US1937680A

US1937680A - Moldable material

Info

Publication number: US1937680A
Authority: US
Inventors: Billings Howard James
Original assignee: Arthur D Little Inc
Current assignee: Arthur D Little Inc
Priority date: 1929-11-06
Filing date: 1929-11-06
Publication date: 1933-12-05
Anticipated expiration: 1950-12-05

Description

Dec. 5, 1933.` H; .1.B1'LLINGs MOLDABLE MATERIAL Filed Nov. 6, 1929 Y Patented 5,

.1.931.680 MoLmiLE MATERIAL Howard James Billings,

South Acton, Mass., as-

signor to Arthur DrLittle. Incorporated, Cambridge, Mass.,`a corporation of Massachusetts Apucagin November aisee. serial No. 405,145

ze: claims.

This invention relates to a moldable material having the property of combining in a plied construction under the influence of heat and pressure and to the methodv for forming and treating lsuch material. l.

'The preferredcomponen'ts of such material are wood pitch suitably treated with a gum, the fibers of the pulp and the particles of binder intimately lo distributed throughoutthe body, which is in sheet form, but the-fibers and particles arel discrete and not adhesively associated until heat and pressure is applied.

. An article formed from such material is moisture resistant and dielectric and is applicable to manynuses wherever such'qualities are" desirable. Such an article is of particular value as a core or backing for a sound recordof the type set 'forth in my copending application Serial No. 378.-- ,893, filed July L7, 192,9,in lace of the one therein described which consisted oflamin of combining and illling sheets alternately arranged.

The combining sheets for the c ore or backing of the sound record set forth inthat application 'contained shellac as a binder and hence are more expensive to manufacture than 'are sheets embodying this invention. Moreover; since a core .embodying this invention consists of lamin; each comprising fibers and a binder, it is more eiiecin my prior application, a' sound record embodying this invention will be substantially unaffected byl moisture-and otherv climaticconditions. l

One object of this invention is to provide a -moldable materiali having the `properties and structure hereinafter set forth.l Another object of this invention is to provide a 'sound' record similar in characteristics to that set forth inmy -Qcopending application but having a core which is cheaper than that disclosed 'thereinand which has a'greaterfrsistancetofwarping. While certain of these characteristics as well `as the structure and the method of making the. sound record be set forthherein, reference may'be made to such application for a fuller disclosure thereof. y 'Other objects will appear from a consideration of the following specification and of the drawing ywhich forms a partthereof andin which Fig. 1 is a diagrammatic view of a sound record plank embodying. this invention. .the various lamifn'aeA being shown as separated 4for the purpose ofclarity; 4 -f Figs. 2 and 3 are enlarged sectional views of a portion of such sound record blank' illustrating tively moisture resistant `than the core disclosed# the relation of the lamina before and after `the sound vgrooves have been formed therein; ,and

Eig. 4 is a view illustrating diagrammatically one way of making upon a paper machine a sound record embodying this invention.

, Referring to the drawing, the sound record 10 briefly paper' pulpanda, binder comprising hard-v c'omprisestwo record sheets 11 which are in the usual way, provided on their exposed faces with playing surfaces and a core 12 here shown as consisting of two lamin or sheets made in the manner described hereinbelow. Forthe purpose of illustrating oneapplioation of this invention I Ahave elected to show the 'core as comprised of two such lamin but it will be understoodthat the number thereof may be varied as desired.

The moldable material is made in sheet form on a paper machine from a composition consist- Y ing of fibrous material and a binder. The fibrous material and binder vary in proportions depending upon the type of fibrous material used, but --it has been found that the composition should contain at least sixty per cent. of binder in order to insure a material having thenecessary cohesive and 'adhesive qualities.

` The' following formula has been found to give satisfactory results:

No. 1 e Pounds y Kraft pulp 20 85"" Fibrous material 32.8%-; Unbleached sulilte. 5

Ground wood 14 l Hardwood pitch ..v `36 Binder 67.2% Ternati gum `36 Rosin 8 90 If desired the unbleached sulte and ground wood may be replaced by nineteen pounds of old newspaper. A coloring material, such as for xamplecarbon black, may be added to the mixture and with the formula above given three and onehalf pounds shouldV be used. Changes in material and in proportions maybe made and I amrnot limited to the above formula which is set forth merely as apreferred illustration.

The fibrous material and-binder are processed into a pulp in the following manner: The fibrous materials given with the yexception of ten pounds -of the kraft pulp is treatedrwith six gallons of waterand. then kneaded with the binder under the influence of heat to effect a thorough distri- Y bution of the binder over the wet fibers. This is preferably accomplished in a kneading machine of .the type in which kneading blades, rotating inwardly, work the mass of' binder land fibrous materialunder a superimposed mechanical pres- 110 sure ei'zerted by a ram fitting into the charging neck of the machine.I The whole mass is then broken down to a watery pulp containing intimately distributed discrete particles of fiber and bindenby the addition of twelvel gallons of hot water. paper mill beater, the kraft pulp previously withheld being added at this time and is now suitable for forming into sheets on a paper machine in the usual manner.

The sheets of moldable material so made must contain a binder which, under thel application of heat and pressure as in a p'ress, becomes suflicientlyiluid to coat the fibers and prevent the absorption of moisture from without and sufficiently cohesive so that the, lamin are firmly united in a solid'mass, the line of demarcation between the lamin being practically eradicated. This requirement necessitates a consideration of the physical characteristics of the binders that might be used, namely, the softening point (determined by, the ball-and-ring method in plastics which have no sharp melting.point) and thesusceptibility factor. .l

'I'he softening points of the hardwood pitch alone and of the binder set forth in Formula No. 1, as determined by the ball-and-ring method, are 180 F. and 210"V F. The comparative susceptibility of these two materials is shown by pene- The susceptibility factor, asordinarilyunderstood in this connection, is a numerical expression which indicates the response of a plastic substance to temperature changes, a material with a high susceptibility factor changing from the solid to the fluid state within a relatively. short temperature range and al material with a low 'susceptibility factor changing from the solid .to the fluidvstate within a relatively long temperature range.

A sheet made in accordance with this invention must thereforecontain a binder which not onlyv has the proper softening point but also has a low susceptibility factor so that it will become increasingly plastic, withoutactually being fluid, in the presence of the heat to which the sheet will be subjected. Such a binder will possess only the necessary amount of flow in the presence of heat and pressure tocement the laminA together and to hold them united after the heat and pressure are removed, and also to ensure a complete coating of the fibers, thus rendering themreasonably impervious to climatic actions of moisture and temperature. A

While shellacis the most satisfactory material .for this purpose, it is too high in price to be used Aas a binder, particularly when it must be the sole binder used. Hardwood pitch when fluxed with -certain gums having a low susceptibility factor, such as a manila gum (for example, ter- .nati gum vor manila nubs), I have found to -be satisfactory forthe purpose described as a substitute for shellac.

with the hardwood pitch if desired.

The hardwood pitch alone has too low a softening point and hence is too 'fluid at the molding The watery pulp is finally .flbrated in a I Copai gums or other gums having a low susceptibility factor might be used temperatures used in'carrying out this invention.` If a coreof hardwoodipitch alone were embodied in a4 soundrecord of the type set forth in my col pending application, it would, due tothis fluidity,4

flow' through the record `sheets to the vplaying surfaces, which would thereby be impaired' and rendered more or less wholly unsulted for playing.

The manila gums, on the other hand, 'have a low susceptibility factor which causes them to become increasingly plastic; without actually melting, through-a relativelylong range of temperaturel in the presence of the required heat but have tool possessed by the manila Jgum. For this reason 'l I have found'the above-recited formula to be satisfactory.

I make a final adjustment of the softening point to the desired level by adding to the manila gum-hardwood pitch mixture a small amount of rosin. I attribute no properties to this rosin other than the .modification of the softening point and it is conceivable thatl other grades of hardwoodl pitch could be used which would Arequire the addition of little or no-rosin.

The mixture made in accordance with' the above f ormula has therefore, dueto the presence of the fibrous material, toug' ess and flexibility and, due tothe presence of the inder, the faculty of flowing freely under the heat and pressure to which it iis subjected and a low susceptibility factor. y In the manufacture of sound records and other 'articles the compound above described is used asa core, having on eachv` outer face a record sheet 11 intowhich the sound grooves are formed by the use of -heat and pressure in a die in the usual manner. The record sheets may be composed as have substantially the following formula:

No. 2- v y Pounds ShQllaG 64 .'I'hermoplasticmaterial.{Roslin 6 Kraft pulp 15 Fibre Unbleached sulflte.. 4 1 Ground Wood 13- Clay 20 Fm and color '-{carbo'n .b1ack- 3% The various materials are treated in the manner above described with reference to the core material and formed into sheets. The formula may be modified in various ways both as to materials and proportions. Thus, in place of shellac and rosin, shellac alone may be used, or other" resins or thermoplastics may be used, either alone orin combination, if suitable for a playing surfface. Other fillers, as for example, graphite may wet method the compositionis ground in water -disclosed, in my copending application or may l 1,os7,cso forming a paint which is applied as a liquid to mesheetsbymeasczabmnormsnyaesired mannerandsetsupondrying.

vOne of making a sound record is to cut from the coreand record sheets discs which are led assshown in Figfi of the drawing aft'er having been thoroughly dried to expel any free moisture therein. then placed in a press' betweenstampers bearing tbe sound grooves. 'I'hese stampers are each mounted on a platenor die through which steam or water may becirculated to raise or lower the temperature of thematerial in the press. The

, press is then closed to bring the stampers into contact with the record sheets, and held in.` that positionfor twenty seconds without exerting the iullpressure. During this period steam is circulated through the platens or dies under a pressure of approximately eighty to one hundred pounds per square inch.- Pressure isthen ap plied for a period of fifteen seconds (thirty tons in lease of .a record blank ten inches in diameter) while the circulation of the steam continues. The steam is next shut off and cold water circulated until the record blank is cold whereupon. the cold water is-shut oth-the press opened and the record-removed.

The heat applied at the first stage ofthe above operation causes the moldable material forming 'thevarious sheets to become plastic so that under the influence y of the heat and pressure. at the following stage the binders will ilow, coating the f fibers and combining the various sheets into a unitary In this connection it will be noted that the softening point andsusceptibility factor of the binder in the core sheets has been so set that the binder therein lwill notexude to any appreciable extent into the record sheets and `thus impair the playing surface, but will how- `ever unite the core sheets to the record sheets. In the record blank made according to the inventiondiscled in my copendingapplication plain 'l binder free filler sheets were inserted between the combining sheets of the core and the record `sheets; this however is not necessary according to the present invention by reason of the materials used in the formation of the core sheets. The binder of the core sheets has asomewhat higher softening point than the binder of the record sheets but has a low susceptibility factor so that the binder of the core s heets will not penetrate therecord sheets to the playing surfaces thereof.

The edges of records made by my process may be smoothed as desired .by simple abrasion. No special type of apparatus is necessary for this purpose and there is no need for much precaution against breaking the records as they are very resistantto shock. When the records aresoabraded, or when their edges are cut with a knife, it will be observed that the record acts as a unitary structure rather than as a\series of laminations; the lamellar structure possessed by the parts before being united in the press having substantial! Aly The grooves in 'theplaying surface are produced and formed in `the` manner and of the structure set forth in detail in myv copendingapplication as-will appear from Fig. 3 of the,

drawing. The sound records so produced like those disclosed in my copending application are much lighter than the sound records commerlcially manufactured at the` present time, are Ytough and not easily frangible. They can therefore be economically transported or sent through the'mailssin the necessityvv of expensive pack- The assembled discs are* ing does not exist. Cne of these records may be dropped upon the floor without injury to the playing surface, may be bent, snapped or subjected to shock and will retain its original condition without developing any surface cracks or hair lines in the playing surfaces which would have a deleterious effect upon its use as a sound record.

A record, ten inches in diameter, comprising two record sheets and two core sheets weighs tween three and one-half and `four ounces, whereas other well known records of 'the same diameter, now on the market, weigh ironijseven to seven and a half ounces each. 'I'he record sheets used are between twenty-three and twentyfour points thick while the core sheets are ap.l

proxmately twenty-eight and a half points thick making a total thickness. of about one-tenth of lanfinch. .While these dimensions have produced records which have proven to be very satisfactory, it is, of course obvious that they may be altered f'as desirediand the number of-core sheets inseparately as in the method above described I have found it desirable to unite part or; all of the record and core sheets directly upon a paper 'machine of the' multicylinlder type. y For instance s a machine having two cylinders may be used .as

vsuggested in Fig. 4. The core sheet 15 and the record sheet 16 are united .at the rollers 17 in the .usual way so that the result is a two-ply sheet,

one ply being a core sheet made according to Formula No. 1 with a Vbinder of hardwood pitch and manila g'um and the other ply being a record sheet made4 according to-Formula No. 2 with a binder of i shellac and rosin or other thermoplastic material capable of providing' a suitable playing surface. vDiscs are then cut from the twoply sheet driedl, assembled with the surfaces of the record sheets exposed and treated in a press in substantially the manner described above. The number of plies may-be. varied by using a paper machine having lmore cylinders. Thus I have found that a very ,satisfactory record can be made by using a four cylinder machine to produce four ply sheets consisting of onerecord sheet.

ply and three core sheet plies and assembling the discs cut therefrom to form an eight ply record. f s

The moldable material having a binder of hard-l wood pitch and manila. gum may be subjected to heat and pressure with or without the moldable material having a binder of shellac and rosin to form poker chips, buttons, tiles, insulating panels and like moldable articles which are-required to be toughand can be made from laminated sheets. In all these articles the binders of the various lamin, under the molding heat and pressure, fiow to coat the fibers therein and bind the lamin in one unitary structure. f

From the above description of the steps of making and molding'this material it will be apparent that it responds to the molding ystep in a very different way from that in which paper saturated .with the above or anyY other binders would respond. This follows from the fact that in the formationA of the sheets the iibers and particles of binder are intimately distributed through the mass but remain substantially independent antl the fibers are felted in the presence of the binders under the application of the molding heat and pressureswhereas the fibers' of a saturated sheet are of course already felted independently of the saturant and thus when the moldingV heat and i5;

, terial and binder consisting of hardwood pitchY pressure are applied the result is a hard frangible structure.

It will be noted that the treatment of the sheets of moldable material embodying this invention includes the step of drying the sheets thoroughly before `placing them in the press. Such treatment however does not require that the sheets4 terial and a binder consisting of hardwood pitch l and a gum having a low susceptibility factor, said binder constituting at least #sixty per cent of the moldable material.

2. Moldablematerial comprising fibrous maand manila gum, said binder constituting atleast sixty per cent of the moldable material.

3. Moldable material comprising fibrous' material and binder consisting of hardwood pitch and manila gum, said binder constituting at least sixty per cent of the moldable material, the fibers and pa'rticles of binder being intimately distributed through the material as" discrete particles.

4. Moldable material comprising fibrous material and binder consisting of hardwood pitch and manila gum, said binder constituting at least sixty per cent of the moldable material, the binderv being thoroughly distributed as particles over the surfaces of the individual fibers and being independent thereof.

5. A laminated sheet of moldable material one lamina comprising fibers and a binder including shellac and another lamina comprising fibers and a binder including hardwood pitch.

6. A laminated sheet of moldable material one lamina comprising bers and a binder including shellac and another lamina comprising fibers and a binder including a gum having a low sus'- ceptibility factor.

7.An article consisting of lamina: of moldable material subjected to heat and presure, the lamina: comprising fibers and a binder including hardwood pitch 'and.manila gum, said binder coating said fibers to prevent their exposure to moisture and uniting sai'a 1amina..

8. An article consisting of lamin of moldable material subjected to heat and pressure, each lamina comprising fibers and at least sixty per cent of binder, said binder includingr substantially equal quantities of hardwood pitch and manila gum coating Said fibers to prevent their exposureto moisture and uniting said laminas.

9. An article consisting of lamin of moldable material subjected to heat and pressure, each laminacomprising fibers and at least sixty per cent of binder, said binder coating said fibers to prevent their exposure to moisture and uniting said lamin.

10. A sound record consisting of lamination of moldable material the outer lamina: comprising fibers and a binder of thermoplastic material suitable for la playing surface, andthe inner lamin comprising fibers and a binder including l hardwood pitch and manila gum.

lhaving playing surfaces and a core consisting of lamin, each comprising fibers and a binder including a hardwood pitch having a relatively low susceptibility factor, said binder coating said fibers to prevent their exposure to moisture, uniting the lamin of the core and uniting the core to the record sheets.l y,

14. The methodl of treating moldable material which method consists in the followingsteps, making a sheet of moldable material comprising fibrous material and a binder consisting of hardwood pitch and a gum having a low susceptibility factor, the fibers and particles of binder being intimately distributed through the sheet as discrete particles and subjecting said sheet to heat and pressure'whereby the binder is caused to flow, coating the fibers and exuding to the surface thereof.

15. Themethod of treating moldable material which method consists in the following steps, making a sheet of moldable material comprising fibrous material and a binder consisting of hardwood pitch and a gum having a low susceptibility factor, the fibers and particles ofv binder being intimately distributed through the sheet as discrete particles, cutting blanks from` said sheet, I assembling said blanks in layers and subjecting said blanks to heat and pressure whereby the binder in the blanks is caused-'to flow, coating the fibers therein and uniting the layers into a unitary structure. f'

16. The method of molding a laminatedsound record in a press, said record including outer lamin each of which comprises fibrous material and a thermoplastic binder, and inner lamin each of which comprises fibrous material and a binder consisting of hardwood pitch and a gum having a low'susceptibility factor, which method includes as steps uniting an outer lamina and at least one inner lamina to form a multi-ply blank, assembling two such blanks with the inner lamin in contact and subjecting them to heat and pressure sufllcient to cause the binder in the lamin to fiow and unite the blanks into a unitary structure.

17. A record blank consisting of laminations of moldable material, the outer lamina comprising fibers and a binder of thermoplastic material, the inner lamina comprising'fibers in a felted' structure and a binder and a playing surface including a binderon the outer lamina adapted to receive and retain record grooves. the binder of the inner lamina having a higher melting point.A

than the binder of the playing surface, said fibers r and binder being intimately associated, land capable of flowing under heat and pressure.

18. A record -blank consisting of laminations of moldable material, the outer lamina comprisingl fibers and a. binderincludjng shellac and provid-A ing a playing surface adapted to receive and retain record grooves,and the inner lamina comprising fibers and a binder including a hardwood pitch Y f f, 1,987,680

having a low susceptibility factor, said fibers and binder being intimately associated as discrete particles. Y

19. A record blank consisting of laminations of moldable material, the outer lamin comprising ilbers and a binder o! thermoplastic material and providing a playing surface adapted to receive and retain record grooves, and the inner lamina: comprising bers and a binder intimately 20.` A record blank consisting ot laminations of moldable material, the outer lamin'comprismg fibers and a binder of thermoplastic material and providing a playing surface adapted to receive and retain record grooves, and the inner lamin comprising fibers and a binder intimately associated as discrete particles, said binder including a hardwood pitch having a low susceptibility vfactor and present in an amount sufl cient to coat said bers and to unite the inner lamin to each other and also to the outer lamina when the record blank is subjected to heat and pressure.

HOWARD JAMES BILLINGS.

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