US3296020A - Process for producing antistatic characteristic in nylon fibers - Google Patents

Description

3,296,020 PROCESS FOR PRODUCING ANTISTATIC CHAR- ACTERISTIC IN NYLON FIBERS Robert E. Sheehan, Bibb Mfg. Co., Macon, Ga. 31202 No Drawing. Filed Aug. 27, 1964, Ser. No. 393,011 12 Claims. (Cl. 11'7138.8)

This application is a continuation-in-part of Serial No. 847,683, filed October 21, 1959.

This invention relates to the treatment of nylon fibers, yarns and to the treatment of finished products incorporating such fibers. More particularly, it relates to the treatment of such fibers and finished or semi-finished products containing such fibers so as to improve the products obtained after such physical processing operations as carding, tufting and the like, or such chemical processing as dyeing and the like, or other physical and chemical opera tions performed on such fibers, for example, in the manufacture of fioor coverings.

For purposes of illustration, the invention will be described as it applies to the manufacture of a floor covering material, but is it to be understood that the treatment disclosed is of general applicability and that the description is therefore to be taken as illustrative rather than as limitative.

Several years ago nylon staple was introduced to the industry for floor coverings of two types of cut pile rugs: the velvet type produced from a crimped heat-set staple which cannot be heat-set further, and a frieze type made from mechanically-crimped staple which can be further heat-set after being made into yarn.

When introduced into the manufacture of cut pile rugs, yarns formed from such staples were found to be extremely diflicult to dye or to finish into rugs with a uniform non-Streaky appearance. The streakiness was observed at various stages during the processing of the nylon fibers, as indicated below.

The first production of nylon staple run through a carding apparatus invariably had a dingy, soiled appearance which would change to a uniform White after staple had been run through the machine for some time. Later, in processing yarns from either beam or creel machines, e.g., in tufting the yarn, breaks, lap-ups and tangled ends were a source of difficulty. Finally, in dyeing the yarn, it was found that streaks present in the tufted nylon carpeting before dyeing invariably appeared in the dyed product.

Briefly, in accordance with the present invention, these and other difficulties experienced in the physical and chemical processing of nylon fibers have been considerably diminished and in many instances have been entirely eliminated, and uniformly dyed products free from streaky or non-uniform appearances have been obtained by treating the nylon at one or more stages of the manufacturing process with composition consisting principally of a product formed by the esterification of mixed fatty acids with alkyl glycols or glycerols, and preferably containing, in addition, both a hygroscopic agent and a rust inhibitor.

While I do not wish to be bound by any specific explanation of the manner in which the invention operates, it is believed that many of the difficulties heretofore experienced in both the chemical and physical processing of nylon staple were the result of a pronounced tendency to accumulate static electrical charges as a result of friction, rubbing or other physical or chemical causes, incident to processing of the nylon.

States Patent "ice . In accordance with the present invention, the first step 111 eliminating the above-noted difficulties comprises removal of any cationic agents or other agents previously applied, by the nylon producer or other processors. Thereafter the nylon, now freed of any surface conditioning agents, is sprayed with -or immersed in the composition of the present invention. The method of application is not critical and may be either a batch procedure or a continuous process, as facilities permit.

After treatment with the composition, it has been found that the afiinity of the nylon for dirt is greatly reduced and this is particularly noticeable in carding, tufting and other processing which is primarily physical. Further, it was observed that the treatment resulted in products which would dye uniformly. The effect of the treatment persists only as long as the treating agent remains present on the nylon, and hence the treatment must be renewed after laundering or dyeing or other treatments involving the use of liquids, if the destaticized effect is to persist in the resulting article.

Essentially the compositions of the present invention may comprise the following:

(1) A fatty ester, such as the naturally occurring animal and vegetable fatty esters, and preferably comprising the product formed by the esterification of fatty acids and alkyl glycols or glycerols.

(2) A substance compatible with the fatty ester which tends to make a solution or dispersion of the fatty ester more hygroscopic, and

(3) A rust inhibitor compatible with the fatty ester.

The ester employed may be any of a number of preparations presently available commercially. Preferably the fatty acids to be esterfied should be those which are readily completely or almost completely esterified by the glycol or glycerol. With esters formed by such fatty acids, little oxidation is experienced with the passage of time, and as a result, nylon fibers treated with the esters are not found to become discolored or yellowed on storage or on exposure to heat at 300 F. The esterification is accomplished by known techniques and forms no part of the. present invention. Preferred fatty acids are stearic, oleic and palmitic. In general, monocarboxylic aliphatic acids with at least 6 carbon atoms in the alkyl chain are preferred. Whatever the acid, or mixture of acids used, the resulting fatty ester product intended for use in the treatment of the fibers must be anionic or non-ionic. It cannot be cationic if the desired results are to be obtained. Accordingly, the esters should preferably be free from such substituents as amine groups as may be present in Sapamines, Avitex R, and other known textile fiber treating compositions.

The glycols and glycerols with which the fatty acids are esterified are preferably short chain polyols, such as ethylene glycol, diethylene glycol, hexalene glycol, or glycerols such as penta glycerol, the relative proportions of fatty acids to glycols being roughly those required to produce a saturated, completely esterified product. Mixed esters and mixtures of esters may be used as well as the pure compounds.

Since the treatment of the invention is being applied to hydrophobic substances, it has been found advantageous to add a hygroscopic agent to the ester to make the preparation more hydrophilic. The hygroscopic additive should constitute between about 5 to 30% of the total preparation, with 15 to 25% being preferred, al-

though the relative proportions do not appear to be critical.

Any hygroscopic agent compatible with the fatty acid ester may be used. Typical useful hygroscopic agents are: diethylene glycol, diethanolamine, triethylene glycol, glycerine, triethan-olamine, and polyethylene glycol, and halogenated ethyl ethers, such as mono and dichloroethyl ether. It is to be understood that this listing of useful hygroscopic agents is only illustrative.

Finally, since a portion of the difliculties stemming from the use of prior art nylon fiber softeners appears to have been due to the oxidation of equipment and particularly machinery and portions thereof formed of iron and iron-base alloys, it has been found advantageous to include a rust inhibitor in the treating composition. When processed in equipment undergoing rusting, nylon becomes discolored from the ferrous oxide present in the system, and it has been found that the iron is exceedingly diflicult to remove from the fibers. This effect is particularly noticeable after shut-downs normal in a Work schedule, such as those occurring on holidays or over weekends.

Substances which have been found to prevent or minimize rust formation in equipment contacted by the composition of the present invention, when incorporated therein, include monoethanolamine, sodium nitrite, silicate of soda, sodium chromate, and similar materials.

The following specific examples will serve to further illustrate the manner in which the invention may be applied.

A shipment of 15 denier, 6 /2 inch nylon staple, as received, was divided into two portions. One-half of the stock was scoured to remove the previously applied softener, Avitex R, a cationic agent applied by the nylon supplier. The scouring bath was formulated to the following composition in which the percentages are by weight:

1% tetrasodium pyrophosphate 1% sequestering agent 1% non-ionic detergent Balance water.

The staple was scoured in the bath at 160-180 F. for 30 minutes to remove cationic agent, and then withdrawn from the bath, and rinsed well. After rinsing, the staple was treated with a solution containing 1% by weight of fatty ester of the type described above. After treatment at 120 F. for 20 minutes, the staple was withdrawn, dried without rinsing and sent through the normal processing operations. The other half of the stock was processed in the same manner, except that it received no pretreatment to remove the cationic softener applied by the supplier, and no subsequent treatment with the formulation of the present invention. Both lots were processed separately into yarn by otherwise identical procedures. The carded fiber treated according to the present invention was uniformly white and clean in appearance and was noticeably whiter and cleaner than staple which had been carded without any treatment other than that originally applied by the supplier.

The carded fiber from each half was spun separately on the worsted system and the resulting yarn was conveyed to a tufting machine. The treated yarn was found to process with much less difliculty than the control yarn, i.e., that which had not received the fatty acid ester treatment. It was noted that the untreated yarn had more fuzzy and frayed ends and had attracted dust and loose dirt to a noticeably greater degree than the treated yarn.

Cut pile rugs were formed of the tufted yarns by sewing onto jute backing. The rug formed of the treated fibers was uniform in appearance 'as compared with the streaky untreated fibers. The streakiness was still evident after dyeing in a bath of 9.0 to 9.5 pH with a premetallized color, on the untreated fibers, While the treated fibers dyed uniformly and without streakiness.

The above was repeated with diethylene glycol in the treating bath and with both diethylene glycol and a rust inhibitor added to the treating bath. The results were still further improved over the use of the esterified fatty acid product alone.

The procedure was repeated with the tufted pile semifinished rug laundered in a built detergent based on tetrasodium pyrophosphate, and thereafter dyed. To retain the benefits, it was found necessary to re-treat the material with the esterified fatty acid after dyeing.

One further point should be noted; namely, that the resulting rugs, in service, did not build up a static charge if given the treatment again after dyeing.

The compositions of the present invention are preferably formed by dispersing the mixed esters in water, in the ratio of about 1:1:2 (fatty acid esterzdiethylene glycolzwater), together with a small amount of rust inhibitor.

The compositions of the present invention may be applied by spraying instead of immersion, and may be applied to either fiber or yarn stock and/ or to finished carpeting.

A comparison of the advantages derived by the use of the treating agents of the present invention with other presently used commercial agents follows:

Fifteen strips, 34 x 6" were sewed from 2.50/2 ply heat set nylon yarn on a 12 needle tufting cut pile machine. All fifteen of these samples were laundered with a solution containing 1% tetrasodium pyrophosphate and 1% Alkanol HCS, based on the weight of material, at the boil. They were rinsed, dried and each strip tested for whiteness. This test revealed that all samples had the same whiteness reading. Two each of the laundered strips were treated with one of the following lubricating and softening agents. One sample was retained as a control.

TABLE I Identification Percent Commercial Company Used Name 1 Avcospin 105 Burkart-Schier. 3 Fibracon C62 Burkart-Schier. 1 M Bibb Mfg. Co. 1 Nopco Chem. Co. 1 E. I. du Pont. 1 General Dyestutl. 3 Drutone BL E. F. Drew.

After application of the seven lubricating and softening agents, by immersing the samples in a liquid bath containing such agent, the samples were withdrawn from the bath and dried without rinsing. The dried samples were then soiled in a soilage machine. After discharge from the machine they were vacuum cleaned. A whiteness reading was taken with a Photovolt machine on which the scale readings are from 0 to 100. is the maximum whiteness recorded, smaller readings representing less white material. After recording the whiteness of the samples, each of the samples was laundered with a built detergent and then dried in a tumble type drier. The dried, laundered samples were again tested for whiteness in the Photovolt machine. Results were as follows:

TABLE II Photovolt Reading Sample N 0.

After Soilage After Laundering 5 After treating and drying the samples, a static reading was taken on each of the treated samples with an Electro- Static Locator.

TABLE IIIELECTRO-STATIC LOCATOR (Machine legend: 1 to -10, static generated; zero, n static generated; +1 to +10, static generated) Agent: Reading Xl -7 X-2 9 X-3 Zero X4 '8 X5 7 X6 X-7 8 The other seven samples treated with the various agents were laundered; then, the jute backing was dyed with the results shown in Table IV.

TABLE IV] UTE DYEING (Test legend: Results desired would be that the pile be uniformly stained, or, preferably, remain white) In the foregoing description, the compositions identified by trade names in Table I are identified in accordance with the definitions of the American Association of Textile Chemists and Colorists as follows:

Avcospin 105Antistatic lubricant for acrylic fibers and yarns. compounded synthetic waxy sorbitol ester.

Avitex R-Cationic softener for cotton and synthetic fiber;

antistatic finish; high alkylamine.

Drutone BLFinishing cotton, nylon and other synthetics increases tear strength. Blend of sulfated synthetic ester and coconut oil.

Fibracon C62-Fiber conditioner.

of non-staining oils and waxes.

Nopco LV-40Antistatic lubricant for synthetics. Fatty amide and ester.

Soromine CS-Cationic softener for cotton, wool and synthetic fibers. Fatty amino amide compound.

The composition identified as M-195 consisted of:

25 %A mixture of esters of stearic, oleic, and palmitic acids esterified with lower glycols. Such esters are commercially available, e.g., under the trade name Profine (Proctor and Gamble, anionic compound with a fatty ester base). Other fatty esters such as Lubritone CP may be used in place thereof provided the fatty ester product is anionic or non-ionic.

25%Diethylene glycol 1%-S0dium nitrite, and

49%Water.

The treatment described is preferably carried out at room temperature (25 C.) or at any convenient temperature between about 10 C. and 50 C., at which the fatty ester is in liquid form. The composition preferably consists of between about 25% and 30% by weight of fatty acid ester, between about and 25% by weight of diethylene glycol and between about 1% and 2% by weight of a rust inhibitor, such as sodium nitrite or monoethanolamine, and may be diluted, if desired, by the addition of compatible solvents, such as water.

Substantive emulsion From the foregoing detailed description it will be evident that there are a number of changes, adaptations, and modifications of the present invention which come within the province of those skilled in the art; however, it is intended that all such variations not departing from the spirit of the invention be considered as within the scope thereof as limited solely by the appended claims.

I claim:

1. A process for producing anti-static characteristics in nylon fibers which comprises: applying thereto a composition consisting essentially of fatty acid ester formed by the esterification of fatty acids having at least 6 carbon atoms in the hydrocarbon chain and lower polyols selected from the group consisting of lower glycols and lower glycerols, diethylene glycol and a rust inhibitor.

2. The process of claim 1 wherein the ester is anionic.

3. A process for producing anti-static characteristics in nylon fibers which comprises: applying thereto a composition consisting essentially of fatty acid ester formed by the esterification of fatty acids having at least 6 carbon atoms in the hydrocarbon chain and lower polyols selected from the group consisting of lower glycols and lower glycerols, hygroscopic agent and a rust inhibitor.

4. A process for producing anti-static characteristics in nylon fibers which comprises: applying thereto a composition consisting essentially of 25 to 30% by weight of fatty acid ester formed by the esterification of fatty acids having at least 6 carbon atoms in the hydrocarbon chain and lower polyols selected from the group consisting of lower glycols and lower glycerols, 5 to 30% by weight of hygroscopic agent and l to 2% by weight of rust inhibitor.

5. A process for producing anti-static characteristics in nylon fibers which comprises: applying thereto a composition consisting essentially of fatty acid ester formed by the esterification of fatty acids having at least 6 carbon atoms in the hydrocarbon chain and lower polyols selected from the group consisting of lower glycols and lower glycerols, hygroscopic agent selected from the group consisting of ethylene glycols, diethanolamine and triethanolamine, glycerine and chloroethyl ethers, and a rust inhibitor.

6. A process for producing anti-static characteristics in nylon fibers which comprises: applying thereto a composition consisting essentially of fatty acid ester formed by the esterification of fatty acids having at least 6 carbon atoms in the hydrocarbon chain and lower polyols selected from the group consisting of lower glycols and lower glycerols, hygroscopic agent and a rust inhibitor selected from the group consisting of monoethanolamine, sodium nitrite, silicate of soda, and sodium chromate.

7. A process for producing anti-static characteristics in nylon fi hers which comprises: applying thereto a composition consisting essentially of 25 to 30% by weight of fatty acid ester formed by the esterification of fatty acids having at least 6 carbon atoms in the hydrocarbon chain and lower polyols selected from the group consisting of lower glycols and lower glycerols, 5 to 30% by weight of hygroscopic agent selected from the group consisting of ethylene glycols, ethanolamines, glycerine and chloroethyl ethers, and 1 to 2% 'by weight of rust inhibitor se-' lected from the group consisting of monoethanolamine, sodium nitrite, silicate of soda, and sodium chromate.

8. Nylon fibers having anti-static characteristics including a coating thereon consisting essentially of a fatty acid ester formed by the esterification of fatty acids having at least 6 carbon atoms in the hydrocarbon chain and lower polyols selected from the group consisting of lower glycols and lower glycerols, hygroscopic agent and a rust inhibitor.

9. Nylon fibers having anti-static characteristics including a coating thereon consisting essentially of 25 to 30% by weight of fatty acid ester formed by the esterification of fatty acids having at least 6 carbon atoms in the hydrocar- 'bon chain and lower polyols selected from the group consisting of lower glycols and lower glycerols, to 30% by weight of hygroscopic agent and 1 to 2% by weight of rust inhibitor.

10. Nylon fibers having anti-static characteristics including a coating thereon consisting essentially of a fatty acid ester formed by the esterification of fatty acids having at least 6 carbon atoms in the hydrocarbon chain and lower polyols selected from the group consisting of lower glycols and lower glycerols, hygroscopic agent selected from the group consisting of ethylene glycols, diethanolamine and triethanolamine, glycerine and chloroethyl ethers and a rust inhibitor. 11. Nylon fibers having anti-static characteristics including a coating thereon consisting essentially of a fatty acid ester formed by the esterification of fatty acids having at least 6 carbon atoms in the hydrocarbon chain and lower polyols selected from the group consisting of lower glycols and lower glycerols, hygroscopic agent and a rust inhibitor selected from the group consisting of monoethanolamine, sodium nitrite, silicate of soda and sodium chromate.

12. Nylon fibers having anti-static characteristics including a coating thereon consisting essentially of 25 to by weight of fatty acid ester formed by the esterification of fatty acids having at least 6 carbon atoms in the hydrocarbon chain and lower polyols selected from the group consisting of lower glycols and lower glycerols, 5 to 30% by weight of hygroscopic agent selected from the group consisting of ethylene glycols, diethanolamine and triethanolamine, glycerine and chloroethyl ethers, and 1 to 2% 'by weight of rust inhibitor selected from the group consisting of monoethanolamine, sodium nitrite, silicate of soda and sodium chromate.

References Cited by the Examiner UNITED STATES PATENTS 2,079,108 5/1937 Dreyfus et al. 1*17l39.5 X 2,103,497 12/ 1937 Schneider.

2,436,978 3/1948 Standley et al. 117--139,5 X 2,512,949 6/1950 Lieber 1064 X 2,664,409 "12/1953 Aickin et al 117--139.5 X 2,739,870 3/1956 Senkus 21--2.5 2,955,960 10/1960 Batty et al. 117-139.5 X

WILLIAM D. MARTIN, Primary Examiner.

T. G. DAVIS, Assistant Examiner.

Claims (1)

1. A PROCESS FOR PRODUCING ANTI-STATIC CHARACTERISTICS IN NYLON FIBERS WHICH COMPRISES: APPLYING THERETO A COMPOSITION CONSISTING ESSENTIALLY OF FATTY ACID ESTER FORMED BY THE ESTERIFICATION OF FATTY ACIDS HAVING AT LEAST 6 CARBON ATOMS IN THE HYDROCARBON CHAIN AND LOWER POLYOLS SELECTED FROM THE GROUP CONSISTING OF LOWER GLYCOLS AND LOWER GLYCEROLS, DIETHYLENE GLYCOL AND A RUST INHIBITOR.