US3113369A - Yarn manufacture and products obtained thereby - Google Patents

Description

United States Patent M 3,113,369 YARN MANUFACTURE AND PRODUCTS QBTATNED THEREBY Homer D. Barrett, Robert T. Estes, and George C.

Stow, In, Decatur, Ala, assignors, by mesne assignments, to Monsanto Chemical Company, a corporation of Delaware No Drawing. Filed May 2, 1%0, Ser. N 25,962. 14 Claims. (Cl. 28-75) This invention relates generally to an improved method for producing organic filamentary materials and to improved products resulting therefrom. More particularly, it relates to an improved method for producing filaments and yarns from synthetic linear superpolymers and to cabled structures embodying the filaments and yarns produced in accordance therewith.

In the manufacture of filament yarns from such syn thetic linear polymers as the polyamides, polyesters, polyalkylenes, polyurethanes, polycarbonates and acrylouitrile polymers, 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 melting 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 cords for inflatable tires.

A particularly troublesome problem encountered when drawing at either ambient or elevated temperatures is the occurrence of filament breakage during the 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 adjustments 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 principle cause of filament breakage while drawing is the build-up of excessive tension on the yarn which in 3,113,359 Patented Dec. 10, 1963 turn is caused, for the most part, by inter-filament friction and by the generation of excessive friciton 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 frictions during drawing can be reduced by applying to the yarn various antifriction 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 the high solvent retention on the yarn and a resulting serious impairment of the drawing operation.

Although the tendency for excessive yarn tensions to develop during drawing can be reduced somewhat by pretreatment with certian known conditioning agents of the pri r art, there is a continuing need for treating compositions which are capable of greater elfectiveness in coping with the problem.

It has now been found that the build-up of excessive yarn tensions during drawing can be greatly minimized by applying a wax-containing aqueous emulsion to the yarn before it is drawn. It has further been found that this procedure not only facilitates the drawing operation, but that in addition thereto substantial advantages are imparted to the ultimate yarn product. For example, products such as various types of rope and rubber reinforcement cords have shown extraordinary increases in flex life when produced from yarns treated in this manner.

As is well known filamentary materials formed from synthetic linear polyamides, polyesters, polypropylene and like synthetic linear polymers are commonly used in the production of cabled structures such as rope and various ty e cords which are used to reinforce rubber products such as, for example, rubber tires, transmission belts, hose and the like. These cabled structures are generally made by twisting and plying together one or more strands of yarn each of which have been previously subjected to a drawing operation in accordance with the procedure as described hereinabove. Although cord structures manufactured from synthetic linear ploymers are employed as reinforcing materials in a wide variety of ruber products, an exceptionally large market has developed in the pneumtaic tire field. At present virtually all aircraft and large oif-the-road equipment tires are reinforced with such cord as well as substantially all of the premium passenger car tires in addition to a large percentage of automobile replacement tires. All such cords or fabrics are subjected to more or less severe flexing during service, and for a more satisfactory performance the cord structure should have a high flex life at elevated temperatures. There has been an existing need for improvement in these respects for all presently available tire cord products.

Accordingly, an object of this invention is to improve the process step of drawing synthetic linear polymers.

Another object of the present invention is to provide a method for producing improved cabled structures from synthetic linear polymeric materials.

A further object of this invention is to provide a method for producing superior reinforceemnt cords for rubber structures from synthetic linear polymeric materials.

A still further object of the present invention is to provide a method for producing tire cord for use in reinforcing infiatable rubber tires having a greater resistance to compression-extension fatigue and consequently an increased flex life.

Gther objects and advantages will become readily apparent in the description immediately following.

As has been noted, the objects of this invention are achieved by treating synthetic polymeric filaments before they are drawn with a composition which contains a wax as the essential element. In addition to the essential wax component, one or more emulsifying agents and an aqueous vehicle are included as part of the treating composition. A lubricant such as mineral oil, fatty acid esters and the like may also be added if desired.

The wax component may be selected from a wide variety of waxes. Thus, for example, there may be employed japan wax, ceresin, carnauba, candelilla, ozocerite, montan wax, parafiin waxes, microcrystalline waxes or any other natural wax. The various synthetic waxes, such as, the phthalimides, polymers of ethylene oxide such as Carbo wax, terphenyls such as Santowax, the polyalkylenes such as polyethylene may also be employed with good results. The waxes may be oxidized or non-oxidized and should preferably have a melting point of between 50 C. to 140 C. and a penetration at 77 F. of between 1 and in accordance with ASTM test method D-l321-55T. Additional properties that are desirable but not critical when employing oxidized waxes are an acid number of between 10 and 50 and a saponification number of between 30 and 100.

Among the many waxes that have been found suitable, best results are achieved with microcrystalline waxes. Microcrystalline waxes are those waxes which have a finer, less apparent crystalline structure than parafiin wax and which comprise a solid hydrocarbon mixture of molecular weight averaging higher than paraflin wax. These waxes possess plastic properties and are obtainable from crude petroleum fractions. All microcrystalline waxes are of about the same molecular weight and are said to be composed of hydrocarbon chains of twice the length of those of the microcrystalline waxes. Commercially available products are exemplified by Crown Wax 23, Crown R50, Bareco Wax C-750O and C-6500 of the Petrolite Chemical Corporation, and Cardis 320, Mekon Y-20 and Fortex of the Warwick Wax Company.

Any of the known emulsifying agents, which are capable of dispersing wax in an aqueous medium to form an emulsion which is stable over extended periods of time and at elevated temperatures, may be employed in the practice of this invention. While a number of available emulsifiers can be employed, the amine soaps are particularly suitable. The amine soap may be derived from a fatty acid containing at least about 8 carbon atoms with from about 12 to 22 carbon atoms being preferred. Oleic acid is highly suitable, but such fatty acids as lauric, palmitic, myristic, stearic, behenic and the like may be used if desired either in whole or in part. Animal, marine and vegetable oils are suitable sources for the fatty components of these soaps. Any water-soluble aliphatic amine may be employed in forming the soap, but the lower alkylolamines are preferred as exemplified by the primary, secondary, and tertiary amines of ethanol, propanol, isopropanol and the several butanols. Triethanolamine and Z-amino 2-methyl l-propanol are particularly outstanding for this purpose. Other suitable amines include the various primary, secondary and tertiary methyl, ethyl, propyl, isopropyl and butyl amines and morpholine. The amine soaps may be either prepared in advance or in situ by the addition of the amine and an appropriate fatty acid to the aqueous vehicle.

It is often desirable to include a non-ionic surface active agent as a part of the emulsifying system in that these materials tend to suppress the accumulation of static during the drawing operation in addition to providing increased emulsion stability. Among agents of this type which may be employed are the polyoxyethylene ethers of a long chain fatty alcohol or thiol and the polyoxyethylene esters derived from long chain fatty acids. The long chain fatty alcohols and long chain fatty acids from which these materials are formed may contain from about 12 to 40 bo atoms in their alkyl chains and these chains may be straight or branched. The fatty acids and fatty alcohols may be commercially pure single compounds or mixtures of such single compounds of one type, ie acids or alcohols, or they may be mixtures that are obtained from naturally occurring products. Suitable long chain fatty alcohols are, for example, dodecyl alcohol, tri

decyl alcohol, cetyl alcohol, myristyl alcohol, linoleyl alcohol and the mixture of alcohols derived from sperm oil. The alkylated phenols such as octyl phenol and nonyl phenol may also be employed. Suitable long chain acids are, for example, lauric acid, oleic acid and the mixture of acids derived from cocoanut oil. In producing the polyoxyethylene ethers and esters, ethylene oxide may be permitted to act directly on the long chain fatty alcohols and long chain fatty acids. Alternatively, the long chain fatty acids and long chain fatty alcohols may be reacted with a polyethylene glycol. The length of the polyethylene oxide chain may be varied over a considerable range, satisfactory results having been obtained with chain lengths of from about 2 to 50 ethylene oxide units. A particularly effective non-ionic emulsifier of this type is the adduct formed by reacting 1 mol of tridecyl alcohol with an average of 9 mols of ethylene oxide.

As has been indicated, a lubricating oil may be included as a part of the yarn treating compositions of this invention. The oils may be of vegetable, marine, or of petroleum origin. Among the vegetable oils, there may be mentioned linseed, soybean, corn, peanut, castor, rapeseed and olive oils. Suitable marine oils are menhaden oil, whale oil and sperm oil. Applicable mineral oils are those whose viscosities vary between the kerosenes and the heavy motor oils with a highly refined, colorless mineral oil being preferred. Mineral oils having Saybolt viscosities of from 30 to 180 seconds at F. are considered of especial advantage. Various of the so-called synthetic lubricants-may also be used to advantage. Among the synthetic lubricating oils which can be suitably employed are the various polyalkylene glycols, commercially available from the Carbide and Carbon Chemical Company and known commercially as Ucons. In addition, the fatty acid esters can be used to advantage. The esters may be either mono-, di-, triesters, etc., or mixtures thereof. The fatty acid portion of the ester can contain anywhere from 1 to about 22 carbon atoms; and may be derived from such fatty acids as acetic, propionic, lauric, myristic, palmitic, stearic, adipic, azelaic, benzoic, citric, abietic, fumaric, phthalic, oleic, ricinolec, sebacic, succinic, tartaric, etc. The alcohol portion may be derived from either monohydric or polyhydric alcohols which contain from 1 to 12 carbon atoms. Suitable examples are methanol, ethanol, Z-methyl l-propanol, l-pentanol, heptanol, glycerol, hexitol, sorbitol, mannitol, pentaerythritol and many others. Among specific examples of suitable esters are isopropyl palmitate, butyl stearate, isopropyl myristate, isobutyl laurate, methyl abietate, dibutyl adipate, di-isooctyl adipate, di-2-ethylbutyl azelate, glycerol monoacetate, glycerol tripropionate, di-n-butyl maleate, n-propyl oleate, amyl oleate, isopropyl palmitate, isooctyl palmitate, dimethyl phthalate, butyl octyl phthalate, di (2-ethylhexyl) phthalate, isobutyl ricinoleate, glycerol monoricinoleate, dioctyl sebacate, n-butyl stearate, octyl stearate, dibutyl succinate, diethyl tartrate, sorbitol tetrastearate, sorbitan monopalmitate, etc. A class of fatty acid esters which are particularly advantageous are mixed triglycerides which may be represented by the following formula:

RCOOOHa RCOOGH RCOOCH:

wherein R designates saturated or unsaturated aliphatic radicals. Either one or two of the R groups contain from 1 to 5 carbon atoms having at most one double bond while the remaining R group or groups may contain from 12 to 22 carbon atoms with from 0 to 5 double bonds.

The location of the shorter carbon chain aliphatic radicals with respect to the glyceryl radical is not of critical importance, i.e. it may be in either the alpha, beta or gamma position. Some examples of suitable compounds of this type are glycerol mono-ricinoleate di-acetate, glycerol mono-linoleate di-acetate, glycerol mono-linolenate diacetate, glycerol mono-acetate di-linoleate, glycerol monoacetate di-ricinoleate, glycerol mono-laurate di-butyrate, glycerol mono-laurate di-valerate, etc. Various phosphoric acid derivatives may also be suitably employed. Examples of such compounds include triethyl phosphate, tributyl phosphate, triphenyl phosphate, tri-(2-ethylhexyl) phosphate, tributoxyethyl phosphate, tricresyl phosphate, cresyl diphenyl phosphate, tri-dimethylphenyl phosphate, diphenyl mono-o-xenyl phosphate, trip-tert-butylphenyl phosphate, diethyl ethylphosphonate, dibutyl butylphosphonate, bis (Z-ethylhexyl) 2-ethylhexylphosphonate, tris (2-chloroethyl) phosphite, etc.

The aqueous emulsions which are used in the practice of this invention can contain up to 30 percent solids by weight without exceeding the viscosity limits normally used for conditioning agents used in yarn production, with from about to percent solids being generally preferred. By the term solids as used herein, there is meant the totality of ingredients exclusive of the aqueous vehicle without regard to physical state. The solids may contain from 10 to 90 percent by weight of the essential wax ingredient and from 10 to 90 percent total of one or more emulsifying agents. In those instances where a mineral oil or other lubricating oil, such as described hereinabove, is employed, this component may be present in an amount constituting up to 80 percent by weight based on the total weight of the solids present.

Conventional methods can be employed in formulating the aqueous emulsion. A simple and convenient method is to merely heat the solid materials together until melted into a blend 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 at an elevated temperature which is near to or at the boiling point.

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 yarn constitute from about 0.1 to about 2.0 percent based on the weight of the yarn. Although lesser or greater amounts may be used best results are obtained when the amount of solids deposited on the yarn is within this range.

As has been emphasized, the above-described treating agent is applied to the filaments or yarn prior to drawing. A conventional and convenient technique of application is to contact the yarn 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 such as the use of a wick or split roll or the yarn may be passed through a bath containing the treating agent.

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 with respect to improvement in 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 I A bundle of filaments, comprising 140 in number and having a total denier of 4500 was formed by the melt extrusion of a polyhexamethylene adipamide polymer, commonly known as nylon 66. The thus formed filaments were then brought together in the form of a yarn which was treated with an aqueous emulsion which contained 12 parts by weight of solids. The solids content consisted of 33 parts by weight of a microcrystalline wax with a melting point of between and C., 25 parts by weight of a mineral oil having a Saybolt viscosity of 50 seconds at 100 F., 17 parts by weight of the amine soap formed from stoichiometric amounts of 2-amino 2-methyl 1-propanol and oleic acid, and 25 parts by weight of the adduct formed by reacting 1 mol of tridecyl alcohol with 9 mols of ethylene oxide. The treating agent was applied by means of a rotating roll in an amount such that 0.39 percent solids were deposited on the yarn, based on the weight of the yarn. The yarn was then taken up on a spin bobbin from where it was passed to a conventional drawtwist machine where it was hot drawn to a tenacity of 8.54 grams per denier. For purposes of evaluating the drawtwist performance the number of thread line breaks and draw roll wraps (broken filaments wrapped on the draw roll) were determined and recorded.

Example 11 A multi-iilament yarn comprising a bundle of filaments and having a total denier of 4500, was formed by the melt extrusion of a polyhexamethylene adipamide polymer. The yarn was then treated with an aqueous emulsion which contained 12 parts by weight of solids. The solids content consisted of 33 parts by weight of a microcrystalline wax with a melting point of between 100 C. and 105 C.; 25 parts by weight of a mixture of triglycerides consisting chiefly of glycerol mono-ricinoleate di-acetate, with glycerol mono-linoleate di-acetate, and glycerol mono-linolenate di-acetate in considerably smaller amounts, the mixed esters being obtained from the monoesterification of glycerol with castor oil acids and further di-esterified with acetic acid; 17 parts by weight of the amine soap formed from stoichiometric amounts of 2- amino 2-methy1 1-propanol and oleic acid, and 25 parts by weight of the adduct formed by reacting 1 mol of tridecyl alcohol with 9 mols of ethylene oxide. The treating agent was applied by means of a rotating roll in an amount such that 0.39 percent solids were deposited on the yarn, based on the weight of the yarn. The yarn was then taken up on a spin bobbin from where it was passed to a conventional drawtwist machine where it was hot drawn to a tenacity of 8.54 grams per denier. As is Example I, the thread line breaks and draw roll wraps were noted and recorded.

Example 111 Yarn identical to that described in Example I and Example II was impregnated before being drawn with a commercially used conditioning agent having a combination of sulfonated peanut oil and a mineral oil as essential components. The application was made in an amount such that 0.85 percent solid material, based on the weight of the yarn was deposited thereon. The yarn was then hot drawn under the identical conditions which were employed in Example I and Example II and to a tenacity which was of substantially the same value.

Drawing performance data wherein Examples 1, II and III are compared from the standpoint of the occurrence of filament breaks and draw roll wraps is given in the following table. Since Example HI was in essence a control, it is so designated.

It is readily apparent from the above data that the conditioning agents of this invention improve the drawing operation to an extent which is even greater than that of one of the most efiective of such agents in the prior practice. Although a hot drawing procedure with high denier yarn has been used for illustrative purposes in the above examples, equally good results are obtainable with lower denier yarns and in drawing at ambient temperatures.

As has been noted hereinabove, the practice of this invention not only facilitates the yarn drawing process step, but surprising and outstanding improvements in ultimate products are also realized. Examples of ultimate products which are greatly improved when produced from yarn which has been processed in accordance with this invention are those which are subjected to compression and/or extension strains during service such as, for example, supporting cables, fish nets, rope, reinforcement cords for rubber structures including pneumatic tires, conveyor belts, power transmission belts, steam hose and various other cabled structures. The product advantages are illustrated in the following examples.

Example IV Yarn produced from a polyhexamethylene adiparnide polymer and having a drawn denier of 840/ 140 was impregnated before drawing with one of the better commercial conditioning agents to the 1.45 percent level based on the weight of yarn. The yarn was then hot drawn at a standard draw ratio for tire cord and thereafter twisted and plied into a cord structure.

Example V Yarn produced from a polyhexamethylene adipamide polymer and having a drawn denier of 840/ 140 was impregnated prior to drawing with an aqueous emulsion having a solids content consisting of 33 parts by weight of a microcrystalline wax having a melting point of from about 100 C. to 105 C., 25 parts by weight of a mineral oil having a Saybolt viscosity of 50 seconds at 100 F., 17 parts by weight of the amine soap formed from equivalent weights of 2-arnino Z methyl 1-propanol and oleic acid, and 25 parts by weight of the adduct formed by the reaction of 1 mol of tridecyl alcohol with 9 mols of ethylene oxide. The amount of solids deposited on the yarn was at a level of 0.56 percent based on the weight of the yarn. The yarn was then drawn at an elevated temperature to a standard draw ratio for tire cord and thereafter twisted and plied into a cord structure.

Example VI Yarn produced from a polyhexamethylene adipamide polymer and having a drawn denier of 840/140 was impregnated prior to drawing with an aqueous emulsion having a solids content consisting of 33 parts by weight of a microcrystalline wax with a melting point of from about 100 C. to 105 C., 25 parts by weight of a mineral oil having a Saybolt viscosity of 50 seconds at 100 F, 34 parts by weight of the amine soap formed from equivalent weights of 2-amino 2-methyl 1-propanol and oleic acid, and 8 parts by weight of the adduct formed by the reaction of 1 mol of tridecyl alcohol with 9 mols of ethylene oxide. The amount of solids deposited on the yarn was at a level of 0.40 percent based on the Weight of the yarn. The yarn was then hot drawn to a standard draw ratio customarily used for tire cord and thereafter twisted and plied into a cord structure.

Example VII Yarn produced from a polyhexamethylene adipamide polymer and having a drawn denier of 840/140 was impregnated prior to drawing with an aqueous emulsion hav: ing a solids content consisting of 33 parts by weight of a microcrystalline wax with a melting point of between 100 C. and 105 C.; 25 parts by weight of a mixture of triglycerides consisting chiefly of glycerol mono-ricinoleate diacetate with minor amounts of glycerol mono-linoleate di-acetate and glycerol mono-linolenate, the mixed tr-iglycerides being obtained by a first esterification of glycerol 1 1, astor oil acids followed by further esterification with acetic acid; 17 parts by weight of the amine soap formed from stoichiometric amounts of 2-amino 2-methyl l-propanol and oleic acid; and 25 parts by weight of the adduct formed by reacting 1 mol of tridecyl alcohol with 9 mols of ethylene oxide. The amount of solids deposited on the yarn was at a level of 0.39 percent based on the weight of the yarn. The yarn was then hot drawn to a standard draw ratio for tire cord and thereafter twisted and plied into a cord structure.

The tire cords of the above examples were built into the walls of pneumatic rubber tires in accordance with the conventional procedure. The tires were inflated to 30 p.s.i.g. maximum pressure and then subjected to the well known wheel test which comprises running a tire under a given load against a belt to simulate road conditions. A 1585 lb. load was employed while the wheel was run at a speed equivalent to 45 mph. with the room temperature being maintained at F.

In the following table, a comparison is made of the results obtained by running the above described test tires until cord failure occurred. Each of the mileage figures given in the table is the average obtained from four tires run to cord failure.

It is seen in the above test results, that the tires which contained reinforcement cords produced in accordance with this invention exceeded the performance of tires reinforced with cords produced in a conventional manner by a totally unexpected factor of approximately 3 times or better. This is even more surprising when it is considered that reinforcement cords of the test control tires contained in excess of 2.5 times the amount of treating agent present on the reinforcement cords of the tires corresponding to the test examples of the present invention. Equally good results were realized with tires having reinforcement cords derived from other synthetic liinear polymeric materials and wherein the cords were processed in the manner of this invention. For example, tire cords obtained from a polyvinyl alcohol polymer and treated in accordance with this invention were built into the walls of inflatable rubber tires.- These tires were then tested against a control by the procedure as described above.

It was found that the test tires exceeded the performance of the control by a factor of from 2 to 2.5 times. That is, the test tires ran a distance of more than twice that of the control before cord failure occurred. Similar tests were conducted on tires containing reinforcement cords obtained from a synthetic linear polyester, i.e. polyethylene terephthalate and comparably excellent results were realized. It is, therefore apparent that the tire cord yarn produced in the manner of this invention possesses a greatly increased flex life, in fact, that the flex life of the yarn often exceeds the useful life of the tire which may end due to failure from other causes.

In addition to having the capacity to withstand the repeated flexing to which the tire is normally subjected in the course of its use, it is also important that reinforcement cords for tires and other products be capable of satisfactory adherence to the rubber structure.

When reinforcing cords are used in the fabrication of rubber products such as tires, it is common practice to dip the cord in a rubber bonding composition, such as a resorcin-formaldehyde latex formulation prior to its incorporation in the rubber tire. This operation is performed to promote better adhesion between the cord structure and the rubber tire carcass. Due to the aqueous nature of the latex dip solution and for several other reasons, many yarn treating agents interfere with the absorption of the proper amount of latex solution by the cord structure and they are said to have poor dip takeup characteristics. The cord structures of this invention, however, have completely satisfactory dip take-up characteristics and adhere remarkably well to the tire or other rubber structures in which they are incorporated.

Although the invention has been described herein with a greater particularity in connection with filaments, yarn cord structures, etc. which have been formed from a polyhexamethylene adipamide polymer, this was done merely to convenience and simplify illustration, for the invention is fully applicable to filamentary materials which comprise a wide variety of synthetic polymeric substances. These include, for example, the full range of polycarbona-mides, e.g. polyhexamethylene adipamide, polyhexamethylene sebacamide, polyoctamethylene adipamide, polyoctamethylene sebacamide, the self polymerization product of 6-aminocaproic acid and also omego-aminoundecanoic acid, polypyrrolidone and others in addition to the many copolymers thereof; the synthetic linear polyesters, e.g. polyethylene terephthalate and the polyester derived from the reaction of terephthalic acid and trans-bis-1,4-(hydroxymethyl) cyclohexane, and various modified polyesters; the hydrocarbon polymers, e.g. polyethylene, polypropylene, the vinylidine and styrene polymers; the acrylonitrile polymers and copolymers thereof, e.g. the copolymers of acrylonitrile and vinyl acetate; the polyurethanes; the polycarbonates; the polyvinyl alcohols and many others.

As various changes and modifications of the invention can be made without sacrificing any of its advantages and without departing from the scope and spirit thereof, it is to be understood that all matter herein is to be interpreted strictly as illustrative; and that the only limitations on the invention are those which appear in the following appended claims.

We claim:

1. An improved method for imparting molecular orientation to filaments formed from synthetic linear polymers comprising the steps of impregnating said filaments prior to the conduct of a drawing operation with a wax-containing aqueous emulsion and thereafter drawing the thus impregnated filaments to impart molecular orientation thereto.

2. The method of claim 1 wherein said wax is microcrystalline wax.

3. An improved method for imparting molecular orientation to filaments formed from synthetic linear polymers comprising the steps of impregnating said filaments prior to a drawing operation with an aqueous emulsion containing up to 30 parts by weight of solids, said solids comprising from about 10 to 90 parts by weight of a Wax, up to about 80 parts by weight of another lubricant and from about 10 to 90 parts by weight of an emulsifying agent, and thereafter drawing the thus impregnated filaments to impart molecular orientation thereto.

4-. The mehod of claim 3 wherein said filaments have been formed from a polyamide polymer.

5. An improved method for imparting molecular orientation to polyamide filaments comprising the steps of impregnating said filaments prior to the conduct of a drawing operation with an aqueous emulsion containing from about 10 to 15 parts by weight of solids, said solids consisting of from about 10 to 75 parts by weight of a microcrystalline wax, from about 5 to 65 parts by weight of a fatty acid ester wherein the fatty acid portion of said ester contains from about 1 to 22 carbon atoms and the alcohol portion from 1 to 12 carbon atoms, from about 7 to 50 parts by weight of the amine soap formed from stoichiometric quantities of 2-amino 2-methyl 1-propanol and oleic acid, 5 to 40 parts by weight of the adduct formed by condensing 1 mol of tridecyl alcohol with 9 mols of ethylene oxide, said solids being deposited in an amount of from about 0.1 to 2.0 percent by weight based on the weight of said filaments, and thereafter drawing the thus impregnated filaments to impart molecular orientation thereto.

6. An improved method for producing cabled structures from synthetic linear polymeric filaments comprising 10 the steps of impregnating said filaments prior to the conduct of a drawing operation with a wax-containing aqueous emulsion; drawing the thus impregnated filaments to impart molecular orientation thereto and thereafter plying a plurality of said filaments into a cabled structure.

7. An improved method for producing reinforcement cords for rubber structures from synthetic linear polymeric filaments comprising the steps of impregnating said filaments prior to the conduct of a drawing operation with a wax-containing aqueous emulsion; drawing the thus impregnated filaments to impart molecular orientation thereto and thereafter plying a plurality of said filaments into a cord structure.

8. A composite product comprising a rubber composition and a reinforcement cord in adhering relation therewith, said reinforcement cord being produced from a plurality of synthetic linear polymeric filaments in accordance with the method of claim 7.

9. A pneumatic tire which comprises rubber and reinforcing cords, said cords being produced from a plurality of organic filaments in accordance with the method of claim 7.

10. An improved method for producing reinforcement cords for rubber structures from synthetic linear polymeric filaments comprising the steps of impregnating said filaments prior to the conduct of a drawing operation with an aqueous emulsion containing from about 10 to 15 parts by weight of solids, said solids consisting of from about 10 to 15 parts by weight of a microcrystalline wax having a melting point in the range of from 50 C. to 140 C., from about 5 to 65 parts by weight of a lubricant selected from the group consisting of a fatty acid ester wherein the fatty acid portion of said ester contains from about 1 to 22 carbon atoms and the alcohol portion from 1 to 12 carbon atoms and a mineral oil having a Saybolt viscosity of 50 seconds at F., from about 7 to 50 parts by weight of the amine soap formed from stoichiometric quantities of 2-amino 2-methyl 1-propanol and oleic acid and from about 5 to 40 parts by Weight of the adduct obtained by reacting 1 mol of tridecyl alcohol with 9 mols of ethylene oxide, said solids being deposited in an amount of from 0.1 to 2 percent by weight based on the weight of the filaments; drawing the thus impregnated filaments to impart molecular orientation thereto and thereafter plying a plurality of said filaments into a cord structure.

11. A composite product comprising a rubber composition and a reinforcement cord in adhering relation therewith, said reinforcement cord being produced from a plurality of synthetic linear polymeric filaments in accordance with the method of claim 10.

12. A pneumatic tire which comprises rubber and reinforcing cords, said cords being produced from a plurality of synthetic linear polymeric filaments in accordance with the method of claim 10.

13. An improved method for producing reinforcement cords for rubber structures from polyamide filaments comprising the steps of impregnating said filaments prior to the conduct of a drawing operation with an aqueous emulsion containing from about 10 to 15 parts by weight of solids, said solids consisting of 33 parts by weight of a microcrystalline wax with a melting point of between 100 C. and C., 17 parts by weight of the amine soap formed from stoichiometric quantities of 2-amino 2-methyl 1-propanol and oleic acid, 25 parts by weight of a mineral oil having a Saybolt viscosity of 50 seconds at 100 F., and 25 parts by weight of the adduct formed by condensing 1 mol of tridecyl alcohol with 9 mols of ethylene oxide, said solids being deposited in an amount of from 0.1 to 2 percent by weight based on the weight of the filaments; drawing the thus impregnated filaments to impart molecular orientation thereto and thereafter plying a plurality of said filaments into a cord structure.

14. An improved method for producing reinforcement cords for rubber structures from polyamide filaments 1 1 comprising the steps of impregnating said filaments prior to the conduct of a drawing operation with an aqueous emulsion containing from about 10 to 15 parts by weight of solids, said solids consisting of 33 parts by weight of a microcrystalline wax with a melting point of between 100 C. and 105 C., 17 parts by weight of the amine soap formed from stoichiometric quantities of 2-arnino 2-methy1 1-propanol and oleic acid, 25 parts by weight of a mixture of triglycerides consisting chiefly of glycerol mono-ricinoleate di-acetate with minor amounts of glycerol mono-linoleate di-acetate and glycerol mono-linoleate di-acetate, said triglycerides being obtained by a first mono-esterificationj of glycerol with castor oil acids followed by a further esterification with acetic acid, and 25 parts by Weight of the adduct formed by condensing 1 mol of tridecyl alcohol with 9 mols of ethylene oxide, {said solids being deposited in an amount of from 0.1 to Zp'ercerit'by weight based on the weight of the filaments; drawing the thus impregnated filaments to impart molecular orientation thereto and thereafter plying a plurality of said filaments into a cord structure.

References Cited in the file of this patent UNITED STATES PATENTS Meyer June 29, Whitehead Jan. 12, Brownell Mar. 30, Myers Jan. 29, Freund Apr. 15, Ambelong Jan. 27, Schlatter et al. Dec. 29, Fortess et al. Jan. 10, Sonnenschein Mar. 25, Tompkins June 10, Fortess et a1. Sept. 23, Chandler Dec. 23, Wentworth Dec. 13, Fronmuller et al. Mar. 7, MacCormack July 4,

FOREIGN PATENTS Great Britain June 29,

Claims (1)

1. AN IMPROVED METHOD FOR IMPARTING MOLECULAR ORIENTATION TO FILAMENTS FORMED FROM SYNTHETIC LINEAR POLYMERS COMPRISING THE STEPS OF IMPREGNATING SAID FILAMENTS PRIOR TO THE CONDUCT OF A DRAWING OPERATION WITH A WAX-CONTAINING AQUEOUS EMULSION AND THEREAFTER DRAWING THE THUS IMPREGNATED FILAMENTS TO IMPART MOLECULAR ORIENTATION THERETO.