SYKTHETIC TEXTILE FIBERS — MAUERSBERGER 215 



It is truly a synthetic fiber, of truly amazing properties and not 

 like any natural fiber — another excellent example of what can be done 

 in creating fibers of special character to meet special needs. 



Modifications and further experimentation in this category of 

 synthetic textile fibers have produced other very interesting and 

 valuable materials in Europe known as Pe-Ce fiber, Synthofil, Igelite, 

 and Permalon. The latter is a vinyldene chloride derivative which 

 the producer, The Dow Giemical Co., calls Saran. According to 

 Pierce Plastics, Inc., of Bay City, Mich., they take this white powder 

 and exude it after heating through a die. When the filament issues 

 from its die it is hot, and thence is passed through a tank of water. 

 It is then taken to a stretching device, where the size of the threads 

 is controlled and at the same time acquires a tensile strength of 

 40,000-50,000 pounds per square inch. When the company first 

 started, it made Permalon threads solely for fishing-leader material. 

 They now make small tubing, which is used for catheters in hospitals. 

 A number of textile concerns are now making a narrow fabric and 

 upholstery seat fabrics of Permalon threads — a very remarkable and 

 interesting development of considerable importance. 



Dow Chemical has also made experiments with ethyl cellulose deriv- 

 atives, known as Etho-raon, Ethocel, and Ethylfil. I am informed 

 that Dow Chemical is not ready to disclose any details, but has stated 

 that these materials are very similar to cellulose acetate rayon. It 

 was first made known at the National Farm Chemurgic Council in 

 Detroit. More information on these new textile fibers may be 

 available later. 



CASEIN FIBERS AND FILAMENTS 



Probably the most extensive and costly research was done on the 

 possibility of producing synthetic textile filaments and fibers from 

 milk casein, first mentioned by Todtenhaupt in 1904. He dissolved 

 casein, which is the coagulable portion of milk, in an alkaline fluid 

 and then allowed the solution to fall, or pressed it in the form of thin 

 threads, into an acid bath. Later the spinning solution was dissolved 

 in zinc chloride, spun and insolubilized in a formaldehyde solution 

 which made the filaments softer and more pliable. The principal 

 objections and early difficulties were the proneness to swell, soften, 

 and stick together at normal temperatures during dyeing. Many ex- 

 periments were necessary to overcome this and finally resulted in the 

 Ferretti process of Italy in 1935, which has produced a satisfactory 

 cormnercial product known as Lanital. 



In Ferretti's process the casein is dissolved in dilute aqueous alkali, 

 allowed to stand 2 to 3 days until the solution becomes thick and 

 viscous. A solvent is gradually added to the desired volume and 

 viscosity, then spun, rendered insoluble, and deacidified. This fiber 



