper web.

8. The method of making a newsprint paper furnish from southern pine sulphate pulp and gumwood ground pu p which consists in combining said ingredients in the ratio of approximately 70% to 80% of the ground gumwood and the balance of south ern pine sulphate pulp.

9. Newsprint paper composed of southern pine sulphate pulp, mechanical gumwood pulp, andcolloidal cellulose.

10. Newsprint paper composed of a mixture of southern pine sulphate pulp, mechanical gumwood pulp, and a flocculent agglutinant.

11. A paper furnish for the manufacture of newsprint paper consisting of southern pine sulphate pulp, southern gumwood ground pulp, and chemical wood fiber colloidal cellulose in substantially the proporlions specified.

12. A paper furnish for the manufacture of newsprint paper consisting of southern pine sulphate pulp and gumwood ground pulp, and a felting agent in suflicient measure to make said furnish sufiiciently feltable to enable the furnish to pass over the paper making machine.

In testimony whereof we have affixed our signatures.

ARTHUR D. LITTLE. CARROLL E. CARPENTER.