USRE22532E - Material anb - Google Patents

Description

R P LUTZ Aug. 22, 1944.

COMPOSITE INSULATlNG MATERIAL AND METHOD OF MAKING SAME Original Filed Oct. 31. 1956 FIG. 2

lNVWTOR R. FLU rz 6% 4 Arrow/m Reluued Aug; 22, r

UNITED? 1s comosrrs;'rssmrrsomrmm;

METHOD OF MAmNG-"sAMu-q Western Electric 'Conih'anm- Incorporated; New? York, N. Y., a' corpora 2,112,445; dated s'eptember Serial No; 108,610, Octo tion tor-reissue January-28,1943, Serial-fr w materials and compositions suitable -ior-impregnating such materials and-to methods of impre hating fibrous materials, and is: a continuation in 2 part of my copending applications,SerialiNoI;

713,866, filed March 3, 193 4, and Serial No. 752,467, filed November 10,1934.

Objects of the invention are to provide materials having good non-hygroscopic andinsulat z,

ing properties for use in electrical apparatus and to provide improved compositions] and -method'sior impregnating fibrous matensm; 1

In accordance with one embodiment oi the 111- vention, a fibrous material suitable for iillingor" encasing electrical coils is impregnated with "VinsoP or a solution or Vinsol and cellulose I derivatives to insulate the coil--and '-prevent corroslon oi the electrical conductors." Other oblects and advantages the description proceeds.

A complete understanding oithe'inventlon may will appear as 1 be-ha'd by reference to the following description taken in conjunction with the accompanying drawing, in which 7 Fig. 1 is a perspective view, partlyin section, of a coil embodyin the invention;

Fig. 2 is a modified form of coil embodyin the invention; and

Fig. 3 is a fragmentary detail view of the covering for the coil shown in Fig. 2.

Referring more particularly to Fig. 1, the coil may be provided with a rectangular fibrous material or the core may be made of a phenol condensation product, of cellulose acetate, or of a phenol condensation product laced with cellulose acetate. wound in layers on the core and each layer is separated by a fibrous sheet or paper, c loth, or the like and a similar sheetls wrapped aroundthe outer layer of wire. Thewire may be bare, it suitably spaced, but preferably comprises enameled wire or wire having a fibrous insulamaterial comprising a gasoline-insoluble pine be immersed in" core 5 of Vinsol" by the HerculessPowcle'r Com 'pany. "Vinsol" is a hard dark-colored resinous wood resin, produced by extracting resinous wood a with a coal tar hydrocarbon by evaporation. exv tracting the v U I v I carbon, removing the solventand recovering the gasoline-insoluble resin as I No. 2,193,026, issued March 12,1940, to Lucius-C. Hall.

residue with a petroleum hydro? described in Patent- The convolutlons 01 wire are v of cellulose acetate maybe dissolved in 400 parts 1 of acetone 1 and the mat'erials then -mixed" to: gether, or Vinsol mayfrbe added directly to' a" plastieor less brittlematerial*-for many iisesnweight-20f acetone:

as uneconomicaLi thoroughly impregnatesthe'flbrous mate'rial mthe -mwde in this manner have-been iound to have 'a 'v'e'ry iow 'hyz ioscopiclty and *high corrosion resistance and' due to theand-lowtdielectric "cone serous-material; the" material is excellently suitedtor insulating 'coilm For some purposes a; coil mad-easdescribedabove may be dipped in'a solution' oicellulose acetateand Vinsol to provide a' 'more elastic-coverin'g for the outside oi the coil or it maybe dipped' in such. a solution without previously ciippmg it"in a solution of' the Vinsol, It has been'w found that a; solution of cellulose acetates in" acetone by" itselfhas poor impregnatingproperties-since it, in efcoil. 'lests made'kon coils high insulation resistance stant'oi the impregnated w cellulose acetate into the'flber. The addition-oi the cellulose acetateto the Vinsol raises themelt ing point'oi the composltion'*over-- that oi the Vinsol alone and the composltion'containlng the two ingredients is, 'thereiore, more'suitable-ior coils which are operated at high temperatures.

In preparing a solutionbi cellulose'acetate and Vinsol, parts '0! .vinsol 'mliy' be first dissolved in about '75 parts 'ot'aceto'neand 100 parts 1 i solutionof 1 cellulose acetate in acetone. 1

Preferably, the cellulose acetate may confstltute" an amount equal'totheamountcf Vinsol, 'al

though these materials are-soluble in all propor-* Vlnsol is. used, the property'oi causlngthe' celthe product becomes brittle and tends to'llakeu- Vinsol alone is qult'eibrlttle an'dtnds to be-" come powdery whendry; igl-lowiever, a' solution oi this materl'alwith a cellulose ester makes-a more This composition is thermoplastic" and :canbe formed lnto'sheets or articles in a" mold under as 'heatandpressure. The material can be prepared lose acetate in acetone to the posite sheet.

for molding lay dissolving the ingredients in acetone', as previously described, evaporating. the

solvent, and pulverizing the residue into particles of suitable size. In preparing this material, a

relatively viscoussolution can be used to reducethe quantity ofacetone required for the impregnating solution. It is also feasible to reduce this solution to sheets ormolding slugs by evaporating the solvent from solution contained in forms of the proper contour. For other applications, the

' cellulose ester and Vlnsol may be mixed'in powdered form, placed in a mold, and subjected to heat and pressure to consolidate the material-and oils without impaira fibrous material impregnated with cellulose acetate and with a resin which is the residue formed by extracting pine wood with a coal tar hydrocarbon, evaporating the coal tar hydrocarbon and other volatile constituents from the extract to produce a solid residue; extracting rosin from said residue with a light petroleum hydrocarbon, and separating the rosin extract from the remaining residue, which is substantially insoluble in light petroleum hydrocarhens and recovering the remaining residue.

3. A method of making an insulating material which comprises impregnating fibrous material with cellulose' acetate and an alcohol-soluble resin which is the residue produced by steaming pine wood chips to remove volatile substances therefrom, extracting the steamed wood chips with a coal tar hydrocarbon, evaporating the coal Fig. 2 illustrates a coil having a core 6 comprised of cellulose acetate or a phenol fiber condensation product faced with cellulose acetate.

The coil iswound on the core in layers and the layers are separated from each other by sheets of fibrous material. After the coil has been wound, it is impregnated with a solution of Vinsol or the coil maybe impregnated witha solution of, Vinsol and cellulose acetate. After the coil is impregnated, heads I of cellulose acetate or phenol fiber faced with cellulose acetate are adhered to the core by applying a solution of celluends of. the core and pressing the head against the core until the solvent dries. If it is desired to have a hermetically sealed coil, an outer sheet I may be applied to the coil. This sheet is made by impregnating a fibrous sheet 9 with Vinsol or a solution of Vinsol and cellulose acetate and then applying a sheet ll of cellulose acetate to each face of the impregnated sheet 9. The cellulose acetate sheets may be adheredto the impregnated sheet 9 by subjecting the composite sheet. plasticize the cellulose to heat and pressure to acetate and mold it integral with the impreg nated fibrous sheet. This procedure insures thorough impregnation of the fibrous material so that when the sheet is raw or unimpregnated fiber. In covering a coil, as shown in Fig. 2, a piece of this composite sheet is cut so that its edges will overlap when wound about the coil and the ends will abut the heads 1. A solution of cellulose acetate inacetone may then be applied between the overlapping edges and along the ends where they abut the heads to completely and hermetically sealthe coil.

- While the invention has been described in connection with particular embodiments thereof, it

will be understood that many changes and modifications may be made without departing from the spirit and scopeof the invention.

What is claimed is:

1.. An insulating material comprising a fibrous sheet impregnated with a composition of cellulose acetate and an alcohol-soluble resin having a methoxy content of about 3% to about 6% which is extracted from pine wood hydrocarbon and from which resin has been extracted with a light petroleum hydrocarbon,

said fibrous sheet having a sheet tate adhered to one face thereof of cellulose aceto form a com- 2. A method of making an insulating material which comprises adhering a sheet of cellulose acetate to one face oi. a composition comprising with a coal tar insoluble components of the residue, extracting rosin from said residue with a lightpetroleum hydrocarbon, and separating the extract from the light petroleum hydrocarbonoriginal extraction of pine wood, applyinga sheet ofcellulose acetate to one face of the thus impregnated fibrous material, and adhering the cellulose acetate sheet to the impregnated fibrousmaterial with heat and pressure.

4. a method of making an insulating material which comprises impregnating a fibrous material with a mixture of a cellulose derivative and. a

resin which is soluble in alcohol and substantially insoluble in light petroleum hydrocarbons and which is produced by extracting pine wood with a coal tar hydrocarbon to produce an extract containing coal tar hydrocarbons, volatile materialasuch as turpentine, and normally solid resinous materials, evaporating the coal tar hydrocarbon and volatile portions. of the extract to produce a solid residue, extracting rosin from said residue with a light petroleum hydrocarbon, separating the said rosin extract fromthe ,then remaining insoluble residue and recovering the said insoluble residue which has the aforesaid and desired. characteristics, and applying a sheet of cellulose derivative to one face of the impregnated fibrous material, and adhering the sheet fibrous material with heat and pressure.

' 5. A method of making, an insulating material which comprises impregnating a fibrous material with. a mixture of cellulose acetate anda resin which is substantially insoluble in light petroleum hydrocarbons and which has a 'methoxy content of between about 3% to about 6%, which resin is produced by extracting pine wood with a coal tar hydrocarbon to produce an extract containing coal tar hydrocarbon, other volatile substances such as turpentine and pine oil, rosin, and a solid residue, removing the coal tar hydrocarbon and other volatile materials to produce a mixture of rosin and said solid residue, extracting rosin from said mixture with a light petroleum hydrocarbon, and separating said rosin extract from said solid residue which has the aforesaid and desired characteristics, applying a sheet of cellulose acetate to one face of the impregnated fibrous material, and adhering thev cellulose acetate sheet to the fibrous material with heat and pressure.

carbon, and separating the rosin extract from. the remaining residue which is substantially insoluble in light petroleum hydrocarbons and re'- separating said rosin extract from said solid residue which has the aforesaid and desired charcovering the remaining residue which has the aforesaid and desired characteristics, assembling a sheet of cellulose acetate to one face of the impregnated material, and applying heat and pressure to the assembly to form the cellulose acetate sheet and impregnated material into a composite sheet.

'7. A method of making an insulating material which comprises impregnating a fibrous material with cellulose acetate and a resin produced by extracting pine wood with a coal tar hydrocar- I bon to produce an extract containing coal tar hydrocarbon, other volatile substances such as turpentine and pine oil, rosin, and a solid residue, removing the coal tar hydrocarbon and other volatile materials to produce a mixture of rosin and said solid residue, extracting resin from said mixture with a light petroleum hydrocarbon, and

acteristics, assembling a sheet of cellulose acetate to one face of the impregnated material, and applying heat and pressure to'the assembly to form the cellulose acetate and impregnated material into a composite sheet.

8. An insulating material comprising a sheet of cellulose acetate and an impregnated sheet adhered to one face of the cellulose acetate sheet to form a composite sheet, said impregnated sheet comprising a fibrous mass impregnated with a cellulose derivative and a resin characterized by freedom from wood rosin, solubility in alcohol, substantial insolubility in gasoline, a methoxy content of about 3% to about 6%, an acid number of about 100, a naphtha insolubility of about 98%, and a melting point of about 125 C., which resin is produced by extracting pine wood with a coal tar hydrocarbon, evaporating the coal tar hydrocarbon and other volatile constituents of the extract from the extract to produce'a solid residue, extracting rosin from said residue with a, light petroleum hydrocarbon, and separating the rosin extract from the remaining residue which is substantially insoluble in light petroleum hydrocarbons and recovering the remaining residue which has the aforesaid and desired characteristics. RAYMOND P, LUTZ.

Re-issue No. 22,552.

Augus t 22, 191414,.

RAYMOND P. LUTZ.

It is hereby certified that error appears in the printed specification of the above number-ed patent requiring correction as follows: Page 1, first column, line 52,after 'carbon," strike out the words "removing the solvent" and insert the same after "hydrocarbon" in line 50, same page and column; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Office.

('Seal) Leslie Frazer Acting Commissioner of Patents.

carbon, and separating the rosin extract from. the remaining residue which is substantially insoluble in light petroleum hydrocarbons and re'- separating said rosin extract from said solid residue which has the aforesaid and desired charcovering the remaining residue which has the aforesaid and desired characteristics, assembling a sheet of cellulose acetate to one face of the impregnated material, and applying heat and pressure to the assembly to form the cellulose acetate sheet and impregnated material into a composite sheet.

'7. A method of making an insulating material which comprises impregnating a fibrous material with cellulose acetate and a resin produced by extracting pine wood with a coal tar hydrocar- I bon to produce an extract containing coal tar hydrocarbon, other volatile substances such as turpentine and pine oil, rosin, and a solid residue, removing the coal tar hydrocarbon and other volatile materials to produce a mixture of rosin and said solid residue, extracting resin from said mixture with a light petroleum hydrocarbon, and

acteristics, assembling a sheet of cellulose acetate to one face of the impregnated material, and applying heat and pressure to'the assembly to form the cellulose acetate and impregnated material into a composite sheet.

8. An insulating material comprising a sheet of cellulose acetate and an impregnated sheet adhered to one face of the cellulose acetate sheet to form a composite sheet, said impregnated sheet comprising a fibrous mass impregnated with a cellulose derivative and a resin characterized by freedom from wood rosin, solubility in alcohol, substantial insolubility in gasoline, a methoxy content of about 3% to about 6%, an acid number of about 100, a naphtha insolubility of about 98%, and a melting point of about 125 C., which resin is produced by extracting pine wood with a coal tar hydrocarbon, evaporating the coal tar hydrocarbon and other volatile constituents of the extract from the extract to produce'a solid residue, extracting rosin from said residue with a, light petroleum hydrocarbon, and separating the rosin extract from the remaining residue which is substantially insoluble in light petroleum hydrocarbons and recovering the remaining residue which has the aforesaid and desired characteristics. RAYMOND P, LUTZ.

Re-issue No. 22,552.

Augus t 22, 191414,.

RAYMOND P. LUTZ.

It is hereby certified that error appears in the printed specification of the above number-ed patent requiring correction as follows: Page 1, first column, line 52,after 'carbon," strike out the words "removing the solvent" and insert the same after "hydrocarbon" in line 50, same page and column; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Office.

('Seal) Leslie Frazer Acting Commissioner of Patents.

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