US3499958A

US3499958A - Process for obtaining x-shaped filaments

Info

Publication number: US3499958A
Application number: US590711A
Authority: US
Inventors: Rene Stuchlik
Original assignee: Rhodiaceta SA
Current assignee: Rhodiaceta SA
Priority date: 1965-11-08
Filing date: 1966-10-31
Publication date: 1970-03-10
Anticipated expiration: 1987-03-10
Also published as: BE689370A; CH461016A; NL6615357A; GB1144376A; LU52308A1; DE1660544A1; FR1473904A

Description

Much 1970 R. STUCHLIK 3,499,958

PROCESS FOR-OBTAINING X'SHAPED FILAMENTS Filed Oct. 31, 1966 FIG. 2.

United States Patent 3,499,958 PROCESS FOR OBTAINING X-SHAPED FILAMENTS Rene Stuchlik, Villeurbanne, France, assignor to Societe Rhodiaceta, Paris, France, a French body corporate Filed Oct. 31, 1966, Ser. No. 590,711 Claims priority, applicatiol France, Nov. 8, 1965, 37 6 4 Int. 01. D01d 3/00, 5/04 US. Cl. 264177 1 Claim ABSTRACT OF THE DISCLOSURE The invention relates to a process for obtaining filaments the transverse crosssection of which is in the shape of an X, and to a spinneret having a new type of perforation and intended to be used for the said process.

It is already known to obtain filaments of X crosssection or H cross-section by dry spinning a solution of a filament-forming material in a volatile solvent, using a spinneret perforated with square holes. However, such processes generally yield yarns in which some filaments have an 'H cross-section and others an X cross-section, without it being possible easily to obtain yarns in which all, or almost all, of the filaments have an X crosssection. The hitherto known spinnerets with square holes have always been perforated in such a way that one of the medians of the square holes coincides with a radius of the spinneret.

The present invention provides a process for obtaining yarns in which most 'or practically all the constituent filaments have a transverse cross-section in the shape of the letter X, which comprises dry spinning a solution of a filament-forming material in a volatile solvent through a spinneret perforated with square holes, such that the drying conditions at two adjacent sides of each square hole are substantially identical. Preferably a spinneret as described below is used.

The invention consists also in a spinneret perforated with square holes which may be used for this process, in which the said square holes are so arranged that each of them has one diagonal making an angle of less than with the radius of the spinneret which passes through the centre of the hole.

By filament-forming materials are meant synthetic or artificial polymeric materials such as cellulosic esters, especially cellulose diacetate (secondary cellulose acetate) or triacetate, and synthetic polymers.

The term volatile solvent is to be understood as any liquid capable of dissolving the material to be spun, but having a relatively low boiling point, preferably not exceeding 80 C.

For reasons of convenience it is generally preferable to use the usual solvents normally employed for dry spinning the filament-forming material such as acetone for cellulose diacetate, a mixture of methylene chloride and a low aliphatic alcohol, especially methanol or ethanol, for cellulose triacetate, a mixture of carbon disulphide and acetone for polymers based on vinyl chloride, etc.

Spiunerets of any shape and size, and made of any 3,499,958 Patented Mar. 10, 1970 appropriate material, may be used, depending on the material which is to be spun. The spinneret may for example be in the form of a plate or a dome and may be perforated with one or more rings of holes. However, it is generally preferable, in the process of the invention, to use a spinneret which does not have: too large a number of rings of holes, or the rings too closely spaced, since in that case the filaments issuing from the holes in the central rings may be produced under poor drying conditions and may not have the expected shape. The spinneret may, equally, be perforated with holes arranged along one or more lines, for example along the sides of a polygon concentric with the spinneret. It will generally be advantageous to use a spinneret in which the perforations are not too close, so that the drying of each filament is not interfered with by the presence of the adjacent filaments.

The same conditions of temperature of the spinning solution, temperature of the walls of the spinning chamber, temperature and rate of flow of co-operative medium, and of stretching on spinning, may be used as are normally employed for dry spinning the same filamentforming material.

The process of the invention makes it possible to obtain yarns in which at least of the constituent filaments have a cross-section in the shape of an X. Such a cross-section gives the filaments special properties, principally very high resilience, this characteristic being particularly appreciated and sought after in carpet piles.

The invention is illustrated in the accompanying drawings, in which:

FIGURE 1 is a view of the external face of a spinneret,

FIGURE 2 is a view of a portion of the spinneret face of FIGURE 1 on a larger scale,

FIGURE 3 is a view of the external face of another spinneret,

FIGURE 4 is a view of the external face of a third spinneret, and

FIGURE 5 shows the transverse cross-section of a filament obtained by the process of the invention.

Referring now to FIGURE 1, there is shown a spinneret comprising a base 1 and holes 2; arranged in one ring.

FIGURE 2 shows that the holes 2 are arranged in such a way that each of the

diagonals

3, 3' and 3" coincides with a

radius

4, 4 and 4" of the spinneret.

In FIGURE 3 the holes 2 are arranged in 3 rings each having 4 holes, one of the diagonals of each hole coinciding with a radius of the spinneret.

In FIGURE 4, the

holes

2 and 2 are arranged along the sides of a polygon concentric with the spinneret face. The holes 2 are so oriented that one of their diagonals coincides exactly with a radius of the spinneret, and the holes 2' in such a way that one of their diagonals, makes an angle of 7 with a radius of the spinneret.

FIGURE 5 shows the shape of filaments 5 which all have a X-shaped cross-section.

The following examples, in which parts are by weight, illustrate the invention.

This solution is warmed to 55 C. and extruded through a spinneret in a vertical dry spinning chamber of internal diameter 60 mm. and height 3.50 m., the walls of which are heated to C. The spinneret has 5 square holes of side length 0.1 mm. arranged regularly in a ring of radius 30 mm., a diagonal of each square coinciding with a radius of the spinneret. Air at the ambient temperature circulates through the chamber in a downward direction, i.e. in the same direction as the filaments at a rate of 4.5 m. /h. A 120 decitex (110 denier) yarn consisting of 5 filaments each of 24 decitex (22 denier) is obtained at a speed of 150 m./ minute; the filaments have an X crosssection such as is shown in FIGURE 5.

By way of comparison, filaments obtained from the same solution, and spun under the same conditions as before but using a spinneret in which the 5 square holes, though of the same size, are arranged in such a way that one of the medians of each hole coincides with a radius of the spinneret, have an H cross-section.

EXAMPLE 2 A solution identical to that of Example 1 is heated to 60 C. and extruded through a spinneret having square holes of side length 0.08 mm. oriented as in Example 1 and arranged in a ring of radius 30 mm., in a dry spinning chamber identical with that used in Example 1, but with the walls heated to 115 C. and with the air passing down the chamber at a rate of 8 in. per hour.

A 130 decitex (120 denier) yarn consisting of 10 filaments each of 13 decitex (12 denier) and each having an X cross-section, is obtained at a speed of 200 m./ minute.

EXAMPLE 3 A solution containing the following is prepared:

Parts Cellulose triacetate 22 Methanol 11 Methylene chloride 67 This solution is heated 55 C. and extruded through a spinneret having 24 square holes of side length 0.04 mm.

4 arranged as in FIGURE 1, in a dry spinning chamber identical to that of Example 1 but with the walls heated to C.

Air is circulated down the chamber at a rate of 6 m5 per hour.

A 110 decitex denier) yarn consisting of 24 filaments each of 4.9 decitex (4.4 denier) and each having an X cross-section is obtained at a speed of 250 m./ minute.

I claim:

1. A process for obtaining yarns in which at least most of the elementary filaments have an X cross-section, which comprises dry Spinning a solution of a cellulose acetate in a volatile solvent selected from the group consisting of solutions of secondary cellulose acetate in acetone and solutions of cellulose triacetate in mixtures of methylene chloride and a lower aliphatic alcohol through a spinneret perforated with square holes, in which each hole has one diagonal making an angle less than 10 with the radius of the spinneret face passing through the center of the hole, as a result of which the drying conditions are substantially identical on two adjacent sides of each square hole.

References Cited UNITED STATES PATENTS 1,902,953 3/1933 Hazell. 2,880,106 3/ 1959 Hawtin 264-207 FOREIGN PATENTS 695,217 9/ 1964 Canada.

JULIUS FROME, Primary Examiner H. MINTZ, Assistant Examiner US. Cl. X.R.