US2533167A - Method and apparatus for applying adhesive to fibrous webs - Google Patents

Description

Dec. 5, 1950 P KILHAM 2,533,167

METHOD AND A1 PARATUS FOR APPLYING ADHESIVE T0 FIBROUS WEBS Filed June 27, 1947 4 Sheets-Sheet 1 ENTOR. Peter Ki l he m METHOD AND AI PARATUS FOR APPLYING ADHESIVE TO FIBROUS WEBS 4 Sheets-Sheet 2 Filed June 27, 1947 INVENTOR. Perer KI I hum Dec. 5, 1950 P. KILHAM 2,533,167

METHOD AND APPARATUS FOR APPLYING ADH SIVE T0 FIBROUS WEBS Dec. 5, 1950 P. KILHAM 2,533,167

METHOD AND APPARATUS FOR APPLYING ADHESIVE TO FIBROUS WEBS 4 Sheets-Sheet 4 Filed June 27, 1947 INVENTOR. P ter Kilhum W AHorney Patented Dec. 5, 1950 unrrso STATES PATENT orncr:

METHOD AND APPARATUSFOR APPLYING ADEESIVE' TO FIBROUS WEBS Peter Kilham, .Plainville, iMass assignor to American Reenforced Paper Company,-Attleboro, Mass, .a corporation of, Massachusetts Application JuneZ'Y, 1947, Serial N0;75'7,511

13 Claims.

"This invention relates "to the application of Jliqu'ids, such as adhesives, to webs of various sorts'iand its object is to apply suchliquids uniformly in limited quantities and thereafter to "heat the web, desirably under pressure, employing equipment which is efiective yet simple and inexpensive.

"Various suggestions have heretofore been made for the manufacture of webs from loose, unspun fibers of sisal, jute, cotton, wool, rayon or ithe'like, without weaving or knitting and using adhesive to unite the fibers into a self-sustaining structure. bonds the fibers together where they contact 'each other and such contacting may occur in various ways.

In such structures the adhesive Thus, the fibers may lay inside by sidecontact with each otherfor portions of their lengths, or they may cross each other; and such crossings may occur either by an :indiscriminate weaving in and out of one of 'thefibers among others in a single layer, orit' will occur more predominantly where the structure made up of several superposed layers offiberswithfibers in one layer crossing the fibers in a the next adjacent layer.

The use of adhesive to unite fibers thus'arranged presents a number of problems. The "fibers are loose and easilyvdisarranged;.it is -di'flicult to distribute the adhesive uniformly in 'small'quantities to bond the'fibers where they contact each other and at the same time avoid loading'of the web as a wholewitheadhesive; and fit is-diificult effectively to apply heat and pres- 1 sure tothe fibers carrying the adhesiveybecause of variation in thickness'of the web and'becausaof' the tendency'of the fibers to adhere to-any --heat and pressure applying instrumentalities which they contact.

*By the present :inventionl have :provided imethod and-apparatus which obviate'these dim-.-

:culties.

Inaccordance with my inventiona'web .Of'lfit- '"tenuated and generally parallel Tfibers is "advan'cedcrover, but out of contact with, 'arsupply -1ofiadhesive in which is immersed a pipe having +perf0rations through which'air flows into and Jupwardly through the adhesive to 'form, on the --adhesive surface, a mass of light frothy "bubbles @of adhesive which rise upwardly from'the 'sur- :faceof the adhesive into contact with the web. The bubbles are so fragile that they burstzread- .ily upon contact with the fibers and deposit their adhesive sparingly yet uniformly without .disturbing the-fiber-arrangement. The web -rof 'fihers; is r then :heatedmand dried: by .:being :;-.drawn Fig. 4;

,ovena'heated cylinder while being pressed thereagainst-byna number of individual pressure applying-elements, :such as steel-- balls, which apply a uniform bonding pressure despite variations in thicknessof the weband which'also act as to -.minimize adhesion of the fibers to the cylinder. rIn-a+modificationofrny invention a heated cylinder which'the web contacts advances at a peripheral speed slightly in excess of the speed I. of advance of the web so that-the cylinder slips relative to *the web. as -.a further precaution against adhesionof the fibers to thecylinder.

I contemplate the adaption of this method and :apparatus to ,a number of uses other than specifically for ;the'- application of adhesive to fibers of the'sortabove referred to, as my inven- -tionis useful as well for the application of other -liquids, such'as dyes,:and for thetreatment of other materials, such as-webs of other fibrous materials,- like paperstrips or wire or fibers composed -'by :teXtile drawing machinery, cards,

-combers, etc; or woven, knitted or netted fabrics;

. or-solidsheets such as paper, metal, wood, plas- -tic and thelike.

In the drawings: Fig.- 1 isa sideelevation view, partly diagramtmatic'of a preferred embodiment of my inven- ..tion;

, Fig. 2 is a plan 'view thereof;

Fig; 3 isa detail plan view of the adhesive tank; .Fig. 4 -isa side elevation view thereof;

Fig. 5is a vertical-section on the line 5--5 of Fig: 6 is a perspective view of the lower heating .cylinderlshowing the balls and frame;

Fig. 7 illustrates a single layer, fabric-like material which, may be made on my machine, and Fig. 7A :shows a multi layer material;

Figsusand 8A, Sand 9A, and 10 and 10A are diagrams indicating the stripping action of the steel balls; and

Eigpll is a vertical section of modification.

.'An unwoven, self-sustaining, fabric-like material which my method and apparatus are well adapted to manufactureis illustrated in Fig. 7

and consists entirely of strands 2 of long, vunspun fibers such as sisal drawn out in generally parallel directions, but also contacting each other as in the side contacting areas, a few of which are indicated at 2a, and also at the crossings 2x where one'fiber crosses another. Alternatively, a number oflayers maybe used, as illustrated in 5Fig.'7A, 'one layer ofxfibers l crossing the other "layer of "fibers. 2, inwhich instance there will of :course :be .-;many.:.additional crossing contacts.

Both the single and the multi layer embodiments are secured together by adhesive which bonds the strands at these places of contact to form a self-sustaining web useful, for example, as a low cost substitute for burlap or for other fabrics made by conventional weaving processes.

At 6 (Fig. 1) is a package of fibers, such as sisal, from which a web 8 of the fibers is drawn and I may use a creel of such packages from which a number of webs 8 are drawn and arranged. side by side to give the desired width of web.

The web is supported on an apron l drawn around rolls i2 and i3 to support the web as it advances in the direction of the arrow from i rolls II, 52 toward rolls l4 and 15. Both sets of rolls, ll, i2 and M, l5 nip the fibers, the bottom rolls of each set being power driven and the upper rolls being geared to the lower rolls and resting by their own weight on the fibers supported by the lower rolls. It is desired to attenuate or draft the web for which purpose rolls [4, l5 are driven at a peripheral speed greater than that of rolls ii, 12, this arrangement being merely suggestive of available equipment adapted to draft the fibers to the desired thinness. The drafted fibers 8a constitute the lengthwise strands 2 (Fig. 7) and are sparsely distributed as indicated.

The web 8a passes from the belt i 0 through the nip of rolls M, i5 and thence at 8b over a tank I6 containing adhesive. The adhesive coated web, indicated at 80, passes in peripheral engagement with the heated drum E8 and the final product, designated 812, is wound up at 20.

The tank i6, shaped in cross-section as shown in Figs. 1 and 5, is at least co -extensive with the web widthwise and contains a supply of adhesive 22 admitted from a source through the pipe 24 opening into the tank. To make the product above described the adhesive is desirably of the starch type, set up by heat. The adhesive is maintained at a level indicated at 22a somewhat below the path of travel of the web. At 25 is a pipe extending across the tank (Figs. 3 and 4)- leading from a supply of compressed air and having a number of holes 28 through which air streams or bubbles flow upwardly through the adhesive in the tank. A water jacket 3!), through which hold water, having ingress at 32 and egress at 34, circulates, is provided to insulate the adhesive 22 from the heat of the drum is (Fig. 1).

From the adhesive tank the web, indicated at 80, passes between cylinders 58 and is either or both of which are heated as indicated diagrammatically at I80. and Mia.

Suitably sup-ported immediately above the cylinder l8 and extending toward the nip of cylinders l8 and i9 is a frame 58 constructed of end members 42 and 44 (Fig. 6) arcuately shaped to conform to the curvature of cylinder !8 and defining an enclosure bounded at one side by a third frame member at and at the other side by the nip of cylinders it and 9. The purpose of the frame is to confine a number of steel balls 59 which have entire freedom of movement within the confines of the frame and which roll about on the web 80 as it issues from between cylinders 58 and 9. The frame does not touch either cylinder and is supported above cylinder It for freedom of clearance of web 80 beneath it.

As the web 8, attenuated at 8a approaches the adhesive tank 16 it is fragile in construction, so that the fibers must be handled with care to avoid disarrangement by the application of adhesive or the application of heat and pressure.

The bubble mass of adhesive rising from the surface 22:]. of the liquid in tank iii is preferably composed of sizeable and fragile bubbles as contrasted, for example, with fine, compact lathers that can be worked up with a soap solution. Desirably the bubbles are in the order of a half an inch or so in diameter. The bubbles are more fragile than the web and hence do not disarrange the fibers but burst readily upon contact therewith to deposit their adhesive thereon. Some of the bubble mass works its way through the gaps in the web to its upper surface (Fig. 5) where they burst and thus the adhesive is deposite uniformly throughout the exposed surfaces of the fibers, but in sparing amounts.

The dimensions and character of the bubbles may of course be varied widely, such as to adapt the treatment to different materials, namely unspun fibers other than sisal, or woven, knitted or netted fabrics, or solid sheets such as paper, wood, metal or plastic, and also depending upon the purpose of the treatment, that is, whether to apply adhesive or a dye or for other uses. Generally speaking the higher the air pressure in pipe 2c the more bubbles will be produced, and the thicker or higher viscosity the liquid 22 the larger the bubbles, and vice versa. For the specific manufacturing operation herein described I employ a starch adhesive containing a wetting agent, such as the sulphonated alcohols available commercially as Aerosol, the adhesive having a viscosity of about that of thin cream, or in the order of about 209 centipoises. practice I have used effectively air holes 28 (Fig. 3) about a inch in diameter and spaced about inch apart with an air pressure of about one pound or less per square inch. If the pipe 25 is too near the surface 22a of the adhesive the air may blow through without forming an adequate bubble mass and I have found that a depth of immersion of one inch is usually not enough but that it should be about 2 inches. These details may, of course, be varied widely as I have suggested, and indeed a gas other than air can be used for certain purposes.

As the web 80, wet with adhesive, passes through the nip of cylinders i8 and is its fibers are not disarranged and it passes thence under the balls 5i]. As indicated in Figs. 1 and 6 the frame curves over the top of the cylinder l8 so that the balls r011 by gravity both toward the nip of cylinders l8 and i9 and toward the outer member :16 of the frame. These balls have several functions; they apply pressure to the web as the adhesive sets up under the heat particularly of the lower cylinder #8, so that their weight must be adequate for that purpose and in practice I have used balls of about inch diameter made of steel. The balls are effective to distribute adhesive which, due to its surface tension, tends to coalesce in uneven masses, particularly at the areas of fiber contact, and by distributing the adhesive more evenly the heating time necessary to set up such masses of adhesive is obviated so that the overall heating time is reduced. The balls are also effective to doctor the lower cylinder i8 of wet or dried adhesive by contact therewith in the spaces between the fibers and an adhesive thus collected by the balls rubs off, after drying, as the balls rub against each other.

The balls, furthermore, by rolling against the upper cylinder If! not only doctor it of adhesive but also strip it of fibers that tend to adgrammatically in Figs. 8 and 8A, 9 and 9A, and

10 and 10A. Figs. 8, 9,.and' 10 are enlarged diagrammatic, side views taken at. the nip of cylinders l8 and i9 showing: the inner row of balls 50a which, .by. gravity, rest both against the web and against the surface of the upper cylinder. The next row of balls is. designated 5912. Figs. 8A, 9A, and 10A are diagrams in plan showing the rows 58a and 56b of steel balls. In these views the dot-dash line. A designatesthe nip of the cylinders. l8. and i9 .and the dot-dash line B designates. the line of contact between the upper cylinder [9: and the row of balls Ella.

Asthe web 80 moves out from the nip. of cylindersv l8 and [9. toward the first: row of balls 50a, let us assume that a. single fiber strand (1 partially adheres to the surface of cylinder [9 as indicated in Figs. sand 8A. As the web advances,

one portion of the strand tends tofollow the cylinder l9 and the other tends to. follow the web as a whole and as this. advance continues the strand becomes wedged between adjacent steel balls in row Ella as indicated at C in Figs. 9 and 9A. As the adjacent balls in row 56a rotate counter-clockwise, (Fig. 9) they pull the strand away from the cylinder lfland deliver it to the row of balls 59b under which it rolls as shown at C" (Figs. 1,0 and 10A) and the stripping action is complete. Although an. adhered fiber may not be disposed. in just the way I have illustrated yet the steel balls do have a stripping action performed by grasping portions of the fibers and pulling them away from the cylinder towhich they are adhered. The halls themselves keep fairly free of adhesive and the fibers do not tend tov wind .around the balls because of their small diameter and smoothness.

In the embodiment of my invention illustrated I have found that little or no adhesion of fibers to the bottom cylinder occurs. -'I-he-:web;-.8d-;preferably continues its contact with the cylinder 18 for a sufiicient distance after leaving the ball frame 40 to assure setting up of the adhesive. Thereafter the finished web isrolled up at 2!).

Although I prefer to employ two heating cylinders with a ball frame, as above described, this may not in all instances be necessary as I have employed successfully, particularly with less visi cid liquids, a single heating cylinder with or without a ball frame. Thus, I have shown a modification in Fig. 11 in which only one cylinder, designated I8, is employed and in cooperation therewith is a heating shoe 6i heated at 6|, between P which and the cylinder l8 the web 80 passes. To assure stripping of the web from the cylinder i8 I preferably drive it faster, for example from 1% to 5% faster, than the web, as determined by the peripheral speed of the rolls M, I 5 (Fig. l) and thus I assure that the web and cylinder slide relative to each other and no adhesion of fibers to the cylinder occurs.

The foregoing is directed to the manufacture of a single layer of material as illustrated in Fig.

'7. Where two or more layers are desired, as illustrated in Fig. 7A., I preferably first form, for each layer, a self-sustaining structure as above described and then superpose as many layers as desired, uniting the layers by repeating the treatment with adhesive and heat to bond the superposed layers to each other. Alternatively, I may deposit loose crossing strands on the web 8a of Fig. 1 before it is treated with adhesive and subjected to heat and pressure, but I prefer to make the. composite; layer: out of layers that have been individually prefabricated.

In; the claims, the term web includes all of the. materials. abovereierred to. except where otherwise indicated.

I claim:

1. Apparatus for applying liquid to. a web, in.- cluding a liqu d upply t nk, me ns for conduct ng gasto. e liquid contained in sa d nk to forma bubble mass, a pair of feed rolls for delivering a. web of. m t ial, over the tank, a cylinder onthe opposite side of the tank from the reuse heat.- sour e adjacent, the ylinder foraD- plying heat to the web as it advances over the cylinder, a drive rotating the rolls at a predetermined. peripheral speed, anda; drive rotating the cylinder-at a peripheral: speed greater than that of the rolls so that a web held by the nip of the rolls will slip relative to the cylinder.

j 2'. The apparatus as defined in claim 1 in which the cylinder is driven about 5% faster than the rolls.

3.. Apparatus for applyin l quid to a web, in-

cludingan open, liquid supply tank adapted to contain a liquid capable of bubble formation upon the injection of a gas below the surface thereof, means for conducting gas to, and below the surface of the liquid to form a bubble mass, feeding means for delivering a web of material over the tank but. out of contact with the liquid to receive the bubble mass from. within the tank, and a heated cylinder to receive the web after it has left contact with the bubble mass.

4. Apparatus for applying liquid to a web, in-

- eluding an openv liquid supply tank adapted to containa liquid, capable of bubble formation upon the injection of a gasbelow the surface thereof, means for conducting gas to, and below the surface of the liquid to form a bubble mass, feeding means for delivering a web of material over the tank but outv of contact with the liquid to receive the bubble mass from within the tank, a heated cylinder to receive the web after it has left con- 1 tact with the bubble mass, a plurality of balls disposed above and pressing upon the web as the web moves over the surface of the cylinder, and a frame for holding theballs in position.

5. Apparatus for applying liquid to a web, including an open liquid supply tank adapted to contain a liquid capable of bubble formation upon the injection of a gas below the surface thereof, means for conducting gas to, and below the surface of the liquid to form a bubble mass, feeding means for delivering a web of material over the tank butout of contact with the liquid to receive the bubble mass from within the tank, a pair of rotatable cylinders positioned one above the other to receive and nip the web after it has left contact with the bubble mass, a guide directing the web around and in contact with a predetermined area of the surface of the lower cylinder after the web leaves the nip of the upper and lower cylinders, means for heating and driving the lower cylinder, a plurality of balls disposed above a portion at least of said predetermined area of the lower cylinder to press the web thereagainst as it passes out from between the cylinders, and a frame for holding the balls in position with some of the balls in contact and rotating with the upper cylinder to remove fibers of the web which tend to adhere to the upper cylinder.

6. The method of applying a liquid adhesive to a web of fibrous material which comprises supporting the web adjacent and above but out of contact with the exposed surface of a pool of liquid adhesive, forcing a gas, inert as respects said liquid adhesive, under pressure upwardly from below the surface of said pool to form and collect on said surface a mass of relatively large fragile bubbles, and passing the web through the bubbles to cause them to burst and deposit their liquid adhesive on the web.

1. The method of applying a liquid adhesive to a web of fibrous material which comprises supporting the web adjacent and above but out of contact with the exposed surface of a pool of liquid adhesive, said adhesive containing a wetting agent, forcing a gas, inert as respects said liquid adhesive, under pressure upwardly from below the surface of said pool to form and collect on said surface a mass of relatively large fragile bubbles, and passing the web through the bubbles to cause them to burst and deposit their liquid adhesive on the web.

8. The method of applying a liquid adhesive to a web of fibrous material which comprises supporting the web adjacent and above but out of contact with the exposed surface of a pool of liquid adhesive, said adhesive having a viscosity in the order of about 200 centipoises, fore ing a gas, inert as respects said liquid adhesive, under pressure upwardly from below the surface of said pool to form and collect on said surface a mass of relatively large fragile bubbles, and passing the web through the bubbles to cause them to burst and deposit their liquid adhesive on the Web.

9. The method of applying a liquid adhesive to a web of fibrous material which comprises supporting the web adjacent and above but out of contact with the exposed surface of a pool of liquid adhesive, said adhesive having a viscosity of about 200 centipoises and a wetting agent, forcing a gas, inert as respects said liquid adhesive, under pressure upwardly from below the surface of said pool to form and collect on said surface a mass of relatively large fragile bubbles, and passing the web through the hubbles to cause them to burst and deposit their liquid adhesive on the web.

10. The method as described in claim 6, which includes the further step of thereafter simultaneously applying pressure and heat to the web on which the adhesive is thus deposited.

11. The method as described in claim 6, which includes the further step of thereafter simultaneously heating the web and supporting one surface of the web While applying pressure to a plurality of selected spaced areas of its outer surface.

12. The method as described in claim 6, which includes the further step of subsequently heating the web and simultaneously supporting one surface of the web while applying rolling pressure to a plurality of predetermined selected areas of its other surface while avoiding pressure in the intervening areas thereof.

13. Apparatus for applying adhesive to a web of unwoven fibrous strands including an adhesive supply tank, means for passing the web over but out of contact with the adhesive in the tank, means for conducting gas under pressure to the tank below the surface of the ad hesive to form bubbles therein which rise to the said surface and break upon contacting the passing web thereby depositing their liquid adhesive on said web, and apparatus for applying heat and pressure to the web, wet with the adhesive, including a pair of cylinders, one above the other, adapted to receive the web, the axis of the upper cylinder being out of vertical alignment with the axis of the lower cylinder toward the inlet side of the cylinders, and a plurality of balls disposed at the outlet side of the nip of the cylinders and positioned to rest on a portion at l ast of the web supported by the lower cylinder, so that the balls on the outlet side roll by gravity into surface contact with the upper cylinder to aid in stripping it of adhered fibers.

PETER. KILHAM.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,235,183 Butterworth July 31, 1917 2,299,689 Fruth Oct. 20, 1942

Claims (1)

1. 6. THE METHOD OF APPLYING A LIQUID ADHESIVE TO A WEB OF FIBROUS MATERIAL WHICH COMPRISES SUP PORTING THE WEB ADJACENT AND ABOVE BUT OUT OF CONTACT WITH THE EXPOSED SURFACE OF A POOL OF LIQUID ADHESIVE, FORCING A GAS, INERT AS RESPECTS SAID LIQUID ADHESIVE, UNDER PRESSURE UPWARDLY FROM BELOW THE SURFACE OF SAID POOL TO FORM AND COLLECT ON SAID SURFACE A MASS OF RELATIVELY LARGE FRAGILE BUBBLES, AND PASSING THE WEB THROUGH THE BUBBES TO CAUSE THEM TO BURST AND DEPOSIT THEIR LIQUID ADHESIVE ON THE WEB.

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