US2886248A - Sealable adhesive composition, tie pad comprising same, and process for using said pad - Google Patents

Description

May l2, 1959 J. J. LAUDIG 2,886,248

SEALABLE ADHESIVE COMPOSITION, TIE PAD COMPRISING SAME, AND PRooEss Foa USING SAID PAD Filed Dec. 3l. 1954 2 Sheets-Sheet 1 v '26 /25 Q fff-mdef/ 33 4 36 /g @mf A 37 7. D M2M 'azfer' 50 53 m A1A 44 T44 '/Oz@ OLYO Filed Dec. 5l, 19 Sheets-Sheet 2 May 12, 1959 J. .LLAUDIG sEALAELE ADHESIVE COMPOSITION, TIE PAO COI/IPR SAME, ANO PROCESS EOE USING sAIO PAO2 54 United States Patent O James J. Lauilig, Scranton, Pa., assignor to The Texas Company, New York, N.Y., a corporation of Delaware y'Application December`31, 1954, serial No. 479,011

s claims. (crass-283) This invention relates to an adhesive sealing composition particularly suitable for railroad tie pads, sealable adhesive railroad tie pads (i.e., seals) rmade therefrom, and process for using said pads.

My basic composition comprises 45-65 weight percent asphalt having penetration between 30 and 50 and softening point between 100 and 170 F., 5-25 weight percent heavy naphthene base residuum of viscosity about 40-55 Saybolt Furol seconds at 210 F., 3-12 weight percent pine tar, and -35 weight percent of at least one rubbery'elastomer.

The above criteria for the bituminous ingredients (asphalt and residiuum) of this composition correspond to test specifications found in the April, 1953, handbook entitled American Society for Testing Materials (A.S.'I `.M.) Standards on Bituminous Constructional Materials, published bythe A.S.T.M., 1916 Race Street, Philadelphia 3, Pennsylvania. Throughout this application the asphalt penetration referred-to` above is taken at`77 F. with 100 gram load. Description of such testing procedure is found on pages 1331-1333 of the handbook. Softening point of the asphalt is measured by |the ring and ball method. lDescription of such testing procedure is found on pagesv 1356-1358 `of the handbook. Further testing procedures, referred. to hereinafter can be found in the handbook as' followsz, ash point (Cleveland Open Cup) on pages 1320-1322, and ductility at 77 F( on pages 1298-1300. i,

Railroad rails are supported customarily on wooden ties by a metal tiel plate placed between the upper tie surface andthe rail bottom. Frequently the lower surface of the tie'. plate isv formed in a grid pattern to grip into k the tie. The ,wood under the plates tends to become and remain damp, leading to loss of ability of the tie to resist attritionin service. Particular deterioration of the tie1also occurs becauseI of the penetration of grit such as sand used for traction entering at various points karound 2,888,248 Patented May 12, 19.59

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, 2 t and autosealing. By this I mean that the pad, wheninterposed between the plate and the tie in normal fashion, adheres tenaciouslyto both of said members and seals crevices and holes from substantial penetration by moisture, micro-organisms, and abrasive materials `without Y additional processing, special equipment, or special care t in the tie plate.

in application. l

Generally .thetie pad ofmy invention is cut about ythe size of the plate. Under pressure of use the composition spreads downwards into cracks and holes in the tie, upwards into unused spike holes and into annular areas around-spikes in the tie plate, and outwards around the edge of the tie plate to prevent water and grit from entering at these points. Particularly important are Ithe adhesive mushroom-like caps which are formed over holes Furthermore, the tenacious adhesive bond formed by my tie pad between the plate and the tie drastically reduces or eliminates relative motion betweenthese two members, thereby lessening abrasion o f the tie because of such motion. Unit cost of my pad is low while the protection and convenience of application it alords are remarkable.

Many of the properties of my'tie pad distinguish it from previous similar tie pads which are either too flowable to last for the extended period of years by which tie life is measured, or those which are too stiff or too brittle at low temperature to maintain satisfactorily continuous and complete adhesion to the plate and tie.

My pad requires no special tools for application -to a tie.y Furthermore, my pad need not be dipped intoan adhesive coating composition prior to application at the track, a procedure which is necessary lat the present time with some currently available tie pads. Thisadvantage of my tie pad cuts cost and contributes to convenience and safety in the pad application by track maintenancel personnel becausepbulky containers of and. heaters for separate adhesive dipping solutionsineed not be,l purchased and transported.

Another important feature of the tie pad of my invention is `its physical consistency and optimum resiliency 1 range which `are such as to `"reducetie cutting by waterborne grit -underrepeated impact loads and movement of tie plate with respect to the'ltie. An overly resilient pad or one containing hard particles such as metal pieces may increase rather than decrease undesirable tie attrition.

The adhesiveness of my tie pad composition, however,.

i is such that it cannot be handled or stacked in slabs withthetie plate, e.g. at unused spike holes, at Vspaces surrounding emplaced spikes, at the periphery of fthe plate where it rests on the tie, and particularly at the high edge of the plate which receives the most drainage. Ties are also subject to deterioration from repeated wetting and drying and from periodic freezing and thawing of moisture-laden sections below the plate. Such deterioration and attrition of the tie leads to loss lof itsr ability to hold spikes and to maintain the rails in their desired position. In a recent year more than -30 million new'wooden crosstiesl were laid ldown by U.S. railroads. New wooden crosstie renewals in the United States for the 5 year period between 1946 and- 1950 averaged 104 per year per mile ofmaintainedtrack. The magnitude of tie replacement expense is evident. The problem of extending tie life economically is an important one. While my composition'has general utility in coating and sealing operations, Yit 'isz'particularly advantageous for making a low cost improved tie pad to extend tie life.

The tie'pad made with my composition is autoadhesive out blocking, i.e. sticking together of one or more slabs. This problem is overcome by making each slab unita composite article of manufacture described broadlyas follows: said tie pad havingat least one of its faces maintained in intimate Contact .with non-blocking coating by the autoadhesion of said face to said coating. Such.

coating prevents sticking of the individual pads piled one on another (blocking) and permits their separation one from' another.` f

The coating can be of the type to render the pad sur-l face non-tacky for atemporary Vor prolonged period, e.g. by surfacing with calcium resinate, selected phenolic resins, ester gums, or methylcellulose containing glycer` ine.y Fine talcalso suggests itself as a non-blocking coating.

However,Y one of the most elective coatlngs which I have found'comprises a lm of high calendered, tough.

paper such as Kraft glassine. The peelable oi' strippable Yproperty of such lm can be maintained by coating or bers an aqueous solution of` the alkaline hydrolyzation products of an organotrihalosilane, then adjusting pH'ofl the fibers to cause an insoluble organosilicon compound Aface of a `silicone polymer applied in a solvent vehicle.

Other non-blocking lrn may be secured by coating the film with vaporized methylchlorosilane, or by applying surface coatings containing polyethylene, paraflin wax and the like.

Another method which I have developed for making the tie pad nonblocking is that of dusting the pad faces with fine rubber particles which, lin track service, incorporate themselves into the pad body and so restore the adhesiveness of the pad.

' Figures 4, 5 and 6 of the drawing show various modes of manufacture vof my pads. These'iigures will be discussed hereinafter.

Figure l shows a single tie pad 1 protected by a coating film 2 on both its faces. Figure 2 shows another tie pad 4 preparatory to packaging. Its bottom and edges are protected by a single sheet of glassine 3 folded upwards around the pad periphery. Figure 3 shows an assembly of my stacked tie pads in Vertical section wherein the overlapping edges of each lower protecting film piece 6 covers the exposed edges of each pad 5 thereon. The overlap also provides a tab for convenient removal of pads from a package, emp-lacement of pads on the tie, and stripping of the film from an emplaced pad. Film piece 7 protects the top of the stack. Suitable pads can be from about A6-3%; inches thick, preferably about inch thick.

Figure 7 shows a cutaway section of rail and tie in typical emplacement using the tie pad of my invention. Rail 61 is set in tie plate 62 resting on pad 63. Line spikes 64 and anchor spikes 65 hold the rail and plate to `wooden cross-tie 66 which is partly submerged in ballast not shown. Holes 67 in tie plate 62 are unused line spike holes. Holes 68 in tie plate 62 are unused holes for anchor fastenings. Items 69 mushrooming over the unused holes 67 and 68, around spikes 64 and 65, and at the edges of the tie plate are vadhering sealing mounds formed by the composition of the pad.

Figure 8 is a cross section taken on line 8-8 of Figure 7 showing more clearly the adhesive sealing mounds of tie pad composition around left hand anchor spike 65 and left hand unused anchor spike hole 68.

A rubbery elastomer in the proportions hereinbefore mentioned is vital in my tie pad composition. The rubbery elastomer can be a single component or mixture of new or reclaimed rubber, factice such as non-asphaltic vulcanizable oil or a highly oxidized paranV wax, or synthetic rubber such as a copolymer of isobutene and isoprene (Butyl rubber), a copolymer of butadiene and styrene (GK-S), and a copolymer of isobutylene and styrene and the like.

For efficiency and economy in the practice of my invention the preferred rubbery elastomer is 'reclaimed rubber suitably from about 8-80 mesh andv most advantageously from about l2-40 mesh (U.S. Standard Screen Size), e.g. reground whole tires slightly coarser than l2 mesh and containing as much as 20% of fibrous rayon material; reground tire tread of approximately 20 mesh; ground mechanical scrap from rubber molding plants at 20 mesh or finer; ground tubes at 2O mesh or finer, tire peelings, dykes, carcass, rubber boots, and rubber hose.

It is recognized that many of these rubbers are cornpounded with filler andA other additives. However, I have found that even such highly compounded rubbers as reclaimed rubber from old automotive tires and similar sources are excellent for my purpose providing that the proportion used in the adhesive sealing composition is broadly between` l andy 35 weight percent, advantageously from about 115 toabout 23` weightpercent and preferably about 20 weight percent. When compounding such reclaimed rubber with my preferred proportions of asphalt, heavy residuum and pine tar, hereinafter discussed, I use about 20 weight percent rubber for superior pad properties. Too little rubber renders the pad too owable, too soft, and quite brittle at low temperature; too much rubber makes "the 'pads unable to maintain continuous effective sealing against moisture and grit, makes the composition quite difcult to process, and prevents formation of the adhesive mushroom-like caps over spike holes for protection thereof against the elements. Rubber imparts toughness and resiliency to my composition, particularly at low temperature. The tight adhesive sealing of the composition about the spikes also protects their Shanks from corrosion.

The proportion of asphalt and the heavy naphthene base residuum as prescribed give ductility, ready miscibility, and sealing eiectiveness to the composition over a wide range of ltemperature. The proportion of pine tar enhances adhesiveness of the composition. The union of properties from these ingredients coacts in admixt'ure with the rubber to make the rimproved tie pad of my invention.

Broadly I can use about 45-65 weight percent asphalt having penetration between 30-50 and softening point between and 170 F. Preferably the proportion of asphalt used is between 50 and 60 percent, and the asphalt is an air-blown asphalt having penetration between 35 and 40 and softening point between 130 and F. Harder asphalt is apt to crack under load and softer asphalt to ooze away too rapidly. Too little asphalt in a composition can result in loss of body and/ or sealing properties, and too much asphalt can lead to loss of resiliency.

I use between 5 and 25 weight percent heavy naphthene base residuum from an oil refining operation, e.g. the product of reducing (distilling) crude oil bottoms by means of Vacuum or steam. Too little of such residuum in my composition makes it undesirably stil and unductile, whereas too much makes the composition too soft. Most desirably I use 10-20 weight percent of a heavy naphthene base vacuum residuum in the viscosity range of 40-55 and preferably 42-50 (Saybolt Furol seconds at 210 F.) to acquire the necessary pad ductility.

The pine tar I prefer to use is a high grade retort tar made by the destructive distillation of wood from trees such as long leaf pine. Broadly, I use 3-12 weight percent pine tar in my composition, and preferably 5-10 weight percent of such tar. Too little pine tar leads to loss of adhesion; too much can make the mixture diicult' to process, and the resulting pad loses weather resistance.

My pad can be a fibrous membrane impregnated and heavily coated with the aforementioned adhesive sealing composition to present a pair of faces lconsisting essentially of said composition. The fibrous membrane can be a single ply or plurality of plies of burlap; canvas; or roofing' felt (an unfilled cellulosic ber mat). Conceivably, llers such as carbon can be added to the lcomposition with discretion, but care must be used lin such addition lest the desired balance of physical properties of the pad be upset. Preferably the uncovered pad of my invention is simply a rectangular slab of my adhesive and sealing composition; it will contain no fibrous membrane and no filler material.

Broadly, the manufacture of the pad comprises: forming, from non-blocking surfacing agent and my adhesive and sealing composition, a slab of said composition having two faces, at least one of which is maintained in intimate contact with said surfacing agent by the autoadhesiveness of said composition, said composition consisting essentially of the aforementioned ingredients in the proportions and having the properties discussedabove.

pable paper, advantageously overlaid 'with a single membrane of cheese cloth or" the like to 'prevent the hot composition from owing beyond reasonable bounds. Then the composition and paper are cut to pad shape. It is also possible to vcast a hot composition directly onto a tie for making the tie pad at its point of use. Use of this procedure permits dispensing with pad coating, but requires special application equipment.

Figure 4 is a ow sheet showing one way for practicing my process of manufacturing tie pads using a fibrous membrane base. A strip of rooting felt 9 is passed through feed rolls 10 and saturated with the aforementioned adhesive composition 12 maintained as a soft plast-ic or molten mixture with heat and agitation -in tank 11. Saturated felt 13 is passed through rolls 14 adjusted to control thickness of the pad piece at desired gage. The strip is then passed through cooling zone 15 where temperature of the strip is reduced to about 100 F. or less. Slip sheet ribbons 16 and 17, comprising glassine or other paper having nonstickin'g silicone treatedy surface are applied -fto the top and bottom faces of the strip by rolls` 18. Tedders 19 feed the covered strip into cutter 20 wherein the strip is severed into a plurality of covered tie pads 21. These tie pads descend chute 22 and are sent to a b-undling machine not shown.

Figure 5 is a flow sheet showing another way of making the tie pads of my invention. A mass of my'adhesive' composition 26 is maintained in plastic condition in extruder and extruded into a continuous strip 28 through slotted die 27. Strip 28 passes into water 30 contained in tank 29 wherein it is cooled to about 80 F. The strip is directed around roll 31 and withdrawn from the tank over rolls 32. Slip sheet ribbons 33, comprising nonsticking glassine, are attached to top and bottom ofthe strip by rolls 34. This laminate is fed by nip rolls 35 into cutter 36 wherein the laminate is cut intol `covered tie pads 37. These are passed down the chute 38 into a bundling machine not shown.

Figure 6 is a ilow sheet showing still another way for making the tie pads of my invention. A continuous strip of my tie pad composition 45 is fed through feed'rollls 46. Then the strip is drawn into cutter 49 by nip rolls 48. Successively `severed portions of the strip fall in slabs like slab 50 onto precut silicone-treated yglassine paper pieces 52. The paper pieces move on conveyor 51 in synchronism with the cutting operation so that each slab falls onto a separate glassine piece overlapping the bottom face of the slab Iby a distance of at least the thickness of the slab in every dimension. The protected slabs are then conveyed to packaging machinery not shown for stacking and packaging.

An alternative method for making the tie pads of my invention without a glassine covering is to extrude a continuous strip of tie pad composition 45 as shown in Figure 6. The vupper and lower surfaces of strip 45 are lightly dusted with line rubber particles from applicators 46, the strip is severed `into a plurality of dust covered slabs, and the slabs are conveyed to packaging machinery Without glassine wrapping.

The following examples show ways of making the composition and tie pads of my invent-ion but are not to be construed as limiting the invention.

In the examples all percentages a-re weight percentages, all parts are weight parts, all test properties are referred to the A.S.T.M. reference heretofore made, and all temperatures are degrees Fahrenheit. The asphalt used in all exemplary adhesive compositions cited below was residuum from vacuum stills. In the raw state the asphalt had penetration of 100 and it was air-blown to 35-40 penetration prior to introduction into the blends used. The heavy naphthene base residuum used in all exemplary compositions was a vacuum residuum. It had specific Vgravity of 0.9574 at 60 F., flash point (C.O.C.) of 510 F., and tire point of 595 F. Its pour point was plus 45 F. and viscosity in Saybolt Furol seconds 6 at 210 F. was 47. Thepine'tar usedA in all exemplary compositions was the high `grade retort tar previously described. The glassine lm usedlwas Riegel TR2 Kraft Amber glassine, previously described, said paper being coated on one side with a'silicone'polymerslab-releasing agent.

Example 1 75 parts of a blend composed of 70.9 percent asphalt, 18.7% heavy naphthene `base vacuum residuum and 10.4% pine tar was heated to temperature of 280300 with agitation in a steel vessel. Then 25 parts of White natural rubber particles predominantly about 14 mesh size was added to the blend with agitation over a period of about 1/2 hour to make a composition consisting of 53.2% asphalt, 14% heavy naphthene base vacuum residuum, 7.8% pine tar and 25% rubber. lThe composition was cast while hot into slabs. The slabs adhered tenaciously to wood and to steel `and were ilexible when Itested over a temperature range of about minus 10 to about 120. i

Example 2.-80 parts of a blend consisting of 70.9 percent asphalt, 18.7% heavy naphthene base vacuum residuum and 10.4% pine tar was heated with agitation to temperature of 280-300 in a steel vessel. Then 20 parts of reclaimed rubber particlesfrom old tire peels (predominantly 8-12 mesh size and containing about 20% by Weight cord content) was stirred into the blend in about 1/2 hour. The Vresulting mixture had composition of 56.7% asphalt, 15% heavy naphthene base vacuum residuum, 8.3% pine tar, and 20% reclaimed rubber. This composition was then cast while hot in slabs onto sheets of glassine paper overlaid with .a single ply of cheese cloth to limit ow of the composition. The slabs were thenvsquared od for application to railroad ties, wrapped in glassine, and stacked for future'use. This lm prevented blocking of the slabs and could be stripped cleanly therefrom by upward jerking motion of the Example 3.-Tie pads described in Example 2 were -interposed between various ties and `corresponding tie plates on a portion of main li-netrack of The Delaware, Lackawanna and Western Railroad p near Scranton, Pennsylvania. The tie pads adhered instantly to the ties upon application thereto, and the treated glassine wrapping stripped readily by hand from the pads. The tie plates and rails were then spiked down into place and the section of track so made up was opened to normal usage for a period of about 10 months. At the end of this period the track was closed, sample sections of the rail removed, and ali tie plates and ties in the general vicinity inspected critically. Adhesion of the plates to the ties where the test tie pads had been inserted was pronounced, necessitating use of a crowbar to remove a plate from a tie. of moisture or abrasive particles penetrating into the tie crevices, -into old spike apertures in the tie, into unused spike holes in the plate; spike holes in the plates were capped over tightly by mushroom-like forms of the composition. Crevices around the plate were filled and l sealed. Virtually no attrition of the tie or tie cutting by the plate was found on the so padded ties. There was no evidence of tie rot or loss of strength, and the ties held their spikes with great tenacity. The pad composition exposed to the air was hardened on its surface, but resilient beneath the surface.

Comparative inspection of track where no pads were used in the vicinity of the test sections showed manifestly several loose spikes, areas of tie attrition or wear below tie plates, and distinct cutting of the tie by the tie plate in several places.

Example 4.-Slabs of adhesive and sealing composition were made according to the method described in Example 2 except that they were not wrapped in glassine, but rather their surfaces were dusted lightly with particles of the same kind of reclaimed rubber as was used in making the the slabs without blocking.

Where plates were removed there was no evidence `Obviously manymodiiicationsy and variations of the invention, as hereinbefore set forth, may be made without departing fromthe spirit and scope thereof, and therefore only suchv limitations should be imposed as are indicated in the appended claims.

I claim:

1. An autoadhesive and autosealing railroad tie seal for positioning between a tie plate and tie comprising a slab of an adhesive sealing composition consisting essentially of 45465 weight percent asphalt having penetration between -30 and 50 and softening point between 100 and 170 F., 5-'25 Weightpercent heavy naphthene base residuum ofviscosity about 40-55 Saybolt Furol seconds at.210 Ff., 3-12 weight percent pine tar, and 10-35 weightpercent ofv at least one lrubbery elastomer selected from the group. consisting of natural rubber, reclaimed rubber, .synthetic -rubber and factice.

2. The tie seal of claim l comprising 50-60 weight percent air-blown asphalt having penetration between 35 and 40 and softening point between 130 and 140 F., 10-20 weight percent heavy naphthene base vacuum residuum of viscosity labout'42-50 Saybolt Furol seconds at 210 F., 5410 weight percent pine tar, and 15-23 weight percent -of 8-80 mesh reclaimed rubber particles.

3. An autoadhesive and autosealing railroad tie seal for positioning between a tie plate and tie comprising a slab vof adhesive sealing composition having at least one of lits faces maintained in intimate contact Iwith substantially nonblocking coating by the autoadhesion of said face to said'coating, said seal consisting essentially of 45-65 weight percent asphalt having penetration between 30 and 50 and softening point between 100 and 170 F., 25 weight percent heavy naphthene base residuum of viscosity about 40-'55 Saybolt Furol seconds at 210 F., 3-12 weightpercentfpine tar, and 10-35 weight percent of at least one rubbery elastomer selected from the group consisting of natural rubber, reclaimed rubber, synthetic rubber and factice.

4. The tie seal of claim 3 wherein said coating consists essentially `of discrete, ne rubber particles, and said seal consisting fessentialy of -55 weight percent -airblown asphalt having penetration between 35 and 40 and softening -point between '130 and 140 F., 10-20 weight percent heavy naphthene base vacuum residuum of viscosity about 42,-50 Saybolt Furol seconds at 210 F., 5-10 weight percent pine tar, and 15-23 weight percen of 8-80` mesh reclaimed rubber particles.

5. A method of lprotecting wooden railways ties that support tie plates, which method consists of interposing therebetween a moldable, substantially cushionless slab comprising a rubberized asphalt composition, subjecting said slab to service pressure, forcing said composition into crevices and apertures in the area of junction of said plate and said tie, and sealing said crevices and apertures.

References Cited in the file of this patent UNITED STATES PATENTS 1,510,472 Farrell Oct. 7, 1924 1,785,251 Etheridge Dec. 16, 1930 2,021,961 MacFarlane Nov. 26, 1935 2,259,560 Glidden Oct. 21, 1941 2,273,732 Quisling Feb. 17, 1942 2,277,808 Wood Mar. 3 1, 1942 2,322,642 Jones June 22, 1943 2,433,849 Lathrop et al Ian. 6, 1948 2,470,141 Caves May 17, 1949 2,517,724 Schuh Aug. 8, 1950 2,681,877 Seymour .lune 22, 1954 2,686,009 Y Crowe Aug. 10, 1954 2,686,166 Taylor Aug. l0, 1954 2,688,005 Clayton et al Aug. 3l, 1954 2,696,452 Trepp Dec. 7, 1954 2,770,421 Wilson Nov. 13, 1956 FOREIGN PATENTS 461,175 Great Britain Feb. 4, 1937 OTHER REFERENCES Asphalts and Allied Substances, by Abraham, 4th edition, page 297. (Copy in Scientific Library.)

Claims (1)

1. AN AUTOADHESIVE AND AUTOSEALING RAILROAD TIE SEAL FOR POSITIONING BETWEEN A TIE PLATE AND TIE COMPRISING A SLAB OF AN ADHESIVE SEALING COMPOSITION CONSISTING ESSENTIALLY OF 45-65 WEIGHT PERCENT ASPHALT HAVING PENETRATION BETWEEN 30 AND 50 AND SOFTENING POINT BETWEEN 100* AND 170*F., 5-25 WEIGHT PERCENT HEAVY NAPHTHENE BASE RESIDUUM OF VISCOSITY ABOUT 40-55 SAYBOLT FUROL SECONDS AT 210*F., 3-12 WEIGHT PERCENT PINE TAR, AND 10-35 WEIGHT PERCENT OF AT LEAST ONE RUBBERY ELASTOMER SELECTED FROM THE GROUP CONSISTING OF NATURAL RUBBER, RECLAIMED RUBBER, SYNTHETIC RUBBER AND FACTICE.

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