US3335209A - Method of treating polyester filaments - Google Patents

Description

United States Patent 3,335,209 METHOD OF TREATING POLYESTER FILAMENTS Herbert S. Morgan, Jr., Apex, and Horace M. Robinson, In, Cary, N.C., assignors to Monsanto Company, St. Louis, Mo., a corporation of Delaware N0 Drawing. Filed May 18, 1966, Ser. No. 550,929 5 Claims. (Cl. 264-136) This application is a continuation-in-part of our copending applications, Ser. No. 290,296, filed June 25, 1963, entitled Improvement in Polyester Fiber Manufacture and Product Obtained Thereby, and Ser. No. 290,297, filed June 25, 1963, entitled Improvement in Polyester Fiber Manufacture and Product Obtained Thereby, both now abandoned.

This invention relates to an improved method for producing articles prepared from high molecular weight synthetic linear polyesters. More particularly, it relates to an improved method for improving the surface characteristics of articles prepared from synthetic linear polyesters.

It is well known to apply finishing agents to textile materials in order to impart to the textile materials certain desirable properties, such as antistatic protection, stiffness, sizing, softness, lubricity, water repellency, shrinkage resistance, flame retardance, and the like. In addition, in the manufacture of filament yarns from such synthetic linear polymers as the polyamides, polyesters, polyalkylenes, polyurethanes, polycarbonates, acrylonitrile poly mers, and the like, it has been known that ultimate yarn tenacity can be greatly increased by employing the technique of drawing, which comprises stretching the yarn filaments after their formation to increase molecular orientation.

Although the drawing operation can be conducted by various means, a common procedure is to employ tWo filament advancing devices generally known as a feed roll and draw roll. Filament stretching is achieved by running these rolls at differential speeds with the amount of stretching or drawing being determined by the ratio of the peripheral speeds of the two rolls. In order to localize the point at which stretching occurs, a braking device is sometimes placed between the feed roll and draw roll. Generally, the braking device consists of a pin, called the draw pin around which the yarn is wrapped a number of times. The draw pin introduces frictional drag on the moving filaments which causes stretching to take place in the area of the draw pin. The introduction of frictional drag to localize stretching is utilized in those instances where there is a tendency for non-uniform drawing to occur since greater uniformity can be obtained by employing this procedure.

It has been known that the drawing operation can sometimes be facilitated when the yarn temperature is elevated during drawing. The heating may be carried out by inserting a hot pin, a hot plate, or hot fluid bath between the feed roll and draw rolls of the drawing apparatus or by using a heated feed roll. Elevated temperatures are effective because intermolecular forces are diminished by the resulting increase in molecular activity, and therefore the ratio of the force required to draw the yarn to that required to break it is lessened. Permissible temperatures which may be used in hot drawing vary somewhat with the nature of the polymer from which the yarn is formed, since the maximum temperature which can be employed is limited by the polymer sticking point. It is a common practice to employ a hot drawing technique when processing yarn for use in products which require great tensile strength, as for example in the manufacture of reinforcement cards for inflatable tires.

A particularly troublesome problem encountered when drawing at either ambient or elevated temperatures is the occurrence of filament breakage during te drawing operation. Thus, at times one .or more individual filaments in the thread line may break and wrap around the draw roll or as sometimes happens the entire thread line may break, in which case production is stopped until adjustment can be made. Such filament breakage not only affects labor requirements and productivity, but the product quality is also affected in an adverse manner.

The principal cause of filament breakage while drawing is the build-up of excessive tension of the yarn which in turn is intensified, for the most part, by inter-filament friction and by the generation of excessive friction as the yarn passes over the draw pin when such device is employed.

It is known that excessive yarn tensions resulting from the development of unduly high and variable frictions during drawing can be reduced by applying to the yarn various anti-friction conditioning agents before it is drawn. These agents are generally applied from an aqueous vehicle rather than from non-aqueous systems to afford a more uniform distribution and better control over the amount of active agent which is deposited on the yarn. These factors are of considerable importance and cannot be controlled when a non-aqueous solvent, for example, is employed as a vehicle. Non-aqueous solvents are highly objectionable because of problems of toxicity and of high solvent retention on the yarn, and also a resulting serious impairment of the drawing operation.

In the case of fibers prepared from high molecular weight synthetic linear polyesters, it is known that these fibers when freshly spun may be slowly cold drawn by hand or rapidly hot drawn over heated surfaces by the methods discussed above. However, when undrawn polyester fibers are allowed to age or lag, the polyester fiber is known to change its amorphous nature and the aged fiber crystallizes causing it to become very brittle and difficult to draw uniformly. This condition is magnified during the drawing step where the individual filaments break at the draw pin and by filament wraps accumulating on the drawing rolls as discussed previously. In some cases, slow drawing speeds can be used to help alleviate this condition to some extent, but this seriously limits the quantity of yarn or fiber which can be drawn in a given period of time. In commercial production it is necessary to test filament coming from spinning lines for proper physical and chemical characterizations. In addition, it is often economical to hold up filament obtained from several spinning positions until filament from a number of such spinning positions may be combined for use in a single drawing operation. The breakdown of equipment often causes filament from the spinning positions to be held up prior to the drawing operation. Although the tendency for brittleness, excessive yarn tensions, and the like, to develop during lagged drawing of polyester fibers may be reduced somewhat by pretreatment with certain known conditioning agents of the prior art, there is a continuing need for treating compositions which are capable of greater effectiveness in coping with the problem.

It is an object of this invention to improve the process step of drawing high molecular weight synthetic linear polyester filament which have been lagged.

It is another object of the present invention to provide static protection and lubrication for improved processing of high molecular weight synthetic linear polyester filament.

It is a further object of this invention to provide a method of reducing the fuming tendency of high molecular weight synthetic linear polyester filament finishes during a hot drawing step.

Other objects and advantages of this invention will become readily apparent from the detailed description thereof immediately following.

It has now been found that brittleness of undrawn high molecular Weight synthetic linear polyester filaments which have been lagged for considerable lengths of time between the extrustion step and the drawing step and the build up of excessive yarn tensions during the drawing of said filaments can be greatly minimized by treating the filaments immediately after extrusion with an aqueous emulsion, the solids content of which 20 to 100 percent by weight of (1) a member selected from the group consisting of a non-ionic surface active ester and a non-ionic surface active ester condensed with ethylene oxide and (2) from about to 80 percent by weight of a non-ionic surface active polyether.

The lag time of the filaments referred to for the purposes of this invention is that time between the extrusion of the filaments and the drawing of the filaments required comprises from about for proper physical and chemical characterizations of the spun polyester filaments to allow proper quality control segregation necessary for the disposition of the final product. The minimum lag time in commercial operation may routinely run from about 12 to 24 hours. However, during difficult times of quality assessment, this lag time may run for extended periods up to about 30 days. Characterizations which must be checked normally as a routine matter are tensile properties, dyeing and color characteristics, heat and light stabilities, byproducts and impurity contamination, and the like. In addition, economics and equipment break-down many times'cause holdups between the filament extrusion step and the filament drawing step.

The esters comprising an essential part of the agents of this invention are preferably long chain fatty acid partial esters of polyhydric alcohols or their anhydrides, such as sorbitan monopalmitate and sorbitan monolaurate. These long chain fatty acid partial esters may be condensed with about 4 to moles of ethylene oxide if de-.

sired. The non-ionic surface active agents referred to in general as polyethers, are prepared by condensing a waterinsoluble hydroxy-fatty acid, or ester of such acid, or mixtures of acid and ester, with from 150 to 250 moles of ethylene oxide.,

Among the polyhydric alcohols or anhydrides from which the partial esters may be made are those having from 2 to 8 carbon atoms, such as manitol, sorbitol, glucose, erythritol, pentaerythritol, glycols such as ethylene glycol, triethylene glycol, propylene glycol, diethylene glycol, tetraethylene glycol, and the like. Various saturated or unsaturated aliphatic acids may be reacted with the polyhydric alcohols in making the partial esters. A preferred group of partial esters are those containing a single ester linkage. However, partial esters containing more than one ester linkage may be used.

The acids used in making the partial esters may he saturated or unsaturated aliphatic acids containing from 10 to 20 carbon atoms. Preferredacids are those which are saturated or contain one olefinic group. Examples of such acids include monoolefinic unsaturated acids such as 7- hexadecenoic acid, 10- undecenoic acid, 13-docosenic and 9-octadecenoic acid; substituted olefinic acids, for example, such hydroxy olefinic acids as l6-hydroxy-7-hexadecenoic and 12-hydroxy-9-octadeceneoic acid; halogenated unsaturated acids, for example, monochloro-9-octadecenoic acid, monochloro-12-9-octadecenoic acid, and halogenated acids derived by dehydration of the castor oil acids followed by chlorination; usaturated fatty acids such as decanoic acid, undecanoic acid, dodecanoic acid, trideca-.

noic acid, tetradecanoic acid, pentadecanoic acid, hexadecanoic acid, heptadecanoic acid, octadecanoic acid, and,

nonadecanoic acid. These saturated acids may also have straight or branched chains, or substituted chain, and may be substituted, for example, with chlorine mother halogen atoms, for example, monochloro-octadecanoic acid, and the like. Specific partial esters suitable for use in this invention include glyceryl monohexadeconoic, glyceryl monododecanoate, glyceryl mono-9-hydroxyoctadecanoate, glyceryl mono-12l-hydroxyoctadecanoate, sorbitan ene glycol monooctadecanoate, diethylene glycol mono-- octadecanoate, and sorbitan monooctadecanoate.

Examples of hydroxy fatty acids which can be used as such or in the form of partial esters with the polyhydric alcohols set forth above, for condensation withethylene oxide to form the ether portion of the compositions of this invention, include both saturated and unsaturated hydroxy acids such as 12-hydroxy-octadecanoic, l2-hydroxy-dodecanoic acid, 16-hydroxyhexadecanoic acid, 11- hydroxy-hexadecanoic acid, IO-hydroxy-octadecanoic acid, 3,12-dihydroxy-palmitic acid, 9,10,l6-hydroxy-hexadecanoic acid, 9,10,12,13-hydroxy-octadecanoic acid, 16-hydroxy-7-hexadecanoic acid, and l2-hydroxy-9-octadecanoic acid.

The synthetic linear condensation polyesters contemplated in the practice of this invention are those formed from dicarboxylic acids and glycols, and copolyesters or modifications of these-polyesters and copolyesters. In a highly polymerized condition, these polyesters and copolyesters can be formed into filaments and the like.

The polyesters and copolyesters specifically useful in the instant invention are those resulting from heating One or more of the glycols of the series HO(CH OH, in which n is an integer from 2 to 10, with one or more dicarboxylic acids, or ester-forming derivatives thereof. Among the dicarboxylic acids and ester-forming derivatives thereof useful in the present invention are terephthalic acid,

isophthalic acid,

sebacic acid,

adipic acid, p-carboxyphenoacetic acid, succinic acid, p,p'-dicarboxybiphenol, p,p'-dicarboxycarbanilide, p,p'-dicarboxythiocarbanilide, p,p'-dicarboxydiphenylsulfone, p-carboxyphenoxyacetic acid, p-carboxyphenoxypropionic acid, p-carboxyphenoxybutyric acid, p-carboxyphenoxyvaleric acid, p-carboxyphenoxyhexanoic acid, p-carboxyphenoxyheptanoic acid, p,p-dicarboxydiphenylmethane, p,p-dicarboxydiphenylethane, p,pT-dicarboxydiphenylpropane, p,p'-dicarboxydiphenylbutane, p,p-dicarboxydiphenylpentane, p,p'-dicarboxydiphenylhexane, p,p-dicarboxydiphenylheptane, p,p'-dicarboxydiphenyloctane, p,p-dicarboxydiphenoxyethane, p,p-dicarboxydiphenoxypropane, p,p'-dicarboxydiphenoxybutane, p,p'-dicarboxydiphenoxypentane, p,p-dicarboxydiphenoxyhexane, 3-alkyl 4-(beta-carboxy ethoxy) benzoic acid, oxalic acid,

glutaric acid,

pimelic acid,

suberic acid,

azelaic acid and the dioxy acids of ethylenedioxide. having the general formula,

HOOC(CH -OCH CH O-(CH ,COOH wherein n is an integer from 1 to 4, and the aliphatic and cyeloaliphatic aryl esters and half esters, ammonium availability of terephthalic acid and ethylene glycol, from which it is made. It also has a relatively high melting point of about 250 through 255 C. and this property is particularly desirable in the manufacture of filaments in the textile industry.

Among the modified polyesters and copolyesters which are useful in the practice of the present invention are those polyesters mentioned above modified with dialkyl esters of saturated essentially linear aliphatic dicarboxylic acids containing 20 carbon atoms having the general formula rank! (H) R1C-(UJ- A---------CO-R3 wherein R and R are alkyl radicals containing from 1 to 10 carbon atoms and more preferably are alkyl hydrocarbon radicals containing from 1 to carbon atoms including methyl, ethyl, propyl, isopropyl, n-butyl, sec. butyl, isobutyl, n-amyl, isoamyl, and the like; A is a linear saturated aliphatic radical containing from 14 to 18 carbon atoms in its chain; n is an integer of either 1 or 2; and y is an integer from 0 to 2. The total number of carbon atoms in A and the side chains thereof is 18. R and R may be the same or may be different alkyl radicals. Representative dialkyl esters found useful in this invention include dialkyl 1,20-eicosane dioate, dialkyl S-ethyl octadecene-l, l8-dioate, dialkyl dimethyl octadecane-l, 18-dioate, dialkyl diethylhexadecane-l, 16-dioate and the like, where the dialkyl groups are methyl, ethyl, propyl, and the like including alkyl hydrocarbon radicals containing from 1 to 5 carbon atoms. Mixtures of any of the materials described above may also be used. For example, mixtures of above 20 to 80 weight percent of dimethyl l,20-eicosane dioate and about 80 to 20 weight percent of dimethyl 8-ethyl octadecane-1,18-dioate are quite useful. The amounts of necessary reactants employed to make the modified polyesters, on a molar basis, are ordinarily one mole equivalent of a mixture of the two types of dialkyl esters of aromatic and C dicarboxylic acids and a molar excess of the glycol. In the mixture of the dialkyl esters, the dialkyl aromatic dicarboxylic acid esters are presented in amounts from about 65 to 95 weight percent and the dialkyl esters of the aliphatic C dicarboxylic acid is present in amounts from about 35 to about 5 weight percent.

Among the modified polyesters and copolyesters which are useful in the practice of the present invention are the polyesters and copolyesters mentioned above modified with chain-terminating groups having hydrophilic properties, such as the monofunctional ester-forming polyesters bearing the general formula wherein R is an alkyl group containing 1 to 18 carbon atoms or an aryl group containing 6 to carbon atoms, and m and n are integers from 2 to 22, and x is a whole number indicative of the degree of polymerization, that is, x is an integer from 1 to 100 or greater. Examples of such compounds are methoxypolyethylene glycol, ethoxypolyethylene glycol, n-propoxypolyethylene glycol, isopropoxypolyethylene glycol, butoxypolyethylene glycol, phenoxypolyethylene glycol, methoxypolypropylene glycol, methoxypolybutylene glycol, phenoxypolypropylene glycol, phenoxypolybutylene glycol, methoxypolymethylene glycol, and the like. Suitable polyalkylvinyl ethers having one terminal hydroxy group are the addition polymers prepared by the homopolymerization of alkyl vinyl ethers wherein the alkyl group contains from 1 to 4 carbon atoms. Examples of such chain-terminating agents are hydroxy polymethylvinyl ether, hydroxy polyethylvinyl ether, hydroxy polypropylvinyl ether, hydnoxy polybutylvinyl ether, hydroxy polyisobutylvinyl ether, and the like. The chain-terminating agents or compounds may be employed in the preparation of the modified polyesters, in amounts ranging from 0.05 mole percent to 4.0 mole percent, based on the amount of dicarboxylic acid or dialkyl ester thereof employed in the reaction mixture. It is to be noted that when chain-terminating agents are employed alone, i.e., without a chainbranching agent, the maximum amount that can be employed in the reaction mixture is 1.0 mole percent. Thus, unexpectedly, the addition of controlled amounts of chain-branching agents along with the chain-terminating agents allows the introduction of an increased amount of the latter into the polymer chain that is otherwise possible when employing the chain-terminating agents alone.

One will readily appreciate that the weight percent of chain-terminating agent which may be employed in this invention will vary with the molecular Weight of the agent. The range of average molecular weight of the chain-terminating agents suitable for use in this invention is from 500 to 5000, with those agents having a molecular weight in the range of 1000 to 3500 being preferred.

Materials suitable as chain-branching agents or crosslinking agents, which are employed to increase the viscosity or molecular weight of the polyesters, are the polyols which have a. functionality greater than two, that is, they contain more than two functional groups, such as hydroxyl. Examples of suitable compounds are pentaerythritol; compounds having the formula wherein R is an alkylene group containing from 3 to 6 carbon atoms and n is an integer from 3 to 6, for example glycerol, sorbitol, hexane triol-1,2,6, and the like; compounds having the formula wherein R is an alkyl group containing from 2 to 6 carbon atoms, for example, trimethylol ethane, trimethylol propane, and the like compounds up to trimethylol hexane; and the compounds having the formula wherein n is an integer from 1 to 6. As examples of compounds having the above formula there may be named trimethylol benzene-1,3,5 triethylol benzene-1,3,5, and the like.

Aromatic polyfunctional acid esters may also be employed in this invention as chain-branching agents and particularly those having the formula and in which R, R, and R" are alkyl groups containing 1 to 3 carbon atoms and R is hydrogen or alkyl groups having 1 to 2 carbon atoms. As examples of compounds having the above formula there may be named trimethyl trimesate, tetramethyl pyromellitate, tetramethyl mellophonate, trimethyl hemimel litate, trimethyl trimellitate, tetramethyl prehnitate, and the like. In addition, there may be employed mixtures of the above esters which are obtained in practical synthesis. That is, in most instances when preparing any of the compounds having the above formula, other related compounds having the same formula may be present in small amounts as impurities. This does not alfect the compound as a chain-branching agent in the preparation of the modified polyesters and copolyesters described herein.

The chain-branching agents or cross-linking agents may be employed in the preparation of the polyesters and copolyesters in amounts ranging from 0.05 mole percent to 2.4 mole percent, based on the amount of dicarboxylic acid or diallcyl ester thereof employed in the reaction mixture. The preferred range of chain-branching agent for use in the present invention is from 0.1 to 1.0 mole percent. In the practice of the present invention, the calculated amounts of chain-terminating agent or chainterminating agent and chain-branching agent or crosslinking agent are charged to the reaction vessel at the beginning of the first stage of the esterification reaction and the reaction proceeds as in any well-known esterification polymerization.

The highly polymeric linear condensation polymers selected from the group consisting of polyesters and polyester-amides, which contain in the molecular structure a substantial proportion of recurring groups having the following structural formula CHz-CH2 H-0H2 wherein the substituted cyclohexane ring is selected from the group consisting of the cis and trans isomers thereof may be used in the practice of this invention. These polymeric linear polyesters and polyester-amides may be prepared by a process comprising condensing (1) either of cis or the trans isomer or a mixture of these isomers of 1,4-cyclohexanedimethanol alone or' mixed with another bifunctional reactant with (2) a bifunctional carboxy compound.

The bifunctional reactants which can be employed contain no other reactive substituents which would interfere with the formation of a highly polymeric linear polymer when condensed with 1,4-cyclohexanedimethanol or a mixture thereof with such bifunctional reactants. These bifunctional reactants adapted for the preparation of linear condensation polymers are quite well known and have been discussed earlier.

The 1,4-cyclohexanedimethanol employed in any of the processes for making condensation polymers can be used in combination with an additional bifunctional coreactant such as when employing a mixture of glycols (it is advantageous to use amounts of the 1,4-cyclohexanedimethanol equal to at least 50 mole percent of the total of such coreactants employed although smaller proportions can alsobe used). The various bifunctional coreactants which can be employed in admixture with 1,4- cyclohexanedimethanol include other glycols and compounds which do not necessarily react with a glycol, e.g., an aminoalcohol. Such coreactants also include diamines, or aminocarboxy compounds.

The bifunctional reactants containing functional groups which can be condensed with 1,4-cyclohexanedimethanol or mixtures thereof are bifunctional compounds capable of condensation so as to form highly polymeric linear condensation polymers. Such bifunctional compounds can be solely inter-reactive with a glycol, e.g., a diearboxylic acid or they can be both (a) coreactive in the sense they can be used'in lieu of or as a partial replacement of the glycol in a polyester, and (b) interreactive in the sense that they condense with a glycol or a bifunctional compound which can be employed in lieu of a glycol. For example, 6-amino-caproic acid is both coreactive in that the amino group is of the type which can be used in lieu of a hydroxy radical of a glycol and also inter-reactive in the sense that the carboxylic group will react with the hydroxy of a glycol or the amine of a bifunctional compound which can be used in lieu of a glycol. The bifunctional compounds which are solely inter-reactive with a glycol include 'dicarboxylic acids, carbonates, and the like. The other bifunctional interreactive compounds include aminocarboxy compounds, or hydroxy carboxy compounds.

The modified linear condensation polyesters, used in accordance with' the present invention, have specific viscosities in the range of about 0.1 to about 1.0, which represent fiberwhere n is defined as the ratio of the viscosity of a solution of 0.5 gram of the polymer in 100 ml. of m-cresol to the viscosity of the solvent, both at 25", C.

The aqueous emulsions which are used'in the practice of this invention may contain up to 20 per-cent solids by weight without exceeding the viscosity limits normally used for conditioning agents used in yarn production, with from about 2 to about 15 percent solids being generally preferred. By the term solids as used herein, there is mean the totality of ingredients exclusive of the aqueous vehicle without regard to physical state. The solids may contain from about 20 to 100 percent by weight of the non-ionic surface active ester component defined above and from about 0 to percent by weight of the nonionic surface active polyether defined above. It is preferred that the solids contain from about '60 to percent by weight of the non-ionic surface active ester component defined above and from about '0 to 40 percent by weight of the non-ionic surface active polyether component defined above.

Conventional methods may be employed in formulating the. aqueous emulsion. A simple and convenient method is merely to :mix the materials together, heat them until the solid materials melt, and then add the molten blend of ingredients to the aqueous vehicle with vigorous mechanical agitation. During this addition step, the water should be maintained atan elevated temperature which is at or above the melting point of the ingredients.

Generally, good results are obtained in both cold and hot drawing operations when the conditioning agent is applied in an amount such that the solids deposited on the fiber constitute from about 0.1 to about 1.5 percent by weight, based on the weight of the fiber. Although lesser or greater amounts may be used, best results are obtained when the amount of solids deposited on the fiber is within this range.

As has been emphasized, the above-described treating agent is applied to the filaments or fiber immediately during or after spinning and prior to drawing. A conventional and convenient technique of application is to contact the fiber while moving or advancing in the course of production with a roll which is made to rotate so that its. lower portion dips into a pan containing the treating composition. The treating agent is pumped from a reservoir to the pan or other container and a constant level is maintained by an overflow pipe or similar device. Other suitable methods and devices may be employed suchas the use of a wick or split roll or the fiber may be passed through a bath containing a treating agent.

The fibers herein described may be modified by incorporation therein of various modifying agents. Illustrative .of suitable modifying agents that may be incorporated into the fibers are pigments, plasticizers, resins, diluents, water repellents, waxes, luster modifiying agents, flame repellents, antistatic agents, softeners, and the like.

The following examples specifically illustrate the manner in which the process of the present invention is conducted and the advantages obtained thereby. That is, advantages which accrue both wtih respect to-improvement of the drawing operation as well as in the ultimate yarn products. The examples are given by way of illustration only and are not to be construed as limitative.

EXAMPLE 1 Filaments :were formed by the melt extrusion of a polyethylene terephthalate polymer modified with approxi-.

molecular weight of about 2000 and approximately 0.125 percent, based on the weight of the polyethylene terephthalate, of pentaerythritol. No finish was applied to these filaments. The filaments were then lagged or held for 17 hours at room temperature, about 23 C. after which time they could not be uniformly cold or hot drawn. Additional filaments were lagged 8 days at room temperature at which time they could not be cold drawn and when hot drawn they were so brittle at a draw ratio of 5.2 that a continuous drawing line could not be maintained over a short time period of minutes.

EXAMPLE 2 Filaments were formed by the melt extrusion of polyethylene terephthalate modified with approximately 6 percent, based on the weight of the polyethylene terephthalate, of methoxy polyethylene glycol having a molecuar weight of about 2000, and approximately 0.125 percent, based on the weight of polyethylene terephthalate of pentaerythritol. These filaments were then treated with an aqueous emulsion containing percent solids, the solids content of which comprised about 60 percent by weight of sorbitan monopalmitate and about 40 percent by weight of castor oil condensed with 200 moles of ethylene oxide. The treating agent was applied by means of a rotating roll in an amount such that 0.83 percent solids were deposited on the filaments, based on the weight of the filaments. The filament yarns were then divided into three parts. The first part was immediately hot drawn on a conventional draw-twist machine at a draw ratio of 4.4lX with excellent results. The second part was lagged for 7 days after which it was hot drawn on a conventional draw-twist machine at a draw ratio of 4.4lX with excellent results. The third part was lagged 31 days after which it was hot drawn on a conventional draw-twist machine at a draw ratio of 4.4lX wtih excellent results.

EXAMPLE 3 Filaments were formed by the melt extrusion of polyethylene terephthalate modified with aproximately 6 percent, based on the weight of the polyethylene terephthalate, of methoxy polyethylene glycol having a molecular weight of about 2000, and approximately 0.125 percent, based on the weight of polyethylene terephthalate, of pentaerythritol. These filaments were then treated With an aqueous emulsion containing 10 percent solids, the solids content of which comprised sorbitan monolaurate condensed with 20 moles of ethylene oxide. The treating agent was applied by means of a rotating roll in an amount such that 0.66 percent solids were deposited on the filaments, based on the Weight of the filaments. The filament yarns were then divided into three parts. The first part was immediately hot drawn on a conventional draw-twist machine at a draw ratio of 4.4lX with excellent results. The second part was lagged for 7 days after which it was hot drawn on a conventional draw-twist machine at a draw ratio of 4.4lX with excellent results. The third part was lagged for 31 days after which it was hot drawn on a conventional draw-twist machine at a draw ratio of 4.4lX with good results.

As various changes in modification of this invention can be made without sacrificing any of its advantages and without departing from the spirit and scope thereof, it

Is to be understood, that all matter herein is to be interpreted strictly as illustrative; as the only limitations of the invention are those which appear in the following appended claims.

What is claimed is:

1. A method of preparing polyester filaments which comprises extruding said filaments, immediately thereafter treating said filaments with an aqueous emulsion, the solids content of which consists essentially of (1) from about 20 to percent by weight of a member selected from the group consisting of a non-ionic surface active partial ester of a polyhydric alcohol having from about 2 to 8 carbon atoms and an aliphatic carboxylic acid and a non-ionic surface active partial ester of a polyhydric alcohol having from about 2 to 8 carbon atoms and an aliphatic carboxylic acid condensed with about 4 to 20 moles of ethylene oxide and (2) from about 0 to 80 percent by weight of a non-ionic surface active polyether prepared by condensing from about to 250 moles of ethylene oxide with a member selected from the group consisting of water-insoluble hydroxy fatty acids, esters of said acids and mixtures of said acids and esters, lagging said treated filaments for periods of about 12 hours to about 30 days and thereafter uniformly drawing said filaments.

2. A method of preparing polyester filaments which comprises extruding said filaments, immediately thereafter treating said filaments with an aqueous emulsion, the solids content of which consists essentially of from about 2 to 15 percent by weight of solids being selected from the group consisting of (1) about 60 percent by weight of sorbitan monopalrnitate and about 40 percent by weight of castor oil condensed with about 200 moles of ethylene oxide and (2) sorbitan monolaurate condensed with about 20 moles of ethylene oxide, lagging said treated filaments for periods of about 12 hours to about 30 days and thereafter uniformly drawing said filaments.

3. A method as defined in claim 2 wherein the polyester is polyethylene terephthalate modified with about 6 percent, based on the weight of the polyethylene terephthalate, of methoxy polyethylene glycol having a molecuuar weight of about 2000 and 0.125 percent, based on the weight of the polyethylene terephthalate of pentaerythritol.

4. A method as defined in claim 3 wherein the solids content of the aqueous emulsions consists of about 60 percent by weight of sorbitan monopalmitate and about 40 percent by weight of castor oil condensed with about 200 moles of ethylene oxide.

5. A method as defined in claim 3 wherein the solids content of the aqueous emulsion consists of sorbitan monolaurate condensed with 20 moles of ethylene oxide.

References Cited UNITED STATES PATENTS ALEXANDER H. BRODMERKEL,

Primary Examiner.

F. S. WHISENHUNT, D. I. ARNOLD,

Assistant Examiners.

Claims (1)

1. A METHOD OF PREPARING POLYESTER FILAMENTS WHICH COMPRISES EXTRUDING SAID FILAMENTS, IMMEDIATELY THEREAFTER TREATING SAID FILAMENTS WITH AN AQUEOUS EMULSION THE SOLIDS CONTENT OF WHICH CONSISTS ESSENTIALLY OF (1) FROM ABOUT 20 TO 100 PERCENT BY WIEGHT OF A MEMBER SELECTED FROM THE GROUP CONSISTING OF A NON-IONIC SURFACE ACTIVE PARTICAL ESTER OF A POLYHYDRIC ALCOHOL HAVING FROM ABOUT 2 TO 8 CARBON ATOMS AND AN ALIPHATIC CARBOXYLIC ACID AND A NON-IONIC SURFACE ACTIVE PARTIAL ESTER OF APOLYHYDRIC ALCOHOL HAVING FROM ABOUT 2 TO 8 CARBON ATOMS AND AN ALIPHATIC CARBOXYLIC ACID CONDENSED WITH ABOUT 4 TO 20 MOLES OF ETHYLENE OXIDE AND (2) FROM ABOUT 0 TO 80 PERCENT BY WEIGHT OF A NON-IONIC SURFACE ACTIVE POLYETHER PREPARED BY CONDENSING FROM ABOUT 150 TO 250 MOLES OF ETHYLENE OXIDE WITH A MEMBER SELECTED FROM THE GROUP CONSISTING OF WATER-INSOLUBLE HYDROXY FATTY ACID ESTERS OF SAID ACIDS AND MIXTURES OF SAID ACIDS AND ESTERS, LAGGING SAID TREATED FILAMENTS FOR PERIODS OF ABOUT 12 HOURS TO ABOUT 30 DAYS AND THEREAFTER UNIFORMLY DRAWING SAID FILAMENTS.