US1945538A - Artificial fabric - Google Patents

Description

Patented Feb. 6, 1934 1 945 533 1,945,538 ARTIFICIAL FABRIC George L. Schwartz, Wilmington, Del., assignor to E. I. du Pont de Nemours & Company, Wilmington, Del., a corporation of Delaware No Drawing. Application May 31, 1930, Serial No. 458,900. Renewed January 19, 1933 8 Claims. (CI. 92-40) This invention relates to new and useful imkaline solution the fibers are thoroughly washed provements in artificial fabrics and more parwith water and are then in the altered conditicularly to fabrics formed from cellulosic fibers tion, exhibiting the appearance of having a that have been artificially crinkled by chemical crinkle as compared with their original condition.

treatment and have been impregnated with rub- These cellulose fibers are then suitably pulped 60 her latex or similar aqueous dispersions of rubber. and felted. For some purposes it is desirable to In prior methods of preparing artificial fabrics hydrate the pulp before felting into paper and to from cellulosic fibers by impregnation with rubthis end the crinkled pulp is beaten while disber solutions in various forms, it has been found persed in water in a standard paper beating ap- 10 that fabrics so prepared have had certain undeparatus for a period of several hours, ranging, 65 sirable characteristics, such as stiffness, a charfor p e, from 2 to 12 hOllrS- In this p acteristic of breaking upon flexing or bending ation it is not desired to cut the fibers but merely the article, a tendency to a poor resistance against to brush them out and hydrate them and to cause abrasion, a tendency for the rubber to oxidize the fibers to exhibit afrayed appearance. Therel5 upon ageing, a poor resistance against tearing, after the fibers are deposited in the form of aweb, 70

and certain other defects. as in known methods of manufacturing paper,

It is an object of this invention to avoid the and the web is thereupon dried. aforesaid difiiculties in the preparation of arti- The dried web is then passed into a rubber flcial fabrics, in other words, to manufacture an latex liquid in order to impregnate it with the artificial fabric from a fibrous cellulosic base rubber latex. This maybe performed in d y 7 by impregnation with rubber so that the fabric impregnating pp The desired P will have the characteristics of flexibility, rea e f th ru er on en will r n e f m a u sistance to tearing, resistance to oxidation on 1 to a g as but preferably in the ageing, resistance to abrasion, and will furtherneighbor d o 0% n the finis d Sh et 0 ebmore have the quality of not breaking upon ric. After the impregnation the article is dried 80 bending and flexing the fabric. in order to coagulate the latex, but other methods The article of this invention may be manu- 0f o u a h a e yp y Such factured by the following preferred form of proas passing the i p d h t t o a cedure: solution of aluminum sulphate or other coagu- The basic material for the fabric consists of a lating agent. When coagulated with chemical 85 fibrous cellulosic material prepared in a special a t th sheets are p d ou h w nser manner as more particularly set for in the apor rollers to squeeze out superfluous liquid and plication of McCormick and Schwartz Ser. No. then dried. At the conclusion of the drying oper- 283 145, filed June 6, 1928, of which Patent, ation the sheets are compressed to give afinished 1,857,100 is a continuation in part. A brief deapp a and y be d d Ot w s 90 scription of this process for treating the fibrous treated, according to the usual practices in this cellulose is as follows: art.

Wood or other suitable fibrous cellulosic pulp The resulting sheet has exceedingly valuable is prepared in any suitable manner and is then characteristics of great utility in the various arts treated with caustic alkali, for example, sodium for which such an article of manufacture is 95 potassium or lithium hydroxide, in aqueous soluadapted. Among its characteristics may be mention at a concentration of from 8% to 35% at tioned its great flexibility, its property of showroom temperature for a short period of time ining no paper-break when bent or sharply flexed, sufficient to cause gelatinization of the cellulose its strong resistance to tear and resistance to fibers. This time treatment is generallyamatter abrasion, and its non-oxidizing properties. In 100 of only several seconds to thirty minutes, the reference to resistance to tear, it should be more preferred practice being to disperse the pulp with particularly stated that the herein-described the caustic without cutting action at high pulp sheet will offer strong resistance against tearing consistencies (low ratio of liquor to pulp), such by hand, and when subjected to the standard 59 as is disclosed in the examples of the mentioned Elmendorf tester it will show a value of between 106 application and patent, in order to minimize the 850 to 1156 in the case of a sheet manufactured effect of time action of the strong caustic on the to contain about 17% rubber and having a fibre pulp. The caustic solution, when the pulp is weight of .615 lbs. per 40 inch yard. This parcompletely wet therewith, is diluted with water ticular example is given merely to illustrate the to stop the reaction. On removal from the altype of fibrous cellulosic-rubber sheet manufac no tured by this process, and it will be understood that, where sheets of other specific fibre weights are made with other percentages of rubber content, the figures on the Elmendorf tester will, of course, vary with those herein given but will be of the same order of excellence. A sheet of the character Just described will have a thickness of about .025inch, and it will accordingly be seen that such a sheet represents a standard article of manufacture useful for bookbinding, base for linoleum, base for wall coverings, auto top materials, auto interior coverings, furniture coverings, and many other similar and analogous uses wherein fabrics find their employment. It has also been found to be useful for preparing products used in the construction of shoes such as soft toe boxes, inner soles, liners, etc. It is furthermore found that the fabric herein disclosed cuts easily like leather without leaving a frayed edge. I

A base material made of artificially crinkled fibers as herein disclosed has unusual strength 4 in view of its extreme porosity. Because of this strength and high absorbency, it is peculiarly adapted to impregnation with latex for the production of vulcanized or unvulcanized sheets having remarkable strength and tear resistance as compared with a product in which this base material is impregnated with solutions of coagulated rubber in organic solvents. In regard to ageing qualities, unvulcanized and coagulated rubber latex ages extremely well. However, the ageing may be afl'ected favorably or adversely by the materials with which the rubber is associated. As previously noted, the product of the present invention has exceptional ageing qualities and it appears, therefore, that the specially prepared base exercises a favorable influence in maintaining the rubber in its non-oxidized state.

It should also be pointed out that this particular fabric is not laminated, but consists of a single deposited sheet impregnated with rubber. It has been found, however, that a laminated sheet may be made by gluing together sheets as herein described or by putting on a multiple deposit during the paper-making step and impregnating the latex into the multiple deposits. Furthermore, instead of laminating,- the sheet may be made thicker than herein described so as to constitute a single deposited article equalling in its thickness a multiple-deposited or laminated sheet, and thereby securing advantages in flexibility and structural strength not possessed by laminated sheets. The latter is a particular advantage of this invention.

many apparently widely different embodiments of this invention may be made without departing from the spirit and scope thereof, it is to be understood that I do not limit myself to the specific embodiments thereof except as defined in the appended claims.

I claim:

1. An article of manufacture comprising a web of artificially crinkled fibrous cellulosic material impregnated with rubber latex coagulated therein, said article being flexible, exhibiting no paper-break, and having strong resistance to tear and strong resistance to abrasion, said web being substantially identical with the web obtained by dispersing paper pulp with 8% to 35% sodium hydroxide solution at room temperature, promptly washing out the caustic and felting the pulp.

2. The invention in claim 1 wherein the cellulosic material exists in the condition of hydrated, frayed, beaten fibers.

3. The process of manufacturing an artificial fabric comprising depositing a web of artificially crinkled cellulosic material, impregnating it with rubber latex, coagulating the latex, and drying the sheet.

4. The process of manufacturing an artificial fabric which comprises treating cellulose fibers in pulp form with caustic alkali having a concentration of between 8% and 35%, removing the caustic after a time not longer than 39 minutes, dispersing the crinkled fibers so prepared in water, depositing a web thereof, impregnating the web with rubber latex, and drying the sheet.

5. The process of manufacturing an artificial fabric which comprises treating wood pulp at high pulp consistences. with caustic alkali having a concentration of between 8% and 35%, removing the caustic after a time not longer than 30 minutes, dispersing the crinkled fibres so prepared in water, depositing a web thereof, impregnating the web with rubber latex, and drying the sheet.

6. The process of manufacturing an artificial fabric which comprises treating cellulose fibres in pulp form with caustic alkali having a concentration of between 8% and 35% for a time not longer than 30 minutes, washing the treated fibres and dispersing them in water, beating the fibres in the water for from 2 to 12 hours to brush them out and hydrate them without cutting them, depositing'a web thereof, impregnating the web with rubber latex, and drying the sheet.

7. The product produced in accordance with the process set forth in claim 5.

8. The product produced in accordance with the process set forth in claim 6.

GEORGE L. SCHWARTZ.