US2807072A

US2807072A - Method of fabricating thermoplastic yarn

Info

Publication number: US2807072A
Application number: US464615A
Authority: US
Inventors: Jr Emory P Mersereau
Original assignee: Mohasco Industries Inc
Current assignee: Mohasco Industries Inc
Priority date: 1954-10-25
Filing date: 1954-10-25
Publication date: 1957-09-24
Anticipated expiration: 1974-09-24

Description

p 1957 E. P. MERSEREAU, JR

METHOD OF FABRICATING THERMOPLASTIC YARN Filed Oct. 25, 1954 INVENTQR. V 5/10 Y /75c/e54z/, fe

A fro/way United States Patent METHOD OF FABRICATING THERMOPLASTIC YARN Emory P. Mersereau, Jr., Thornwood, N. Y., assignor to Mohasco Industries, Inc., a corporation of New York Application October 25, 1954, Serial No. 464,615

7 Claims. (Cl. 2872) This invention relates to a method of making a fabric from yarn composed of synthetic thermoplastic materials and has for an object to produce a fabric having novel and improved characteristics.

Another object is to produce a woven pile fabric of the above type in which the pile is cockled or coiled.

Another object is to provide a method for temporarily setting a cockled or coiled synthetic thermoplastic yarn in straight condition for weaving.

Another object is to provide a method for treating such a yarn to cause the yarn to assume a permanent cockled or coiled form after having been woven while in a temporarily straight form.

Other objects and advantages will be apparent as the nature of the invention is more fully disclosed.

U. S. Patent No. 2,662,558 describes a method of making a coiled pile tuft which involves giving a hard ply twist to a yarn composed of two or more plies, permanently setting the ply twist, then twisting the yarn in the reverse direction a sufiicient number of turns to pass the Zero twist point and impart a loose twist in the reverse direction, and temporarily setting the reverse twisted yarn while held under sufiicient tension to maintain the yarn straight. The straight set yarn is then woven as pile in a pile fabric in an Axminster loom after which the temporary straight set is removed, whereupon the yarn coils upon itself with the plies separated to form interleaved helices due to the internal strains produced by the reverse twist.

When synthetic thermoplastic yarns are used, such as nylon, Orlon, Dacron, Acrilan, saran or the like which have well defined memory characteristics, they may be permanently set in the hard twisted, plied condition by suitable heat treatment to bring the yarns to the plastic condition required to remove the internal strains which give rise to the memory characteristic. However, such yarns, after reverse twisting cannot be temporarily set by heat alone since the heat would be ineffective until the above plastic conditions are reached and this would produce a permanent set in the reverse twisted form instead of the temporary set which is desired. Since such yarns are hydrophobic the addition of moisture likewise is ineffective.

In accordance with this invention the thermoplastic yarn is set temporarily in straight form by first pulling the yarn straight, then coating the yarn with a soluble sizing which is capable of forming a protective coating on the yarn of sutficient stiffness to overcome the physical forces which tend to cause the yarn to cockle or coil and is capable of holding the yarn in straight, but flexible form suitable for weaving. The effect continues until the coating is removed by washing or dissolving the coating after which the yarn is free to assume its natural form. The temporary set must of course be removed before the cold flow of the yarn produces a permanent set in its straight form. For most yarns of the above type many months at least would be required for this to take place so there 2,807,072 Patented Sept. 24, 1957 ice , 2 is no practical limitation as to the time between treating and weaving.

Examples of sizing agents which can be used are: Sodium polyacrylate, methyl cellulose, polyvinyl alcohol, cooked cornstarch.

As a specific example, nylon staple is spun into a suit able singles yarn and is then ply twisted to a high ply twist in the same direction as the singles twist, or in the reverse direction depending upon the result desired. A ply twist in the same direction usually produces a harder yarn which will coil more effectively in the final treating step. The yarn may then be skein dyed, the fibers may have been stock dyed prior to spinning, or the yarn may remain in undyed form prior to weaving, as desired.

The yarn in its high twist form is then permanenfly set by subjecting the same to steam under pressure or by heating under conditions commonly used for setting thermoplastic yarn.

The permanently set yarn is then reverse twisted to impart a final ply twist of the opposite hand of about onehalf the number of turns of the original ply twist.

The reverse twisted yarn is then dipped in a 0.24% solution of sodium polyacrylate (dry solids basis). After immersion the yarn is dried under straightening tension at F. for one-half hour or under equivalent drying conditions to leave a dry coating of the sodium polyacrylate on the yarn.

The yarn now remains straight and can be woven as cut pile on an Axminster loom or over pile wires on a velvet or Wilton loom or may be fabricated into upholstery fabric, flat fabric, or a knitted fabric using the usual fabricating techniques.

After fabrication the fabric is treated with wet steam at atmospheric pressure or with warm water to remove the coating and allow the yarn to assume a shape to relieve its internal strains. The reverse twisted yarn above described coils into helical form with the plies separated and forming interleaved helices as shown in the Mersereau et al. patent above mentioned. In the case of flat or knitted fabrics the yarn coils to produce increased fullness and also contracts in a lengthwise direction.

The same technique can be employed for other types of yarns which are to be temporarily set. For example hard twisted frieze yarn which is twisted to a point where it tends to cockle when released can be temporarily straight set as above described, woven as pile, or otherwise fabricated into fabric and relaxed to assume its cockled form.

A typical pile fabric embodying this invention is shown in the drawing wherein the figure is a detail view of an Axminster pile fabric. The pile fabric is shown as comprising a backing 10 and a plurality of pile tufts 11 which are composed of multiply yarn with the plies 12 separated and coiled into the form of interleaved helices.

Various other embodiments will be apparent to a person skilled in the art.

What is claimed is:

1. The method of making an Axminster pile fabric, which comprises hard twisting a synthetic thermoplastic multiply spun yarn in one direction, heating said yarn to permanently set the same, reverse twisting said yarn to impart a loose final reverse twist, applying to said yarn while under straightening tension a coating of a material having sufiicient stiffness to resist the internal forces produced by said reverse twisting, weaving an Axminster fabric employing said coated yarn as the pile yarn, and subjecting said fabric to a treatment for removing the coating from said coated multiply yarn and causing the plies of the pile yarn to separate and coil into the form of interleaved helices.

2. The method of making an Axminster pile fabric, which comprises hard twisting a synthetic thermoplastic multiply spun yarn in one direction, heating said yarn to permanently set the same, reverse twisting said yarn to impart a loose final reverse twist, dipping said yarn in a coatingsolution of sodium polyacrylate, drying-saidyarnwhile the same is held under straightening tension, weaving ani Axminster fabric employing said coated yard as the pile yarn, and subjecting said fabric to a treatment forrernoving the coating from said coated multiply yarn and causing the plies of the pile yarn to separate and coil info the form of interleaved helices.

3. The method set forth in claim 1' in which said coating material comprises sodium polyacrylate.

4. The method set forth in claim 1 in which said coating material comprises methyl cellulose.

5. The method set forth in claim 1 in which said coating material comprises polyvinyl alcohol.

6. The method set forth in claim 1 in which said coating material comprises cooked cornstarch.

7. A fabric produced in accordance with the method set forth in claim 1.

References Cited in the file of this patent UNITED STATES PATENTS 2,018,017 Fulton et al Oct. 22, 1935 2,089,947 Dickie et al Aug. 17, 1937 2,089,948 Dickie et al. Aug. 17, 1937, 2,265,202 Schneider et a1. Dec. 9, 1941 2,401,828 Kahil June 11, 1946 2,662,588 Mersereau et a1 Dec. 15, 1953 2,771,660 Ephland Nov. 27, 1956