US1900427A - Manufacture of fibrous articles - Google Patents

Description

March 7, 1933. A L CLAYPP- 1,900,427

MANUFACTURE OF F IBROUS ART I CLE 5 Filed Dec; 20, 1927 l/lll/Ilzl VIII! 1 n n I Z0 Patented Mar. 7, 1933 PATENT ormcr.

ALBERT L. GLAIPP, OI DANVERS, KASSACEUSETTS MANUFACTURE OF FIBROUS ARTICLES Application filed December 20, 1927. Serial No. 241,436,.

This invention relates to the manufacture of fibrous articles using paper pulp as a raw material and using papermaklngmachmery,

. so that such articles may be manufactured] 6 rapidly and economically.

In manufacturing fibrous articles using paper pulp as a raw material, it has sometimes been the practice to mould the ulp in a free or lightly beaten condition un er suc- 10 tion or pressure between foraminous moulds, .then to remove the articles from the moulds and dry them. Articles thus produced are quite orous and .of comparatively poor. strengt doubtless because -of the loose, ran- 35 dom arrangement of the fibers resulting from moulding. If it be attempted to improve the characteristics of such articles by thorcughly beating the pulp or by incorporating filling or sizing materials into the pulp, it

0 is'found that the slow or beaten pulp or such filling materials tend to interfere with successful moulding, by plugging up the in terstices of the foraminous moulds.

One of theobjects of the present inventionis to make possible the roduction of fibrous articles in which the bers exist in the compacted, interfelted condition'result-- ing from manufacture on papermaking machinery. The method of the present invention involvesrunning the paper pulp ofi into a web on a paper machine, and then while the web is still wet, preferably as it comes Off the wet end of the machine, forming it into ar-* ticles of the desired shape.

A methodsuch as described is particular- 1y advantageous when it is desired touse filling and/or sizing materials in the manufacture of fibrous products, as such materials may be incorporated into the pulp in 40 the beater engine, and the pulp run off into a web on the. wet end of a paper machine without difliculty, even if .such material would cause difliculty on the dry end of the machine. Any waste material resulting from cutting or mouldingthe wet web may be returned to the beater engine and easily disintegrated and conditioned for the production of other web material. My method may, for instance, be employed to advantage when thermoplastic waterproofing materials in finely divided or dispersed condition are incorporated into the pulp, as any waste resulting from the production of articles from a wiet web prepared from the pulp may be easi on t e other hand, a web containing such thermoplastic material wereonce dried andthe material fused on the fibers, it would be quite difiicult. to disintegrate the web into its component fibers and to condition them for satisfactory web formation. My method also permits t thermoplastic material with the pulp in the beater furnish, as the beater furnish may be run off into aweb on the wet end of a paper machine without difliculty, whereas sticking and breaklng of the web would be likely to take place if it were attempted to run such a web over the dry end'of the machine.

The wet web may be cut or moulded into various articles.- For instance, if a wet web of the proper caliper and containing sufiicient waterproofing material for the manufacture of roofing products is prepared, it may be cut up into roofing shingles of the desired shape, or moulded into roofing tile, any

waste resulting from cutting or moulding being returned to the beater engine. The shingles or tile may then be dried at atemperature sufficient to cause a fusion of the thermoplastic waterproofing material contained therein and thus to ensure the encasing of the fibers and thefilling of the pores and interstices of theweb with'such material. If desired, drying may be effected between heated dies under pressure to effect a compacting of .the product.

A web of pulp comes off the wet end of the paper machine in a sufficiently dewatered condition to be self-sustaining, but it is still of low strength, so that when it is desired to mould articles therefrom, moulding must conditioned for web formation. If, 5

e use ofhigh proportions of be efiected gradually and under light pressure, as otherwise the web would be liable to break. Furthermore, the moulds must also be designed to allow moulding without breaking of the web. Tothis end, the. moulds which are employed are preferably lined with a soft or yieldable material such as felt,

which serves to backup the wet web while it is being moulded. After moulding, the articles are removed from the moulds and dried. Inasmuch as light, yielding pressure is applied durin moulding, the articles may have substantial y the same water content as the wet web before moulding.

If articles are moulded from a wet web of ordinary paper pulp, such as kraft, suloptimum density. and strength. The amount of asbestos fiber necessary for this purpose will vary, depending upon the character of the pulp used as a raw material and the shape or other characteristics of the articles, some pulp yielding articles having greater tendencies to warp than others. Thus, articles made from kraft. pulp have a greatertendency to warp than similar articles made of sulphite pulp, and those made of the latter pulp have a greater tendency to warp than those made of ground-wood pulp. I have further found that if sufiicient amount of thermoplastic waterproofing material is incorporated into the pulp, it will also inhibit warping of articles moulded from a web prepared from such pulp.

Various non-warping pulp compositions may be employed in the practice of my invention. For instance, I may employ a composition comprising 90 parts ground-wood pulp and 10 parts' asbestos fiber, or one comprising 50 parts of kraft pulp and 50 parts asbestos fiber, or another comprising 20 parts sulphite pulp, 50 parts ground-wood pulp, and 30 parts asbestos fiber. rials such as ound-asbestos, lime, ma"- nesium oxide, c ay,'cellite, infusorial eart and wood flour, whenincorporated into the pul also tend to prevent warping of articles ma e from the sheeted pulp, but I prefer to use asbestos fiber along with such mate-v rials, for when such materials alone are used -in suitable quantity to prevent warping, a product of optimum. strength is not obtained. In lieu of, or in addition to asbestos'and/or other filling materials, I may incorporate suitable thermoplastic waterproofing materials into the pulp and produce a precipitate therein to fix such waterproofing materials on the fibers. For instance,I maycharge the beater engine with parts of pulp and arts of thermoplastic material in pulveriz condition or dispersed 1n a suitfacture of roofing Filling mate-,

silicate solution. Ten parts of 40 Baum sodium silicate may then be added, together with 5 parts of alum, to produce a fiocculent precipitate of aluminum silicate, which serves to carry down and fix the thermoplastic material on the pulp. The beater furnish may then be run off into a web on the wet end of a paper machine, and the wet web then moulded into articles which when dried have no tendency to warp. Drying is preferably performed below the softening point of the thermoplastic material, as otherwise the articles tend to sag and become deformed, owing to their high content of thermoplastic material. This tendency to sag may be overcome by substituting asbestos for part of the thermoplastic material. For instance, if a heater furnish comprising parts of pulp, 20 parts of asbestos, and 20 parts of Waterable dispersing agent, e. g., soap or sodium proofing material is run off into a wet web moulded into articles, such articles may be dried .at a temperature sufiiciently high to cause fusion ofthe thermoplastic material therein without danger of sagging. If the wet web is cut into flat articles, such as roofing shingles, however, the proportion of thermoplastic waterproofing material may run as high as from 40% 'to 80% of thetotal dry materials added to the beater, and drying may be effected while the articles are supported ina fiat condition, at a temperature sufiiciently high to cause the fusion of the thermoplastic material therein.

Various thermoplastic materials may be employed to prevent warping and to waterproof the product, depending upon the characteristics desired in the final product. For

instance, where discoloration of the product is to be avoided, waxes such as paraflin, montan, or carnauba, to ether with free rosin, may be employed. ere discoloration of the product is immaterial, as in the manuroducts, bitumens, or asphalts, e. g., those aving a melting pomt ranging from 200 to 400 F. may be an ployed.

Another object of the present invention 1s to provide a method of and means for continuously moulding articles of the desired shape from the wet web of pulp as it comes off the wet end of the paper machine. this end, the wet web is passed between one or more pairs of endless series of moving moulds, which, gradually close and act to mould successivel portions of the web into articles of the esired shape, then sever the articles from the web, then open, whereupon the articles are successively. removed from the moulds, and then return to initial position. Preferably, the articles are removed onto an endless conve or belt which serves to car them in continuous fashion through a drying chamber.

The present invention will now de I vention. Where asbestos or fillers'such as 1ime-are incorporated into the pulp to prevent warping and articles such as pie plates are being made, I may advantageously treat the wet web or the articles made therefrom with sodium silicate solution, as the treat? ment yields a product which is waterproof,

'easeproof, and fireproof after drying;

referably, this treatment is effected after the articles are formed, so as to avoid sticking and tendency the forming of. the articles.

On the accompanying drawing,

Figure 1 represents somewhat diagrammatically and conventionally an assembly of means for manufacturing pie plates in accordance with the present invention.

Figure 2 represents a side view, partlyin section, of a pair of endless series of moulds operating on a wet web of pulp as it comes from the web-forming mechanism.

Figure 3 represents a section through a pill! of mould members for forming the p ates.

Figure 4 shows in perspective a portion of the web of pulp after moulding has been completed.

Figure 5 is a perspective view of the moulded plate.

Referring in detail, first, to Figure 1 of the drawing, A represents as a whole the webforming mechanism, which ma ,be of any suitable type, that shown in t e drawings being the wet end of a cylinder papermak ing machine. The machine comprises a vat 1, into which the paper pulp is introduced at the usual papermakin consistency' Rotating partia ly submerged'in the pulp contained in the vat isa cylinder mould 2, on which a web of pulp is continuously deposited, the web being picked up from the unswbmerged portion of the mould by a traveling felt 3 maintained in contact with the cylinder mould by a couch roll 4. The felt carries the web under an upper felt 5, where it is sufiiciently dewatered to withstand passing between press rolls without being disintegrated, whence it carries the web successively between pairs of press rolls 6 and .7. The web now has a water content of about 60% to and while it is still liable to break, it is sufiiciently strong to selfsustaining, and asshown passes from the paper machine between one or more pairs of endless mould carriers C, arranged transversely on the sheet.

As shown in Figure 2, one carrier of a pair is arranged immediately above the other carrier, both carriers gradually converging in the. direction of travel of the paper web of the web to break during W as it passes therebetween from the paper "machine. The upper carrier comprises an endless chain 9 mounted on a pair of sprockets 10, 10a, either one of which may be driven and thus serve to drive the chain. An endless series of male mould members 11, designed to mould pie plates, are carried at regularl -spaced intervals by the links of the chain. The lower carrier is of a construction similar to the upper one, except that it carries an endless series of female mould members 13. Preferably, the upper stretch I of the lower carrier is kept from sagging by a supporting platform 14, over which it passes. rate of speed in the direction of travel of the web, and the mould members are mounted to cooperate with one another as they come together, there being suflicient slack inthe chains to permit proper alinement of the moulds. When the carriers havepassed around the sprockets 10a into substantially horizontal position, a male mould 11 descends to press the web of pulp slightly into the female mould 13. As the carriers proceed, the moulds gradually come together and close, thus pressing portions of the web downwardly out of the plane of the remainder of the web into plate form. The pressure exerted is quite gradual and light, so that there is little tendency to break or disin- Both carriers are driven at the sametegrate the web. Preferably, as shown in 4 Figure 3, each of the mould members is lined witha layerof soft cloth or felt 17 ,-so that any excess pressure or shocks will be absorbed.

As the forming of the plate is being completed, an annular knife 18 fixed to the marginal portion 19 of the upper mould member cuts through the web against-the lower mould member and severs the formed plate moulded plate. As shown on the drawing,

the lower sprocket shaft 15 .is made hollow, so that air may be delivered thereinto from a supply pipe 20. Communicating with the interior of the shaft 15. and arranged radially thereof, is a blast pi e 21, which delivers a blast of air against t e bottom of a formed plate, when a port 22 formed through the bottom of the mould member 13 to the felt lining comes into registry therewith. .Preferably, as shown, a conveyor belt 23. is arranged to receive the platesas they fall from the successivemoulds, the belt carrying the plates through a heati chamber 24, wherein they are dried and t on delivered onto a table 25, from which they may be removed for packing and shipment.

As illustrated in Figure 4, three pairs of series of moulds operate on a sin leweb of pulp as it comes from the we eforming mechanism. A greater or less number might of course be used if desired. If desired, the wet web may be slit longitudinally between the several series of moulds before being moulded, as indicated by the dotted lines. The web material remaining after the plates have been cut therefrom may be returned to the beater while still in wet condition, where disintegration into pulp may be easily effected, or, as shown inFigure 1, may be wound up into a roll R before being returned to the beater. Articles may be moulded and cut in the manner just described, from single or multi-ply webs;

I am aware of the fact that it has been proposed to dampen or wet previously dried paper prior to moulding articles therefrom,

but my invention departs considerably from such practice, for a web coming oil the wet end 0 a paper machine is in a quite different condition from a web which has, been dried. In such latter case, the web is in a compact, shrunk condition, so that moulding must take place between metal moulds under considerable pressure. Such latter procedure is furthermore much more expensive, as it involvesthe expense incident to drying and rewetting the paper, and it requires much more power to disintegrate and beat up the resultmg waste paper.

I do not herein c aim per se the treatment of a fibrous web or articles containing asbestos or fillers such as lime, with an aqueous solution of sodium silicate, or the product resulting therefrom, as this: is disclosed and claimed in my application, Serial No. 94,329. filed March 12, 1926.

Having thus described certain embodiments of this invention, it is obvious to those skilled in the art that various changes or modifications might be made therein without departing from the spirit or sco of invention as defined by the appended c aims.

What I claim is:

1. Steps in the manufacture of pulp articles, which comprise preparin an aqueous pulp suspension containing su cient nonhydratable material to form a non-warpin composition, interfelting the pulp into a we on a paper machine, removing the web while wet from the machine, forming articles of the desired shape from the wet web, impregnating the articles with sodium'silicate solution, and drying the treated articles.

2. Steps in the manufacture of pulp articles, which comprise interfelting the ulp into a continuous web on a paper mac e,

continuously removing the webfrom the wet I end of the machine, progressively moulding portions of the web gradually and under light pressure out of the plane ofthe web into articles of the desired shape, and severing the moulded articles from the web.

3. Steps in the manufacture of pulp articles, which comprise interfelting the lplillllp into a continuous web on a paper mac e, continuously removing the web from the wet end of the machine progressively moulding portions of the web gradually and under light pressureout of the plane of the web into articles of the desired shape, severing the moulded articles from the web, and drying the moulded articles.

4. Steps in the manufacture of pulp articles, which comprise incorporating suflicient non-hydratable material into cellulose pulp to form a non-warping composition, interfelting the composition into a web on a paper machine, removin the web while wet from the machine, moul ingarticles of the desired shape from the wet web and out of the plane of the web, severing the moulded articles fi'om the wet Web, and drying the wet artic es.

5..Steps in the manufacture of pulp articles, which comprise incorporating suificient asbestos into cellulose pulp to form a nonwarping composition, interfelting the composition into a-web on a paper machine, removing the web while wet from the machine,

moulding articles of the desired shape from signature.

ALBERT L. CLAPP.

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