US3852947A

US3852947A - Flame retardant fiber blend

Info

Publication number: US3852947A
Authority: US
Inventors: M Mayer
Original assignee: Celanese Corp
Current assignee: Celanese Corp
Priority date: 1971-12-10
Filing date: 1971-12-10
Publication date: 1974-12-10
Anticipated expiration: 1991-12-10

Abstract

There is provided a flame retardant fiber blend which is especially useful for children''s sleepwear. This blend is comprised of from about 10 to about 90 percent (by weight of blend) of polyester fiber and at least 10 percent (by weight of blend) of a flame-retardant acetate fiber which is comprised of from about 0.5 to about 25 percent (by weight of acetate fiber) of at least one tris(polyhaloaliphatic) phosphate.

Description

United States Patent Mayer 1 1 Dec. 10, 1974 [5 1 FLAME RETARDANT FIBER BLEND 3,744,534 7/1973 Henry et a] 57/140 BY x [75] Inventor: Michael Dainis Mayer, Charlotte,

N.C. Primary Examiner-John Petrakes [73] Assignee: Celanese Corporation, New York, Attorney Agent or Firm-Thomas Morgan [22] Filed: Dec. 10, 1971 [57] ABSTRACT Appl. No.: 206,852

US. Cl 57/140 BY, 161/169 Int. Cl D02g 3/04, D02g 3/44 Field of Search.... 57/140 R, 140 BY; 161/169, 161/170, 168

References Cited UNITED STATES PATENTS 5/1973 Feller 57/140 R 8 Claims, N0 Drawings FLAME RETARDANT FIBER BLEND This application relates to a novel fiber blend which is useful for the preparation of flame-retardant childrens sleepwear.

The childrens sleepwear market is currently dominated by 100 percent cotton fabric sleepers and by nylon/acetate and nylon/triacetate napped tricot fabrics for nightgowns; the aforementioned fabrics are very flammable.

Because of possible danger to young children in wearing flammable sleepwear, the Secretary of Commerce recently issued the Childrens Sleepwear Standard for the Flammability of Childrens Sleepwear (DOC FF 3-71, issued July 27, 1971). This standard, which covers any product of wearing apparel up to and including size 6X ...intended to be worn primarily for sleeping or activities related to sleeping..., sets forth a test via which one can determine whether any specified piece of wearing apparel will meet acceptance according to the standard.

There thus is a vital commercial need for childrens sleepwear which will pass the aforementioned test. Accordingly, it is an object of this invention to provide a fiber-blend which can be used to make flame-retardant childrens sleepwear.

In accordance with this invention, there is provided a flame-retardant fiber-blend comprised of at least 10 weight percent (by weight of blend) of flame-retardant acetate fiber and from about 10 to about 90 weight percent (by weight of blend) of polyester fiber, wherein:

1. said flame-retardant acetate fiber is comprised of from about 0.5 to about 25 weight percent of at least one tris(polyhaloaliphatic) phosphate containing from about 3 to about 24 carbon atoms, and

2. at least 90 weight percent of the remainder of the fiber-forming material in said blend (i.e., the material which is not flame-retardant acetate) consists of polyester.

The term acetate" as used herein refers to a fiber in which the fiber-forming substance is cellulose acetate, and this term is generic to both primary and secondary acetate. Cellulose triacetate (primary acetate) is a cellulose ,ester having less than 0.29 free hydroxyl groups per anhydroglucose unit and an acetyl value of at least about 60 percent; another definition which may be used in that primary acetate is cellulose acetate wherein not less than 92 percent of the hydroxyl groups are acetylated. Secondary acetate fibers are generally considered to be those having an acetyl value of less than 59 percent, more particularly between about 50 to about 58 weight percent calculated as acetic acid.

The acetate fibers used in this invention are flame retarded by the inclusion therein of from about 0.5 to about 25 percent (by weight of acetate fiber) of at least one tris(polyhaloaliphatic) phosphate. It is preferred that the acetate fiber be comprised of from about 3 to about 18 weight percent of said phosphate, and it is even more preferred that from about 3 to about 10 weight percent be used. in the most preferred embodiment, from about 3.5 to about 7 weight percent of said phosphate comprises the acetate fibers used in this invention.

The prior art discloses some of the flame-retardant acetate fibers used in this invention. Reference may be had, e.g., to British Pat. Nos. 973,355 and 958,120, the disclosures of which are hereby incorporated by reference.

It is preferred that the tris(polyhaloaliphatic) phosphate contain from about 3 to about 24 carbon atoms, and it is even more preferred that it contain from about 2 to about 8 carbon atoms. The halogen substituents on the phosphate may be bromine. Thus, e.g., some preferred phosphates include, e.g., tris(dibromoethyl) phosphate, tris(tribromomethyl) phosphate, tris(dibromoethyl) phosphate, tris(tribromoethyl) phosphate, tris(tetrabromoethyl) phosphate, tris(pentabromoethyl) phosphate, tris (dibromopropyl) phosphate, tris(tribromopropyl) phosphate, tris(tetrabromopropyl) phosphate, tris(pentabromopropyl) phosphate, tris(hexabromopropyl) phosphate, tris(heptabromopropyl) phosphate, tris(dibromobutyl) phosphate, tris(tribromoheptyl) phosphate, tris(tetrabromooctyl) phosphate, and the like. Alternatively, the phosphate may be substituted by both bromine and chlorine (subject to the limitation that there is at least one bromine substituent on each of the alkyl groups of the phosphate); tris(1-bromo-3-chloroisopropyl) phosphate, e.g., works especially well. The most preferred phosphate is selected from the group consisting of tris(2,3-dibromopropyl) phosphate and tris(l-bromo- 3-chloroisopropyl) phosphate.

When the flame-retardant acetate fiber used in this invention is fiber-blended with other fibers, the resulting fiber-blends generally fail the test set forth in Children's Sleepwear Standard DOC FF 3-7l. Thus, e.g., when 35 per cent (by weight of fiber blend) of flame retardant acetate is fiber-blended with either regular acetate fiber (which does not contain the aforementioned phosphate), nylon fiber, modacrylic fiber, acrylic fiber, flame-retardant rayon fiber, rayon fiber, or cotton fiber, each of the fiber-blends produced fails the aforementioned flammability test. Polyester fiber is not inherently more inflammable than, e.g., nylon fiber, and thus it is very unexpected and surprising that a fiber-blend of flame-retardant acetate fiber with polyester fiber passes said flammability test.

A textile article comprised solely of flame-retardant acetate will pass the aforementioned flammability test; however for many uses it will not possess satisfactory strength or aesthetic properties. Textile articles made from the fiber-blend of this invention, however, are self-extinguishing (and pass the flammability test) and have improved aesthetics and durability; moreover they are more economical than fabrics consisting of only flame-retardant acetate or flame-retardant polyester.

The fiber-blend of this invention is comprised of at least 10 percent (by weight of blend) of flameretardant acetate fiber. It is preferred that it be comprised of at least 25 percent (by weight of blend) of flame-retardant acetate fiber, and it is most preferred that it be comprised of at least 50 weight percent of such acetate fiber. At least 90 percent (by weight of blend) of the remainder of the fiber in said fiber blend consists essentially of polyester fiber; it is preferred that all of the remainder of the fiber in the fiber blend consist essentially of polyester fiber. As used herein, the term polyester refers to a manufactured fiber in which the fiber-forming substance is any long chain synthetic polymer composed of at least percent by weight of an ester of a dihydric alcohol and terephwherein n is from 2 to 10 (preferably n is 2 to 4 and most preferably n is 2).

Textile articles made from the fiber-blend of this invention are self-extinguishing," i.e., they are fire resistant to the extent that once an igniting flame has ceased to contact unburned parts of the textile structure the article has the inherent ability to resist further propagation of the flame along its unburned portion, thereby stopping the internal burning process. Recognized tests to determine whether a textile article is selfextinguishing include, inter alia, the American Association of Textile Chemists and Colorists Test Method 34-1966 and the National Bureau of Standards Test described in DOC FF 3-71.

The term blend" as used herein refers to both mixtures (wherein two or more types of staple, e.g., are combined so that the components remain visually distinct from each other on close examination) and blends (wherein the fibers are combined so intimately that in the final yarn or fabric it is difficult to distinguish the component fibers). The fiber-blend of this invention may be prepared by any of several methods well known to the textile art. Thus, e.g., fiber-blending prior to textile processing or draw-frame-blending of sliver stock may be used. Thus, e.g., a wet lay process may be used. Thus, e.g., a process wherein two or more beams of filament or staple yarn are employed to prepare a tricot fabric may be used. Nay, any process which provides a textile structure (such as a yarn or a fabric) with the specified combination of fiber types will provide a fiber blend" within the meaning of this invention and may be employed.

It is understood that, although not necessary to the present invention, the polyester component of the fiber-blend may also contain a flame retardant additive.

Char Length (5.5" max.)

weight percent of flame-retardant acetate.

The fabric was washed, rinsed, and then subjected to the AATCC-34-66 Vertical Flammability Test (no glass thread); its performance is shown below:

Course direction Wale direction Burn Time (2 sec. max.)

() Glow Time (2 sec. max.) 0

This fabric is superior to the best prior art childrens sleepwear fabric. Prior to this invention, the only way to produce cellulosic sleepwear fabrics which were flame retardant was to treat these fabrics with a flame retardant finish; this finish treatment is expensive, has a limited durability to washing, and renders treated cotton fabrics weak and stiff. The fabric of this invention is superior to cotton fabrics treated with a flame retardant finish inasmuch as the former has good aesthetics, superior fabric strength, permanence to washing, dry cleaning, and bleaching, and is neither toxic nor irritating to the skin; furthermore the former is cheaper than the latter.

Example 2 A spun single knit jersey fabric with a density of 6 ounces per square yard was produced from a 50/50 polyethylene terephthalate/flame-retardant acetate 10/1 cc spun yarn; the flame retardant acetate was comprised of 4 weight percent of tris(2,3-

f dibromopropylphosphate). This fabric passed AATCC test 34-66, having a Wale direction burn time of 0 seconds, a glow time ofO seconds, and a char length of 3.5 inches. Example 3 The following fiber blends (yarns) were prepared from 3 denier per filament 1.5 inch flame-retardant ac- 0 etate staple (which is comprised of4 weight percent of tris(2,3-dibromopropylphosphate) and polyester.

Percent Flame I Retardant Acetate Percent Specified Polyester Polyester Used 10 2.25 d.p.f. 1.5" polyester 25 2.25 d.p.f. l 5" polyester 25 L5 d.p.f. l 5" polyester 35 2.25 d.p.f l 5" polyester 35 2.25 d.p.f. 1.5" polyester 2.25 d.p.f. l.5" polyester 50 L5 d.p.f. 1.5 polyester In order to better illustrate their invention, applicants present the following examples which are not to be deemed limitative of their invention. Unless otherwise stated, all parts are by weight and all temperatures are in degrees centigrade.

EXAMPLES Example 1 A napped tricot fabric with a density of 2.5 ounces per square yard was knitted with ajersey stitch from 40 denier polyethylene terephthalate (back bar) and denier acetate which was comprised of 4 weight percent of tris-(2,3-dibromopropyl-phosphate); this fabric was comprised of 33 weight percent of polyester and 67 In each of the above cases, the polyester used was poly (ethylene terephthalate). When 6 ounce/square yard jersey fabrics produced from each of the aforementioned yarns lO/l cc spun yarn) are tested by the childrens sleepwear standard test, the fabrics pass the test,

I having a char length of from 1.5 to 2.5 inches and no Example 6 The following fiber blends were made from 3.0 d.p.f. 2 inch flame-retardant acetate staple (comprised of 4 weight percent of tris-2,3-dibromopropylphosphate) and modacrylic (Dynel):

Percent of Specified Modacrylic Percent Flame Modacrylic Used Retardant Acetate 90 3.0 d.p.f. 2" 75 25 3.0 d.p.f. x 2" 65 35 3.0 d.p.f. 2" 50 50 3.0 d.p.f. x 2'' Each of these blends when made into a jersey fabric with a density of 6 ounces/square yard burned the entire length of the fabric when tested in accordance with AATCC 34-66. It is noteworthy that fabrics made from either 100 percent of modacrylic or 100 percent of flame-retardant acetate pass the AATCC 34-66 test.

Example 7 A blanket sleeper fabric with a density of 10 ounces/- square yard was made from a polyester/flame-retardant acetate/acrylic blend. The back yarn was 16/] cc 50/50 1.5 d.p.f. X 1.5 inch polyester/3.0 d.p.f. X 1.5 inch flame-retardant acetate. The face yarn was 50/50 3.0 d.p.f. 2 inch modacrylic/3.0 d.p.f. 2.0 flame-retardant acetate. This three way blend fabric burned when tested by AATCC 34-66 and failed the test.

A blanket sleeper with a density of 10 ounces/square yard was made with the back yarn described above but with a face yarn of 100 percent 3.0 d.p.f. 2 inch flameretardant acetate. It passed the aforementioned AATCC test.

Example 8 When, in substantial accordance with Example 1, flame-retardant acetate and flame retardant rayon (the latter containing about 20 weight percent of tris[2,3- dibromopropyl] phosphate) were blended in dry lay non-woven fabrics and tested by AATCC 34-66, the fabrics failed the test..

Example 9 An 80/20 tricot fabric with a density of 2.5 ounces/- square yard produced using 80 percent of 55 denier flame-retardant acetate on the face of the fabric and 20 percent of 15 denier nylon 6.6 yarn on the back of the fabric was produced. This fabric was not selfextinguishing and thus failed the AATCC 34-66 test.

As used herein, the term fiber-blend refers to staple blends, filament blends, fabrics, and the like. Thus, e.g., a doubleknit fabric comprised of the specified amounts of flame-retardant acetate fiber and polyester fiber is within the scope of this invention. A dou bleknit fabric comprised of at least 30 weight percent of yarn ends composed of a blend of polyester and flameretardant acetate also is within scope of this invention. In said fabric it is preferred that the polyester and acetate yarns be continuous filament yarns of opposite torque which are randomly intermingled.

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 flame-retardant fiber-blend comprised of at least 10 weight percent (by weight of blend) of flameretardant acetate fiber and from about 10 to about weight percent (by weight of blend) of polyester fibers, wherein:

a. said flame-retardant acetate fiber is comprised of from about 0.5 to about 25 weight percent of at least one tris(polyhaloaliphatic) phosphate containing from about 3 to about 24 carbon atoms, and

b. said polyester fiber comprises at least 90 weight percent of the non-flame-retardant acetate fibers of the blend.

2. The fiber-blend of claim 1, wherein:

a. said flame-retardant acetate is comprised of from about 3 to about l8 weight percent of said phosphate,

b. said polyester is poly(ethylene terephthalate), and

c. at least about 25 percent of said fiber blend is comprised of said flame-retardant acetate fiber.

3. The fiber-blend of claim 2, wherein said phosphate is tris(dibromopropyl) phosphate and said acetate fiber is comprised of up to about 10 weight percent of said phosphate.

4. The fiber-blend of claim 3, wherein said phosphate is tris (2,3-dibromopropyl) phosphate and said phosphate comprises from about 3.5 to about 7 weight percent of said flame-retardant acetate fiber.

5. The fiber-blend of claim 2, wherein said phosphate is tris( l-bromo-3-chloroisopropyl) phosphate and said acetate fiber is comprised of up to about 10 weight percent of said phosphate.

6. A doubleknit fabric of enhanced flame resistance comprising an effective proportion of at least 30 weight percent of yarn ends composed of the fiber-blend of claim 1.

7. The fabric of claim 6, wherein said yarn ends comprise a false twist textured continuous filament poly- (ethylene terephthalate) yarn randomly intermingled with at least 10 weight percent (by weight of yarn ends) of a false twist textured, continuous filament, flameretardant acetate yarn, said acetate yarn being comprised of from about 0.5 to about 25 weight percent of at least one tris(polyhaloaliphatic) phosphate.

8. The fabric of claim 7, wherein said false twist textured yarns are of opposite torque.

Claims

1. A FLAME-RETARDANT FIBER-BLEND COMPRISED OF AT LEAST 10 WEIGHT PERCENT (BY WEIGHT OF BLEND) OF FLAME-RETARDANT ACETATE FIBER AND FROM ABOUT 10 TO ABOUT 90 WEIGHT PERCENT BY WEIGHT OF BLEND) OF POLYESTER FIBERS, WHEREIN: A. SAID FLAME-RETARDANT ACETATE FIBER IS COMPRISED OF FROM ABOUT 0.5 TO ABOUT 25 WEIGHT PERCENT OF AT LEAST ONE TRIS(POLYHALOALIPHATIC) PHOSPHATE CONTAINING FROM ABOUT 3 TO ABOUT 24 CARBON ATOMS, AND B. SAID POLYESTER FIBER COMPRISES AT LEAST 90 WEIGHT PERCENT OF THE NON-FLAME-RETARDANT ACETATE FIBERS OF THE BLEND.

2. The fiber-blend of claim 1, wherein: a. said flame-retardant acetate is comprised of from about 3 to about 18 weight percent of said phosphate, b. said polyester is poly(ethylene terephthalate), and c. at least about 25 percent of said fiber blend is comprised of said flame-retardant acetate fiber.

5. The fiber-blend of claim 2, wherein said phosphate is tris(1-bromo-3-chloroisopropyl) phosphate and said acetate fiber is comprised of up to about 10 weight percent of said phosphate.

7. The fabric of claim 6, wherein said yarn ends comprise a false twist textured continuous filament poly(ethylene terephthalate) yarn randomly intermingled with at least 10 weight percent (by weight of yarn ends) of a false twist textured, continuous filament, flame-retardant acetate yarn, said acetate yarn being comprised of from about 0.5 to about 25 weight percent of at least one tris(polyhaloaliphatic) phosphate.