US2457154A

US2457154A - Phonograph record

Info

Publication number: US2457154A
Application number: US404204A
Authority: US
Inventors: James H Hunter
Original assignee: Columbia Records Inc
Current assignee: Columbia Records Inc
Priority date: 1941-07-26
Filing date: 1941-07-26
Publication date: 1948-12-28
Anticipated expiration: 1965-12-28

Description

Patented Dec. 1948 l 2,457,154 rnoNoGmirn accom) James Il. Hunter, Bridgeport, Conn., assignor to I Columbia Records Inc., a corporation of Dela- Ware Application July 26, 1941, Serial No. 404,204

Claims. (CL 154-43) This invention relates to `a. phonograph record of the laminated type and it has for its objects the provision of a record relatively economical to manufacture having a playing surface of low surface noise" characteristic and of good wearing quality under constant use.

The above objects are attained, according to the present invention, by providing a relatively thick core adapted to substantially determine the over-all mechanical properties of the record after pressing, and a thin playing surface of l an aggregate including a binder and a first comminuted filler material having irregular particles varying in size from substantially less than a micron u p to the order of four microns in largest dimension, and a second finely-divided filler material having substantially uniform size particles of an order permitting ready dispersion thereof both upon the surfaces of and between the irregular size particles. The ratio of binder to the total amount of said fillers is such that, after pressing, the particles of the fillers are homogeneously distributed in close relationl substantially without intervals therebetween.

As the result of extensive investigation, it has.

been found, contrary to the description lof United States Patent No. 2,221,270, that the use of fillers having substantially uniform size particles of the order therein described, yield what Will be termed a brittle playing surface having a high surface noise characteristic. By the use of an aggregate including a binder as above described, comparable to concrete aggregate, i. e., different size stones, sand, and cement, a playing surface having a very low surface noise is obtained which stands up under constant wear better than the playing surfaces heretofore proposed. In addition, 'it has been found that aplaying surface in the form of an aggregate including a binder in accordance with the invention, wears the point of the reproducing needle less than any shellac type record now upon the market. This may be attributed When manufacturing the improved records in accordance with the present invention in the form of single or double face disc records, paper sheets coated with the playing surface material may be used' on one or both sides of the core material, as

Athe case may be. In the` record pressing operation carried out with the customary press, the relatively thick core serves as a mechanical support for the thin playing surface or surfaces.

Core material suitable for use in accordance with the invention is composed esentially, for example, of green slate filler, cotton flock, and a binder such as shellac or resin or both. Since the core material isemployed solely for the purpose of producing a relatively thick core to provide support for the thin playing surface or surfaces, and to establish the over-all mechanical properties of the record, its constituents may be varied, as will be readily understood. Anyone of the well-known compositions for core material may be employed for the purposes of the invention.

The following example illustrates a. preferred formula for the aggregate including the binder, to be used for the thin playing surface, parts being given by weight:

It will be observed that the shellac binder con- Calcium stearate stitutes approximately 25% by Weight of the agto the fact that the particles of the flllers used In reducing the efl'ec- I gregate. Thus, the ratio of binder to filler is substantially one to three.

After thorough mixing of the above constituents, the powdered material is appropriately applied to discs'of paper of suitable size for forming the playing surface of the records.

The diatomaceous earth is comminuted by fine grinding to produce irregular particles varying in size from substantially less than a micron up to three or four microns in largest dimension. As is well known, this material is porous in structure.

The constituent 'Iibar HH is a precipitated pigment` of titanium dioxide and barium sulfate. The nature of the chemical precipitation is such that the particles are of substantially uniform,

size and of the order of one-quarter micron.

Due to the small particle size of the Tibar HH,

.it is readily dispersed into the pores and upon the surfaces of the diatomaceous earth particles.

The amount of shellac or binder employed and the ratio thereof to filler (diatomaceous earth and Tibar HH) is such that, after pressing, the

essaies particles of said fillers are hcmesenecusly distributed in close rel-ation substantially withoutv intervals therebetween.

Qther materials may be substituted for the material Tibar an; ior example titanium dioxide A' per se or any other of the known precipitated and extremely fine fillers and the like. Also mixtures of shellac and other natural and synthetic resins may be employed, such as the natural resins conso gum and manila gum and the synthetic resins, for example, poly-vinyl acetate and its various derivatives.

A cross-sectional view of a laminated sound record made in. accordance with the present invention is shown in the accompanying drawing.

Itis to be understood that the foregoing description of a preferred embodiment is set forth by way of example or illustration and that the thin playing surface of an aggregate inclu e.

'binder may be composed ofl various ingredients and produced in various ways for the particular purpose for which it is required and that the invention is :not limited to these specific embodiv ments, except as donned in the accompanying claims.

I claim:

tively thick core adapted to substantially provide the over-all mechanical properties of the pressed record, and a thin playing surface of an aggregate includingI a binder and a first filler of comminuted diatomaceous earth having irregular d particles varying in size from substantially less than a micron up4 to the order of four microns in largest dimension, and a second chemically pre- .cipitated filler of titanium dioxide and barium sulfate having substantially uniform size particles of 'the order of one-quarter micron permitting ready dispersion thereof both upon the 'surfaces of landlbetween said diatomaceous earth particles, the particles of said llers being, after pressini.

homcgeneously distributed in close relation subst-antially without intervals therebetween.

1. A laminated sound record comprising a relaparticles varying in size from substantially less I than a micron up to the order of four microns in largest dimension, and a second iiller having substantially uniform size particles of the order o! one-quarter micron permitting ready dispersion 'thereof both upon the surfaces of and between said diatomaceous earth particles, the ratio of binder to ller being of the order of one to three so that after pressing the particles of said fillers i are homogeneously distributed in close relation substantially without intervals therebetween.

2.v A laminated sound record comprising a relatively thick core adapted to substantially provide the over-all mechanical properties of the pressed record, and a thin playing surface of an aggregate including a. binder and a first ller ci comminuted diaitomaceous earth having irregular particles varying in size from substantially less than a micron up to the order of four microns in largest dimension, and a second chemically precipitated filler of titanium dioxide and barium sulfate Ahaving substantially uniform size particles of the order of one-quarter micron permitting ready dispersion thereof both upon the surfaces of and between said diatomacecus earth particles, the particles of said fillers being, after pressing, homoseneously distributed in close relation sub--V stantlally without intervals therebetween.

3. A laminated sound record comprising a relal tively thick core adapted to substantially provide the over-all mechanical properties of the pressed record, and a thin playing surface of an aggregate including a shellac binder and a nrst filler of comminuted diatomaceous earth having irregular i. A laminated sound record comprising a rela'- tively thick core adapted to substantially provide the over-all mechanical properties of the pressed record, and a thin playingsurface of an aggregate including a binder and a nrst ller of comminuted diatomaceous earth having lirregular particles varying in 'size from'substantially less than a micron up to the order of four microns in' largest dimension, and a second ller comprising titanium dioxide and having substantially uniform size particles of the order of one-quarter micronv permitting ready dispersion thereof both upon the surfaces of and between said diatomaceous'earth particles, the ratio of binder to `filler being of thev order of one -to three so that after pressing the particles of said iillers are homogeneously distributed in close relation substan tiallyvwithout intervals therebetween.

5. A laminated sound record comprising a relatively thick core adapted to substantially provide the overall mechanical properties of the pressed record, and a thin playing surface of an aggregate including a binder and a iirst 1111er of comminuted diatomaceous earth having irregular particles varying in size from substantially less than a micron up to the order oi four micronsv in largest dimension, and a second filler o! chemically precipitated flne material having substa.n.A

tially uniform size particles of the order of onequarter micron'permitting ready dispersion thereof both upon the surfaces,y of and betweens-aid diatcxnaceous earth particles, the ratio of binder to filler being of the order of one to three so that after pressing the particles of said llers are.

homogeneously distributed in close relation substantially without intervals therebetween.

.TALES H. HUNTER.

REFERENCES CITED The following references are ci' record in the viiie oi this patenti UNITED STATES PATENTS Number Severin Nov. l2,