US3727392A

US3727392A - Fibrillation jet

Info

Publication number: US3727392A
Application number: US00129738A
Authority: US
Inventors: J Gibbon
Original assignee: Fiber Industries Inc
Current assignee: Celanese Corp
Priority date: 1970-07-30
Filing date: 1971-03-31
Publication date: 1973-04-17
Anticipated expiration: 1990-04-17

Abstract

There is provided an improved forwarding jet especially useful where a fibrillatable tape is to be subjected to the action of at least four fluid twisting means. This apparatus is comprised of a housing having a tubular passageway therethrough for the passage of a fibrillatable tape and a fluid manifold for the delivery of pressurized fluid to said tubular passageway. Said tubular passageway is comprised of at least two spaced apart bores of common axis, each of said bores having a fluid passageway tangentially intersecting it at an angle of from about 15* to about 70* with respect to the common axis of said bores. The tangential intersection of the bores is of opposite incidence so that the direction of twist imparted to the tape is reversed between adjacent bores.

Description

United States Patent 91 [451 Apr. 17, 1973 Gibbon F IBRILLATION JET [75] Inventor: John D. Gibbon, Charlotte, NC.

[73] Assignee: Fiber Industries, Inc.

[22] Filed: Mar. 31, 1971 [21] Appl. No.: 129,738

Related US. Application Data [63] Continuation-impart of Ser. No. 70,713, Sept. 9,

[56] References Cited UNITED STATES PATENTS 2/1967 Pitzl ..57/157 F UX 1/1964 Breen et a1. ..57/34 B UX FOREIGN PATENTS OR APPLICATIONS 864,695 4/1961 Great Britain ..57/34 B 6,912,566 2/1970 Netherlands ..57/34 B PrimaryExaminer-Donald E. Watkins Attorney-Thomas J. Morgan, S. D. Murphy and H. J. Greenwald [57] ABSTRACT There is provided an improved forwarding jet especially useful where a fibrillatable tape is to be subjected to the action of at least four fluid twisting means. This apparatus is comprised of a housing having a tubular passageway therethrough for the passage of a fibrillatable tape and a fluid manifold for the delivery of pressurized fluid to said tubular passageway. Said tubular passageway is comprised of at least two spaced apart bores of common axis, each of said bores having a fluid passageway tangentially intersecting it at an angle of from about 15 to about 70 with respect to the common axis of said bores. The tangential intersection of the bores is of opposite incidence so that the direction of twist imparted to the tape is reversed between adjacent bores.

8 Claim, 3 Drawing Figures PATENTEDAFR 1 7197s FIG. 3

FIG. 2

' INVENTOR JOHN D. GIBBON BY & 2 v

FIBRILLATION JET This is a continuation-in-part of US. application Ser. No. 70,713 (filed Sept. 9, 1970).

As is disclosed in applicants copending application Ser. No. 70,713, an economical process for fibrillating a fibrilla-table tape comprises the step of subjecting a travelling fibrillatable tape under a tension of from about 0.05 to about 0.2 grams per denier to the action of at least four fluid twisting means wherein the direction of twist imparted to the tape is completely reversed between adjacent twisting means; the use of the tension on the tape insures good fibrillation.

When prior art fluid twisting means are used, there is a tension loss between adjacent twisting means. Thus, e.g., when the jets disclosed in New Zealand Pat. No. 149,327 and U. S. abandoned application Ser. No. 563,234 are used in the process of application Ser. No. 70,713, the tension loss encountered in one jet is sufiicient to put the tension in the second jet outside of the range of satisfactory operation. This tension loss may be overcome by technically complex and expensive devices; this, however, is not desirable.

It is thus an object of this invention to provide an improved fibrillation jet wherein the aforementioned tension loss does not occur so that two or more of said jets may be used on a single threadline without the need for costly devices to correct for tension loss. In accordance with this invention, there is provided a forwarding jet comprised of a housing having a tubular passageway therethrough for the passage of a fibrillatable tape and a fluid manifold for the delivery of pressurized fluid to said tubular passageway, said tubular passageway comprising at least two spaced apart bores of common axis with each of said bores having a fluid passageway intersecting it at an angle of from about 15 to about 70 with respect to the common axis of said bores, said intersection being at a tangent to said bores so as to impart a rotational motion to fluid exhausting into said bores, said tangential intersection being of opposite incidence in each succeeding bore thereby reversing the rotational motion in adjacent bores.

The jet of this invention is comprised of a housing having a tubular passageway therethrough. The tubular passageway need not be cylindrical; thus, e.g., an oval shaped passageway is within the scope of this invention. It is preferred, however, that the tubular passageway be cylindrical.

The tubular passageway is comprised of at least two coaxial bores; these bores do not communicate with each other. In each jet it is preferred that there be only two bores and that they each have the same diameter if they are cylindrical. It is also preferred that the bores have a perimeter of at least 3 millimeters apiece and that adjacent bores not be more than about 3 inches apart (as measured from center-point to centerpoint); it is more preferred that the bores have a perimeter of from about 5 to about 20 millimeters and that adjacent bores not be more than about 1 inch apart.

Each of the bores is tangentially intersected by a fluid passageway at an angle of from about to about 70 with respect to the common axis of said bores, said tangential intersection being of opposite incidence'in each succeeding bore (thereby reversing the rotational motion in adjacent bores). It is preferred that the angle formed by said fluid passageway with respect to said common axis be from about 30 to about 60, and it is more preferred that said angle be from about 45 to about 60.

It is preferred that the perimeter of each of the fluid passageways be at least 0.5 millimeters, and it is more preferred that said perimeter be from about 1.25 to about 10 millimeters.

In the preferred fibrillation process utilizing the jets of the instant invention, it is preferred that the ratio of the fibrillatable tape perimeter/bore perimeter be from about 0.1 to 1.5 (and preferably from about 0.3 to about 0.7) and that, when both the bores and fluid passageways are cylindrical, the ratio of the bore diameter/fluid passageway diameter be from about 0.1 to about 0.7 (and most preferably from about 0.2 to about 0.5

The fluid used in the jet of the instant invention may be virtually any gas which approaches ideal gas behavior and does not react with the tape to be fibrillated. Thus, e.g., air, steam, nitrogen, oxygen, carbon dioxide, etc. may be used in said process; because it is one of the cheapest gases, it is preferred to use air as said fluid. When said jet is used in the aforementioned fibrillation process, the fluid velocity should reach from about 0.5 to about 1.0 sonic velocity at the point of contact with the strand in each bore.

It is preferred to utilize at least two of the jets of the instant invention to fibrillate a fibrillatable tape. When this is done the distance between each jet should be as great as is practical; thus, e.g., two such jets may be from about 1 to about 1,000 inches apart. It is preferred that the two adjacent jets be from about 1 to about 500 inches apart, and it is more preferred that they be from about 1 to about 72 inches apart.

The jets of this invention maintain the fibrillatable tape under a tension of from about 0.05 to about 0.2 grams per denier, thereby insuring good fibrillation. The preferred tension is from about 0.05 to about 0.15 grams per denier, and the most preferred tension is about 0. 1 grams per denier.

In the fibrillation process using at least two of the jets of this invention, air (or another suitable fluid) is supplied to each of the jets at a pressure of from about 10 to about 250 p.s.i.g. The preferred pressure is from about 20 to about 100 p.s.i.g., and most preferred pressure is from about 40 to about 80 p.s.i.g.

Reference to FIGS. 1, 2, and 3 will illustrate one of the preferred embodiments of applicants invention.

FIG. 1 shows one of applicant's preferred fibrillation apparatuses. FIGS. 2 and 3 are cross-sectional views of the apparatus of FIG. 1, FIG. 2 being the view along line 22 and FIG. 3 being the view along line 3-3. Apparatus 10 is comprised of a U-shaped member with

coaxial bores

12 and 14 respectively; in applicants apparatus it is preferred thatthe housing be comprised of at least one tape string up slot (such as slots 16 and 18) for each of the bores. Fluid is supplied to manifold box 20 by connector 22 (which is supplied with a pressurized fluid such as, e.g., water or air), and this fluid then passes through

fluid passageways

24 and 26 into

bores

12 and 14 respectively. Said fluid passageways are essentially tangential to bores 12 and 14, and they intersect said bores at an angle of from about 15 to about degrees with respect to the common axis of said bores; they are positioned in

bores

12 and 14 so as EXAMPLES EXAMPLE Poly(ethylene terephthalate) with an intrinsic viscosity of 0.61 and 2 percent (by weight of polyethylene terephthalate) of polypropylene with a melt flowindex of 15 were mixed and then subjected in a pack to a shear force of 120 sec for about 1 second and extruded via a pack through a slit die (1 inch-X 0.0005 inch); the extrusion temperature was 280 centigrade. The extruded tape was quenched in water and spun. The spun tape was 10 mm wide and had a total spun denier of 3150. The spun tape was then drawn in a first stage at a draw temperature of about 110 centigrade and a draw speed of 175 feet per minute to a draw ratio of 3.5/1, and thereafter it was drawn in a second stage at a drawtemperature of about 200 centigrade and a draw speed of 120 feet per minute to a draw ratio of 1.4/1.

This tape was then fibrillated with one of the fibrillation apparatuses of the instant invention (comprising two fluid twisting means wherein the direction of twist imparted to the tape is completely reversed between adjacent twisting means) and two of said fibrillation apparatuses (hereinafter referred to as jets). The maximum speeds onecould use to get any given degree of fibrillation with one jet and two jets operated'at the same conditions are shown below.

Number of Fils/ Maximum Speed One Maximum Speed Q're Tape Can Use with One Can Use with Two .let to obtain the Jets to Obtain the Specified Degree Specified Degree of Fibrillation of Fibrillation (Feet/Minute) (Feet/Minute) (i.c., at no speed could the one jet give one this degree of fibrillation) 50 0 I70 40 70 300 35 I30 410 30 230 greater than 600 25 500 greater than 600 EXAMPLE 2 .A poly(ethylene terephthalate) tape was prepared in substantial accordance with the procedure described in Example 1, with the exception that the first stage draw ratio was 3.6/1, the first stage take-up speed was 1,080 feet per minute, the first stage draw temperature was 127 centigrade, the second stage draw ratio was 1.3/1, and the second stage take-up speed was the same speed as the fibrillation speed. The tape was comprised of poly(ethylene terephthalate) with an intrinsic viscosity of 0.61 and 2 percent polypropylene with a melt flow index of 15.

This tape was then fibrillated with one jet and two.

jets. The results are presented below.

Number of Fils/ Maximum Speed One Maximum SpeedOne Tape Can Use with One Can Use with Two Jet to Obtain the Jets to Obtain the Specified Degree Specified Degree of Fibrillation of Fibrillation (Feet/Minute) (Feet/Minute 30 650 greater than 2000 This example differs from Example 1 in that the tape was prepared at much higher drawing speeds; this effect increases the fibrillation for a given speed through a the jets and at the higher speeds make the fibrillation less sensitive to changes in speed.

It was observed that the use'of the two jets decrease the number of large filaments, thus contributing to the uniformity of the yarn. To quantify this observation the cross sections made for Example 2 were examined and the number of fils with a breadth to thickness ratio greater than 6 were tabulated. On averaging, the following results were obtained.

Wide Fil Count (Average) l jet 2 jets Temp. of 4.5 2.2 Speed effect averaged Hot Plate, I70 2.2 C 200 0.6 1 Speed 400 3.8 0.6 Temperature effects 800 4.0 1.6 average fpm 1200 3.8 2.0 1600 5.0 2.2 Overall average 3.7 1.5 Temp & speed effects Total averaged This experiment shows that the addition of the second jet is very effective in reducing the number of wide fils. Another effective method of reducing wide fils is to increase the hot plate temperature to 200 centigrade. With the use of two jets and a hot plate temperature of 200 centigrade, the incidence of wide fils was almost eliminated.

EXAMPLE 3 units are in deciliters/gram. Measurements may be made of relative viscosity (on an 8 percent solution polyester in orthochlorophenol) and converted to intrinsic viscosity by an empirical formula. The tape was 8 mm wide and had a total spun denier of 4,000. The draw ratio used was 5/1 and the draw speed was 1,500 feet per minute. The tape was fibrillated with one jet and two jets, and the results are shown below.

Although the above examples and descriptions of this invention have been very specifically illustrated, many other modifications will suggest themselves to those skilled in the art upon a reading of this disclosure. These are intended to be comprehended within the scope of this invention.

What is claimed is l. A forwarding jet comprised of a housing having a tubular passageway therethrough for the passage of a flbrillatable tape and a fluid manifold for the delivery of pressurized fluid to said tubular passageway, said tubular passageway comprising at least two spaced apart bores of common axis with each of said bores having a fluid passageway intersecting it at an angle of from about to about 70 with respect to the common axis of said bores, said intersection being at a tangent to said bores so as to impart a rotational motion to fluid exhausting into said bores, said tangential intersection being of opposite incidence in each succeeding bore thereby reversing the rotational motion in adjacent bores.

2. The jet of claim 1, wherein each of said bores has a perimeter of at least 3 millimeters and each of said fluid passageways has a perimeter of at least 0.5 millimeters.

3. The jet of claim 1, wherein the centerpoint of each of said bores is no further than about 3 inches away from the centerpoint(s) of its adjacent bore(s).

4. The jet of claim 1, wherein said housing is comprised of at least one tape string up slot for each of said bores, said tape string up slots communicating with said bores.

5. The jet of claim 1, wherein said tubular passageway is comprised of two of said bores.

6. The jet of claim 5, wherein:

a. said bores are cylindrical;

b. each of said bores has a perimeter of at least 3 millimeters, and each of said fluid passageways has a perimeter of at least 0.5 millimeters; 1

c. the centerpoint of each of said boreslis no'further than about 3 inches away from the centerpoint of the adjacent bore; and

d. said housing is comprised of one tape string up slot for each of said bores, said string up slots communicating with said bores.

7. The jet of claim 6, wherein: a a. said fluid passageways intersect said bores at an angle of from about 30 to about with respect to said common axis of said bores;

b. said bores have the same diameter; and

c. each of said bores has a perimeter of from about 5 to about 20 millimeters, and each of said fluid I passageways has a perimeter of from about 1.25 to about 10 millimeters.

8. The jet of claim 7, wherein:

a. the centerpoints of each of said bores are no further apart than about 1 inch, and

b; said fluid passageways intersect said bores at an angle of from about 45 to about 60 with respect to said common axis of said bores.

Claims

1. A forwarding jet comprised of a housing having a tubular passageway therethrough for the passage of a fibrillatable tape and a fluid manifold for the delivery of pressurized fluid to said tubular passageway, said tubular passageway comprising at least two spaced apart bores of common axis with each of said bores having a fluid passageway intersecting it at an angle of from about 15* to about 70* with respect to the common axis of said bores, said intersection being at a tangent to said bores so as to impart a rotational motion to fluid exhausting into said bores, said tangential intersection being of opposite incidence in each succeeding bore thereby reversing the rotational motion in adjacent bores.

6. The jet of claim 5, wherein: a. said bores are cylindrical; b. each of said bores has a perimeter of at least 3 millimeters, and each of said fluid passageways has a perimeter of at least 0.5 millimeters; c. the centerpoint of each of said bores is no further than about 3 inches away from the centerpoint of the adjacent bore; and d. said housing is comprised of one tape string up slot for each of said bores, said string up slots communicating with said bores.

7. The jet of claim 6, wherein: a. said fluid passageways intersect said bores at an angle of from about 30* to about 60* with respect to said common axis of said bores; b. said bores have the same diameter; and c. each of said bores has a perimeter of from about 5 to about 20 millimeters, and each of said fluid passageways has a perimeter of from about 1.25 to about 10 millimeters.

8. The jet of claim 7, wherein: a. the centerpoints of each of said bores are no further apart than about 1 inch, and b. said fluid passageways intersect said bores at an angle of from about 45* to about 60* with respect to said common axis of said bores.