US1930803A

US1930803A - Manufacture of artificial filaments

Info

Publication number: US1930803A
Application number: US314324A
Authority: US
Inventors: Harrison William
Original assignee: Individual
Current assignee: Individual
Priority date: 1927-11-01
Filing date: 1928-10-22
Publication date: 1933-10-17
Anticipated expiration: 1950-10-17

Description

@Ct. 17, 1933. w soN 1,930,803

MANUFACTURE OF ARTIFICIAL FILAMENTS Filed Oct. 22, 1928 III i Patented Oct. 17, 1933 William Harrison, Kilmacolm, Scotland Application October 22, 1928, .Serial l\To. 314,324,

and in Great Britain November 1, 1927 2 Claims. (01; 18-54) It is known to spin viscose by what is known as the stretch spinning process according to which the formed threads are drawn away from the jet orifices at a greater velocity than that 5 at which the viscose solution issues from the orifices.

It is also known to produce artificial silk of higher strength than usual, that is to say, higher strength than is obtained by a simple process of stretching, e. g., 2 grams per denier, by the use of a swelling agent for cellulose such as strong acids of hydrion concentration greater than that of a 45% solution of sulphuric acid, zinc chloride and calcium thiocyanate, the thread being stretched while in a plastic state occasioned by the use of a swelling agent immediately after (one bath process) or some time after (two bath process) the setting or -decomposition operation during-which cellulose is formed from the viscose. In other words, the cellulose formed in the setting process is caused to swell by the application of a cellulose swelling agent; or agents and while thus swollen the threads are stretched considerably and the swelling agent removedu The object of this invention to produce strong threads from viscose without the use of such swelling agents and without the use of exceptionally strong acids, that is to say, without usingacids of hydrion concentration corresponding to that of a 45% solution of. sulphuric acid,the acids if used being advantageously of considerably lower concentration.

I'attain my object by the application of tension and extension in a manner'and under con-' ditions hereinafter described which have not hitherto been applied in the spinning of viscose silk.

' According to one embodiment of my invention I use as coagulantsfor the viscose, preferably viscose made from unaged or only partially aged alkali cellulose, baths containing strong or mineral acids of hydrion concentration less than that of a 7% solution of sulphuric acid, down to even 0.5% or less, preferably in the presence of neutral salts, and thereby effect coagulation of the viscose and slow decomposition into cellu lose. With such a coagulating bath the viscose after coagulation exists for 'a short time in an evanescent oran active plastic state, that is to say, a condition in which'the viscose remains plastic but active in so far that evanescent cellulose formed by the decomposition process is present and combining or polymerizing, its duration being the shorter and its distribution throughout the filaments being the lesshomogeneous the greater is the hydrion concentra tion of the coagulating acid; for example, in-a solution of hydrion concentration equal to that ofa 0.5% solution of sulphuric acid the active plastic state exists for distinctly less than 30' seconds, with a filament of about 1 denier, and most probably less than 10 seconds. 7 Ina solution of 7 percent sulphuric acid the existence of the active plastic state is terminated in distinctly less than 3. seconds and probably less than 1. second, and,,superficially, considerably less than 1 second and between these concentrations one. I has suflicient time to complete the stretching Process." I

In order that the .stretchingprocess may be completed within the. duration of existence of the active plastic state, as soon as the filaments have sufficient solidity to permit of contact with asolid surface I begin to apply tension which continues with increasing :stressso that the threads are extended at least 25% or even 100% or. more during the time the-viscose is'being decomposed, that is to say, during the existence of theactive plastic state. The time of applic'a tion of tension is suchthat decompositionof the viscose into-cellulose is practically completed while the threadsarelbeing subjected to tension. In practice the threads may remain under tension for a longer time than theaduration of existence ofthe active plastic state, but the'actual extension of the threads only' proceeds while the viscose is in the plastic state.

According to a. further modification I use as coagulants-in a first bath any of the coagulants already referred to, but immediately or very soon after their formation I pass the threads into a bathbf water, the second bath, to which have been added such substancesas, while'permitting or'even assisting theswelling of the formed threads possibly by virtue of the presence of some active xanthogenate groupings, will not carry the swelling process far enough to cause dissolution of the threads or will prevent such dissolution; for example, neutral salts with addition of one or more orgamc'substances such a jet with many orifices, say a 150 hole jet is used.

Permissible variants and details unnecessary to describe at length include the employment of viscose made in a particular way, and the use of mechanical devices of any form in the performance of the invention.

The figure of the accompanying drawing illustrates diagrammatically apparatus preferred for performing the process.

In the drawing A denotes a spinning bath into which viscose is delivered through a jet. B denotes a pulley over which the filaments formed in the bath A are led from the bath. In the particular apparatus illustrated, the pulley B, assumed to have a circumference of 38.6 centimeters, rotates at the speed of twenty revolutions in seventy-two seconds. From the pulley B the filaments are led to the pulley C rotating at the same speed as the pulley 13. From the pulley C the filaments pass to the pulley D, of the same circumference as the pulley IB and performing twenty revolutions in fifty-four seconds. The pulley D dips into the bath E, i.e., the second bath. From the pulley D the filaments submerged in the bath E pass to the pulley F rotating at the same speed as the pulley D. From the pulley F the filaments pass to the pulley G, thence to the pulley H and thence to the spool J, which dips into an acid bathK.

In the particular apparatus illustrated, the

spool J, having a circumference of 29.8 centimeters, performs sixty revolutions in sixty-six seconds.

I claim:

1.The improvement in the manufacture of artificial filaments from viscose, consisting in coagulating the viscose in the form of filaments in acids of a hydrion concentration less than that of 7% H2804, causing the viscose to enter an evanescent active plastic state, then passing the filaments into a bath of water to which have been added substances which permit the swelling of the formed filaments by the action of the water, without bringing about dissolution of the filaments, and stretching the filaments before complete decomposition of the viscose, substantially as described.

2. The improvement in the manufacture of artificial filaments from viscose, consisting in eifecting coagulation of the viscose, in the form of filaments, in acids of hydrion concentration less than that of 7% H2504, whereby the filaments are caused to enter an evanescent active plastic state, and gradually applying tension to the filaments to effect extension of the filaments commencing with solidification of the filaments and continuing While the filaments are in said evanescent active plastic state, whereby the filaments are extended at least 25% before complete decomposition of the viscose.

W. HARRISON.