US27653A - Improvement in the manufacture of straw paper - Google Patents

Description

UNITED STATES ATENT Erica.

ROBERT T. SMART, J. 7. SMART, AND A. J. SMART, OF TROY, NEW YORK.

IMPROVEMENT IN THE MANUFAGTURE OFSTRAW PAPER.

Specification forming part of Letters Patent No. FY3853, dated March 27, 1560.

To all whom it may concern:

Be it known that we, ROBERT '1. SMART, J OSEPH W. SMART, and ANDREW J. SMART, of Troy, in the county of Itensselaer and State of New York, have invented a certain new and useful Process for Making White Paper from Straw or Similar Substances; and we do hereby declare that the following is a full, clear, and exact description of the nature of said process and the effect thereof on the pulp and paper produced from straw or similar material.

In the manufacture of white paper from straw and similar vegetable fibers several methods have been pursued, among which may be mentioned that set forth in Letters Patent No. 9,910, wherein hydrate of soda or potash is used in a peculiar apparatus to operate upon straw cut up by a chaff-cutter. After this operation the straw is washed in a mass and before the fibers are separated or opened. The mass is then subjected to hypochlorite of alumina for bleaching. The half-stuff, after all these chemical operations have been performed on' the unseparated mass, is washed and beat in an ordinary engine and made into paper. Another process set forth in Letters Patent No. 17,387 relates to subjecting straw, 850., to heat, pressure, and agitation in a boiler containin g alkali, then the stuff is washed, steeped in sulphuric acid, washed, bleached, and then beat into pulp; and a somewhat similar process has been pursued, (see Patent No. 26,202,) using a stronger alkali and greater pressure.

Our invention and process differ from all others in the manner and order in which our successive operations are performed, whereby the fibers are more thoroughly separated and perfectly bleached, so that the paper produced in entirely free from colored spots and much stronger on account of the perfect separation of the fibers in the pulp-engine and by the operations to which they are subjected.

In all the processes heretofore in use with which we are acquainted the bleaching operation was performed upon the straw or similar fiber before it was reduced to half-stuff, or when it arrived at this stage in the paper-making and before being reduced to pulp. The consequence was that the chemical bleaching agents did not penetrate and remove all the coloring-matter from the knots and thick or lumpy parts, and hence when beat into pulp and formed into paper spots of coloring-matter were clearly visible. Besides this the bleaching agent required to be very powerful to penetrate the straw, and even then did not act upon the separate fibers in the efficient manner necessary to make a good quality of white paper quite free from coloring-matter.

In preparing paper-pulp we pursue the following method:

First. We take the straw, either cut or uncut, or other vegetable matter properly reduced, if necessary, by cutting, grinding, or breaking, and place the same in a suitable vat or tub containing a strong alkaline solution and boil the same by steam or fire heat; and for this purpose we make use of soda-ash or potash, either alone or in connection with hydrate of lime. This operation is continued the necessary or desired length of time, until the silicious or aluminous matter is loosened or separated from the vegetable fiber and the mass reduced to the proper state for the next operation.

Second. We place said vegetable fibrous matter in any ordinary or suitable engine, in which the same is thoroughly washed and the fibers separated or reduced to a pulp.

Third. From the pulp-engine the material is passed into a receiving chest or tub, and then we allow a small stream of pulp to run into a vat through which a stream of clean water is flowing. The pulp as carried along with the water is thoroughly washed and opportunity given for any heavy lumps and unseparated parts to subside, and receptacles may be formed for these by pieces of board set across the bottom of said vat. The water passes through a cyl--- inder covered with wire-cloth, which cylinder arrests and in its revolutions lifts out the pulp. The fibers are taken up and the water expressed by press-rollersu Fourth. The fibers, being separated and reduced to a soft pulp by the foregoing operation, are put into an engine or vat and chloride of lime applied to the same. We afterward add sulphuric acid in such proportions and strength as may be necessary, accordingto the character of the stock operated on. These chemical agents act to separate and remove any albuminous, silicious, or woody matter from the fibers and commence the bleaching operation, and in the fine state to which the stock has been reduced these agents act much more thoroughly and effectively. At the same time they do not require to be of so great strength as necessary for operating upon the half-stuff, as heretofore practiced.

Fifth. After submitting the pulp to the foregoing operation for the necessary length of time-say from six to twenty-four hours, according to circumstances-the pulp is to be thoroughly washed and cleaned in either engine or vat, and chloride of lime applied in sufficient quantity and allowed to remain the necessary time to bleach the fibers to the desired whiteness, and. then the pulp is made into paper in the usual manner; and for this purpose the pulp may be either washed again or put into a pulp-engine for beating the fibers still finer, if a better quality of paper is to be made.

Upon examination of paper produced by our process and comparing the same with any paper made by others from a corresponding stock it will be found that our article is free from yellow or colored spots, while that heretofore made from straw contains more or less spots of a yellowish color when viewed by transmitted light, said spots arising from the fact that the bleaching agents are applied before the paper is reduced to pulp, so that such chemical agents do not act uniformly and thoroughly throughout the particles; and besides this byour process all foreign substances are so effectually removed from the fibers that there is nothing to impede or neutralize the bleaching chemicals.

The paper made by our process is not only whiter and clearer from yellow spots caused by particles remaining in their natural color and proving a blemish and imperfection in the manufacture, but it is also very much stronger and tougher than paper ever before made from straw or similar vegetable fibrous substances. In fact, it is strongeraud tougher than mostof the paper made from rags.

I We do not claim the use of alkaline solutions, either in an open vessel or under pressure, (endangering life by risk of explosion;) neither do we claim the use of chloride of lime or sulphuric acid; but

What we claim as our invention, and desire to secure by Letters Patent, is-

The method herein specified of treating straw or similar vegetable fiber for making white paper by the successive operations of boiling, washing, and separating or beating, and then applying the chemicals used for bleaching to the pulp, substantially as set forth.

In witness whereof we have hereunto set our signatures this 13th day of January, 1860.

ROBT. T. SMART. J. WV. SMART. A. J. SMART.

Witnesses LEMUEL W. SERRELL, WALTER RALIGH, THos. GEO. HAROLD.