US2142911A - Manufacture of artificial materials - Google Patents

Description

Jan. 3, 1939. R. w. MONCRIEFF ET AL 2,142,911

MANUFACTURE OF ARTIFICIAL MATERIALS Filed July 23, 1937 Patented Jan. 3, 1939 PATENT OFFICE 2,142,911 MANUFACTURE OF ARTIFICIAL MATERIALS Robert Wighton Moncriefl and Frank Brentnall Hill, Spondon, near Derby, England, assignors to Celanese Corporation of America, a corporation of Delaware Application July 23, 1937, Serial No. 155,192 In Great Britain July 30, 1936 Claims.

This invention relates to improvements in the manufacture of artificial materials, and particularly to improvements in processes for stretching artificial filaments and other products hav- 6 ing a basis of cellulose acetate or other organic derivative of cellulose.

In U. S. application S. No. 17,242, filed April 19, 1935, processes are described for the stretching of artificial filaments, foils and similar materials in which the materials are passed in substantially non-slipping contact with'a positively driven feed device contained in an end chamber which contains a compressed inert fluid, and from this chamber into a pressure treatment chamber communicating therewith, which contains hot water and in which they are stretched. The specification also describes and claims apparatus for carrying out this process. By means of the 'end chamber flow of hot water through the inlet passages for the materials into the treatment chamber may be reduced or eliminated. The materials may issue from the treatment chamber directly into the outer air, or they may pass from the treatment chamber into a second end chamber containing a compressed inert fluid and having a similar function and thence into the outer air.

It has now been discovered that particularly good results may be obtained by the use of cold, or relatively cold, water as the inert fluid present in the end chamber or chambers. The water may be at atmospheric temperature or below or at a temperature above atmospheric temperature, for example a temperature of 25 or 35 C. or even more, but the temperature must not be so high that softening and stretching of the materials takes place in the end chamber or chambers themselves. The pressure of the water in the end chamber or chambers may be equal to or greater or less than that of the water in the stretching chamber, but is preferably substantially the same. For example, the pressure of the water in the end chamber may be slightly lower than the pressure in the treatment cham- 45 her, e. g., of the order of 1 to 5 pounds per square inch lower.

For details with regard to the stretching conditions and the apparatus which may be employed reference is made to U. S. application S. No. 17,242. Stretching may be effected in hot water at a temperature of, for example, 110 0., 125 C., 140' C. or more, and at a pressure corresponding with the vapour pressure of water at the temperature employed. The materials may be stretched to a relatively low degree, for example,

150, 200 or 300% of their original length, or to a considerably greater extent, for example to 1000% or more of their original length. As stated above either a single end chamber containing a feed device for the materials and situated at the inlet end of the stretching chamber may be employed, or end chambers at both ends of the stretching chamber may be employed, in which case the chamber at the outlet end may contain the stretching device.

The water in the stretching chamber may contain solvents or plasticizers preferably in low concentrations, e. g., concentrations of 1-5 or 10%. Examples of suitable substances are methyl and ethyl alcohols, dlbutyl tartrate, diethyl lactate, aromatic sulphonamides, e. g., toluene parasulphonamide and benzyl alcohol. Examples of other substances which may be employed are given in U. S. Patent No. 2,072,251.

The accompanying drawing illustrates, more or less-diagrammatically, an apparatus which may be employed in carrying out the process of the present invention.

The apparatus comprises an end chamber 4 connected with a pressure treatment chamber 1 by means of small orifices 6 for the passage of the materials. The chamber 4 is provided with an inlet II and an outlet l3 by means of which water may be passed through the chamber. Itis also provided with inlet orifices 3 for the materials, apressure gauge 12 and a positively driven feed device 5. The pressure treatment chamber 1 comprises an inlet pipe l5 and outlet pipe l8 by means of which hot water may be passed through the chamber, a heating coil H, a pressure gauge i4 and a valve controlled drain l8. It is also provided with outlet orifices 8 for the materials.

In carrying out the stretching process according to the present invention using apparatus such as that illustrated in the drawing a number of filaments 1 taken from a creel of bobbins 2 may be passed through the inlet orifices 3 into the end chamber 4 which contains cold water under pressure. After entering the chamber they pass in contact with the positively driven feed device 5, and then through the orifices 6 into the treatment chamber I where they are stretched during their passage through hot water by means of the positively driven feed devices 9 positioned outside the chamber. From these devices they pass to a creel of take-up bobbins Ill.

The following example illustrates the invention, but is not to be regarded as limiting it in any way.

Example Cellutose acetate yarn is passed through end chamber in contact with a positively driven feed device and then through a stretching chamber communicating with the end chamber, the stretching chamber containing hot water at a temperature of about 143 C., while cold water at a temperature of about 20 C. is circulated through the end chamber. 'I'he pressure oi the water in the end chamber is'about 5 pounds per square inchdess than that of the water in the stretching chamber. n issuing from the stretching chamber the yarn passes in contact with a stretching device which is rotated at a peripheral speed such that the materials are stretched in the stretching chamber toabout 10 times their original length. In this manner products having a high tenacity and a good'extensibility may be obtained.

The materials after being stretched may be subjected to a shrinking process and/or a saponification process carried out continuously with stretching. For example on emerging from the stretching apparatus they may be shrunk by passage through a shrinking bath containing methylene dichloride or other suitable shrinking agent as described in U. S. Patent No. 2,658,422, and then, after drying if necessary, through a saponiiying bath containing sodium hydroxide, methylamine, ethylene diamine or other suitable saponii'ying agent wherein they are partially or wholly saponified. Z 1 N The process is particularly valuable for the stretching of filaments, threads, and other materials of cellul ose acetate but is also applicable to the stretching of materials made of other organic derivatives of cellulose, e. g., cellulose:

propionate and "butyrate and ethyl and butyl cellulose e Having described our invention what we desire to secure by Letters Patent is: r V 1. Process for improving the properties of artificial filaments, threads and similar materials of cellulose acetate, which comprises running the materials from the outer air into an end chamber, which communicates with a pressure treatment chamber and contains water at a temperature below that at which it exerts any softening action on the; materials, in substantially nonslipping contact with a positively driven feed de- I vice in the end chamber, thence throughethe communication between the end and treatment chambers into hot water, at a temperature above 100 C. and a pressure substantially the same as that of the water. in the end chamber, contained in the treatment chamber, and finally into the outer air, the materials being stretched while in the hot water.

2. Process for improving the properties of artificial filaments, threads and similar materials of cellulose acetate, which comprises running the materials from the outer air into an end chamber, which communicates with a pressure treatment chamber and contains water at a temperature below 35 C., in substantially non-slipping contact with a positively driven feed device in the end chamber, thence through the communication between the end and treatmentchambers into hot water, at a temperature above 100 C. and a pressure substantially the same as that of the water in the end chamber, contained in the treatment chamber, and finally into the outer air, the materials being stretched while in the hot water.

3. Process for improving the properties of artificial filaments, threads and similar materials 0! cellulose acetate, which comprises running the materials from the outer air into an end chamber, which communicates with a pressure treatment chamber and contains water at a temperature below that at'which it exerts'any softening action on the materials, in substantially nonslipping contact with a positively driven feed device in the; end chamber, thence through the communication between the end and treatment chambers into hot water, at a temperature above 120 C. and a pressure substantially the same as that of the water in the end chamber, contained in the treatment chamber, and finally into the outer air, the materials the hot water.

4. Process for improving the properties of artificial filaments, threads and similar materials of cellulose acetate, which comprises running the materials from the outer air into anend chamber, which communicates with a pressure treatment chamber and contains water at a temperature below that at'which it exerts any softening action on the materials, in substantially non-slipping contact with: a positively driven feed device in the end chamber, thence through the communication between the end and treatment chambers into hot water contained in the treatment chamber at a temperature above 100 C. and under a pressure between 1 and '5 pounds per square inch greaterihan that of the water in the end cham-' ber and finally into the outer air, the materials being stretched while in the hot water.

5. Process for improving the properties of artificial filaments, threads and similar materials 01' cellulose acetate, which comprises running the materials from the outer air into an end chamber, which communicates with a pressure treatment chamber and contains water at a temperature below that at which it exerts any softening action on the materials in substantially non-slipping contact with a positively driven i'eed device in the end chamber, thence throughjthe communication between the end and treatment chambers into' hot water contained in the treatment chamber at a temperature above 120 C. and under a pressure between 1 and 5 pounds per square inch greater than that of the water in the end chamber and finally into the outer air, the materials being stretched while in the hot water.

ROBERT WIGHTON MONCRIEFF. FRANK BRENINAIL HILL.

being stretched while in 7

Images