US3367813A - Process for splicing ends of yarns - Google Patents

Description

United States Patent Cfifice 3,367,813 Patented Feb. 6, 1968 3,367,813 PROCESS FDR SPLICKNG ENDS F YARNS Winfried T. Holfeld, Wilmington, DeL, astignor to E. H. du Pont de Nernours and Company, Wilmington, Del. a corporation of Delaware No Drawing. Filed Feb. 2, 1965, Ser. No. 429305 8 Claims. (Cl. lid-? ABSTRAQT (BF THE DESCLOSURE This invention is concerned with the splicing of yarns, especially yarns of synthetic fibers. It is particularly concerned with a process of making strong, non-tacky splices of yarns of synthetic fibers in a short period of time.

Some textile operations, such as tufting for making pile fabrics, require yarns free of knots for economical operation. Tufting is an operation in which the yarns pass through the eyes of the tufting needles, and a knot in the yarn will cause an interruption of tufting. It is common practice to splice tufting yarns by means of a latex adhesive to yield a joint which will pass through the eye of the tufting needle. This splicing process is satisfactory for W001 yarns and the splice can be made readily and will quickly develop strength and become non-tacky. However, when this splicing method is used on yarns of synthetic fibers, the splices remain wet and tacky for an intolerable time and develop strength very slowly.

Since the latex adhesives which have been used for splicing wool yarns did not result in satisfactory dry splices rapidly for yarns of synthetic fibers, other adhesives and other means of cementing the ends of the yarns together have been tried. No other adhesives have been found to replace the lattices based on natural rubber or synthetic, rubber-like polymers. Ends of yarns have been fused together by means disclosed in Us. Patents 3,040,153 to Seney or 3,055,786 to Hendrix, but these processes are not suitable for use in the present invention.

It is, therefore, an object of the present invention to provide a process of making splices of yarns of synthetic fibers which splices will rapidly develop high strength and become non-tacky.

This and other objects are attained in the present invention in which there is supplied, to a latex adhesive on the ends of yarn to be joined, a finely divided, waterabsorbing powder, before or after overlapping the yarn ends. The union is then consolidated as by rubbing the splice between the fingers. In this simple fashion, the latex is promptly coagulated and rendered non-tacky, as is now accomplished when using such lattices in splicing wool.

Satisfactory solids for carrying out the present invention include a large number of finely divided solid materials which will absorb water. The preferred materials will not only absorb water but are positively charged particles which will hasten the coagulation of the latex, which normally is negatively charged. Thus the colloidal aluminas and other basic oxides or hydroxides of metals are most satisfactory for purposes of this invention. One of the preferred materials is a fibrous alumina monohydrate having the boehmite crystal lattice. The preparation of this alumina is described beginning at line 15, column 5, of US. Patent 2,915,475. Aluminas prepared from aluminum hydroxide or from basic salts of aluminum are also satisfactory. An amalgamated aluminum can be reacted with water to yield a very finely divided alumina which is suitable, after drying, for use in this invention. Bentonite, Fullers earth and other types of clay can be used if in a very finely divided state. Silica of or near colloidal particle size will serve in the present invention but is inferior to positively charged aluminas. A fine particle size silica can be prepared by burning silicon tetrachloride in oxygen. These materials are sometimes called aerogels, and are suitable for use in this invention. Aluminas can likewise be prepared by burning aluminum trichloride in oxygen. Finely powdered chalk, sometimes referred to as whiting or french chalk, is also satisfactory. If positively charged lattices are used, then the silicas and clays will peform more satisfactorily. Boric acid will also function satisfactorily but may offer a health hazard under some conditions. Salts of polyvalent metals will quickly coagulate the negatively charged adhesive latexes and can be used alone or with aluminas, silicas or clays to hasten the development of strong bonds.

Any particle size of the solid power can be employed. However, particles of micron size or smaller down to an impalpable fineness provide a relatively large surface area per unit weight of powder and may speed the conversion of the latex to a coagulated, non-tacky body. The quantity of solids applied need not be regulated. Simple immersion or dipping of the coated fiber ends (or splice) in a container of the dry powder is effective in applying a suitable quantity of the powder. Any other method of application can be used as well. The powder, of course, must be sufiiciently dry that it retains water adsorption capacity when used, and may be heated, if desired or necessary, to remove occluded moisture prior to use.

The invention preferably is practiced with the latex adhesives presently used in the textile industry for splicing wool. These can be of a natural or synthetic origin and are used in aqueous dispersion, suitably with minimum water content. Any other adhesive that will set-up promptly to a nontacky mass at room temperature upon abstraction of water can also be used. As already noted, the adhesive and powder can be applied to yarn ends which are then overlapped, or the yarn splice can first be made and the adhesive and powder then applied. Preferably, the yarn ends are relatively free from oil and greases during splicing.

The invention will be described further in conjunction with the following examples in which parts and percentages given are by weight unless otherwise indicated or apparent.

EXAMPLE I A 12 denier (1.33-Tex) filament is spun as a bicomponent fiber by the process of US. Patent 3,038,236 to Breen, from the following polymer solutions.

Polymer Solution II:

Terpolymer of:

Acrylonitrile 93.6% Methyl acrylate 6.0% 93 Sodium Styrenesulfonate 0.4% Tris(dibromopropyl)phosphate 7 Each solution contains about 29 parts of the polymer and 71 parts of dimethylformamide as solvent.

The spun fiber is washed, drawn, crimped, cut into 3 inch (7.6 cm.) staple and dried.

A homofiber is spun from polymer Solution II alone. This fiber after washing, drawing (2.3x), crimping, cutting and drying has a denier of 17 (1.89Tex).

The bicomponent fiber and the homofiber are blended in equal amounts and spun into a 1.25 Wool run (240-Tex) yarn with 4.5 turns per inch (1.77 turns per cm.) Z twist, two plied and twisted 3.0 turns per inch (1.18 turns per cm.) S.

Ends of this yarn are spliced by dipping each end up to 0.25 inch (0.6 cm.) into a commercial aqueous latex adhesive dispersion designed for splicing (Bordens Splic-lt). The ends are then dipped into a dry, colloidally fine powder of alumina having the boehmite crystal lattice structure made according to U.S. Patent 2,915,475 to Bugosh, and the ends then overlapped 0.5 inch (1.3 cm.) and rubbed between the fingers to entangle the fibers and to distribute the latex. The resulting splice is strong and non-tacky. Control splices are made in similar manner but without using the alumina. The bond strength is determined within one minute from the time the splice is made. The results for a number of splices are shown in Table I below:

TABLE I [Force (in lbs. and kilos) to pull spliced yarns apart] *Average.

The results in this table show that higher strength bonds are formed when the alumina is used than when it is not. Moreover, the splices made with alumina were also non-tacky whereas those without alumina remain tacky for several hours.

EXAMPLE II A denier (1.65Tex) staple fiber of a polyester of ethylene glycol and terephthalic acid is spun into a 1.25 wool run (240-Tex) yarn and this is two-plied. This twoply yarn is spliced by the method disclosed in Example I using the same adhesive with and without Waterabsorbing powders. The powders used are an alumina prepared according to U.S. Patent 2,915,475 and a silica aerogel made by burning silicon tetrachloride in oxygen. As in Example I, the yarn ends are dipped first in the latex adhesive dispersion, then in the alumina in one series of experiments and in silica in the other series. The results are shown in Table 11 below:

TABLE II.FORCE (IN LBS. AND KILOS) TO PULL SPLICED 4. EXAMPLE III A nylon 66 staple fiber of 3 inch (7.6 cm.) length and 15 denier is carded and spun into a 1.25 wool run yarn and two-plied to prepare a carpet yarn. This yarn is spliced with the same adhesive and powders used in Example II. Results are shown in Table III below:

TABLE III.FORCE (IN LBS. AND KILOS) TO PULL SPLICED YARN APART These measurements, like those in Examples I and II, are made within one minute after the splices are completed. Splices made with adhesive alone remain tacky for several hours whereas those with alumina or silica are non-tacky at the end of the splicing operation.

From the foregoing discussion and description it is evident that the present discovery constitutes a uniquely simple and effective process for splicing yarn ends of synthetic fibers. It will be appreciated that changes from the details given can be made without departing from the scope of the discovery. For example, any other splicing adhesive or other synthetic fiber can be substituted for those mentioned in the examples, such materials being well known in the art and commercially available.

I claim:

1. In the process of joining the ends of two yarns of synthetic fibers in which portions of those ends are arranged in overlapping relationship and an aqueous latex adhesive dispersion is applied to each yarn end portion, the improvement comprising applying to the aqueous latex dispersion a finely divided, dry desiccant solid material having an electrical charge opposite to that of the aqueous latex dispersion.

2. The process of claim 1 in which the yarn ends are first coated with said aqueous latex dispersion and dry solid material and then are overlapped to splice the end portions.

3. In a process for splicing ends of two yarns, the steps comprising arranging the yarn ends in overlapping relationship, dipping the overlapped end portions in an aqueous latex adhesive dispersion, then coating the latex covered yarn portions with finely divided dry desiccant solids having an electrical charge opposite to that of the aqueous latex dispersion.

4. A process in accordance with claim 3 in which the aqueous latex dispersion is negatively charged and the dry solids are positively charged, and pressure is applied to the solids-containing overlapped ends to consolidate the resulting joint.

5. A process of splicing two polyacrylonitrile yarns comprising the steps of arranging the ends of the yarns in overlapping relationship, coating the yarn ends with an aqueous latex adhesive dispersion that contains latex particles that are negatively charged, applying to the surface of the latex on the yarn ends dry positively charged particles of a desiccant solid, and consolidating the coated yarn ends to produce 9. splice.

6. A process in accordance with claim 5 in which the latex is a natural rubber latex and in which the dry solids comprise fibrous alumina monohydrate having the boehmite crystal lattice.

7. A process in accordance with claim 5 in which the latex dispersion is a synthetic polymeric material and the dry solids comprise fibrous alumina monohydrate having 2,121,717 6/1938 Sullivan 117163 the boehmite crystal lattice 2,169,225 8/1939 Copeman 280-1535 8. A process in accordance with claim 4 in which the 2,421,363 5/1947 Young 117-- 163 X synthetic fibers are composed of a material selected from 2,526,431 10/ 1950 Strickhonser 117-163 X the group consisting of polyacrylonitrile, nylon and 5 3,257,229 6/1966 Nielsen 117-100 polyesters.

References Cited EARL M. BERGERT, Primary Examiner.

UNITED STATES PATENTS M. L. KATZ, Assistant Examiner. 1,986,974 1/1935 Kellog 156158