US2665450A - Method and apparatus for continuous production of absorbing material - Google Patents

Description

1954 c. A. J. LINDQUIST 2,665,450

METHOD AND APPARATUS FOR CONTINUOUS PRODUCTION OF ABSORBING MATERIAL Filed March 27, 1950 0 6Q I I I; \r J'" O l .l N

I 'I" I B II II H F I; I 4A 'I'b :E III! A INVENTOR ATTORNEY Eatented Jan. 12, 1 95 4 METHOD AND APPARATUS FOR CONTINU- OUS PRODUCTION OF ABSORBING MA- TERIAL Curt Axel John Lindquist, Norrkoping, Sweden,

assignor, by m'esne Celloplast,

assignments, to Aktiebolaget N orrkoping, Sweden Application March 27, 1950, Serial N 0. 152,092

Claims priority, application Sweden December 12, 1949 9 cities; (01. 1s 15).

This invention relates to the art of producing absorbing or sponge material from a cellulose ester such as cellulose xanthate or viscose. The invention is particularly concerned with the production of sponge cloth and an object i to provide a method and an apparatus which will be continuous in their operation and will produce a sponge sheet of desired thickness for sponge cloths having the requisite strength and other desired properties. Other objects of the invention are economy in production, simplicity and reliability in operation, and uniformity of product.

Artificial sponge material is commonly made by the intimate mixture of a pore-forming substance, such as sodium sulphate decahydrate or Glaubers salt with viscose, followed by coagulation and the customary after treatments, the sponge material frequently being molded into the desired final form. The salt dissolves and incidentally coagulates the adjacent viscose, thereby forming cavities or pores in the body of the material. It is also customary to augment the in herent strength of the product by the incorporation of a fibrous material into the product. For example, cotton or hemp fibers are commonly added to the intimate mixture without any control as to their directional dispositions and consequently the fibers lie in all directions. If a block of such sponge material is cut into thin sheets or layers a sponge cloth is obtained. However, as

the fibers in a cloth produced in this manner are not oriented in the plane of the cloth only, the strength is not so high as would be the case if the longitudinal disposition of the fiber was confined to the plane of the cloth.

Due to the thickness of the original sponge material from which sponge cloths may thus be cut, a considerable time is required to effect coagulation throughout andconsequently it is difficult to produce such material by a continuous operation.

These disadvantages are obviated by this invention which contemplates the formation of a sheet of the proper thickness for sponge cloths by a continuous operation which includes a control that efiects the orientation of the fibers in the plane of the cloth in both a transverse and longitudinal direction, thus strengthening the sheet in both dimensions.

More particularly in accordance with the method the intimate mixture of viscose, Glaubers salt and fibers is deposited upon a traveling belt and is spread out evenly and is subjected to both transverse and longitudinal surfac rubbing or 2 agitation which tends to orient the fibers in those respective directions.

This method makes possible the production of a thin layer or sheet of the material having the thickness of the desired cloth product with the consequent rapid coagulation throughout its thickness and hence the possible continuous operation. Moreover because of the quick coagulation weakening of the material is avoide Which results from the prolonged immersion in the hot coagulation bath usually required in the production of artificial sponge material.

. In order to make the sponge cloth more pliable and supple, it may have a surface pattern imparted to it by providing the belt with a complementary pattern. If it is desired to form a pattern on the upper sides of the cloth, this may be done by subjecting that surface to pressure by a mold device such as a roller having the desired surface design, in advance of the coagulation. Either or both of such patterning procedures may be used on the traveling web.

As an apparatus the invention contemplates an endless belt of a material resistant to the chemicals in the viscose solution and in the coagulating bath and an extrusion press such as a screw conveyor for discharging the mass upon the belt, with means to drive the belt and to direct it into and out of a coagulating bath. To spread the mass at the orient the fibers in the plane of the web more or less in a direction transverse to the travel of the belt, a spreader is laterally reciprocated over the belt at, the proper distance therefrom and in a positionafter the extrusion press. Following the reciprocating spreader is a surface contacting device having continuous relative movement in the direction of travel of the web. A-cceptably such a device may be a roller properly spaced from the belt and rotating at a peripheral speed exceeding the speed of the belt and in the same direction as the belt.

Other features and advantages of the invention will appear from the following description of the construction and operation of th apparatus shown by way of illustration in the accompanying drawing.

The mass used for the production of the sponge is poured into the hopper of a screw press 5 and is discharged by said press as a string on to an endless belt 2 which is preferably patterned and made of rubber. The mass i 3'swinging back and forth in the transverse direction, whereby the material is spread according as it passes along the belt, so that when proper thickness and to spread by an arm leaving the swinging sector of the arm 3, it has obtained the desired thickness. The thickness of the mass is determined by adjusl ln the height of the arm above thesurfaceof thebelt.

The mass now follows the belt and the fibers of the mass will preferably become oriented in the transverse direction, for which reason the web of mass, if not further mechanicallyttreated,would position so as to be oriented in the longitudinal direction. By adjusting the speed and the, pressure of this roller, any desired number of fibers can be directed parallel with the longitudinal direction of the belt,

D to the above po sib l ies eembinatienit has appeared in practice that th strength can be o t n n he on i udinal-bench as in the transverse direction ofithe sponge cloth, and as the fibers now he inthe se two directigns. and naturally to a certain extent also, in other direc-q tiene in e plane he eb. maestbe strength becomes considerably higher than a sponge cloth cut from a block.

The belt 2 then conducts the, mass intca ,coagu: lation bath 5, which simply may consist oiiaillot (i. e. heated to about the boiling point) solution of sodium sulphate. Quripg its passage. throirgh the bath the mass coagulates, and after having passed a roller 6 in the bath, the spongle cloth now formed is continuously drawn on:- iromthe. belt 2 at a roller 1 outside the, coagulation bath. The cloth 3 thus obtainedis thensubjected. to. further chemicaltreal ment, i. e.,des111phurising, bleaching and so on, and is dried Before new mass can be, discharged on the rubber belt 2, said belt should be. cooled and brushed clean, which isdone ina v bath 8, consisting oi cool water and possibly containing cer:

tain chemicals which preventthe mass. when sub- 1 jected to the subsequent coagulation, from adher-. ing so tightly to the belt that the mass cannot be easilydrawn ofi at the roller 7:. Thebrushing is preferably carried out with, brushes til operating in the cooling bath.

It will be appreciated that. an incidentat advantage of forming the sheet. on. the-conveyor belt is that the belt forms. a reinforcing support for the nascent sheet through the hot liquor until the coagulation is eiE -ected and thus.makes.possible the continuous sheet formationat high operating speed with minimum likelihoodofrupture.

The belt is guided over a roller after the. sep-.

ara'tion of the web into the bath 5; through which it is guided by two rollers and thence over a roller. on the level at which the material. is deposited;

which latter roller is power driven and drivesthe belt.

It will be understood that the particular ape.

p s s o n t nsendaboredescribed.

is illustrative only and that the invention defined in the following claims may be variously. otherwise embodied.

What is claimed is:

1. The method of producing a ,continupussheet of absorbing material consisting; in depositing. an intimate mixture of viscose, salt crystals and fibersin a continuous-stream on an endlesstraveling belt, subjecting the deposited material on the, belt to a surface rubbing action ina certain direction in the plane of the belt sufiicient to orient a substantial portion of the fibers in the i ect e i ub n subjectin h p sited material on the belt to a, second surface rubbing in a direction at a substantial angle to the first rubbing sufiicient to orient a substantial portion of the fibers in the last mentioned direction conveying the Web qnthe belt after the rubbing treatmentthrougha coagulating bath, and then separating the. sheet so formed from the belt.

2, The method oi producing a continuous sheet ofabsorbing material consisting in depositing an intimate mixture oi viscose, salt crystals and fibers in a continuous stream on an endless traveli-ng belt, subjecting the deposited mixture to a laterally reciprocatory spreading action, thereby orienting some of the fibers in a transverse direction, conveying the mixture on the belt following such action through a coagulating bath, and then separating the sheet so formed from the belt.

3 hemethod prod cin Sh e of absorbin mate al. c nsis n n ep siting an intimate m x re oi. e ei salt e i'a send. stars i a c n nuous; str am. on. ndl ss rav eling belt, sub e n the. depos ted. mixt re. tee. at a y r eip oeator pre din when and-- thereby sprea sitevenlr nthebe ten Qr e. s. som of hefibers n rener ee dir etien subjectin he. sheet so formed; o ie erd y moving rubb n aet en. uffie e tte rie -1t. some f. the fi ers a n udina ir tien, e re ins; the heet o r d on the e t ro a. hot coagulating bath, and then separating the, sheet irom'the belt,

A method as claimed in. cla m 3. to ther wi h the t p of mold ng arettern. n. a Su face; of the. sheet while onthe belt,

5,. apparatus; for producing a, continuous.

web to be. formed, and means for reciprocating said spreading means in a direction transverse to the. movement. of the belt.

6. An, apparatus ,forproducing a contirnmus; sheet of absorbingmaterial coml risinga driven endless. belt, a coagulating bath, a cooling bath, means to guide the, beltsuccessively through said. baths-, means for; depositing a continuous stream of viscose, on thebelt, aspreader; for the mate=. rial spaced from the belt thelthickness of thesheet and disposed betweenthe. said means. and

the coagulating bath, a rotatable roller disposed transversely over the, belt between the spreader andcoagulating bath in position toengage a sheet.

of the. material; means capable of rotatin the roller in the direction of movement of the belt'at a peripheral speed-exceeding the speed-of he b t.-

7. An apparatus iorproducing a continuous. sheet: oi absorbing material comprising a driven endless belt, a coagulating bath, a cooling bath, meansto. guide the belt successively through said baths, means for depositing a continuous stream;

of viscose on the belt, transversely reciprocatoryspreading means. adjacent the. material depositingmeans and disposed over andspaced from the beltby-thethick-nessof thesheet to be formed, a rotatable roller disposed; transversely over the belt between the. spreader: and coagulating bath in position to engage a sheet of the material and means capable of rotating the roller in the direction of movement of the belt at a peripheral speed exceeding the speed of the belt.

-8. The method of producing a continuous sheet of absorbing material consisting in depositing an intimate mixture of viscose, salt crystals and fibers in a continuous stream on an endlesss traveling belt, subjecting the deposited mixture on the belt to a laterally reciprocatory spreading action to orient some of the fibers in a transverse direction, conveying the mixture on the belt after such spreading through a coagulating bath and separating the sheet so formed from the belt.

9. The process of claim 8 wherein a belt having a patterned surface is employed and such pattern is molded into the surface of the sheet in coritact With the belt.

CURT AEKEL JOHN LINDQUIS-T.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,590,999 Czapek et a1 June 29, 1926 2,289,713 Land July 14, 1942 2,308,951 Novotny et a1 Jan. 19, 1943 2,336,944 Madge et a1 Dec. 14, 1943 2,540,906 Overton et a1 Feb. 6, 1951 V FOREIGN PATENTS Number Country Date 435,128 Great Britain Sept. 16, 1935

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