US3321819A - Process for sizing and desizing textile fibers - Google Patents

Description

y 30, 1967 A. T. WALTER ETAL 3 L PROCESS FOR SIZING AND DESIZING TEXTILE FIBERS Filed Dec. 24, 1964 ETHYLENE- ACRYLTC ACID TNTERPOLYMER SODIUM SALTS I END USE APPLIQATION AREA PROFILE I 1 WATER SOLUBLE g T 5 E2 |oo- I m LL! w E Q g p. T 05 95 F i ff g u U G: 1 :1 T T To a; g lo r Q (I E; E E T L. 0 --1 WATER INSOLUBLE M 0 l I 1 I r 1 I a I M o 2 4 s a T l2l4l6 l8 |22242a2s 32343638 5254 IO 20 30 4o 50 WT. "a SODIUM ACRYLATE TNT TTERPOLYMER SALT INVENTORS ANDREW T. WALTER GEORGE M. BRYANT CHESTER L. PURCELL A 7' TO/PNE V 3,321.819 PRQCEfiis K 81i filiZh lG AND DESHZTNG TEXTELE FTBERS Andrew T. Walter, Charleston, and George M. Bryant, South Charleston, W. Va, and tlhester L. Purcell, Somerville, Ni, assignors to Union Iarbide Corporation, a corporation of New Yuri:

T tled Dec. 24, 1964, Ser. No. 421,160 16 Claims. (til. 2t3--72.e}

This invention relates to alkali metal salts of ethyleneacrylic acid interpolymers and more particularly to recov erable textile warp sizes made therefrom.

A warp size is a chemical applied to the yarn comprising a warp for the purpose of protecting the yarn during subsequent handling and weaving. In these operations the yarns running in the warp direction are subjected to considerable abrasion from guide surfaces of split rods, drop wires, heddles, reed, shuttle and adjacent yarns. On a staple yarn such as cotton, the size coats the yarn, protects it against abrasion and covers up such warp defects as knots, crossed ends, slabs, and weak spots which occur in the normal variation of textile production. This is accomplished as a result of the gluing down of protruding fibers, and the abrasion resistance of the coating. On a filament yarn the size coats the yarn and cements the filaments together to form nearly a monofil thus preventing chafing between filaments and between the yarn and guide surfaces.

A size is used to form, on the surface of a yarn, a coating or film which can withstand the abrasion occurring during slashing and weaving. In slashing the size solution is applied to a sheet of yarn, and dried on steam-heated rolls. It is necessary, as the sheet of yarn leaves the last drying roll, to separate or split each end of yarn. This is done by a series of bars. As this point in order to separate the ends without tearing the size from the yarn, the size film connecting the yarns in the sheet should have a lower cohesive strength than adhesive strength for the yarn. The size should then regain strength after splitting to form a tough abrasion-resistant coating. Moreover, in order to protect a warp against abrasion, a size must adhere to the yarn Without. scaling off during slashing and weaving.

in a textile mill slashing operation, it is not uncommon to prepare batches of size and then hold them in a heated state for extended periods of time prior to slashing. The size in question must, therefore, be stable to shear degradation which may occur between the mixer blades and the kettle batlies. During the actual slashing operation a large amount of air is pulled into the hot size solution by the incoming yarn. It is, therefore, necessary that the size solution be stable to aeration and exhibit low viscosity loss in this phase.

A size should be stable to heat (at least up to 120 C.), oxidation and aging. No change in solubility should occur as the result of drying the size on yarn up to 100 C.

Since most present-day weave rooms are run at high relative humidities, it is necessary that the size film remain non-tacky at humidities up to 85% normally found in weave rooms. A tacky material would cause size buildup on drop wires, heddles, reed and shuttle. A material which can become tacky is not acceptable.

Another instance of tackiness is the tendency of some sizing materials, to bond together when a sized Warp is stored. Such a warp is lost because it is impractical to unwind it.

A third instance of tackiness is sometimes observed where the sized yarn comes in contact with a drying roll. A tacky size will leave an excessive amount of deposit on the roll.

tacs Patent 3,3Zl,8 ll Patented May 30, 1967 A size should be soluble or dispersible in water up to about 15% and also be easily removable after weaving, preferably by rinsing in water.

In the past, textiles have been sized with various agents such as, starch, gelatin, polyvinyl alcohol and the like. However, none of these compounds have been able to provide all the desired properties described above. They are subject to biological oxidation and degradation and each has specific shortcomings. For example, starch While a good size for cotton is of no value for synthetic fibers. Some sizes are useful on filament yarns but not on staple yarns, or vice versa. Of late, one of their most serious defects has become increasingly critical and that is the difficulty of removing them from waste Water. As stream pollution increases and municipal sewage systems become more overtaxed, the need for recoverable sizes has become urgent. A size which is reusable as well as recoverable is obviously of even greater commercial interest in the textile industry.

It is, therefore, an object of this invention to provide a textile warp size which can be applied from an aqueous solution to the textile fibers of both filament and staple yarn, have sufiicient adhesion thereto and physical strength to protect the fibers during weaving and slashing operations and be easily removable from the fibers at the end of the weaving operation by a hot Water wash.

It is another object that the size be effective on and applicable to a wide spectrum of fibers, both natural and synthetic.

It is another object that the size be recoverable from the wash Water and reusable as a size.

It is another object that the aqueous size solutions be shear and thermally stable, upon aging at elevated temperatures and resist oxidative breakdown.

It is another object that the size be non-tacky at relative humidities up to about Other objects of this invention will become apparent to those skilled in the art upon examination of the description which follows.

It has now been found that water soluble alkali metal salts of ethylene-acrylic acid interpolymers said interpolymers having a melt index of about 15 dg./rnin. to 1000 dg./tmin. and containing from about 12% to50% by weight of an acrylic acid having 3 to 4 carbon atoms interpolymerized therein, with their acrylic acid alkali metal salt moieties including both comprising about 12% to 55% by weight of the total ethylene-acrylic acid interpolymer salts, are excellent recoverable textile warp sizes.

The term acrylic acid alkali metal salt moieties includes both the acrylic acid anion and metal cation.

The term acrylic acid is used herein to include acrylic acid, CHFCHCOOH and methacrylic acid,

Surprisingly, these interpolymer salts readily dissolve in hot water and remain in solution when cooled to room temperature but do not readily dissolve in cold water initially. While not wishing to be bound by any one theory, this phenomenon may be explained by assuming that at room temperature the hydrophilic ionic sites of the polymeric salts are embedded within the hydrophobic coils of the polymer moiety and are not accessible to the water phase. Upon raising the temperature of the polymer salt by exposure to hot water, the polymer moieties uncoil sufficiently to expose the ionic sites to the water and solution is effected. Cooling back to room temperature would not then be expected to result in insolubilization of the polymer salt because the original coiled state of the polymer salt is a bulk property not achievable in solution. A limping analogy might be drawn between this visualization and the apparently'anomalous increase in the reduced viscosity with dilution encountered in attempting to determine the intrinsic viscosity of ionic polymers of polyelectrolytes.

Thus, a novel process for warp sizing and desizing textile fibers was discovered comprising the steps of:

(a) Sizing textile fibers with an aqueous sizing solution of the above-identified Water soluble alkali metal interpolymer salt at a concentration sufficient to deposit an effective sizing amount on the fibers;

(b) Weaving said textile fibers into cloth; and

(c) Desizing the textile fibers in said cloth by contacting the fibers with a hot water wash in which the salt is soluble.

A further advantage of this process is that the sizing interpolymer salt can be recovered by acidifying the wash water to a pH of about 4. to 6 thereby precipitating the ethylene-acrylic acid interpolymer and then isolating the interpolymer. The interpolymer can be reconverted to salt and then reused to make fresh sizing solution. This recycling of the textile warp size not only provides a more economical sizing process than those using a non-recoverable size, but eliminates the need and cost of Waste disposal and waste treatment systems.

The term sizing amount as used in the specification, including the claims, is defined as a sufi'icient percent by weight of dry size, based on the weight of the yarn, to effectively size said yarn. Those skilled in the textile art can readily determine the quantity of size which is satisfactory for the specific textile yarn to be used by them.

In general, the textile size described in the present invention is employed as a size for the longitudinal or warp yarns inasmuch as the traversed yarns (Woof or weft yarns) are not ordinarily sized since they are subjected to little or no abrasive action from the loom. However, if desired, both weft and warp yarns can be treated with this textile size.

Both older fibers, such as cotton, wool, rayon and like fibers as well as the newer synthetic materials, such as, polyamide, polypropylene, polyacrylonitrile, polyvinyl chloride, acrylonitrile-vinyl chloride copolymer, polyethylene terephthalate and like fibers can be sized by this novel textile size. This size is effective on both filament and staple yarns.

The concentration of the aqueous size solution is not narrowly critical and the preferred concentration can be determined for each particular textile to be treated.

The percent weight of size on the yarn or add-on, suitably employed is governed by several addition factors, such as economic consideration, type and weight of the yarn fibers, concentration of size, the pressure on the squeeze rolls, the construction of the fabric to be woven and the like. Thus, for example, when weaving cloth with cotton yarn, it is preferred to use aqueous solutions containing up to 15% by weight of size and to obtain an addon of up to about 14% size on the yarn. However, higher concentrations of size and higher add-on can be employed, if desired.

Ethylene-acrylic acid interpolymer alkali metals salts can be categorized into three classes by physical characteristics, viz., structural, breathable (but water-insoluble) and water-soluble. These characteristics are determined by a combination of several variables including melt index and composition of the parent ethylene-acrylic acid interpolymer, melt index and composition of the interpolymer salt and percent neutralization of the parent interpolymer. The ethylene-acrylic acid interpolymer salts of the present invention are found in the water-soluble class.

In general, as the {rrlelt index of the interpolymer is lowered the acrylic acidsalt content must be increased to obtain a water soluble interpolymer salt. Conversely, as

the melt index is raised a lower interpolymer salt content is required to achieve water-solubility with the lower limit being about 12% by weight. This relationship is delineated in the figure where the logarithm of the melt index of the starting interpolymer is plotted as the ordinate against weight percent of sodium acrylate in the interpolymer sodium salt. Lithium and potassium salts show similar plots in the ranges of about 12 to 54% and 17 to respectively. The figure also shows the requirements for breathable (insoluble) interpolymer salts and structural interpolymer salts as well as a transition or gray Zone between the two. The line of demarcation between the breathable and water-soluble classes is not as sharp as that between structural and breathable class. This is understandable in the light of the nuances existing between interpolymer salts forming solutions and those forming emulsions in water as revealed by light scattering techniques discussed later. In a broad sense, the water-soluble class of salts is also breathable at ambient temperatures.

Although the suitable textile warp sizes of the present invention can be prepared from ethylene-acrylic acid interpolymers having melt indices of about 15 dg./min. to 1000 dg./min. and containing about 12% to 55% by weight of acrylic acid interpolymerized therein, it is preferred to employ those interpolymers in the range of about 15 dg./rnin. to 700 dg./min. containing about 15% to 35% acrylic acid interpolymerized therein. It is particularly preferred to employ interpolymers in the range of about 18% to 30% acrylic acid and having melt indices of from about 200 to 500 dg./rnin. Furthermore, although the alkali metal salts of these interpolymers can contain from about 12% to 55% by weight of acrylic acid salt moieties, it is preferred to employ those containing about 15% to 35% salt groups.

Ethylene-acrylic acid interpolymer alkali metal salts can be prepared with varying salt contents, depending on the end use class for which it is aimed. This range extends from water-soluble completely neutralized ethyleneacrylic acid interpolymers, obtained with stoichiometric amounts of base, through water-soluble incompletely neutralized interpolymers, through water sensitive and breathable (but not water-soluble) partially neutralized interpolymers to the water insensitive, lesser neutralized interpolymers (containing 8% salt or less in the interpolymer). The term breathable interpolymers is used herein to mean those which exhibit high moisture vapor transmission and oxygen and carbon dioxide permeability. The neutralization of these ethylene-acrylic acid interpolymers can be effected by contacting them with free alkali metal, with alkali metal salts such as formates, acetates, nitrates, carbonates or bicarbonates and with alkali metal bases such as hydroxides or alkoxides. Preferred alkali metal bases are lithium hydroxide, sodium hydroxide and otassium hydroxide in solution, slurry or in the melt. For convenience, it is preferred to blend the interpolymer and base on a two-roll mill, in a Ban-bury mixer or with simi lar commercially available mixing equipment well known in the art. The salt content of a given interpolymer can be determined by infrared analysis of a film specimen in the 5.0 to 6.0 region. The absence of this carbonyl absorption band indicate a :stoichiometric neutralization, that is, complete conversion of the acrylic acid moieties in the ethylene-acrylic acid interpolymer to acrylic acid salts.

Where less than stoichiometric amounts of base are reacted with the interpolymer, their solubility behavior in water is such that at certain levels of neutralization a change from colloidal solution to a large particle size emulsion occurs, the specific point depending on the molecular weight (melt index) of the original ethyleneacrylic acid interpolymer and the concentration of salt moiety in the interpolymer. The point can be determined by light scattering techniques available with conventional light scattering apparatus in which a light beam is passed through a 1% solids aqueous colloidal solution or emulsion of the sample with back scattered light measured at an angle of 135 and transmitted light at an angle of 45 from the transmitted beam. Where the ratio of light intensity at 45 light intensity at 135 is 1 a colloidal solution is indictaed whereas ratios of 1 indicate a larger particle size emulsion.

The molecular weights of the ethylene-acrylic acid interpolymers are indicated in terms of melt index at 44 psi. and 190 C. in units of decigrams per minute (dg./ min.) in conformity with ASTM D-l238-62T.

Other ASTM tests methods employed in the present invention include the following:

Durometer hardness (D) D1484-57T Oxygen permeability D-l43458 Inasmuch as the actual evaluation of textile sizes empirically in an actual weaving operation is expensive and time consuming, it is customary to subject candidate compounds to preliminary tests on a bench scale to screen out those compounds which lack desirable basic recoverable size properties such as water solubility, facile precipitation from aqueous solution, size solution sta' bility, ease of size removal from fabric, adhesion and the like or which have undesirable size properties such as pi tuitousness, tackiness and the like. Candidate compounds which pass these preliminary tests are then subjected to more sophisticated tests and actual runs as sizes in a weaving operation.

The tests used for screening are described below.

The pituitousness of aqueous textile warp size solutions, which is undesirable because it results in size buildup on dry cans during slashing, is determined by squeezing a drop of size solution between the index finger and thumb. These two fingers are then pulled apart slowly and the distance at which the size splits is noted. The following ratings were then given:

Less than 0.5 inch Not pituitous. 0.5 to 1.0 inch Slight pituitousness. Great than 1.0 inch Pituitous.

Films of test sizes were prepared by pouring 100 g. of a aqueous solution into a level 21 x inch glass plate, drying at room temperature overnight followed by 10 minutes at 110 C. The films were conditioned at 70 F. and 65 relative humidity for 24 hours.

Tackiness was determined by touch with 2 inch film squares after a minimum of 12 hours in a relative humidity of 92.5% at 25 C.

Film solubility was determined by recording the time and temperature necessary to dissolve a 1 inch square of film in a heated test tube contining 50 ml. of water.

Adhesion was determined essentially using the method outlined in the American Dyestult Reporter 38, No. 9, page 372 (1949). Adhesion was classified as follows:

Class 1Very poorly adherent. Size film curled away from substrate.

Class 2Slightly adherent. Size film sticks to substrate but the entire size film can be lifted with gentle probing.

Class 3Strongly adherent. Considerable work is required to separate the size film from the substrate.

Class 4--Very strongly adherent. The size film is very difficult to separate from the substrate and comes away only where the probe enters the size film.

Ease of size removal from fabric was estimated by first raveling a 10 inch square of fabric /8 inch on each side, and drying it in a forccd-air oven for 10 minutes at 110 C. and conditioning it at 70 F. and 65% relative humidity for four hours. The fabric was then padded with a 10% size solution under conditions to give 100% wet pickup. The sample fabric was dried for 10 minutes at 110 C. and then desized by rinsing in Water at C. for 5 minutes. The sample dried at 110 C. for 10 minutes was conditioned for four hours at 70 F. and 65 relative humidity and weighed. From this value the percent size retained was calculated.

Following the simpler screening tests varying concentrations of the aqueous sizes of the present invention were applied to 40/1 cotton and 42/1 polyethylene terephthalate-cotton using a Callaway laboratory slasher.

The various samples of yarn that had been sized on the Callaway slasher were tested on the Warp Shed Tester. This tester is an instrument designed to simulate all the actions of a loom except the laying in and beating up of the filling yarn by the shuttle and reed. The tester consists of a tension controlled let-off spool, two sets of harnesses and heddles, a reed, a beat-up motion, drop wires, and a take-up mechanism. The mechanical motion of the various parts simulates a loom operation.

The invention is further illustrated by the following examples in which all parts and percentages are by weight unless otherwise specified.

Example 1.--Etlzylene-acrylic acid interpo lymer salt preparation An ethylene-acrylic acid interpolymer (1180 g.) containing 18% acrylic interpolymerized therein and having a melt index of 200 was mixed with 118 g. of solid sodium hydroxide and 5 g. of water in a Banbu-ry mixer at 150 C. for twenty minutes. Complete neutralization of the acrylic acid moiety was achieved as shown by infra-red analysis of the product.

An ethylene-acrylic acid interpolyrner (100 g.) containing 18% acrylic acid interpolyrnerized therein and having a melt index of 200 (lg/min. was mixed with 14 g. of solid potassium hydroxide on a two roll mill for 20 minutes at 150 C. Infrared examination of the product showed complete neutralization of the acrylic acid moiety.

In a similar manner, using lithium hydroxide, the lithium interpolymer salt was also made.

Samples of a number of interpolymer salts prepared as described above were tested for water solubility at C. The results are given in Table I below.

Run N0. Acrylic Acid Melt Index Metal Salt Water (Wt. percent) (dg./min.) Prepared Soluble 12 50 12 140 13 7 13 50 14 60 15 Na Yes 18 200 Li, K, Na." Yes 22 200 Na Yes 27 1e Li,K,Na Yes 40 40 K Yes Films of the potassium salt prepared from the ethyleneacrylic acid copolymer (18% acrylic acid, 200 dg./min. melt index) were prepared by molding, casting from water at 100 C. and casting from water at 23 C. and various physical properties of these films compared with each other and with a molded film of the parent ethyleneacrylic acid interpolymer. The data obtained are presented in Table II.

3,3a1,s1e

TABLE II.PHYSICAL PROPERTIES OF ETHYLENE-ACRYLIC ACID INTERPOLYMER AND POTASSIUM SALTS Chemical Form Acid. Salt Salt S t.

Film Preparation. Molded Molded Sol. cast (23 C.).

Secant Modulus, p.s. 6, 330-.. 9, 990 23, 320.

Tensile Strength, p.s.1 2, 335. 1,690.

Elongation, percent .1 437 363..

Solubility: A

Cold H2O (23 C.) Insoluble Insoluble Insoluble. Film dlslntegratcs. Hot H O (100 C.) de Soluble Soluble 1. Soluble.

1 Instron Tensile Tester, 10%/min. strain rate. 2 Instron Tensile Tester, 100%/min. strain rate.

Table III contains like data obtained with an ethyleneacrylic acid interpolymer (27% acrylic acid, 16 melt index) and its potassium salt.

TABLE III.PHYSICAL PROPERTIES OF ETHYLENE-ACRYLIC ACID INTERPOLYMER AND POTASSIUM SALT Chemical Form Acid t Salt. Film Preparation Molded" Sol. east (110 C.) Sol. cast (23 0.). Secant Modulus, ,270 6, 310 Tensile Strength, p.s. 4, 330 .1 1, 728 .1 1020. Solubility:

Gold 11 (23 C.) Insoluble. Insoluble- Insoluble Part solubl Hot H O (100 C.) do. Soluble Soluble- Soluble.

1 Instron Tensile Tester, 10%lrnin. strain rate. 1 Instron Tensile Tester, 100%/1nin. strain rate.

Example 2.Light scattering examination of and containing 13% acrylic acid interpolymerized therein. interpolymer salts The physical properties including Water absorption and moisture vapor transmission of the parent copolyme'r and copolymers having increasing sodium salt contents are contained in Table V.

The solubility characteristics of various ethylene-acrylic acid interpolymer potassium and sodium salts Were fur- 30 ther investigated using the light scattering technique pre- TABLE V.EFFECT OF SODIUM ACRYLATE CONTENT ON PROPERTIES OF POLYMER SODIUM SALTS Polymer Salt Composition 1 Secant Wa r A 2 Run Percent M.I. Modulus at 1% Tensile Elonga- E B fi ggf No. Ncutral- (dg./rnin.) Elongation Strength tion, T i i izcd Percent Percent Percent (p.s.i.) (p.s.i.) Percent Wt. Percent Material Loss, g./1neter /24 hr.

C AA SA Pick Up Wt. Percent 0 87 13 0 6. 7 11, 300 4, 061 470 0. 26 07 11 25 86. 1 9. 7 4. 2 1. 7 41, 200 3, 957 370 0. 5G 06 14 50 85. 1 6. 5 8, 4 0.7 55, 200 6, 217 380 l. 05 08 10 75 84. 6 3. l 12. 3 0. 09 41, 800 6, 857 340 14. 3. 4 38 100 83. 1 0 16. 3 0. 05 40, 600 7, 180 335 14. 1 2. 3 386 1 C AA, SA Ethylene-acrylic acid-sodium acrylate. 1 Immersed in Water at 23 C. for 7 days. 3 Film 5-8 mils thick.

viously described. Data indicating which salts formed Example 4.Physical properties of various ethylenecolloidal solutions and which large particle size emulsions 50 acrylic acid interpolymer sodium salts at 1% solids content in water are contained in Table IV With polyvinyl alcohol and sodium chloride as controls. The combmed effects of melt index of both the Parent ethylene-acrylic acid intc-rpolyrner and sodium salt, sodi- TABLE IV.-LIGHT SCATTERING DATA ON VARIOUS 1% SOLIDS SOLUTIONS AND EMULSIONS Acrylic Acid Melt Equivalent of Angle Run No. Solid Mateual in Polymer, Index, Salt Caustic per Intensity Aqueous Wt. Percent dgJrnin. Equivalent of 136 Angle Form Acrylic Acid Intensity 1 Ethylene Acrylic Acid Interpolymer 12 Na 1. 0 0. 96 Border-li 2 0; 12 140 Na 1. o 0.91 D 3 15 50 K 1. 0 1. 2 Solution. 4 14 50 Na 1.0 1.4 D 5 15 110 No. 1.0 1.25 Do. 6 18 200 K 1. 0 1.12 Do. 7 22 200 Ne 1.0 3.2 Do. 8 27 16 K 1. 0 2, 5 D 9 18 200 K 25 0. 02 Emulsion. 10 18 0 K .50 1.1 Solution. 11 27 16 K 50 0.76 Emulsion. ContrOL Polyvmy 2. 0 Solution Do 1% Aqueous 5. 5 D0.

Example 3.--The efiect of interpolymer salt content 0 physical properties urn acrylate content of the mterpolymer and percent conversion by neutralization With sodium hydroxide to the The efiect of varying the amount of acrylic acid neucopolymer salt on physical properties are demonstrated tralized in the ethylene-acrylic interpolymer was demonin Table VI. For purposes of comparison the secant modstrated with an intcrpolymer having a melt index of 7 ulus, tensile strength, percent elongation, water absorpis 10 I .1: tion and moisture vapor transmission of high density tioning samples are two relative humidity conditions, viz., polyethylene, low density polyethylene, and an ethyl- 50% RH and 90% RH at 23 C. and 35 C. for 24 hours vinyl acetate interpolymer are also given in Table VI. and 7 days. The effects of immersion in Water at 23 C.

TABLE VI.PROPERTIES OF POLYMER SODIUM SALTS Starting Composition Water Absorption l Polymer Percent Secant Moisture Run Conv. to MI Mod. Tensile Elonga- Vapor N 0. Sodium (dg./min.) at 1% Strength tion, Transmission Per- Salt Percent Percent Percent Elongation (p.s.i.) Percent Wt. Material (g./meter 2 cent MI Ethylene Acrylic Sodium (p.s.i.) Percent Loss, Wt. 24 hrs.) AA Acid Acrylate Pick up Percent 15 High Density (0.94) Polyethylene- 5.0 150, 000 4, 600 15 03 4 O. 2

l6 Low Density (0.92) Polyethylene. n) 1. 5 23, 000 1, 800 000 01 7. 5

1 Immersed 7 days in 1120 at 23 C.

2 All measurements on 5-8 mil film, unless otherwise stated. 3 Control.

4 Film thickness, 10 mils.

Example 5 .C0mp0siti0ns representative of structural, breathable and water soluble inter-polymer salts Seve m1 ethylene acryhc acid interpolymer Salts were ror 24 hours and 7 days were also recorded. The results prepared showing the effect of such variables as melt in- 40 are contamed m Table VIII dex and composition on the physical characteristics which This lnterpolymer before. P i an Izod determine their end-use class. These data are presented in pact Strength of excellent resistance to Table VII.

TABLE VII.-POLYMER SODIUM SALTS Composition (wt. percent) of Composition of Start Salt 1 Melt ing Polymer (wt. Run N 0. Application Area Indegc, percent) 1 Melt Index,

dg./1n1n. (lg/min.

C3 AA SA C2 AA 1 Structurall- 84. 6 9.8 5. 5 0.3 -87 13-15 5 84. 5 9.1 6. 4 1. 6 85-89 13-15 50 2 Breathable (Water insoluble) 82.3 6.0 11.7 0.2 85437 l3-15 50 3 Water Soluble 78.9 4.3 16.8 0.7 82 18 1 Cz ethylene; AAzncrylic acid; SA soclium acrylate.

Example 6.-Efiect of water on ethylene-sodium 20 arafiin base lubricatin oil as de onstrated b ne liacrylale interpolymer 60 p o In y g gible pick up after 7 days immersion in this oil at 23 C. The physical properties of an ethylene-sodium acrylate and 50 C., excellent grease resistance and a brittleness interpolymer (76.6%:23.4%) were studied after conditemperature of 15 C. to -20 C.

TABLE VIII.EFFECT OF WATER ON PROPERTIES OF POLYMER SODIUM SALTS INTER- POLYMER COMPOSITION: 77.8/22.2 ETHYLENE-SODIUM ACRYLATE Ultimate Yield Sewn; Tensile Tensile Percent Experiment N 0. Modulus Stmmm Strength Elongatwu Conditiomng (p.s.i.) (p.s.i.)

35,805 3, 840 3, 840 193 23 0., 50% RH, 24 hrs. 42, 968 3, 926 3, 926 210 23 0., 50% RH, 7 days. 11, 496 1, 445 1,067 325 35 C., RH, 24 hrs. 8, 576 1, 421 1, 012 ass 35 0., 90% RH, 7 days. 3, 101 608 608 105 Immersed H O, 23 0., 24 hrs. 3, 499 583 583 Immersed H O, 23 0., 7 days.

Example 7.Screening interpolymer salt (23% sodium acrylate) Aqueous solutions of up to 20 weight percent of an ethylene-acrylic acid interpolymer sodium salt containing 23.4% sodium acrylate interpolymerized therein made by neutralizing with NaOH an ethylene-acrylic acid interpolymer having a melt index of 200 dg./min. and an acrylic acid content of 18% (cf. Table VI-Run No. 15) were prepared by heating the solid salts in water at 95 98 C. With stirring. No gelling or precipitation occurred when the above solutions were cooled to room temperature. The pH of the 20% solution was between 11 and 12.

Recoverability of these sizes from solution was demonstrated by coagulating them as the free acid by adding dilute hydrochloric acid, dilute ortho phosphoric acid or glacial acetic acid to the above salt solutions until a pH of about 6 was reached.

polymer salt prepared in Example 7 were treated with 1% solutions of hydrochloric, formic, sulfuric and acetic acids until all of the interpolymer coagulated. The co agulated interpolymers were filtered, rinsed with water three times and dried at 60 C. in an oven. Ten grams samples of each were pasted with g. of 3% NaOH, dispersed in 70 g. of water and heated while stirring at 80 C. until dissolved. The film properties of these recovered salts were compared with the original interpolymer salt and presented in Table IX. These results, particularly the adhesion and solubility data, show the excellent adaptability of these salts to the requirements of a textile size.

Solutions of the interpolymer salts before and after coagulation were also made using hard water, containing 1000 p.p.m. of calcium salts, which level exceeds that normally encountered in actual mill practice.

TABLE IX Film Properties Coagulant pH of Identification Salt Elon- Solubility Adhesion 65% RH Adhesion 90%RH Appear- 1% Solution Solution Tensile, gation, Stifiness in water, ance of p.s.i. per- Modulus 95 C. Film cent Mylar Glass Cellophane Mylar Glass Cellophane l0. 7 1, 443 248 11, 917 Soluble Fair Very Very Fair Good. Very Clear,

Good. Good. Good. lcoloress. 12.2 720 79 7,250 80% Soluble. do do do.. do do do Do. 11.5 841 32 14, 600 Solubledodo do... do Fair Do. 11.3 do Good Good do Good .do Good Hazy} l e Uncoagulated con- 12. 5 1,172 102 15, 700 do Fair do "do Fair do Very Clear, lilllfl interpolymer Good. folorsa 1; ess.

Redissolution of the coagulated copolymer was demonstrated by addition of base such as 10% (weight) aqueous solutions of sodium or potassium hydroxide until a pH of about 11 was attained.

Films of the interpolymer sodium salt, cast from solution and dried at 125 C. in a forced air oven, were readily soluble in hot water with agitation. The tensile strength and percent elongation of films made from the original salt and from coagulated and redissolved salt, were about the same, viz., 15501925 p.s.i. and 190% respectively.

The desizing of interpolymer salt from a textile fabric and its coagulation from the wash bath was demonstrated as follows.

The 20% solution of interpolymer salt made above was padded onto unmercerized cotton at a 100% wet pick up and dried at 125 C. for 4 minutes. A dried add-on of 20% was achieved. The sets of fabric samples were then scoured at the boil for one hour using two different baths, each having a liquor to fabric ratio of to 1. One bath comprised distilled water only while the other was an aqueous solution of 0.5% sodium carbonate and 0.1% Tergitol NPX (trademark for an ethoxylated nonyl phenol, non-ionic detergent sold by Union Carbide Corporation). In both cases, over 90% of the copolymer salt was removed from the fabric after one scouring. A second scouring removed the remaining salt size. The interpolymer was then coagulated from the scouring baths by adjusting the pH to 6, by adding 3% aqueous hydrochloric acid. The coagulated interpolymer could be reconverted to a soluble salt in solution by trituration with 3% aqueous sodium hydroxide followed by dispersion in water and heating with agitation at 80 C.

Example 8 .-Rec0verability of coagulated Ethyleneacrylic acid interpolymer To demonstrate further the feasibility of recovering the textile warp sizes of this invention, coagulation with four acids and the properties of the salts recovered thereby was investigated. Aliquots of a 10% solution of inter- Examples 9-24 In the following sizing experiments in which cotton and polyethylene terephthalate/cotton were used as substrate aqueous solutions of two different sizing materials were employed. For cotton a sodium salt of an ethylene-acrylic acid interpolymer containing 18% acrylic acid interpolymerized therein and having a melt index of 145 dg./min. was used. This salt was prepared by neutralizing of the free carboxyl groups of the parent interpolymer so that the sodium salt then had a melt index of 0.1 dg./ min. and contained 72.2% ethylene, 1.8% acrylic acid and 21% sodium acrylate interpolymerized therein.

For polyethylene terephthalatc/cotton a sodium salt of an ethylene-acrylic acid interpolymer containing 18% acrylic acid interpolymerized therein and having a :melt index of 200 dg./min. was used. This salt was prepared by completely neutralizing the parent interpolymer thus aifording a salt containing 23.4% sodium acrylate and 76.6% ethylene interpolymerized therein and having a melt index of 0.01 dg./min.

The sizing materials were applied to 40/ 1 cotton and 42/1 polyethylene terephthalate/ cotton (65 35 on a Callaway laboratory slasher, threaded with 252 ends spaced to produce a density of 84 ends per inch on the slasher. Slasher speed was 10 yards per minute, with dry can temperatures of (1) 200 F. (2) 210 F., (3) and (4) 220 F.

Size box temperatures and solution characteristics of each material are listed in Table X.

A sample of each test warp was desized by the appropriate method of determine size add-on. A sample procedure for desizing is given below.

(1) Dry duplicate samples (3-5 grams) 4 hours at 221 F. Cool-weigh.

(2) Desize using a solution containing 2% Na CO and 2% Tergitol NPX at 212 F. for one hour.

(3) Rinse twice using running hot water F.-

13 160 F.) for 1 /2 to 2 minutes. Follow this with a cold rinse.

(4) Dry desized yarn overnight at 221 F. Coolweigh. The percent size is then calculated:

l4- poly-mer containing 23.4% sodium acrylate (derived from an ethylene-acrylic acid interpolyrner containing 18% acrylic acid and having a melt index of 200 dg./min.) was demonstrated with a dye technique described below.

A A I 5 In both cases the yarns were sized in a Callaway slasher Welght of i i j g of f ya] X100: and run through the warp shed tester prior to desizing. 61g t O esue yam The samples were scoured, along with unsized controls, Percent Size add'on for one hour in an aqueous bath containing 2.5% Tergitol The percent water soluble content of the unsized yarn NPX and 2% Sodium f f f (based on Wfilght of is obtained in the same manner; therefore, percent size y held near t bollms p Thescoured a p add on minus the percent Water l l content of were then rinsed in water near the boil for 5 minutes, sized yarn=percent corrected size addcooled for 3 minutes, dried at 110 C. conditioned at 65% All size add-on determinations are reported as percent l add"01'1$ corrected i dd To determine if complete desizing' had taken place, one The sized yarns were treated on the Warp Shed Tester 15 Sfit of p Were dyed With 1 PfifCeIlt l y Bfllllant at 75 F., and 72% relative humidity. The warps were Blue, a (lISPBYSe y and a swnd Set Wlth Percent drawn in a plain Weave pattern on two double-bar har- CalcodurResm Fast Blue 3G,ad1r@ctdye- The dlrect y nesses, and reeded 3 ends per dent in a 30 dents per inch W111 W the Cotton and to some eXTent the p y y f Teeti Th Warp Sh Tester was Operated at 200 i k terephthalate/cotton, but not the polymer salts. The disper minute, .69 i k per i h perse dye has afinity for polyethylene terephthalate and Test amples gre run for approximately yards 01 polymer OT its salt, but IlClt cotton. The dfislZed COlltOIl 47 760 i l when dyed with the dispersed dye tinted to the same level Th h f each Warp was couected and Weighed, as the control, indicating that there was little or no polyalong with the warp. The percent shed was calculated as 1116f Salt prfisfillt- The Presfince of P y Would have follow sulted in a darker shade. The desized cotton dyed to the W i 1 same level as the control when the direct dye was applied. t 0 sled ]()t)= t h d Both th direct and dispersed dyed desized cotton and Welght of Warp and shed polyethylene terephthalate/cotton samples showed dye- Th shed was desized in the same manner as the yarn ability BqlllVfll6l'llI t0 i116 control, indicating that the size No correction factor was used, and all of the residue left had been removed to a level which did not affect the dyeafter desizing was assumed to he fiber. The percent fiber ability of either yarn. was calculated as follows: To further determine the desizability of polymer salt Desized Wei ht n sized cotton yarns, a set of skeins of cotton yarn were jfigfia ggfi'm the Shed padded with a solution of the polymer salt containing TABLE X.SLASHING DATA Squeeze Roll Solution Size Box Solution Example Pressure Solids Temp. Viscosity Type of Shedding at Add-On (lbs/linear (percent) F.) (Brookficld Split Split Rods (percent) i ch) cps.)

2a 9.37 100 3 Easy.. Light 9.4 15. o 9. 37 160 3 1 1 12. 7 23 10.81 100 11 7.2 23 10.35 160 c 7.9 23 5.64 160 5.5 3.1 23 5. 01 160 10. 5 3.1 23 14. so 160 6 13. 7 23 14. 97 160 5. 5 10. 2

Polymer salt on polyethylene tcrephthalatc/cotton (65%/35%). I Polymer salt on cotton.

, The data obtained from the Warp Shed Tester, presented in Table XI indicate that the interpolymer salts of this invention function well as a size on both cotton and polyethylene terephthalate/cotton yarn.

* Polymersalt on polyethylene tercphthalate/cotton (cm/35%). b Polymer salt on cotton.

Examples 25 and 26 The desizing of cotton yarn sized with an interpolyrner containing 19% sodium acrylate (derived from an ethylene-acrylic acid interpolymer containing 18% acrylic acid and having a melt index of 145 dg./min.), and a polyethylene terephthalate-cotton yarn sized with an inter- 19% sodium acrylate described above, at 180 F. The padded skeins were dried at 225 F., conditioned at percent RH and F., and the dry add-on determined (see Table XII). The conditioned sized samples along with an unsized control were scoured as outlined above and the weight loss determined. After correcting for the weight loss of the unsized cotton, the corrected add-on Was compared with the dry add-on. It is evident from these figures that complete removal of the polymer salt tool; piace when this desizing method was used.

The desizing of sized yarn with a Na CO /Tergitol NPX bath described here is similar to the scouring method currently being used in the textile industry.

Dry Add- Scourcd Add Corrected Sample Number 1 011, percent 011, percent Scourcd Add- 011, percent 6. 9 9. 4 7. 0 8. 2 10.8 8. 4 A 8. 3 10.7 8. 3 Uusized Control 2. t

1 Natural cotton yarn. tcolrrected add-ou=scourcd add-on of sized yarn, scoured add-on of con ro Example 27 Table XVII and the spun Dynel Callaway slashing data Sizing solutions containing varying amounts of an ethylm Table XVIII ene (7 3%)/acrylic acid (%)/sodiurn acrylate (22%) TABLE I-C K A HING AT interpolymer having a m index f 0 a inw r Squeeze roll pressure, lbs./linear inch 15.6 evaluated with polypropylene, polyethylene, terephthalate, 0 Solution Solids, percent 13 40/ 1 polyethylene terephthalate/cotton (65 and Size box temp Q R 1 0 polyamide filament yarns and spun Dynel (trademark for sclution viscosity Br kfi ld (cps 4 vinyl chloride-acrylonitrile 60% fiber) yarn. Type f split Easy A Callaway slasher was used to size all but the poly- Sh d i at the split d Li ht ethylene terephthalate/cotton yarns for which a Cooker 0 Corrected add 0n, pal-cent 14 slasher Was used. The latter yarns were tested on a Draper Slasher speed, yards/min, 1O XD loorn. The warp was drawn in a plain weave pattern '1 mm XIV P0 XTTHYLDND TDRDPH PH XLATF u if. L i J to produce a fabrlc having a construction of 120x60. COTTON (6570/3575)! 40/1 LOOM DATA Approximately 41 yards of fabric were Woven. Data obr qt 1 tamed with the Cooker slasher are presented in Table i 4964 XIII. Loom data are presented in Table XIV. z i 3 The yarns sized on the Callaway slasher were tested 40 on the Warp Shed Tester at 75 F. and 72% relative hu- We 7 3E1 midity. The warps Were drawn in a plain weave pattern 90 q T o erate to $2 On tWo double-bar harnesses and reeded as shown in F ma g Table XV which contains filament Warp Shed Tester data a 0 and Table XVLwhich contains spun Dnel Warp Shed 1 7 Tester data. The Warp Shed Tester was operated at 200 3 0 picks per minute and picks per inch. Test samples of W C F T 0 approximately 20 yards or 47,760 picks were run. d a pawn 14 1 Construction 120 G0 The filament Callaway Slashrng data are presented in TABLE XV.FILAMENT WARP SHED TESTER DATA Theoretical Construction Size Shedding Stops/20 Yards (Yarn) Type of Corrected Break Add-On, Total Ends/ Dent Drop Heddle Reed Fuzz Break Knot Other Percent Ends Dent Reed Wires Ba POLYPROPYLENE 1G5 DENIER 20 FILAMENT 1/2 T.P.I.

100 4 24 None None None 0 0 0 0 3. 5 100 4 24 None None None 0 0 0 0 2. 5

POLYETHYLENE TEREPHTI'IALATE DENIER 34 FILAMENT 5-7 T.P.I.

100 2 50 None None None 0 4 0 0 Clean 2. 7 100 2 50 None None None 0 2 0 0 Clean 2. 6

POLYAMIDE 70 DENIER 34 FILAMENT 5-7 T.P.I.

100 2 50 None None None 0 5 0 0 Clean 3. 3 100 2 50 None None None 0 7 0 0 Clean 2. 0

TABLE XVI.SPUN DYNEL WARP SHED TESTER DATA Theoretical Construction Stops/20 Yards of Yarn Shed, Cling Corrected Percent Rating Add-On, Total Ends/ Dent Fuzz Break Knot Other Percent Ends Dent Reed Ball TABLE XVII.FILAMENT, CALLAWAY, SLASHING DATA Squeeze Roll Solution Size Box Solution Type Size Shedding Corrected Slasher Pressure, 113.] Solids Temp., Viscosity of Split at the Split Add-on, Speed,

linear inch (Percent) 1*. Bf0kfi)eifl Rods Percent yards/min.

cps.

POLYPROPYLENE, 1G5 DENIE R, 20 FILAMENT, 1/2 T.P.I.

15.6 9.74 3.5 Easy None 3.5 10 15.6 7.09 140 3.5 Easy None 2.5 10

POLYETHYLENE TEREPHTHALATE, 70 DENIER, 34 FILAMENT, 5-7 T.P.I.

15.6 9. 74 4 Easy None 2.7 10 15.6 7. 09 150 3 Easy None 2.6 10

POLYAMIDE, 70 DENIER, 34 FILAMENI, 5 7 T.P.I.

15.6 9.64 150 4 Easy None 3.3 10 15.6 6. 39 150 3.5 Easy None 2.0 10

TABLE XVIII.SPUN DYNEL CALLAWAY SLASHING DATA Squeeze Roll Solution Size Box Solution Type Shedding at Corrected Slasher Pressure, 1b.] Solids, Temp, Viscosity of Split The Split Add-On, Speed,

linear inch Percent F. Brpokfifld Rods Percent yards/min.

cps.

SP UN D YNEL 15. 6 9.60 150 4 Easy Moderate 10. 3 10 15.6 6. 55 150 3 Easy Moderate 9. 5

Although the invention has been described in its preferred forms with a certain degree of particularly, it is understood that the present disclosure has been made only by way of example, and that numerous changes can be made without departing from the spirit and scope of the invention.

What is claimed is:

1. A process for warp sizing and desizing textile fibers comprising the steps of:

(a) sizing textile fibers with an aqueous sizing solution of a warp size comprising essentially a water soluble alkali metal salt of an interpolymer of ethylene and an acrylic acid having 3 to 4 carbon atoms, said interpolymer having a melt index of about decigrams/minute to 1000 decigrams/minute and containing about 12 to 54% of an acrylic acid interpolymerized therein and with the acrylic acid alkali metal salt moieties comprising about 12 to 65% by Weight of the total interpolymer salt;

'(b) weaving said textile fibers into cloth;

(0) desizing the textile fibers in said cloth by contacting the fibers with a hot water wash in which the interpolymer salt is soluble;

(d) adding on acid to the hot water wash until its pH is about 4 to 6 thereby precipitating the interpolymer;

(e) isolating the precipitated interpolymer from the hot water wash; and

(f) reforming the alkali metal salt of the interpolymer by contacting the isolated interpolymer with an alkali metal base.

2. The process claimed in claim 1 wherein the alkali metal is sodium and the acrylic acid alkali metal salt moiety comprises about 14% to 54% by weight of the total interpolymer salt.

3. The process claimed in claim 1 wherein the alkali metal is potassium and the alkali metal salt moiety comprises about 18% to 65 by weight of the total interpolymer salt.

4. The process claimed in claim 1 wherein the alkali metal is lithium and the alkali metal salt moiety comprises about 12% to 54% by weight of the total interpolymer salt.

5. The process claimed in claim 1 wherein the acrylic acid is acrylic acid,

i CH2=CCOOH 6. The process claimed in claim 1 wherein the acrylic acid is methacrylic acid CH CHZ=(IJCOOH 7. The process claimed in claim 1 wherein the textile sized is a filament yarn.

8. The process claimed in claim 1 wherein the textile sized is a staple yarn.

9. The process claimed in claim 1 wherein the desizing step is carried out at a temperature of about C. to C.

10. The process claimed in claim 1 wherein the recovered warp size is recycled and reused to replenish the aqueous sizing solution.

11. The process claimed in claim 1 wherein the textile sized is cotton.

12. The process claimed in claim 1 wherein the textile sized is a mixture of cotton and polyethylene terephthalate.

13. The process claimed in claim .1 wherein the textile sized is a polyethylene terephthalate.

14. The process claimed in claim 1 wherein the textile sized is a polyamide.

15. The process claimed in claim 1 wherein the textile sized is a vinyl chloride/acrylonitrile copolymer.

16. The process claimed in claim 1 wherein the textile sized is polypropylene.

References Cited UNITED STATES PATENTS MERVIN STEIN, Primary Examiner.

ROBERT R. MACKEY, L. K. RIMRODT,

Assistant Examiners.

Claims (1)

1. A PROCESS FOR WARP SIZING AND DESIZING TEXTILE FIBERS COMPRISING THE STEPS OF: (A) SIZING TEXTILE FIBERS WITH AN AQUEOUS SIZING SOLUTION OF A WARP SIZE COMPRISING ESSENTIALLY A WATER SOLUBLE ALKALI METAL SALT OF AN INTERPOLYMER OF ETHYLENE AND AN ACRYLIC ACID HAVING 3 TO 4 CARBON ATOMS, SAID INTERPOLYMER HAVING A MELT INDEX OF ABOUT 15 DECIGRAMS/MINUTE TO 1000 DECIGRAMS/MINUTE AND CONTAINING ABOUT 12 TO 54% OF AN ACRYLIC ACID INTERPOLYMERIZED THEREIN AND WITH THE ACRYLIC ACID ALKALI METAL SALT MOIETIES COMPRISING ABOUT 12 TO 65% BY WEIGHT OF THE TOTAL INTERPOLYMR SALT; (B) WEAVING SAID TEXTILE FIBERS INTO CLOTH; (C) DESIZING THE TEXTILE FIBERS IN SAID CLOTH BY CONTACTING THE FIBERS WITH A HOT WATER WASH IN WHICH THE INTERPOLYMER SALT IS SOLUBLE; (D) ADDING ON ACID TO THE HOT WATER WASH UNTIL ITS PH IS ABOUT 4 TO 6 THEREBY PRECIPITATING THE INTERPOLYMER; (E) ISOLATING THE PRECIPITATED INTERPOLYMER FROM THE HOT WATER WASH; AND (F) REFORMING THE ALKALI METAL SALT OF THE INTERPOLYMER BY CONTACTING THE ISOLATED INTERPOLYMER WITH AN ALKALI METAL BASE.

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