US2820724A - Textile treatment - Google Patents

Description

rnxmn TREATNENT James K. Sneed,Wilmington, Del, assign: to E. L ll Pont deNenionrs and Company, Wilmington, De i a corporation-of Delaware iD a in Apn afia D c herz i,11953 Serial No. 460,095

'4'Claims. (Cl. 117139:5)

:This invention relates to the treating of textile mate rrals,part1cularly so as to render them antistatic without deleteriously affecting their handle.

Many non-cellulosic polymeric substancesused in the manufacture of synthetic fibers, such'as polyacrylic, polyamide, and polyester compositions, are notably hydrophobic; electrical charges produced on them are slow to flow oti or dissipate, especially in atmosphere of low humidity. The presence of electrostatic charges and resulting forces) along a textile material or between it and its surroundings isunpleasant for both processorpand consumer, leading as-it does to poor yarn control and enrollment, difiiculty in maintaining fabric in register during layout and pattern cutting, and clinging of gar mentsto the person when worn, as well as accumulation of dustby the material at any stage and uncomfortable electrical'discharge eflfects for persons coming into con-j tact with the material.

The literature shows that considerable efiort has been expended in an attempt to render the newer textile materials antistatic; however, nearly all the treatments so far devised are non-permanent. Antistatic compositions that are soluble or easily dispersible in Water or in the fluids harsh boardiness to the material thus treated. 'Suchan.

unpleasant handle greatly limits the usefulness of textile materials.

.;A primary object of :this invention is treatrnentof, textile materials ,to render them permanently antistatic. .An-

othernobject is improvement in resin treatments for textiles so. as not to impair thehandle of the treated material.

Eurthenobjects will be apparent from the followingdiscussion.

Attainment of the objects of the present invention is exemplifiedby use ,of a composition comprisinganaqueous, dispersion of acrossflinlgable oxygenrcontainingpolyamide,..a cross-linking catalyst, and a. water-dis'persible nonrcross linking polyether. (As usedhere, dispersion,

Mostof such resins used ffdifilfirsibb, and :-related terms apply to true molecular distributiom;i..e.,.solution, as well as colloidaLor nearcolloidalfldistrihution.) When such-a composition-is appliedto, a-textilernaterial that then is dried, cured," and washed, theitextilecarries a cross-linkedderivative of an oxygen-containing polyamide resistant to washing and dry-cleaning and endowedwith, antistatic propertigs, the handle of -the textile'being substantially unchanged.

To endow a textile material with antistatic properties in the practice of this invention an oxygen-containing polyamide should comprise at least four percent oxygen (by weight other-than that contained in the carbonamide groups, located either intralinearly on the hydrocarbon chain (asin Patents 2,158,064 and 2,191,556) orextralinearly (as in -Patent2,176,074). Usually this oxygen content Will be-distributed throughout each repeating unit of the polymer structure, although copolyarnides in'which a minority of the repeating units are free of this oxygen willp fove satisfactory if their total contentof suchoxygen is atleast fouripercent. One-fifth or ,morepf the hydrogen-bearing nitrogen atoms should carry cross-linkable subst-ituent.groups. These polyamides. neednot be sufiiciently high in molecular-Weight to be fiber-forming, though preferably haying an intrinsic viscosity of at least 03." They should be dispersible in alcohols, in aqueo us alcohols, and in water (to an extent depending raglan upon-thedegree of substitution andthe oxygen content) so as to be'applicableconveniently to textiles from such media. i i Y A conventional cross-linking substituent is an alkoxymethyl group, whichreacts with amide hydrogen to split out the corresponding alkyl alcohol; methoxymethyl is perhaps most readily available, although ethoxyni'ethyl and -higher analogues may be used as Well. Among suitable cross-linking catalysts for such a substituent are acids ofintermediate strength, being as strong as trirnethyl acetic -acid:but not stronger than p-toluene sulfonic acid. Criteriaof acidity for this kind of catalyst, along with other examplesiof suitable catalytic acids, are set forth in: Patent 2,430,860;

To be thoroughly satisfactory, the polyether should be water-'dispersible, despite heating or other usual circumstances, so as to be'removable from the treated material by a conventional scouring operation. For best results, the polyether should have a molecular Weight of about 1000 or more. W/Vater-dispersible polyeth e'r derivatives,

such as a condensation product of ethylene oxide and an alkylated 1 phenol or a polyoxyalkylene derivative of a hydroxyestenxwherein the polyether partofthemolecule accounts for about- %;v or more of the total weight, should prove generally acceptable. i V

The oxygen-containing polyamide and the polyether may be present in a treating composition of this invention in a, weight ratioof. from about 10:1 toabout 1:10; a range friom, about ,10i1,t0 about 2:1 appears togive best results. .The catalyst is present in comparatively small amount, usually a tewipe'rcent basedfuponthe combined weightsofthese two-ingredients, or only a'few tenths of one percent based upon the weight of the treating: composition (including aqueous or alcoholic dispersant), 'as

the composition is usually between. about 5% and 15% total solidscontent The amount of catalysts dependsiin part upon ithe c iring temperature and time. The treat EXAMPLE I A. Preparation of oxygen-containing polyamia'e Amounts of 73.3 grams purified adipic acid and 67.3 grams purified 4-oxaheptamethylenediamine are dissolved in 140 ml. water. The pH of this solution is adjusted to 7.48 by the addition of adipic acid. A 20 ml. portion then is placed in the glass liner of a pipe autoclave and polymerized according to the following cycle:

( 1) Charge and purged (2) Held at 200-210? C. and 250p. s. i. maximum, 45

minutes (3) Raised to 210-250 C., 250 p. s. i. maximum, 30 r sure levelness, resulting in a 40-50% wet pickup or apminutes (4) Held at 250 C., 250 p. s. i. maximum, 30 minutes (5) Reduced to atmospheric pressure at 250 C., 30

minutes (6) Held at 250 C., atmospheric pressure, minutes '(7) Reduced to pressure equivalent to 2 mm. Hg (or less), 250 C., 30 minutes (8) Held as in (7) for 2 hours The resulting poly-4-oxaheptamethylene adipate exhibits an inherent viscosity of 0.98 in m-cresol solution.

B. Preparation of N-methoxymethyl derivative of polyamide 4 D. Formulation of treating composition An amount of 2800 grams of the N-methoxymethylpolyamide prepared in Example I-B is dissolved in 10% n-propanol solution composed of 5320 grams n-propanol and 47,880 grams water. To this solution are added 168 grams crystalline citric acid and 2800 grams of the polyether prepared in Example I-C, both of which also go into solution.

E. Treatment of textile material with the compositon Twenty yards each of a plain weave fabric woven from staple yarns spun from polyethylene terephthalate, a 2 x 2 twill fabric woven from staple yarns spun from polyacrylonitrile, and a plain weave fabric woven from continuous filaments of nylon (polyhexamethylene adipamide) are sewn as a strip with suitable leaders at each end to permit processing on conventional textile equipment. The treating composition of Example I-D is'. placed in the solution tank of a Buttcrworth padder and the goods run through at 10 tons pressure on the squeeze rolls. The goods are run through a second time to inproximately 5% solids based on the weight of the fabric (i. e, about 2 /z% being polyether and 2'/2% being N- methoxymethyl polyamide). The goods are tentered once at 300 F. and 3 Y. P. M. to get a dry fabric, and again at 350 F. and 2 Y. P. M. to cure and insolubilize the N-methoxymethyl polyamide on the goods; these rates correspond to heating time of approximately 1 and 1 minutes respectively. These high temperatures cause some yellowing of the fabric but the color bleaches out in subsequent washing. The fabrics as removed 1 removed from the fabric.

reveals that optimum curing with citric acid requires 2- consisting of one part formaldehyde (paraformaldehyde.

and water equivalent to 80% aqueous formaldehyde by weight) and one part methanol, with sutficient sodium hydroxide to effect solution at the boil. Addition is'slow for the first minute, then more rapid so that all the solution is added in 3-5 minutes. The reaction mixture is stirred for 19 minutes longer, and one additionalpart of methanol is added rapidly. .After 11 more minutes the reaction mixture is poured into 25 parts of water. The resulting solution is filtered to remove insolubles and is made slightly alkaline with concentrated ammonium hydroxide. A portion of the product precipitates at this point as a viscous paste; precipitation is completed by the addition of salt. the aqueous phase and driedin a vacuum oven over phosphorous pentoxide. The yield is 22.4 grams of N- methoxymethyl poly 4 oxaheptamethylene adipamide from 20 grams of the original polyamide. In the product an average of about one out of every two of the active hydrogen-bearing amide groups is substituted with an N-methoxymethyl group. a

C. Preparation of polyether A particularly useful polyether is prepared by polymerizing 1,2-propylene oxide to molecular weight of 1700 followed by graft polymerization of the product with ethylene oxide to molecular weight of 2200 to give a final product in which about 20% of the ether units are derived from the ethylene oxide. Suitable equipment and procedures for such preparation are known to those skilled in the art; written descriptions may be found in British Patent 610,505 and in Natural and Synthetic Polymers (p. 245) by K; H. Meyer, published in 1950.-

The product is separated from fromthe tenter have an unacceptably boardy hand. However, after scouring on a beck at 160 F. in an aqueous bath containing Duponol ME (a commercial grade of sodium lauryl sulfate furnished by E. I. du Pont de Nernours and Company, Inc.) for 30 minutes and drying on a tenter, the fabrics have a softened hand nearly equivalent to that of the original untreated .fabric. In the washing step the polyether is essentially completely (Subsequent experimentation 5% of this catalyst while heating the fabric for 5-71 minutes at 266 F. or equivalent heating for 10-14 minutes at 248 F.) Results of this treatment on the electrostatic charge characteristics of the treated textile fab- V 2 tie appear in Table H below, along with data for the following control treatment and the treatments of additional examples.

F. Control treatment with composition lacking polyether A treating composition similar to that prepared in-Example I-D except for omission of the polyether is used aceptably boardy hand. However, in this instance scouring treatment on the beck'does not soften the fabric.

A further attempt to soften the fabric by running the goods through a button breaker is unsuccessful, even.

after ten successive passes.

EXAMPLE II Amounts of 39.5 grams 3,6-dioxaoctamethylene diamine and 36.7 grams adipic acid are dissolved in 76 ml.

water. A 20 ml. portion of this solution, with pH adjusted to 7.5, is polymerized by the cycle described in Example I-A. The product is poly-3,6-dioxaoctamethylene adipamide, which has an inherent viscosity (in m-cresol) of 0.78. Following a procedure like that given in Example I-B, this polyamide is converted to an N-methoxymethyl derivative such that slightly more than 60% of the active hydrogen-bearing nitrogen atoms are substituted with methoxymethyl groups. Continuing simiassesses larly to Example I-C, a treatingcomposition is prepared. N-methoxymethyl poly-3;6.dioxaocta-.=

1,2-propylene oxide to obtain apolyether having a.molec-- ular weight of 1700 and, inturn, copolymerizing this.

product with ethylenev oxide. to obtain'a final polyetherhaving a molecular Weight of 8000 wherein 80% of thepolyether units are derived from ethylenev oxide..- Thistreating composition is applied to. fabric according to the procedure described inExample I-E.

EXAMPLE IH Amounts of 55 grams 1,2-bis-(3 amino propoxy.).-

ethane and 45 grams adipic acid are dissolved in 100ml. water with the pH then adjusted to 7.52. A ml. portion of this solution is polymerized as described in xample I-A. The product is poly-4,7-dioxadecamethylw ene adipamide with an inherent viscosity (in m-cresol) of 0.39. Twenty grams of this product are treated as de. scribed in Example IB to produce N-methoxymethyl poly-4,7-dioxadecamethylene adipamide in which 65% of the active hydrogen-bearing nitrogen atoms are substituted with methoxymethyl groups; a treating composition is andDyeing, Siiver-Spring,;Md. The index-ofifabric hand (orhandleyis a measurement of-the bendinglength' according. tothe hanging-heart procedure described by Pierce in Journal -of.-.-the; Textile institute. 2-1 T377 1930) i TABLET Percent Inherent amide hydroviscosity Example Polyamide gens replaced in with m-cresol -GH OCH3- N methoxymethyl poly-S-meth- 43 I 1. O5

oxyhexamethylene adipamide. N 'ruethoxyrrlethyl poly-4,7-di- 93' 0. 95'

oxadecamethylene 2, 5 dioxahexamethylene 1, 6 dicarboxamide. 7 VII N -methoxymethyl poly-4,7-di- 49 0. 71

oxadecamethylene adipamide/ polyhexamethylene 4 2,5 dioxa hexamethylene 1.5 --dicarbox. amide (50/50 molratio). VIII N 'methoxymethyl poly-4,7-di-- 57 D. 92

, oxadecarnethylene 1 adipamide. 1X do 73 0. 92

Norm-Based upon-100 parts of solvent (byweight), the treating compositions of these examples-contains parts polyamide, 1.25 parts of the same polyether as Example 1-0, and 0.3 part citric acid. Water is used as the solvent in Examples VI. VIII, and IX, 15% aqueous n-proprepared by dissolving this adipamide in Water 10" give a pan'ol inExample V, and 10% aque0us n-propanol in Example VII.

TABLE II Nylon Dacron 1 Orion 1 (Untreated: hand= 1.33, (Untreated: hand=1.67, (Untreated: hand= 1.79, ESP=1 700) ESP=2,000) ESP =2,000)

Example Hand ESP Hand. ESP Hand ESP Treated Treated Treated Treated Treated Treated Treated and and 5 Treated and and 5 Treated and and 5 washed washings Washedi washings washed washings 2. 03 1. 53 400 2. 74' 1. 86 350 2. 96 1. 91 300 2. 16 2. 08 400 2. 78. 2. 43' 350 3. 01 2. 63 5O 1. 97 1. 48 250 2:66 1. 85 250 2. 84 1. 88 250 1. 85 1. 43 300' 2. 61' 1. 77' 200 2. 79 1. 97 200' 1. 92 1. 51 350 2. 73 1. 91 300 2. 92 2.01 350 1. 81 1. 49 400 2:54 1.88 350 2. 65 l. 86 300 1. 71-. 1. 38 600- 2.06 1. 69 800 2. 92 1. 78 (350 1. 90 I 1. 300 2. 28 1. 87 250 2. 53 1.91 200 2.07 1. 57 250 2. 73 1182 200 2. 95 1.93 250 1. 76 1. 40 250 2. 54 1. 74 200 2. 71 1. 84 200 No'rn.-Electrostatic 100 volts for I-0ontrol.

potential (ESP) of all examples after treatment and before washing was volts, except 1 Trademark of E. I. du Pont de N emours and Company, Inc.

5% solution. Crystalline citric acid is added to give a 0.3% solution, and a polyether prepared by polymerizing ethylene glycol to obtain a molecular Weight of 4000 is added to the extent of five percent. Fabric is treated with this composition as described in Example I-E.

EXAMPLE IV N-methoxymethyl poly-4,7-dioxadecamethylene sebacamide is prepared similarly to the procedure described in Examples I-A and 1-13 and made into a textile treating composition by dissolving in 10% propanol, adding citric acid, and the same polyether as described (with the same proportions) in Example IC. This composition then is applied to fabric as described in Example I-E.

Following the procedures previously described, the N-methoxymethyl polyamides and copolyamides listed in Table I below are prepared and made up into the respective treating compositions. These are applied to fabrics made from hydrophobic fibers, such as those described in Example I-E. Properties of fabrics treated with the treating compositions of Examples I, II, III, IV, and the treating compositions of the examples on Table I are summarized in Table II. Textile World 101, No. 1 (Jannary, 1951), pp. 1167, describes the washing procedures used and the measurement of an electrostatic potential. The dry-cleaning was carried out in standard commercial systems as described in Applied Science for Dry Cleaners published in 1951 by the National institute of Cleaning Table II shows the desirable antistatic and handle benefits conferred according to this invention upon three fabrics woven from yarns made (as in E) of representative hydrophobic polymeric materials: Nylon (polyhexamethylene adipamide), Dacron polyester fiber (polyethylene terephthalate), and Orion acrylic fiber (polyacrylonitrile). In most instances the compositions exemplified in the table maintained the ESP of the treated fabrics at less than one-fourth of the corresponding untreated values, often one-tenth or less, which suggests the relative improvement from rather high susceptibility to accumulation and retention of electrostatic charges to a comparatively static-free condition, even after five cleanings. Initially unfavorable hand determinations (in the vicinity of 2.0 or higher) produced by application and curing of the respective compositions invariably drop to acceptable readings (near or below 1.8) upon one cleaning. Although the mechanism of the hand restoration is not thoroughly understood, removal of the polyether at the first post-treatment washing apparently breaks up the resinous coating produced on the textile to an extent sufiicient to eliminate boardiness but not to such an extent as to preclude the desirable antistatic effect of the remaining resin; of course, no polyether was used in Example IControl, which accounts for the continued excessive value there in the hand column.

The degree of permanence of the antistatic efiect of treatment according to this invention depends largely upon the weight of the textile material. Materials made up of staple yarns generally require less intensive" treatment than similar materials comprised of continuous filaments. Polyamide textiles may be protectable at a lower treating level than is appropriate for some of the other hydrophobic materials.

Textile materials of all kinds may be treated successfully according to this invention, whether made of staple fiber or continuous monofilament or multifilaments or any combination of these, and whether in the form of silver, tow, top, individual yarns, yarn sheets, or any kind of fabric, whether woven, knitted, felted, or otherwise formed. The treating composition may be applied by dipping, padding, spraying, or other conventional method, followed by the requisite curing. The textile may be immersed in the treating composition at room'temperature with subsequent heating continued throughout removal of the textile from the composition to insolubilize the oxygen-containing polyamide on the textile. ,Scouring of the treated material removes the polyether or derivative thereof and restores a desirably soft handle to the'textile,

, exclusive of carbonyl content, and a water dispersible which will usually have become relatively harsh during the curing step- Although the usefulness of this invention in providing desired antistatic properties has been emphasized, it is apparent from the description as a whole that the presenceother cross-linkable polymers and with urea-formalde- V hyde, melamine-formaldehyde, and other resins.

What is claimed: U p 7 V j n 1. A process -forrenderinga textile material Iessretentive to electrostatic charges without adversely affecting its handle comprising treating the textile material with a composition containing an insolubilizable oxygen-containing polyamide, containing at least 4% oxygen by weight polyether and an 'insolubilizing agent, insolubilizing the polyamide on the textile material and removing the polyether from the treated textile material.

2. The process of claim 1 in which the polyamide is insolubilized by heating in the presence of a cross-linking catalyst and the polyether is removed by washing with ReterencesCited in the file of this patent UNITED STATES PATENTS 2,081,180 Leupold I May 25, 1937 2,191,556 Carothers Feb. 27, 1940 2,393,863 Myers Jan. 29, 1946 2,425,755: Roberts Aug. 19, 1947 2,425,845 Toussaint Aug. 19, 1947 r 2,443,450 Graham et a1. June 15, 1948 "2,456,283 Jeiferson Dec. 14, 1948 2,467,186 Cairns Apr. 12, 1949 2,495,845 Jefferson et a1. Ian. 31, 1950 2,593,207 Silver Apr. 15, 1952 5: 2,714,075 Watson et al July 26, 1955 r 2,714,097 Watson et a1. July 26, 1955 OTHER REFERENCES Chem. and EngQNews, vol. 30, No. 22, pages 2283 and 2284 June 2, 1952-;

, Synthetic Organic Chemicals, 13th ed., 1952, Carbide and Carbon Chemicals Co., pp. 44, 45, 50, 51, 52 and 53.

Claims (1)

1. A PROCESS FOR RENDERING A TEXTILE MATERIAL LESS RETENTIVE TO ELECTROSTATIC CHARGES WTHOUT ADVERSELY AFFECTING ITS HANDLE COMPRISING TREATING THE TEXTILE MATERIAL WITH A COMPOSITION CONTAINING AN INSOLUBILIZABLE OXYGEN-CONTAINING POLYAMIDE, CONTAINING AT LEAST 4% OXYGEN BY WEIGHT EXCLUSIVE OF CARBONYL CONTENT, AND A WATER DISPERSIBLE POLYETHER AND AN INSOLUBILIZING AGENT, INSOLUBILIZING THE POLYAMIDE ON THE TEXTILE MATEREIAL AND REMOVING THE POLYETHERE FROM THE TREATED TEXTILE MATERIAL.