US3713347A

US3713347A - Spinning tape

Info

Publication number: US3713347A
Application number: US00121360A
Authority: US
Inventors: E Atwell; H Ballard
Original assignee: Burlington Industries Inc
Current assignee: BI/MS HOLDINGS I Inc A DE CORP
Priority date: 1971-03-05
Filing date: 1971-03-05
Publication date: 1973-01-30
Anticipated expiration: 1990-01-30

Abstract

A spinning tape which has a cured resorcinolformaldehyde/latex finish thereon, the tape being characterized by its essential freedom from lint build-up and glazing in use.

Description

United States Patent 11 1 1111 3,713,347 Atwell et al. 1 1 Jan. 30, 1973 [54] SPINNING TAPE [56] References Cited [75] Inventors: Everett C. Atwell, Greensboro, UNITED STATES PATENTS Banard south 3,533,830 10/1970 Marzocchietal ..117/126 GB x 3,583,882 6/1971 Bartrug ..117/126 GBX [73] Assigneez Burlington Industries Inc" Green- 3,156,084 ll/l964 Van Dijk'et a1. ..57/51.6x

Show NC 3,444,1 16 5/1969 Gagnon et al. ..117/126 GB x 3,506,476 4/1970 Marzocchi ..117/126 GB X [22] Filed: March 5,1971 3,437,610 4/1969 Moult ..117/126 GB X [21] Appl' 121360 Primary Examiner-Leonard l-l. Gerin Attorney-Cushman, Darby & Cushman [52] U.S. C1 ..74/231 R, 74/231 P, 74/231 S,

117/126 GB [57] ABSTRACT 49 5 3 g g A spinning tape which has a cured resorcinolformaldehyde/latex finish thereon, the tape being characterized by its essential freedom from lint build-up and glazing in use.

9 Claims, 2 Drawing Figures PAIENIEIlmso um I 3713.347

, sum 1 or 2 BY a Z i A'TTORTT?YT1 v SPINNING TAPE The present invention relates to a novel textile tape which is suitable for use in various textile operations, e.g. in the form of an endless belt to drive a spindle in a yarn twisting or spinning apparatus.

Conventional twisting or spinning tapes tend to pick up lint which causes uneven spindle speed and a resultant lack of uniformity in the yarn twist. Considerable effort has been directed towards over-coming the problems associated with lint pickup and there has been some degree of success in this direction. However, in most instances, this has brought about a rather substantial increase in the cost of the tape.

A particularly complicating factor on tape performance has been the development and use of greatly increased spindle speeds of, for example, 8 12,000 RPM. Heat tends to build up in the tape at these high speeds with the result that synthetic fibers therein, e.g. nylon 6 or 66, may melt and cause a glazing condition which brings about early breakage of the tape. Such degradation and early breaking can be avoided with the use of Nomex polyamide fibers (E. I. DuPont) which do not melt at the temperatures of use. However, this is a very costly approach to the problem. Other altematives have included impregnation of the tape with various types of antistatic compositions but these have not been particularly effective because of other problems, e.g. undesirable glazing still occurs, the anti-static compositions lose their effectiveness during use, and/or the tape may be too smooth and thus suffers from poor driving traction.

In view of the foregoing, the principal object of the present invention is the provision of a tape of the type indicated, e.g. a spinning or twister tape, which is free from the above-mentioned disadvantages of prior art tapes. A more specific object of the invention is to provide such a tape which does not suffer from undesirable lint buildup and the problems attendant thereto even after long periods of use. Another specific object of the invention is to provide a tape which can be effectively utilized at high spindle speeds without undesired glazing and lint pickup and which is further characterized by its strength, abrasion resistance, improved coefficient of friction or driving traction and overall suitability for sustained use. Other objects will also be hereinafter apparent from the following detailed description of the invention and the accompanying drawings.

Broadly stated, the objects of the invention are realized by providing a tape which has a resorcinol-fonnaldehyde/latex finish thereon, referred to herein as RFL finish or finishing composition for convenience. The success of the invention is believed to be a function of the lowered resistivity provided by this finish, which permits a discharge of accumulated static to ground along the length of the treated tape as the static is generated. Discharge to ground occurs through contact with metal components of equipment on which the treated tape is mounted. In this way, it is believed that the resorcinol-formaldehyde reaction product (or resole) and latex, both described in more detail later herein, cooperate together in some unique fashion to bring out the unexpected results of the invention, e.g.

the prevention of lint buildup on the tape, exceptional abrasion resistance and elimination of any tendency for melting or glazing of the tape. As an illustration, the

finish used herein can reduce the electrical resistivity of a nylon driving tape to l X 10 or even lower at 72 F. and a relative humidity of 65 percent compared to resistivity of more than 1 X 10 for the nylon tape without the finish thereon. This reduced resistivity represents a very substantial reduction in lint pickup when the tape is used to drive a high speed spindle.

The RFL finish used herein may be more specifically described as an aqueous emulsion or dispersion of a partially condensed resorcinol-formaldehyde reaction product and a synthetic rubber latex, e.g. a neoprene, styrene-butadiene and/or vinyl pyridine-butadienestyrene terpolymer latex. The properties of the tape processed according to the invention, e.g. abrasion resistance or electrical resistivity, can be suitably varied by selection of the latex or mixtures thereof. For instance, styrene-butadiene latex may give the lowest resistivity but abrasion resistance may not be as high as when a neoprene latex is used alone or blended with the styrene-butadiene latex. By suitable selecting the nature of the latex composition, the properties of the finished tape can be essentially tailored to give the optimum combination of properties for any particular type of use.

The resorcinol-formaldehyde reaction product is preferably a base catalyzed resole prepared as described in U. S. Pat. Nos. 3,030,230; 3,240,620; 3,240,649; 3,240,650 and 3,240,651, i.e. by partial reaction of resorcinol and formaldehyde using an alkaline catalyst, notably caustic soda. The subject matter of these patents is incorporated herein by reference.

One specific type of latex'useful herein is the vinyl pyridine-butadiene-styrene terpolymer latex available under the trade name Gentac (General Tire). Other equivalent terpolymers which may be used are available as Hycar 2518 (Goodrich) and Pyratex B (Naugatuck). These terpolymers may comprise, in parts by weight, from 50 to parts butadiene, 5 to 50 parts vinyl pyridine and, per parts of vinyl pyridine-butadiene, from 5 to 30 parts styrene. Typically suitable terpolymers for use herein are described in Mighton U.S. Pat. No. 2,561,215; Cislak et a]. U.S. Pat. No. 2,402,020 and Wilson U.S. Pat. No. 2,652,353.

Preferably the RFL finishing composition includes a neoprene latex as at least part of the latex component and advantageous results are obtained when such latex is used with a vinyl pyridine-butadiene-styrene terpolymer latex such as Gentac. Examples of available neoprene'latices are Neoprene 751 and Neoprene 750 (DuPont).

The ratio of resole to latex solids in the finishing composition used herein can be widely varied but usually will fall in the range of about 1:12 to about 1:25 in parts by weight and the molar ratio of resorcinol to formaldehyde in the resole will usually be about 121.2 to 1:275. An organic solvent may be included in the composition although organic solventfree compositions are preferred. Zinc oxide or other chlorine acceptor (5 15 percent on the weight of latex solids) may also be advantageously included in the finish, particularly when a neoprene latex is employed.

The solids content of the finishing composition can be widely varied depending on other operating conditions. Usually, however, the solids content of the finishing composition will fall in the range of -35 percent by weight although concentrations outside this range may also be used. In any event, it is preferred that the compositions be sufficiently thick that the fabric is' not completely impregnated. In other words, it is prefera- 5 tape and this may prevent them from moving indepen- 5 dently thus raising the possibility of early breakage of the tape. Then, too, since surface characteristics represent the essential consideration, complete im-' pregnation is somewhat wasteful inasmuch as finish within the fabric cannot contribute to these characteristics.

It will be recognized that the RFL finish may be applied to the tape in any convenient fashion, e.g. by knife coating, dipping, padding or spraying. Ad-

vantageously, the tape is treated by a clipping and wiping technique or by dipping and nipping.

The amount of finish applied to the tape will vary depending on various factors such as the weight and construction of the tape. However, in the usual case, the solids add-on will. be in the range of 5-25 percent by weight of the fabric. 7

After application of the finish, the tape should be dried and then cured. Various drying temperatures and techniques may be used for this purpose. For example, the tape, after padding on the RFL finish and wiping off excess, may be passed through a continuous drying apparatus where the tape is contacted with a countercurrent flow of drying air at the desired temperature (e.g.

up to 230 F.). Curing may be accomplished by heating in an oven or the equivalent at, for example, 320-375 F. for 2-10 minutes.

Tapes, according to the invention may be woven, non-woven or knitted and they may comprise any desired yarn combination and/or construction. Thus,

any of the conventional twister or spinning tape constructions involving natural and/or synthetic yarns, e.g. cotton, nylon, polyester and the like, may be used. However, one spinning tape construction which has been found especially effective when processed in the manner described herein'in avoiding the lint build-up in the spinning of coarse short staple cotton, where lint build-up is normally a very serious problem, is a 100 percent filament nylon tape with a double-faced satin construction. This construction (referred to hereinafter as Tape A) is as follows:

Warp: Body Ends 204 of2l0/34/3/4 Type 330 DuPont Nylon Edge Ends 16 of 210/34/3/4 Type 330 DuPont Nylon Filling Picks: 51 of2l0/34/3/4 Type 330 DuPont Nylon Edge Weave: 2-2 Tape Body Weave: 4;! Top Satin 1-4 Bottom Satin Break Strength: 700 Pounds Apart from its outstanding resistance to lint build-up, I Tape A, when surface finished according to the invention,, demonstrates superior traction,

elongation, strength to weight ratio, wear or abrasion resistance and general overall performance when compared with an identical tape which does not include the RFL finish employed herein and other spinning tapes which are currently available.

Another specific tape construction (Tape B), which demonstrates outstanding performance characteristics, including freedom from lint build-up and glazing, when processed according to the invention, is made from cotton and polyester fibers (e.g. 37 percent cotton and 63 percent polyester). The construction of this tape is as follows:

Warp Ends Body and Edge 46 ends of 21/3 spun blend of 63% polyester and 37% cotton Filling Picks 34 of 21/3 spun blend of 63% polyester and 37% cotton Weave 2-2 Herringbone twill EXAMPLE 1 An RFL finish composition was prepared as follows:

(A) Resin Solution Parts Resorcinol 17.] 37% Formaldehyde 21.8 Sodium hydroxide pellets 0.85 Water 375.00 (6.25% total solids) 414.75 (B) Finish Parts 50% Neoprene latex 750 130 57% Zinc oxide paste 13 6.25% Resin solution (A) M5 558 Latex solidszresin solids 2.5:] Total solids in (8) Finish l7.6%

Preparation of Part A The water for Part A was measured into a clean resin preparation tank or drum. The caustic soda was then added with stirring until the caustic was dissolved. The resorcinol was then added and dissolved by stirring and the 37 percent formaldehyde was then added while the temperature of the mixture was kept between F and F The resulting mixture was aged at this temperature for 6 hours.

Preparation of Part B The neoprene latex was measured into a clean drum. Thereafter, the zinc oxide paste was added with thorough stirring and the resin solution (Part A, above) .was then added slowly while stirring. The water was mixed in and the resulting finish was then ready for use with a maximum storage time of up to 72 hours at room temperature or for longer periods under refrigeration.

220F., after each pass using hot air. Finish add-on mounted to 10 12 percent on a dry basis. The dried as otherwise indicated (parts and percentages being by weight). As indicated various different RFL finishes were used to determine their effect on abrasion resistance and electrical resistivity of the treated tape.

tape was then oven-cured at 350F. for 3 minutes. The 5 Example 4 shows the results obtained with no finish at resulting product was made into an endless belt by joinall and it will be noted that the electrical resistivity of ing together the ends and then used as the spinning tape the tape is considerably higher in this case. The examfor a ring spinning frame to spin cotton yarn at a spinples also show that when using styrene-butadiene latex die speed of 12,000 rpm. After 26 days of continuous exceptionally low resistivity is realized but the abrasion use, the tape was still operating in completely satisfacl resistance can be unfavorably affected. Preferably, tory fashion. There was no lint build-up on the tape therefore, styrene-butadiene latex is used in relatively during this period of operation and no significant abraminor proportion with, for example, neoprene latex, to sion was observed. obtain optimum abrasion resistance and electrical rek sistivity. The electrical resistivity was measured in conp 5 ventional fashion at 72F. and 65 percent relative hu- The process of Example 1 was repeated using Tape B midity. The abrasion resistance was measured after 100 above with essentially equivalent results. strokes on the Wyzenbeek abrasion tester.

Finish compositions Ratio latex Percent Percent Gentac SBR RF to ZnO dry abrasion Resistivity latex latex resin resin paste add-on loss (ASTM) 77. 2 3. 0x10 :0 11.2 07.5 2. 7x10 10:0 0 10.5 61.8 2. 0x10 10:0 15 15.0 04.1 2. 0 10 10=0 15 1a. a s1. 11 2. 6X10" 10:0 15 11. a s4. 2 241x10 10:0 0 10. 2 s0. 4 110x10 21:1 0 15.0 00.0 1.0 10 11:1 15 15. 5 00. a 7. 3x10 11:1 0 15. s 51. 5 123x10 8:1 15 12. 0 02. 5 2. 3x10 8:1 0 10.0 55. s 1. s 10 8:1 15 12.4 70. 0 4 0x10 EXAMPLE 3 the finish and wiping by pulling through parallel steelv rods with further drying to a total solids add-on of 18.2

percent. Essentially equivalent results were obtained with the tape finished in this way.

Further examples illustrating the invention and its advantages are set forth below, using the 100 percent nylon fabric and other conditions of Example 1 except The above examples 4-17 indicate that best overall results from the standpoint of abrasion resistance and reduced resistivity are realized using neoprene latex and resorcinolformaldehyde resin. As noted earlier, the use of SBR latex offers the best reduction in resistivity but does not give as good abrasion resistance as is obtainable with neoprene latex and/ormixtures thereof with Gentac" latex, and resorcinolformaldehyde resin.

The following further examples represent modifications of Examples 5-17. In each of these further examples the fabric was passed three times through the finish composition, the latter containing either 26.0 parts by weight of resorcinolformaldehyde resin and a latex to resin ratio of 5:1 (Examples 18-27) or 52 parts resin and a latex to resin ratio of 2.5:1 (examples 28-37).

Referring now to the drawings, FIG. 1, illustrates diagrammatically the manner in which the tape of the in and 16 and the front rolls 18 and 20. Roving R of cot-.

ton stapleor the like from a package 24 on creel 12 is fed over a roll guide 26 through a trumpet guide 28 between the rear rolls 14 and 16, the aprons 22 and front rolls 18 and 20. Drafting of the fibers of roving R occurs in the draft zone Z intermediate the front and rear rolls as the front rolls are rotated at a faster speed than the rear rolls.

The frame includes the bobbin 31 mounted for rotation by tape 32, the latter being driven by means not shown. The frame also includes a traversing ring 33 which is provided with the usual traveller 34 rotating about the traversing ring as the package P is formed from the staple fibers of the roving R. lt will be appreciated that, according to the present invention, tape 32 will be a tape which has been given a resorcinol-formaldehyde/latex finish as described in more detail above.

One way of processing the tape herein is illustrated diagrammatically in FIG. 2 of the drawings. As shown therein, tape T of suitable construction wound on spool 36 is passed into a dip tank 38 where it is coated or wet out in finish 40, passed through a through a pair of nip rolls 42, the top roll preferably being of rubber while the bottom roll is steel, for removal of excess finish, then vertically upwardly and downwardly between faces of a Chromalox unit 44 where water in the finish is driven off by heat. Thereafter the tape is passed into curing oven 46 wherein the finish is cured. The tape then makes several turns around a pull roll 47 so that no slippage can take place. Roll 47 is turned at constant speed while rolls 42 are turned by a variable speed drive so that tension on the tape can be adjusted. The further rolls 48 are fast turning and are covered with cloth or tape so as to exert enough drag on the tape to pickup the slack as it leaves roll 47 and convey the tape to one of several receiving boxes 49. All of the indicated rolls etc., can be associated with a number of guides (not shown) so as to carry multiple ends of tape through the process simultaneously.

Variations can obviously be made in tape speed, temperature of the curing oven 46, yardage in the oven, tension and pressure on the nip rolls. Two or more passes can be carried out by feeding directly from the boxes 49 into the dip box 38 or the tape emerging from the Chromalox unit 44 after the first dip and nip may be fed into a second dip and nip unit (not shown), then back through the Chromalox unit and then into the curing oven.

It will be appreciated from the foregoing that the tape is completed for use by bonding together the ends thereof to form, in essence, an endless belt. With the finish applied to the tape, it is possible to join the ends together in conventional manner, e.g. by inserting a polyamide strip between the overlapped ends and then applying pressure and heat sufficient to melt the strip. However, the bond formed is very weak. It is also possible to bond the ends by using uncured SBR rubber compounds or uncured neoprene rubber compounds in the form of 20-40 mil thick calendered sheets from which appropriate size strips are cut and used in the same manner as conventional polyamide strips, i.e. interposing the rubber strips between the overlapped ends and subjecting the same to heat and pressure. However, the indicated rubbers require a minimum cure time of 3 minutes, preferably 4, at a temperature of 390- 400F. This is no longer cure time than desired from a production standpoint. Accordingly, it is preferred to bond the tape ends together by means of an adhesive solution that will permit carrying out the bonding operation in a shorter time, preferably 1 minute or less. It has been found that an adhesive solution with a relatively high resorcinol content will perform in such fashion combined with the application of heat in the bonding step. It is believed that resorcinol and heat cause gelation and mutual bonding of the nylon fibers as heat and pressure are applied to create a more durable bond in a shorter time interval. One such adhesive solution consists of a second stage resorcinolformaldehyde resin in water and resorcinol flakes dissolved in water. The mixture is diluted to any desired viscosity by the addition of one or more volatileorganic solvents that are sufficiently miscible in water to form a clear solution of all the components, e.g. ethyl acetate. Resorcinol at elevated temperatures swells and softens nylon or like fiber in the tape and the second stage fusible resorcinol resin is also converted at such temperatures to an insoluble state. Under heat and pressure, this adhesive solution effects an excellent bond between the tape ends. Such bond is facilitated by the fact that the finish on the tape contains resorcinol-formaldehyde and latex which give excellent wetting and compatibility between the adhesive and the finish. As a specific example of an adhesive suitable for use in bonding together the ends of tape prepared according to the invention there may be mentioned the following formulationz Wet Solids Resorcinol flake 80.7 80.7

45% Koppers 11-2 1 min 42.8 19.3 Solvent (ethyl acetate) 76.5

This composition can be prepared by dissolving the resorcinolflake into the solvent while heating the latter and stirring followedby adding the Koppers R-2l70 solution. The latter-is a solution of a second stage, water-soluble phenol-formaldehyde resin dissolved in isopropyl alcohol. I I a The ends of the tape are prepared for bonding by cutting or scraping away the surface adjacent the ends, preferably on a bias, to give a smooth joint when the ends are overlapped. Normally, the ends are overlapped by about one-fourth three-eighths inch. The adhesive is then painted over the areas to be overlapped and the ends are superimposed and subjected to heat and pressure to complete the bond. Temperatures of the order of 250200F. with a pressure of 20-40, e.g. 30 psi, applied for 30-45 seconds provide a suitable bond. The temperature, time and pressure can be widely varied but in any case, care should be taken to insure that these conditions are not so severe that the yarns are mashed into a solid mass. In such state, the splice becomes stiff and will have a tendency to split length-wise or break at the juncture between the normal yarns and the mashed area. Care should also be taken to provide sufficient curing such that the bond will not soften in the presence of later generated heat.

Another suitable resorcinol adhesive solution contains 35-50 percent resorcinol, a mixture of solvents, and may contain 0.1-1.0 percent nylon 6 to aid in sealing the bond, and 0.5-2 percent formic acid to aid dissolution of nylon in the tape, as well as any added nylon. A trace of dyestuff may be included to provide desired color to the bonding agent. The solvent mixture may comprise 15-30 percent ethyl alcohol for quick evaporation to speed drying, 5-15 percent isopropyl alcohol', and 15-25 percent water. The latter components evaporate more slowly to retard drying, as desired. A preferred example of this composition is as follows, wherein the indicated amounts may be subject to 5-10 percent variation:

% By Weight Nylon 6 l Resorcinol 42 Ethyl Alcohol 26 lsopropyl Alcohol 10 Formic Acid 1 Water 20 This adhesive composition, in solution form, is painted over tape areas to be overlapped, which are then superimposed and subjected to heat and pressure, for example, at temperatures of 300-365F. for about 30-45 seconds in a spring loaded press set at a pressure in the range of 20-2,000 psi. to handle tapes of varying widths, for example from less than about 1% inch wide to greater than about 2 inches wide. A pressure in the range of 50-250 psi. is preferred.

As will be appreciated from the foregoing, tape prepared according to the invention is characterized by a number of desirable properties, e.g. reduced electrical resistivity (l X 10 ohms per square unit or even lower at 72F., 65 percent relative humidity) such as to eliminate or substantially reduce lint pickup even after long periods of continuous use; substantially reduced abrasion loss, better frictional characteristics for driving pulleys, and improved useful life.

Various modifications may be made in the invention described herein. Hence, the scope of the invention is defined in the following claims wherein:

We claim:

1. A spinning tape in the form of an endless belt, said tape being fabricated of textile fibers which would normally tend to pick up lint and glaze during use but having a cured resorcinol-formaldehyde/latex finish on the outer surface thereof whereby said tape is characterized by its essential freedom from lint built-up and glazing in use.

2. A tape according to claim 1 wherein the tape is woven of nylon and the latex in said finish comprises a neoprene latex.

3. A tape according to claim 2 wherein said latex also includes a vinyl pyridine-butadiene-styrene terpolymer latex.

4. A tape according to claim 3 wherein said finish is essentially only on the surface of said tape or at most only partially irnpregnates said tape.

5. In combination, a rotatable spindle and a spinning tape for rotating said spindle, said spinning tape being in the form of an endless belt, said tape being fabricated of textile fibers which would normally tend to pick up lint and glaze during use but having a cured resorcinol-formaldehyde/latex finish on the outer surface thereof whereby lint build-up on the tape and glazing thereof are avoided.

6. A tape according to claim 1 wherein the ends are bonded together with a strip of uncured rubber compound.

7. A tape according to claim 1 wherein the ends are bonded together by means of an adhesive comprising resorcinol and a resin from the group consisting of resorcinol-formaldehyde or nylon dissolved in organic solvent, said adhesive softening the tape to enhance adhesion and fusion b heat and pressure.

8. A tape accor mg to claim 3 wherein the textile fibers are nylon or polyester.

9. A tape according to claim 8 which is woven of nylon, said tape having an electrical resistivity of l X 10 ohms per square unit or lower at 72F, 65 percent relative humidity.

Claims

4. A tape according to claim 3 wherein said finIsh is essentially only on the surface of said tape or at most only partially impregnates said tape.

7. A tape according to claim 1 wherein the ends are bonded together by means of an adhesive comprising resorcinol and a resin from the group consisting of resorcinol-formaldehyde or nylon dissolved in organic solvent, said adhesive softening the tape to enhance adhesion and fusion by heat and pressure.

8. A tape according to claim 3 wherein the textile fibers are nylon or polyester.