US1727040A - Duplicate sound record and process of making the same - Google Patents

Description

Patented Sept. 3, 1929.

UNITED STATES ,1,12'7,040' PATENT OFFICE.

LEO RUSTEIN, OF NEWARK, NEW JERSEY, ASSIGNOR TO CELANESE (JOZRIIPORA'LII )Ill OF AMERICA, A CORPORATION OF vIDIEILAWARE.

DUPLICATE sounn aEcoan AND raoonss or MAKING THE sum No Drawing.

This invention relates'to improved, duplicating sound records, tablets, disks or other bodies to be used in sound recording and sound reproducing machines, of tou h, flex,-

ible, permanent material, capable o receiving and retaining an impression thei'eon and an accurate copy of the matrix, containing no ingredient which will evaporate or distort or otherwise injuriously affect the permanency or value of the record surface, at the same time practically non-inflammable, and

this invention relates to the production of a duplicate sound record of this improved, im-

pressionable material.

Sound records made by my improved process are superior to those heretofore made in the respects, firstly, that the obtained impression is provided with a true cast surface, the material having no tendency to alter in composition, condition or form, and there-- fore retaining the record impressionunimpaired in accuracy and tonal qualities for an indefinite period; and secondly, that the record can be made of less thickness and lighter weight than has been customary heretofore, with perfectly solid and homogeneous I walls, there being no tendency in the finished record to crack, flake, peel or warp, or to soften at normal summer temperatures.

By my composition a record mass results which has the desirable properties of flexibility, toughness, elasticity, resiliency, Waterinsolubility andnon-inflammability, possessin also great tensile'strength, and hence satis actory wearing qualities combined with desirable accoustic and sound reproduction properties. I

Sound records used for phonographs,

gramophones and similar apparatus glve 4.0 blurred, indistinct and impure tones after a very short use. {,Ihis is usually due to m1cro scopically smallinjuries' to the edges of the sound grooves,- or' to the sound re roducmg stylus cutting into the grooves t emselves 4.5 from the brittleness or softness of the foundation 'material of shellac, rosin, pitch, as-

. phalt andthe like, usedfor making such 's'oundrecords. -Mar(iiyattemp{tshavebeenmade to overcome. this rawbac by incorporating in the quantities in this connection, but it has its foundation materiail suclfipliiogucts. as celluloid xylonite','p 'xy in, g a 't durated gelatin, vulcam t e and ebonite, which. materials,however have proven unsuitable n" man re ects. elluloid' which has been rates, propio'nates, hthal ates and benzoates, particular y recommended, gradually changes,

Application filed February 24, 1923. Serial No. 621,109.

in shape due to volatilization of camphor and camphor substitutes contained therein, resulting in distortion of the record and impairment of its tonal qualities. Celluloid is also highly inflammable." When celluloid shrinks, its tension then becomes so altered as to warp the record; Furthermore, celluloid is too hard, and produces shrill, harsh ltones.

Shellac at the present time is used in larger limitations. Shellac has desirable properties of thermoplasticity, softening at a temperature slightly above the temperature of'; boiling water and being sufliciently rigid at ordinary atmospheric temperature to render sound waves made thereon, quite durable. I But'shellac is a natural product of varying composition and propertie's, and subject to extensive adulteration. ,It must be imported from long distances, and is subject to marv ket manipulation. In recent years the cost of' shellac has risen to a point where its use is almost prohibitive, and forms a menace to the continued expansion. of this industry. While many substitutes of shellac have been brought forward and patented, the majority of these are lackingin the desirable property of thermoplasticity, or are obtainable in. insufficient commercial quantities and at a pro hibitive price. I

Synthetic resins such as the phenol-aldehyde condensation products, while admirably suited for general molding purposes, when used as phonograph record masses, require to long a time in the impression molds. to render their use in sound'records useful on account of materially diminished speed of produc- -tion.- When it is remembered that a comfor the production of suclr sound records is r apparent. I I I As the result of my researches, it has been found that excellent phonograph sound records mayvbe manufactured by a malsifiin which cellulose esters of reduced infla abilit are used through the record mass, the specific cellulose ester which Iprefer' to employ being the cellulose acetates, although the use of other cellulose esters of a similar nature and degree of infiammability, such as, for example, the cellulose formates, buty- "ould fall withint e scope guy invention r10 when used for this purpose. B my invention, record bodies are-produce wanting in the undesirable properties reviously mentioned, but of the requisite egree of tough-- ness coupled with a sufiicient degree of hardness, readily workable through the malaxating rolls and on the steam table, and resulting in the production of a record wherein the versed in the art, in order to have a faithful reproduction of music or of the voice, the impression upon the master record must reproduce in the minutest detail the micro scopic sound undulations, otherwise the reproduction sounds mufiled and possesses other disagreeable properties.

I employ in place of the shellac normally used inphonograph record masses, an organic ester of cellulose such as cellulose acetate, in conjunction with a substantially non-volatile organic plastifier, employing for this purpose an allryl substituted carbocyclic sulfonamide, such as methyl or ethyl substituted benzene-, toluene-, or xylcne-sulfonamide, either alone, together, or in conjunction with triphenyl-, or tricresyl-phosphate. The amount of cellulose ester and plastifier required and the specifieplastifying component to be selected, willdepend upon the absorptive capacity and other physical propertiesand amounts of inert material present in the record mass, and the temperature, pressure and treatment to whichthe mass is to be subjected in the various steps leading to record formation, t3- ether with the properties desired in the finlshcd record. Of the alkyl-substituted carbocyclic sulfonamides, I have found monoethyltoluenesulfonamide and monomethylxylenesulfonamide to give satisfactory results in phonograph record mass manufacture.

In producing a sound record composition according to my invention I first weigh out the desired amounts of eac of the inorganic filling materials such as clay, barytes, gypsum, k-ieselguhr, mica or red iron oxide, to which is usuallly added in a manufacturing way, a proportion of waste record material from previous manufacture and ground records,'this mixture being then mechanically mixed to a homogenous, finely divided powder. Coloring matter as lampblack, and binder as finely divided cotton flock may then be incorporated by mixing, after which any amount of powdered shellac, in quantity dpending upon the amount of organic cellulose ester required, is added, and mixing con- .sound record composition.

tinned until a mass of uniformity in appearance to the eye results. Finally the uninflammable cellulose ester with a plastifier is added, there being no volatile solvent required in the entire mixture, and mixin continued until the powder is apparently omogeneous. This powder is then placed on the softened on the steam table, rolled into a ball,

inserted under the reproducing matrix, and steam and pressure then forms the finished record, which, after removal, trimming'od the burr-on the edge, becomes the finished record of commerce. those skilled in the art, that the proportions of filling materials, coloring matter, binder,

and cellulose acetate or other organic ester of cellulose, and non volatile cellulose ester plasticizer employed, will vary. depending upon the heat, pressure and time the mass rea It will be obvious to mains on the malaxating rolls, and the heat,

-pressure,-and time of imprint in the record forming presses. In general, the larger the proportion of lnertmaterial to plastifying components, the greater heat and pressure will be required to form the finished sound record, and the less the tensile strength, ten

aclty and suppleness of the record will be. 1

Are a plastifying component for the organic cellulose ester employed, I may employ any non-volatile roduct which works harmoniously with s ellac or shellac substitute, or I may omit the use of a; cellulose ester plas tifier entirely, and depend upon the shelllac and cellulose ester for the plasticity of the I einplo an amount of cellulose acetate and. plasti er forth'e same in amounts from 25 percent to 50 percent of the weight of the completed batch, 'and depending upon the amount of shellac also present, a specific example of a satisfactory mixture embodyingmy invention being as,f0llows:- To 100 pounds of finely ground record stock from which the paper. from the labels has beenremoved, and the iron taken therefrom elec'trically, is added 100 lbs. rotten stone, 75 lbs" china clay, 40 lbs. mica, 5 lbs. 'lampblack, and 10 lbs; cotton flock, and the mixture thoroughly intermingled. There is.

then added 70 lbs. finely ground orange shellac and 50 lbs. cellulose acetate, 20lbs. commercial alkyl toluenesulfonamide, 10 lbs. triphenyl phosphate,.themass being then rendered homogeneous in appearance by further mixing. This mixture is then transported to the mixing rolls and -manipulated until the mass has sheeted, when it is marked out into individual record masses, softened on the steam table, placed under the reproducing matrices, heat and pressure applied to the record mass, when a commercial record results. The manipulation of this mixture on the malaxating rolls, naturally differs from that in which the plasticity is entirely due to shellac. In general, less'time and a lower steam pressure is required, resulting in greater production per unit working force, an notable coal saving.

Records produced asabove have an unusually high tensile'strength, give sound reproductions remarkable for their fidelity and sonority, are less liable to breakage, not so prone to soften at elevated temperatures, an are somewhat lighter in weight, due to the added strength of the cellulose ester, the

diameter of the record may be diminished.

In the illustrative formula above given, satis'factory results are obtained with 50 pounds steam pressureo'n the malaxating rolls, and from 50 to 60 pounds steam on the steam table where the record is formed from the plastic mass. The record may be colored black with lampblack, or if large amounts of red iron oxide be used, the finished record will be of the corresponding color.

It may be mentioned that while it is old to make sound records from celluloid or nitrocellulose, or to provide such records with a coating of celluloid or of nitrocellulose, or to coat phonographic records with an extremelythin film of celluloseester preparatory to the impression of the phonetic wrlting by applyin a cellulose ester in a volatile solvent as a cglorhydrin; and while it is old to use such materials as paraflin, chlorinated fatty acids,

or salts thereof in conjunction with cellulose acetate for this purpose, all day of February, 1923.

such combinations have the drawbacks ofeither eva oration of camphor or camphor substitute rom the mass, or the splitting off of chlorine from the chlorine-substituted compounds used as adjuncts to the cellulose acetate, or of softening the record mass by the introduction of paraflin or other fatty or waxy materials acting similarly all these, but what I do claim and desire to secure by Letters Patent is I 1. A- composition of matter suitable for sound record production, consisting. of acetated cellulose and alkyl-substituted carbocyclic sulfonamide plasticizers of the same, shellac, fillers, coloring matter and cotton flock, substantially as described. I

2. A composition for phonograph records comprising a mixture of china clay, barytes, rotten stone and iron oxide, with a relatively small amount of lamp black as a coloring matter, and cotton flock as a binder, and from 25 to 50 percent of the weight of the finished" mass of plastifying material consisting of cellulose acetate with alkyl-substituted carbocyclic sulfonamide plastifier therefor and shellac. j

3. A composition comprising a mixture of 100 stone, 100 pounds finely groun record mass, 75 pounds china clay, 40 pounds mica, 5' pounds lamp black, 10 pounds cotton flock, 70 pounds orange'shellac, 50 pounds cellulose acetate, '20 pounds commercial alkyl-substituted toluenesulfonamide, and 10 pounds triphenyl phosphate.

i 4. A. composition for phonograph records comprising fillers, coloring matter, cotton flock, cellulose. acetate, alkyl-substituted carfor phonograph records ounds rotten bocyclic sulfonamide, shellac and non-volatile 8 organic ester solvent. I This specification signed this twenty-third LEO RUTSTEIN.

I disclaim