US1905827A - Floor covering - Google Patents

Description

April 25, 1933. I E LIS 1 1,905,827

FLOOR COVERING Filed Nov. 12., 1926 TREAD 0F NWROBELLULDSE DR ETC, CDMPDMUONJ FELT ETC. SUPPORT.

m'nocELLuLosz an. TREAD.

FELT ETC. SUPPORT.

3 PRMER can-nus.

Fig.2.

gwwmtor 5% k 1 WM,

5 rious ethers of cellulose.

I Patented Apr. 25, 1933' UNITED STATES PATENT .orl-" ca GARLETON ELLIS, OF MON'ICLAIR, NEW JERSEY,

TO REZYL CORPORATION, OF NEW YORK, N. Y., A CORPORATION OF DELAWARE FLOOR COVERING Application filed November 12, 1926. Serial No. 148,112.

This invention relates to floor coverings and relates in particular to floor coverings containing cellulose plastics, cellulose nitrate or acetate, and also the va- The invention will be illustrated by compositions in which nitrocellulose is an essential component.

The drawing illustrates floor coverings made in accordance with the present invention, in

Figure 1, a section through such floor covering; and in Figure 2, a section through a modified form of floor covering.

Floor coverings of the linoleum type, or those made from a .felt base saturated with asphalt, the upper surface of which is printed in various designs, have certain disadvantages which need not be enumerated here. These products have as an essential constit uent of the surfacing material a boiled oil or drying oil component. In the present invention it is an object to employ as a binder or carrier of pigment a nitrocellulose plastic in lieu of the boiled oil material. i Floor coverings of the so-called rug type made from linoleum composition or saturated felt base, should have the property when rolled out on the floor, of flattening and not show any tendency at the corners to curl. They should be of a character which permits rolling and shipping without cracking. Nitrocellulose, especially that, type which forms solutions of high viscosity forms a tough finish on the surface of a floor covering, but when used as the sole component of such surface is too hard and slippery and also causes the floor covering to curl. cases these tend to lose their eflicacy after a time.

Rugs surfaced in this manner with nitrocellulose also have the disadvantage of being very readily inflammable, and in the present invention it is an object to obtain a floor as for example,

If plasticizers are added, in many h covering containing nitrocellulose,'with the fire hazard reduced to a minimum. I

In carrying out the present invention it is desirable not to employ nitrocellulose throughout the floor covering, but to employ it only as a surfacing and permitthe under portion of the rug to be made of cheaper materials. Thus, the under stratum may be prepared by saturating the so-called felt base with-asphalt of a somewhat rubbery and flexible character. For this purpose petroleum oils and residues may be blown with air at a temperature of around 500 F. until a pitch or asphalt of the proper consistency results, and the felt, cloth, burlap, jute, paper, or other material impregnated therewith.

As an oily surface makes it difiicult to secure adhesion of the nitrocellulose, it is desirable to employ asphaltum or blown asphalts and pitches. which are as free as possible from oily substances.

Even when repared in this manner the bondin effect etweenthe nitrocellulose and the un er stratum may be weak, and in such cases it is desirable to employ an intermediate layer of cement. 'Thus, it is possible to a ply by means of coating rolls a paint composition containing ordinary linseed and tung oils and resin, together with a pigment or filler and the like, and alsuch as whitmg, ochre, low this coating to dry and form the priming coat as it were for the nitrocellulose ASSIGNOR, BY MESNE ASSIGNMENTS,

acteristics of viscosity and working quali-" ties, and in making floor coverings employing pyroxylin I may use nitrocellulose of igh or low viscosity, or preferably mixtures of nitrocellulose of high and low viscosity.

In preparin a nitrocellulose taining a consi erable amount of ground wood, cork, and the like, the high viscosity nitrocellulose enables a better mix ing and kneading effect to be secured, but it lplastic conller such as does not supply a large proportion of binder. The high viscosity nitrocellulose may be regarded as simply distended in the solvent which may be employed, giving the appearance of body or substance, but as a matter of fact, furnishing very little real binding quality. The low viscosity nitrocelluloses are weaker but can be used in, much higher concentrations, and therefore by employing the high viscocity nitrocellulose to obtain kneadabllity and strength, and the low viscosity nitrocellulose to yield greater nitrocellulose content, -I propose to obtain new and improvedresults in the commercial production of floor coverings.

With the nitrocellulose I may employ a resinous substance if desired, such substance giving additional body and in the case of certain synthetic resins which I shall later describe concerning what may be termed a protective influence on the nitrocellulose and improving its resistance to alkali. Since linoleum and other floor coverings are frequently subjected to the action of soap and water, and since nitrocellulose by itself is quite easily affected by alkalipthe addition of a protective resin is of cdnsiderable importance in some cases.

The viscosity and strength 'of nitrocellulose is very quickly altered by contact with alkali. For example, high viscosity pyroxylin such as celluloid cotton may be transformed into a low viscosity product by treatment in solution with a small amount of ammonia. On standing for a few hours in contact with the ammonia, the viscosity instead present of being represented by the viscosity designation 50 or seconds, may be, for example, reduced to a low viscosity cotton of the A; second type. Methods of making the low viscosity cotton do not form a part of the invention, but I may use such pyroxylin, whether obtained by chemical methods; by heat treatmentof nitrocellulose, by pretreatment of the cellulose fibre, or by s cial methods of nitration. In any event, t5: sensitiveness of nitrocellulose to alkali, such as would be present in soap and water used for washing the surface of a nitrocellulose floor covering, is such thatprotective means are generally required, and the synthetic resins referred to above may be employed for this purpose.

A series of resins having a protective influence on nitrocellulose in lacquers, and the like, are set forth in several of my copending applications, 142,532 and Serial No. 144,647. In the latter .case I have stated that by the incorporation with a mixture of or solution of nitrocellulose and such synthetic resins of various fillers, as for example, ground cork, wood flour, and the like, floor coverings or linoleum substitutes may be made. It is also stated that floor coverings made from such a duplex such for example as Ser1al No.

Glycerol.

binder may be printed or inlaid in colors contained in a composition comprising said binders. v

A series of such protective resins. set forth in Serial No. 142,532 are the following, proportions parts by weight:

Glycerol 94 Phthalic anhydride 160 Fatty acids of linseed oil 80 Heated to 250 C. for about 2 hours. Light brown resin, acid number 20.2 compatible with nitrocellulose and soluble in butyl acetate.

(B) Oottonseed phtkalz'c glycem'de resin Glycerol 94 Phthalic anhydride 160 Fatty acids of cottonseed oil ..v 80

Heated to 240 C. about 4 hours. Li ht brown resin, acid number 22.4 compati le with nitrocellulose and soluble in butyl acetate.

(0) Blown rapeseed phtl ialz'c glycem'de resi/n Glycerol 94 Phthalic anhydride 160 Fatty acids of blown rapeseed oil 80 Heated to 260 C. for 2 hours. Dark brown tough resin, acid number 20.6 blends well with nitrocellulose.

(D) Soy a bean phthalz'c 'glyceride resin GlyceroL 94 Phthalic anhydride 160 Fatty acids of soya bean oil 80 (E) Benzoic glycemde [Benzoic acid 98 Phthalic anhydride 118 Glycerol 94 Heated to 230 C. wit hour. A vacuum of 28 inches was t 11 applied and the temperature slowly raised to 290 C. Product is a pale slightly tackyl resin of acid number 16.6, soluble in ct yl and butyl acetates and compatible with nitrocellulose. (F) Benzoic nitro-benzoio Phthalic gZg ceride resin 1,

Phthalic anhydride Benzoic acid containing about 10 per cent p-nitro-benzoicacid Heated to 280 C. in 2 hours. Dark colored resin, acid number 18.8.

Phthahc anhydride 160 (G) C'astor-oz'l phthalz'c glycol resin Mixture of about equal parts ethylene and propylene glycols 104 Castor oil 80 Heated to 240 C. in 1% hours. Pale, soft,

sticky resin, acid number 15.3. Soluble in butyl acetate and compatible with nitrocellulose.

(H) Uastor-oz'l phthalic gZg cerz'de resin Glycerol v 94 Phthalic anhydride 160 Castor oil 80 free fatty acids of vegetable oils (viz, Ex-

amples A, B, C, and D The term protective resins as hereinafter used is intended to cover resins made from polybasic acids and polyhydric alcohols, such as those of the phthalic glyceride type, which resins also include a fatty oil orfatty oil acid. Resins of this character incorporated with nitrocellulose of high or low viscosity, or mixtures of these, and with the further addition of a plasticizer, in some cases, may be admixed in an appropriate solvent with.fillers of quite varied character, including those above mentioned, and various fibrous substances, such as wood pul sawdustj'bagasse, exploded wood, and the li e. Pigments may be added or substances which neutralize acidity. In the present invention I preferably employ aliantacid or neutralizing substance such as chalk, carbonate of lime, zinc oxide, and the like. When pleasin color effects are desired, zinc oxide may e employed in considerable proportion, strong lakes or other pigments being added to tint to the requisite shade. The fatty acids which maybe employed in the production of resins include the following as set forth in application, Serial No. 144,647 the fatty acids derived from the various animal and vegetable fats and oils including corn, cottonseed, linseed, tung, castor, rape, fish, lard, tallow, peanut, soya bean oil, and the like and mixtures ofsuch fatty acids.

Since a floor covering must be made chea 1y, it is not always feasible to em by t e highest grades of nitrocellulose, and I preferably employ nitrated alpha cellulose, or nitrated wood flour, or similar nitration products derived from cheap materials which While such procedure would not be appropriate in the manufacture of smokeless owder as requisite stability probably coul not be maintained, the same restrictions are not imposed in the case of a floor covering beare not necessarily clean' or pure cellulose.

cause the latter may contain a large proportion of whiting or zinc oxide as antacid pig terials aids in making a product of low cost wishout tending to involve increased fire hazar The high degree of inflammability of nitrocellulose may be better reduced b the in corporation of a synthetic resin an may be further reduced by the addition of such substances as triphenyl phosphate or tricresyl phosphate. These act as plasticizers and tend to increase the flexibility and yielding qualities of the nitrocellulose.

By incorporation of synthetic resins as aforesaid and a plasticizer such as tricresyl phosphate, not only is the inflammability greatly reduced, but furthermore a floor covering may be produced which does not curl at the corners. This is of the utmost importance as a floor rug which lifts from the floor at the corners, or which buckles seriously is highly objectionable. The synthetic resin, therefore, in addition to its protective effect on the nitrocellulose against alkalies, may be regarded as a flattening agent.

Additional fire resistance may be secured by the incorporation of fillers having water of hydration, for example, calcium sulphate containing water of hydration. Such a filler has a considerably greater suppressing influence on inflammability than substances such as ground cork or wood flour.

A filler material, therefore, may advantageously consist of:

(1) An antacid pigment such as zinc lose, synthetic resin and plasticizer, as indicated above,by kneading in a powerful machine, as for example, a Werner Pfleiderer mixer. The composition may then be sheeted onto a saturated felt base or other lower stratum. For example, this may be carried out on millin rolls or differential rolls b running the s eet of saturated felt throug the rolls while the latter are kept charged 130 with nitrocellulose plastic. By adjusting the space between the rolls a thin or thick coating may be applied. If one of the rolls is operated at a speed greater than that'of the other, a differential effect results which gives a smoother and more polished surface to the sheeted material than is obtained with rolls running at the same speed.

Finally, should it be desired to give to' the surface of this sheeted material a high finish or gloss, the sheet may be coated with av nitrocellulose synthetic resin solution such as those described in various of my copending applications. See for example, Serial No. 142,532 and Serial No. 144,647. Furthermore, this final coat if desired may have pigments or dyes added. If the clear solution only is applied, the color of the sheeted material beneath is enhanced and a surface more or less glossy, depending upon the amount of the resin present, results.

The operation may be carried out continuously by having the saturated felt material feeding from a source" of supply through the feeding rolls, there receiving its coating or sheeting of the plastic and finally passing through the finish-coating apparatus where the final nitrocellulose finish is applied. This yields a three layer effect, the lower layer (when the rug is on the floor) being the saturated felt, the second layer being the sheeted nitrocellulose plastic, and the third layer being the film of nitrocellulose resin and so forth. The latter coating, as indicated, may be omitted if desired. Intermediate the sheeted material, as previously noted, there may be a layer or cementing coat in order to more firmly attach the sheeted material to the saturated felt. On the under side of the felt there may be a thin coating of a high melting point wax, as for example, montan wax, containing a small amount of iron oxide or other pigment. The latter being in contact with the floor prevents any asphaltic substance from causing The under. side, how-- ever, may if desired, be finished with a burlap or cloth baging.

Another form of the invention is that which consists in treating saturated felt as aforesaid. with a coating of pigment and drying oil, for example, printing a suitable design in colors on the surface with colors ground in varnish. After drying by passing through a 'festooning chamber, this material may be glazed or surfaced on the wearing side by'applying a solution containing nitrocellulose and a synthetic resin, with or without a plasticizer. If the latter is employed,

preferably it should be of the type which rep duces' infiammability, as, for example, tricresyl phosphate. The proportion of nitrocellulose and resin in such coating mixture should be adjusted to give good flexibility and to avoid curling at the corners.

. printing press.

A third form of floor covering is that which involves printing on an unsaturated felt with pigmented compositions containing nitrocellulose, with or without synthetic resin and plasticizer, and preferably employing a high boiling solvent such as furfural, as set forth in my copending applications, or other solvents such as ethyl lactate, secondary hexyl alcohol, and the like.

In other cases a quite volatile solvent such as ethyl acetate may be employed and the volatility of this solvent in the coating composition suppressed by including a small amount of wax. For example, A to 1 per cent, more or less, of paraflin of .ceresin wax may be employed. In like manner, mixtures of acetone and ethyl acetate, or other appropriate volatile solvents may be included in the coating composition and have their volatility reduced by wax, thereby enabling printing of the design with the coating composition to be carried out without undue drying and gumming of the type, printing rolls or plates.

Another form of the floor covering is that which includes a saturated felt as the lower stratum 011 which is applied a white coating, as for example, a pigmented varnish or drying oil mixture. This is applied very thin, just sufficient to give a white surface for printing a design. The latter is produced by means of a printing roll, the felt in the form of a long strip being run through a rotary- Such an imprint would wear away quickly under foot, and I propose to protect this impression by surfacing with a coating composition containing nitrocellulose and synthetic resin, the nitrocellulose preferably being of low viscosity.

Another method is that of applying to the lower stratum such as the saturated felt a sheet composed of nitrocellulose and a plasticizer such as tricresyl phosphate. Camphor is not so suitable because it does not improve fire resistance and furthermore, possesses acharacteristic odor. However, .celluloid sheets may in some cases be employed in this manner, although such feature does not constitute the preferred phase of the present invention.

The saturated felt is fed through a sheeting roll simultaneously with the introduction of a sheet of thenitrocellulose material. The

' rolls are heated sufficientlyto render the nitrocellulose sheet plastic and adhesive, or the saturated felt may be coated with a cement on the side which is to receive the nitrocellulose plastic sheet. By passing through the rolls the two sheets are welded into a comosite or duplex sheet, the upper side being the nitrocellulose portion and the lower side the saturated felt. By employing a nitrocellulose sheet in which various colored designs appear, a floor covering may be obtained which is .of novehappearance. For exa smooth surface on one side.

ample, by employin a nitrocellulose sheet containing essence o pearl, e. g., a mercury compound giving a pearl-like appearance when the nitrocellulose plastic composition is properly manipulated. A pearl-like surface may be produced in a floor covering, a result, which, so far as I am advised, has never heretofore been obtained.

It is believed that'products of this character offer a wider scope to floor coverings made from sheeted materials and that the present invention constitutes a substantial advance in the art.'

Using a burlap backing a plastic nitrocellulose composition containing filler may be applied thereto by means of milling rolls or s eeting rolls, using suflicient. pressure to force the plastic into the fabric and forming On this side there may then be placed inserts or inlays of nitrocellulose plastic compositions of various colors, using for example, symmetrical designs, in order to obtain 'a floor covering which, so far as general coloring effect is concerned, is, or may be of conventional design. Such inlaid material may be produced on an inlaying machine, which applies to the backing the squares, diamonds, discs or other inlay pieces,'and forces them into the plastic composition previously applied to the burlap. If desired, the first coat of nitrocellulose composition applied to the burlap may be dried in case solvent is present and a second coat colored with pigment to ajford the tint required in the background of the finished floo'r covering is then sheeted on. This can be dried, seasoned, tempered, or otherwise treated, in case the surface is not then in readiness for the inlay pieces. Finally, the latter are applied and in some cases a .finishin composition may be applied to the sur ace to yield a smooth or lustrous effect. The latter may be a modified plastic composition or may be a nitrocellulose lacquer.

Instead of the burlap backing, paper or paper plastic material, e. g., a mixture of equal parts ground wood and sulphite pulp may be used.

Instead of sheeting the plastic composition on such paper sheets, for example, nitrocellulose sheets containing plasticizer may be applied. Ordinary celluloid, as noted, is not satisfactory and nitrocellulose should be employed which is free from curling action. In other words, a flattening agent should be present.

When a paper backing which would be weakened by contact with water is used, it is Y preferable to waterproof it to some extent by wax, asphalt, and the like. Calcium chloride or magnesium chloride, glycerine, etg, may be incorporated in the paper to allow 1t to more easily flatten'when placedon the floor.

Other forms of under stratum which may be used are compositions prepared from glue,

glycerine,- molasses, and the like, sometimes treated with formaldehyde to render more water resistant. Casein maybe used under certain conditions. It isimportant in using such materials, however, to add substances which will be distasteful to rodents in order to avoid mutilation from that source.

The simplest form of the composition is a paper backing or. support on which ,is printed a design and the surface is then'lacquered with a composition comprising nitrocellulose, a protective resin hereinafter described, with or without a plasticizer.

In carrying out the coating operations with compositions containing a solvent, means may be provided for solvent recovery In some cases water dispersions of nitrocellulose and the resinous material, plasticizer, and the like, may be utilized. in order to avoid the loss of costly solvents and to eliminate objectionable vapors from the workroom atmosphere.

A floor covering primarily must not have a slippery surface. If it is too smooth and glossy without reasonable foothold, it will not be satisfactory in the majority of cases, and in the preferred form of the invention suflicient filling material in conjunction with the protective resin aforesaid is provided to eliminate slipperyness.

A form of resin which may be used in the body of the floor covering or on the surface, in conjunction with nitrocellulose is one which is produced by treating a fatty acid phthalic glyceride resin with sulphur monochloride. The resin may be dissolved in a solvent which is not affected by sulphur chloride. For example, a trichlorethylene, or a mixture of benzol and trichlorethylene or monochlorbenzol may be employed as a solvent material and to this solution of the resin from 1 to 4 per cent of the sulphur chloride is added. Reaction takes place with a change in the quality of the'resin, the melting point usually increasing a few degrees.

Such sulphur chloride fatty acid phthalic acid glycerine resinsshould be freed from any unconverted sulphur chloride or hydrochloric acid before incorporation with nitrocellulose. I

In some cases it may be appropriate to apply to, for example, a burlap backing, or to asphalt saturated felt, a plastic composition composed offiller, resin and solvent, without nitrocellulose. In such case it is not necessary to use nitrocellulose solvents but hydrocarbons such as benz'ol, toluol, xylol, tetralm, and the like, may be employed, with or without chlorinated hydrocarbons such as trichlorethylene or monochlorethylene.- Resins I which have not been made at too high a temperature or those which have been made with a somewhat larger proportion of the oil fatty 'acid mentioned above, are better solublein straight hydrocarbon solvents than those which have been heated to a higher temperature orcontaining a larger proportion of the phthalic radical. In such cases cases it is advisable to employ a suflicient amount of chlorinated hydrocarbon solvent to secure solution. The resin made from castor oil, is, however, of quite a different character and is not soluble in such hydrocarbon solvents when prepared according to the procedure given above.

.The protective resins used herein are not limited to the illustrative ones set forth, but may be made from various other acids or their anhydrides, including maleic acid and anhydride, succinic, lactic, tartaric, citric, salicyclic, cinnamic, di henic acids and so forth. Mixtures of di erent resins maybe employed and also, in some cases, natural resins such as dammar, Congo, pontianac and various oopals, in natural state or heat-treated. Modified resins such as hardened rosin, rosin ester or ester gum, and the like, may also be used. Still other additions of various substances :and any of the usual pigments are not precluded. Organic antacids such as urea and amino compounds may be introduced as desired.

It should be noted that the asphalt saturated felt used was'free from oil and that in consequence good adhesion of the tread to the felt support was secured. This bond was .so

- effective that the tread could not be removed without tearing off apart of the felt support. As an illustration a tread composition was made as follows:

450 parts by weight of wet nitrocellulose of a viscosity 0 :40 seconds and containing 360 parts dry n'trocellulose, the remainder being denatured alcohol, were mixed with 480 parts tricresyl phosphate and approximately 900 parts secondary butyl acetate. This composition was agitated in a Werner Pfieiderer mixer for about three hours.

550 parts of the above mixture, 175 parts ground cork of 80-90 mesh, 30 parts tricresyl phosphate, 100 parts of a per cent solution of cottonseed fatty acid phthalic glyceride resin 1n a mixture of equal parts secondary bugyl acetate and secondary butyl alcohol t an 100 parts mineral filler were incorporated in a erner Pfieiderer mixer until of uniform co istency.

. A base or under stratum was used which was made by impregnating with blown asphalt, a thick rag paper or so-called felt being employed as a supporting medium. The mixture of the nitrocellulose plastic and filler was placed on a milling roll with the sheet of saturated felt. Differential rolls were used, that is, the speed of one roll was greater than the other, and the plastic was applied to the saturated felt by means of the more rapdly rotating roll. To accomplish the sheeting or application of the tread composition, the felt sheet was inserted in the rolls with a mass of the plastic and by rotation of the rolls forced rapidly through. A thin sheet or coating of the plastic was thus laid smoothlyon the under stratum of saturated felt and through rolls. It was observed that by dusting the surface of the inlay with cork, or

other appropriate dusting powder, the daner of the inlay adhering to the roll and therey being stripped from its support was mini- In the particular case referred to the inlay material was a colored design composed of celluloid nitrocellulose of about 35 second viscosity rated on the lacquer method of determination. It contained tricresyl phosphate and a fire retarding filler. The latter was not present in suflicient quantity to destroy the definite film forming character of the nitrocellulose. The result was an inlaid effect of geometrical desi 11 formed by squares of the multi-colored m in a background or tread composition of uniform color.

Another composition containing both nitrocellulose of 40 second viscosity and of second viscosity was made as follows:

350 parts of second wet nitro cotton, containing 245 parts nitrocellulose, the balance being denatured alcohol, were mixed with 300 parts tricresyl phosphate and 180 parts secondary butyl acetate.

From this stock mixture 180 parts were taken and mixed with 225 parts of the nitrocellulose (40 second viscosity) solution described above; this being the solution before resin was added. 150 parts of ground cork and 75 parts of mineral filler were added and mixing was accomplishedin a Werner Pfleiderer machine. 1

This plastic composition was likewise sheeted on a saturated felt base to form a tread-composition. By varying the spacing of the sheeting rolls layers of different thicknesses could be applied. In this manner it was possible to apply a tread which was very thin, as well as others which were of considerable thickness and of more substantial wearing qualities. A third modification is that of applying to the tread surface, made for exam le 1n the foregoing manner, a coating or ishto yield about 30 per cent of total solids, no

plasticizer being added, was applied to the sheeted tread surface of the foregoing and was found to yield an improved finish and greater resistance to cracking when the floor covering is bent sharply at right angles. The last mentioned result is of value in preparing floor covering which is likely to be subjected to rather rough handling.

As illustrated in the drawing, in Figure 1, a base 1 of felt, paper, etc., may carry a tread or sheeted surface 2 containing the nitrocellulose compositions or synthetic resin compo- 1 sitions referred to hereinabove. In Figure 2, a modified form of covering is shown wherein a primer 3 is interposed between the case 1 and tread 2 in order when desired to seal the base or to increase adhesion of the base and tread.

What I claim is 1. A floor covering comprising a backing of asphalt-saturated felt substantially free from oil, coated with a flexible selfattening layer comprising a mixture of high viscosity nitrocellulose and low viscosity nitro= cellulose.

2. A floor covering comprising a backing of asphalt-saturated felt substantially free I from oil, coated with a flexible self-flattening 3 layer comprising a mixture of high viscosity nitrocellulose and low viscosity nitrocellulose and a synthetic protective resin.

3. A floor covering comprising a flexible backing carrying a substantially non-slippery self-flattening soap-resistant composition comprisingla mixture of nitrocellulose of high viscosity and of low viscosity and a protective resin.

4. A floor coyering of a slow burning type comprising an asphalt-saturated felt under coating and an upper or tread coating consubstances, carrying a coating containing low viscosity nitrocellulose and a protective synthetic resin.

I 8. A self-flattening floor covering having a tread layer comprising nitrocellulose, a

protective synthetic resin, and ester gum.

9. A self-flattening floor covering comprising a flexible backing carrying a layer containing nitrocellulose and a protective resin.

CARLETON ELLIS.

taining nitrocellulose, tricresyl :pl osphate and a protective resin.

5. A floor covering comprising a backing of felt saturated with a. blown asphalt'sub stantially free from oil, coated with an adherent nitrocellulose layer comprising a mix-- ture of high viscosity nitrocellulose'and low viscosity nitrocellulose. Y

6. A covering comprisin a backing coated with an oil paint composition, said oil paint composition being coated with a nitrocellulose layer carrying a protective synthetic resin.

saturated felt substantial I 7. A floor covering comprising arfi asphallt- 5 y ree rom my I 4

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