US1850791A - Felt component and process of making same - Google Patents

Description

Patented Mar. 22, 1932 i UNITED STATESPATENT OFFICE- PIERRE nnnwsnn, or'ELMnURsr, NEW YORK, ASSIGNOR 'ro THE BARRETT comrn w,

. 'A CORPORATION or NEW Jnnsmr FELT COMPONENT AND PROCESS OF MAKTNG SAME v ii'o Drawing.

, This invention relates to processes for producing fibrous materials for paper or felt,

. roofing, mulching, and other purposes.

This paper making fibrous material maybe obtained from the bast fibres of certain plants such as flax, flax tow, jute, manila and other strong fibrous substances, by treating the raw fibre simultaneously .with chemical and mechanical processes in such a manner that the greater portion of the original natural.

strength of the individual fibres is largely retained, and the ultimate fibreslargely or entirely separated from one another. The principal elements or, characteristics desired" of the fibrous substances from which this tvpe of felt paper is made are strength,'

absorbency and low material cost, and the principal characteristics desired for methods of producing such fibres is extreme simplicity of manufacture and low cost of operation, both consistent with reasonable quality and uniformity of product. The process which I set forth herein is one for the production of a fibre in which strength is the predominant characteristic thereof, altho such fibre will naturally be absorptive also to av certain deree. g It has been found that a very desirable method of preparing this fibre consists in a simultaneous mechanical and (chenncal dlsmtegrating treatment of such fibrous substances as jute, jute bagging, flax, flax tow,-manila rope, etc., which are commonlyknown as, and which will hereinafter be referred to in the claim as, cordage fibres. Any one or more of these fibres are placed in the ordinary type of paper mill beater, withhot water maintained at 90 to 100 degrees centigrade, to which I strong alkali, such as caustic soda, or caustic lime, etc, has been added to the extent of approximately 10% by weight of the raw fibrous substances used. Live or exhaust steam may be used for heating and the steam may be introduced directly into the water in the beater operations.

Application filed February'16, 1926. Serial 88,710. I

by means of a steam pipe, or the heating may be accomplished by steam coils or other similar device. The time of treatment varies with the strength ofthe alkali used, the nature and strength of the fibrous substance, and the capacity and efiiciency of the beater. When jute fibre is treated, for instance with hot water 1 to which has been added caustic lime to the extent ofapproximately 10% of the weight of the untreated jute, in a 1000 lb. beater of the ordinary paper mill type, it will require about two hours, more or less, exclusive of the time required for washing, in order todefiber the material and remove a substantial amount of the intercellular incrusting substances. A sheet'of paper formed from the I treated fibre thus produced, will possess considerably more strength than a sheet of paper made from the raw fibre merely beaten with cold water as has been commonly done in the prior art. When flax, flax tow or manila rope are treated, a longer time is required than'for jute. all other conditions remaining equal.

Before the fibre produced in this manner is used in the manufacture of'paper, it should be washed with water to remove the chemicals used in the treatment, in order to avoid difiiculties in the subsequent paper making The heating may be conducted on the inter- '80 mittent individual system by which the stock passes from one beater to the next one in the series by gravity or by pumping. With the continuous system. provision should be made forheating the initial and subsequent beaters in order to maintain the efficiency of the combined chemical and mechanical action. This invention is not to be limited to theuse of the ordinary type of paper mill beater, since any apparatus designed to perform the same mechanical disintegrating and chemical defibering action may be used with similar results. y I

The washing-of the fibreafter this treat- 9 mentmay be done by means of'theordinary form of beater drum washer, or it may .be conducted in a continuous manner by means of a washer or series of washers of the Decker or pulp'thickener type, or other type,

either in conjunction with the intermittent or the continuous heating system. 7 v A sheet of paper produced from fibre prepared in this manner possesses greatstrength, for instance, comparable to that of kraft or strong unbleached sulphite pulp, and this fibre may be used alone, or as a component in the furnish for the manufacture of paper, such as saturating felt, etc. it is especially 10 useful in combination with other fibrous felt paper making materials which possess less strength but greater saturating capacity than the beater cooked fibrous substance which I have described.

v For instance, where low absorptivity in the final sheet is desired, 15% of jute or flax fibre, prepared as herein disclosed, may be combined with 85% old-paper stock or well cooked cereal crop fibre such as straw. If a sheet of high absorptivity is required, of

the type of fibre herewith disclosed may be combined with fibre of high absorptive capacity such as stock prepared from roofing rags containing substantial percentages of 2 wool and raw jute, and 35% filler fibre such as old paper stock or well cooked cereal crop fibre such as straw.

One of the advantages of this process over prior known processes for producing fibrous 30 material to be used as the main strength giving material in the manufacture of paper, especially saturating felt, etc, is in the elimination of the operation of cooking the fibre in a a rotary or other type of digester before it is treated in a beater or other disintegrating machine, which advantage results in a considerable saving in labor and equipment. Another advantage lies in the saving in time, A since this process is much more rapid than those employing digester cooking, inasmuch a it requires, for the present process, only a. small fractionof thetime necessary to fill the digest'er, cook it, empty it, and transport the cooked material to a beater.

I claim: I The process of preparing raw bast flax fibers for use in the manufacture of roofing paper which comprises subjecting the raw ast flax fibers to mechanical and chemical disintegration in alkaline solution containing about 10% by weight of alkali based upon the dry weight of the fibre at a temperature in the neighborhood of C. to remove intercellular incrusting material in the fibres. Q 7 In testimony whereof I afiix my signature.

PIERRE DREWSEN. r