MXPA99011080A - Liquid crystalline polymer monofilaments having improved adhesion characteristics - Google Patents

Abstract

The invention is directed to LCP monofilaments and yarn made therefrom which have improved adhesion properties, said monofilaments, and yarn made therefrom, comprising a liquid crystalline polymer filament having a finish selected from the group consisting of esters formed between (a) pentaerythritol and saturated polyols of up to 10 carbon atoms and 2 to 6 hydroxyl groups, and (b) a carboxylic acid of formula CxH2x=1COOH, wherein x is from 2 to 20, and wherein 2 to 6 of the hydroxy functions are convened to ester functions. In a preferred embodiment of the invention the finish is an ester formed from the reaction of pentaerythritol and a carboxylic acid of formula CxH2x=1COOH, wherein x is from 2 to 20, and preferably between 14 and 20. The most preferred esters are pentaerythritol tetrapelargonate and pentaerythritol tetraisostearate.

Description

CRYSTALLINE LIQUID POLYMER MONOFILAMENTS THAT HAVE IMPROVED ADHESION CHARACTERISTICS FIELD OF THE INVENTION This invention relates to monofilaments of liquid crystalline polymer (LCP) and in particular to LCPs having improved adhesion characteristics.

BACKGROUND OF THE INVENTION Thermotropic liquid crystalline polymers (LCPs) are an important class of polymers, which are generally fully aromatic molecules containing a variety of heteroatom linkages including ester and / or esteramide linkages. When heated at sufficiently high temperatures, the LCPs melt to form a liquid crystalline melting phase (often called an "anisotropic phase") rather than an isotropic fusion. In general, LCPs consist of linear molecules ("rigid rod") that can be aligned to yield the desired liquid crystal order. As a result, LCPs exhibit low melt viscosity and therefore improved processabilities and performances. Because the LCPs are oriented to form linear "rigid rod" molecules, the LCPs exhibit extremely high mechanical properties. Therefore, it is well known in the art that LCPs can be formed into shaped articles, such as films, rods, tubes, fibers, and various other molded articles. Furthermore, it is also known in the art that LCPs, particularly in fiber form, exhibit exceptionally high mechanical properties after a heat treatment process. However, all methods known in the art describe the formation of only low denier fibers, for example, of about 5 deniers per filament (dpf), which exhibit high mechanical properties in their forms as they are spun as well as in those treated by heat. Additionally, there are no reports in the prior art that filaments having a multilobal cross section can be made from LCPs. More importantly, the filaments of LCPs generally do not adhere to several other similar or dissimilar materials. Numerous patents and publications describe LCPs, methods for manufacturing LCPs and the characteristics and uses of such LCPs. Among these are the following, all of which teachings are incorporated herein by reference: U.S. Patent No. 4,183,895 describes a process for treating polymeric products that form anisotropic melt. A heat treatment procedure reportedly yielded fibers that have improved mechanical properties, and the tenacity of the fiber was reported as increased by at least 50% and by at least 10 grams per denier.

The U.S.A. No. 4,468,364 describes a process for extruding thermotropic liquid crystalline polymers (LCPs). It is claimed that the extrusion of a LCP through a die orifice having an LD ratio of less than 2 (preferably 0), and at a stretch ratio of less than 4 (preferably 1), yields filaments exhibiting mechanical characteristics. high The U.S.A. No. 4,910,057 discloses a highly elongated member of substantially uniform cross section whose configuration is capable of improved service as a stiffening support in a fiber optic cable. The U.S.A. No. 5,246,776 discloses an aramid monofilament and the method for manufacturing same. The U.S.A. No. 5,427,165 discloses a reinforcing assembly formed at least in part from continuous monofilaments of liquid crystal organic polymer (s). The polymers used in it are mainly aramid. Japanese open patent No. 4-333616 describes a method for making filaments from 50 to 2000 dpf from molten liquid crystalline polymers. The mechanical properties of heat treatment of these filaments were significantly lower than the properties reported for the corresponding lower denier filaments of 5 to 10 dpf.

J. Rheology 1992, Vol. 36 (p.1057-1078) reports a study of the rheology and orientation behavior of a thermotropic liquid crystalline polyester using capillary dies of different aspect ratios. J. Appl. Polym. Sci. 1995, Vol 55 (p 1489-1493) reports the orientation distribution in extruded rods of thermotropic liquid crystalline polyesters. The orientation function is increased by increasing the apparent cutting speed from 166 to 270 sec "1, but decreases by increasing the apparent cutting speed from 566 to 780 sec" 1. Although much work has been done and many improvements have been made in relation to the LCPs, an area in which further improvement is desired is in relation to improving the adhesion characteristics of LCPs to one another and to other materials, for example, materials made of rubber or that have a rubber coating. Accordingly, it is an object of this invention to provide thermotropic LCP filaments, fibers, yarns and monofilaments, and ropes made therefrom, which have improved adhesion characteristics, and in particular to provide LCP filaments, fibers, yarns and yarns. monofilaments, and ropes made thereof, which have improved adhesion characteristics to rubber and rubber coated materials or substances. It is a further object of this invention to provide LCP filaments of heavy denier, fibers, yarns and monofilaments, and ropes therefrom, which have improved adhesion characteristics and in particular to provide LCP filaments, fibers, yarns and monofilaments, and strings made thereof, of more than 50 denier having improved adhesion characteristics to rubber and rubber coated materials. It is a further object of this invention to identify substances that can be applied to LCP filaments, fibers, yarns and monofilaments, and ropes made therefrom, to improve the adhesion of such filaments, fibers, threads and monofilaments, and ropes made from same, to rubber and rubber-coated materials. Another object of this invention is to provide a method for "treating" or "finishing" LCP filaments, fibers, threads and monofilaments and ropes made thereof, in order to provide filaments, fibers, threads and monofilaments, and ropes made of they have improved adhesion characteristics to rubber and rubber coated materials. Additional modalities will be apparent to those skilled in the art by means of the specification and examples contained herein.

BRIEF DESCRIPTION OF THE INVENTION The invention is directed to LCP filaments, fibers, yarns and monofilaments, and ropes made thereof, which have improved adhesion properties, said filament consists of a liquid crystalline polymer filament having a finish containing 60% or more, preferably 80% or more, of components selected from the group consisting of esters formed between: (a) pentaerythritol and saturated polyols of up to 10 carbon atoms and from 2 to 6 hydroxyl groups, and (b) a carboxylic acid of formula CxH2x-? COOH in which x = 2 to 20, in which 2 to 6 of the hydroxypolyol functions are converted to ester functions. In a preferred embodiment of the invention, the finish is a clogged polyester that has no beta hydrogen atoms on the carbon atom adjacent to the oxygen atom of the alcohol moiety of the molecule. In another preferred embodiment of the invention the finish is an ester formed from the reaction of pentaerythritol and a carboxylic acid of the formula C x H 4 .iCOOH in which x = 2 to 20, and preferably between 14 and 20. A preferred ester for high denier filament application is tetrapelargonate pentaerythritol. A preferred ester for low dpf filament application is pentaerythritol tetraisostearate because of its effectiveness in minimizing stickiness of the filament during heat treatment and therefore improves conversion efficiencies. The selected esters for maximum thermal stability, minimum volatility, are the tri- or tetrafunctional esters of higher molecular weight that could intertwine the surface of the fiber by ester exchange.

DETAILED DESCRIPTION OF THE INVENTION The term "filament" as used herein means any filament, fiber, yarn and monofilaments, or cords made thereof, made of a liquid crystalline polymer (LCP) material of any composition. Examples and definitions of liquid crystalline materials and polymers can be found in the "Encyclopedia of Polymer Science and Engineering", Vol. 9 (John Wiley &Sons, New York 1987) pages 1-61; "Kirk-Othmer Encyclopedia of Chemical Technology", 4th Ed., Vol. 15 (John Wiley &Sons, New York 1995), pages 372-409; and on the Internet, for example, on a Mitsubishi Company website located at http: //www.angleview. LCP materials are commercially available from several sources; for example under the trade name "VECTRA" of Ticona LLC, Summit, New Jersey; under the trade name "ZENITE" of DuPont, Wilmington, Delaware; under the trade name "XYDAR" of Amoco Corporation, Chicago, Illinois; under the trade name "THERMX" of Eastman Chemical Company, Kingsport, Tennessee; or under the trade name "GRANLAR" of Granmont Corporation. LCPs can be made into filaments by methods known to those skilled in the art. One step in producing such filaments is to apply a "finish" to such filaments after they are produced, for example, spinning an LCP material into a monofilament. This invention is directed to such finishes, and in particular to finishes whose application to such filaments improves the adhesion characteristics of the resulting filaments. The finishes of the invention are applied at levels of 0.1 to 5.0% by weight, and preferably 0.3 to 3.0% by weight. The level of finish depends on the application. For example, for tire cord applications the level is from 0.1% to 2.0% by weight, and preferably from 0.3% by weight to 1.5% by weight. For other applications, for example, using LCPs on conveyor belts in the paper industry or in rope applications, the finishing level can be higher, up to 5% by weight. The finishes according to the invention can be applied to LCP filaments of any denier capable of being produced by commercial or laboratory equipment. Any method of application known to one skilled in the art can be used to apply the finish to the LCP filaments. A preferred method of application is to use a low concentration of the finish in an emulsion or a solvent carrier such as isopropanol or perchlorethylene, or any other suitable solvent, in a double application, to improve the uniformity of the finish. Filaments having a finish according to the invention can be made into ropes, for example, rim ropes, by any method known to one skilled in the art. The finishes applied to the filaments remain on the filaments according to the invention and improve the adhesion of the filaments and cords to the rubber and to substances with rubber coating. Such ropes may be of any denier and filament arrangement suitable for use in tires or other applications in which the rope will be used. Many finishes for LCP filaments are known in the art. Examples of such finishes include T-60 (active ingredient: trimethyoleate tripelargonate), T-111, XF-2724, etc. containing esters of inter-linking; and other types of finishes such as T-55 (active ingredient: glycerol epoxide) and XF-2577 active ingredient: sorbitol epoxy). The type 70642 finish, known as a chloro-hydroxy base, is a low concentration emulsion to provide better dispersion than oil-based finishes. Although many of these finishes known in the art produce filaments having acceptable adhesion characteristics in some applications, they have not been found suitable for use in conjunction with rubber and rubber-coated materials. For example, standard heavyweight and lightweight PET denier production lubricants with up to 50% blocked polyol esters are not suitable for this application due to poor adhesion. In addition, surprisingly, the epoxy and halohydroxy finishes of the types described in US Patents 3,793,425 and 5,328,765, known to give good adhesion with PET fibers, are also unsuitable for this application due to their poor adhesion. Therefore, new finishes are desired which have improvements in adhesion characteristics for rubber associated applications. Such improvements are desired in particular by the tire industry in which the LCP filaments are used in the production of tire cords to which the rubber materials are bonded during the production of tires. In particular, it is desirable to identify a finish that can be applied to LCP filaments to reduce the sticking of filament to filament during a heat treatment step while retaining its lubricating properties. Such a finish, in addition to reducing tackiness and retaining the lubricating properties, should also be capable of being uniformly applied and should have or impart adhesion characteristics at least equivalent to the finishes known in the art, and preferably superior to those known finishes in the technique. It has been discovered that various carboxylic acid derivatives of selected polyols, including pentaerythritol as a preferred polyol, can impart the desired properties to various degrees. Pentaerythritol has the formula C (CH2OH) 4 and is commercially available from Aldrich Chemical Co., Milwaukee, Wisconsin. Similar carboxylic acid derivatives of other saturated polyol compounds (substances containing a plurality of hydroxyl groups) are equally useful in the practice of the invention. Polyols of up to 10 carbon atoms and having 2 to 6 hydroxyl groups available for reaction with the selected carboxylic acids are useful for forming the finish used according to the invention. In relation to the hydroxyl hydrogen atoms, it is preferred that from 70% to 100% of the hydroxyl hydrogen atoms be replaced by carboxylic acid groups. Examples of such polyols include, but are not limited to, sorbitol, arabitol, mannitol, pentaerythritol, dipentaerythritoltrimethylolpropane, penta (ethylene glycol), neopentyl glycol and the like polyols; pentaerythritol, neopentyl glycol. and dipetnaerythritol trimethylolpropane and similar polyols being preferred. Chemically, such sorbitol-, mannitol-, neopentylglycol-, pentaerythritol- and polyol carboxylic acid derivatives and others are esters and can be referred to as such herein. In general, the carboxylic acids used to form pentaerythritol and similar polyol esters are carboxylic acid of the formula CxH2x +? COOH, wherein x = 2-20. Preferred are carboxylic acids having x = 14-20. Specific examples illustrating the carboxylic acids used in such ester finishes are pentaerythritol tetraisostearate, pentaerythritol tetrapelargonate, pentaerythritol tetraoctanoate, pentaerythritol tetralaurate, pentaerythritol tetrastearate, pentaerythritol tetrabenzoate and similar substances. A preferred substance for mono-filament application is pentaerythritol tetrapelargonate. Pentaerythritol tetraisosterate is a preferred ester for low dpf filament applications due to its effectiveness in minimizing filament stickiness during heat treatment and thus improved conversion efficiencies. Enter the properties required in a finishing agent is that it is a substance that remains liquid through severe heat treatment conditions; for example; heat treatment at temperatures of 250 to 300 ° C for a time of 10 to 24 hours in a 2 substantially nitrogen atmosphere wherein the oxygen content is less than 4%, and preferably less than 2%. The additional requirements are that it does not degrade and remain on the filament or rope at sufficient levels to improve the adhesion characteristics of the filament or rope. A possible adhesion characteristic is to reduce the tendency to surface fibrillation by interlacing the fiber surface through the application of the reactive finish. Non-uniformity of the adhesive finish on LCP filaments, which is considered to be prone to fibrillation, would result in very high stresses in local areas and would cause a premature failure of the adhesive bond on the surface of the fiber. The invention is best exhibited by means of examples, comparing the use of finishes according to the invention. The finishes according to the invention may also contain antioxidants, emulsifiers, inks and similar additives known to those skilled in the art up to 20% by weight.

EXAMPLES OF MONOFILAMENT EXAMPLE 1 Example 1 demonstrates that the mechanical properties of high denier, round and multilobal denier-treated filaments of a fully crystalline liquid aromatic polyester filament, produced as described below, which was coated during spinning with 1.5% by weight of the finish of the invention using a dosing applicator to distribute the finish uniformly. The results showed comparable properties, except that the adhesion to the gum which was improved and commented in another part of the present, to those not coated with any finish. A sample of the polymer, a fully aromatic thermotropic liquid crystalline polyester HBA / HNA (HBA = 4-hydroxybenzoic acid; HNA = 2,6-hydroxynaphthoic acid) sold under the tradename "VECTRA ™ A" (Ticona LLC, Summit, NJ ), was dried overnight at 130 ° C under vacuum. The polymer exhibited a melting temperature of 280 ° C and an inherent viscosity of 6.30 dL / g when measured at a concentration of 0.1% by weight in a solution of equal parts. by volume of pentaflurophenol and exafluoroisopropanol at 25 ° C. The polymer was melted in a 2.54 cm diameter extruder, and the extruded material was metered using a conventional polymer metering pump to the spin pack where it was filtered through 50-80 metal shot. The molten material was then extruded through a single-hole spinner having an aspect ratio (L / D) higher than 2 and at a draw ratio (DD) equal to or higher than 4. Cross-flow shutdown was applied to the emerging filament to provide cooling and a stable spinning environment. The shutdown was placed 4 cm below the face of the spinner, and was 120 cm long by 15 cm wide. The shutoff flow rate at the top was 30 mpm (0.5 mpsec). During extrusion, the monofilaments spun as they were were coated with the finish of the present invention (identified herein as 72096; a composition comprising 95% pentaerythritol tetrapelargonate and 5% octadecyl-3,5-di-t-butyl -4-hydroxyhydrocinnamate [Irganox 1076]). To improve the finish distribution, several different finishing application techniques were tested. These were as follows: (1) By means of two applicators. (2) Hot yarn (spinner at 30 cm below) (3) Higher finish levels [approximately 2.5% finish for monofilaments with (1)]. (4) By spraying (5) Oil in solvent (isopropanol, perchlorethylene, etc.). (6) Use of an air jet after finishing application. (7) (1) and (2) combined. (8) (1) and (5) combined. (9) (1), (2) and (5) combined. (10) (4) and (5) combined. For this example 1, the following two methods were used: (a) the concentrated finish formulation (oil), and (b) the Isopropanol (IPA) solution of the finish using 10% (by weight) of 72096 and 90% (in weight) of IPA. The finish was applied during the spinning, before passing the filaments around an advance system that controls the speed of consumption. The monofilaments were finally taken on a Sahm coil winding machine. The coated monofilaments were then subjected to a heat treatment in stages as follows. The heat treatment of the monofilaments was carried out under low tension in a flow of dry nitrogen using a programmed temperature profile. The temperature profiles programmed for each of the heat treatments of monofilaments are listed in Table 1. The mechanical properties of the monofilaments produced according to this example 1 were measured in accordance with ASTM D3822, and the results are listed in FIG. Table 1. The monofilaments were tested in a manometer of 25.4 cm in length; a deformation speed of 20% and filament breaking of 10%. For comparison objects the round and octalobal monofilaments were extruded and treated by heat. The data given in Table 1 clearly demonstrate that finished coated filaments of properties comparable to those without the finish can easily be made by following the process conditions of the present invention.

TABLE 1 * Percentage (by weight) of finishing on filaments (FOF) before heat treatment, measured by the extraction method.

EXAMPLE 2 This example 2 demonstrates the general increase in gum adhesion of a high denier filament of a fully crystalline liquid aromatic polyester produced in accordance with the present invention. The 220 denier round and octalobal monofilaments were extruded and heat treated as described in Example 1. The monofilaments were coated during spinning with approximately 1.5% by weight of the finish of the invention type 72096 using dosed finish with single applicators and double to compare the uniformity of the finish. In this example 2, only the concentrated finish was used. For adhesion measurement, the filaments were treated with a presumption composition based on epoxy and a resorcinol formaldehyde latex adhesive (RFL) by methods known to those skilled in the art. The presurgical composition was 4.0% by weight of epoxy. The RFL composition was as follows: the molar ratio of formaldehyde to resorcinol (F / R) was 2.0 and the weight ratio of resin to latex (R L) was 0.17. The RFL also contained about 10% by weight of blocked diisocyanate in its composition. The adhesion of the filaments treated with RFL to the rubber was measured by means of a Test H (maximum point). The results are listed in table 2. Kgs. = A kilos (unit force) required to pull the rubber monofilament. Std. (D.E.) = standard deviation. A high "Kgs" value is better than a low value.

TABLE 2 EXAMPLE 3 This example 3 demonstrates the overall increase in adhesion to the rubber as a function of the improved finish distribution uniformity due to the double application of a diluted 90% IPA solution of the finish. The 220 denier monofilaments produced according to example 2 were coated with the present inventive finishing composition of 90% IPA and 10% finish 72096. The adhesion results are shown in table 3.

TABLE 3 This example 4 demonstrates the superiority of the finish of the current invention compared to other commercially available materials. The 220 denier monofilaments produced according to examples 3 were compared with the filaments which were coated after heat treatment with various silane-based finishes obtained from Dow Corning. The samples were: Z-6032 (58% by weight methyl alcohol, 40% by weight silane aryl alkoxy amine chloride, 2% by weight of aminoethyl aminopropyl trimethoxysilane and 0.2% by weight of diethylhydroxylamine), Z-6040 (99% in weight glycidoxypropyl trimethoxysilane and < 2% by weight methyl alcohol) and Z-6076 (99% by weight chloropropyltrimethoxysilane). The results of adhesion are listed in table 4.

TABLE 4 EXAMPLE 5 Example 4 was repeated, except that in this case the 220 denier monofilaments were first produced according to Example 2 (unfinished) and then coated, after heat treatment, with the Ciba ECN-1400 finish ( a dispersion of cresol novolac epoxy in water). The objective was to improve its surface characteristics, including adhesion to the rubber. The adhesion results are listed in Table 5. This example demonstrates that the application of the ECN-1400 finish on top of the finish of the invention does not improve the characteristics of adhesion to the rubber.

TABLE 5 EXAMPLE 6 Example 5 was repeated except that in this case the monofilaments were coated, after heat treatment, with a chlorohydroxy-based finish known as a 70642 finish (a halohydroxy finish based on US Patent 5,328,765) which was an emulsion of low concentration to provide a better dispersion than type 72096 based on oil. Based on the experience with PET, this finish was expected to penetrate the fiber and provide polar groups on the surface of the fiber, and therefore will result in improved adhesion. The application method was similar to that for PET yarn, requiring a small amount of heat in order to make it adhere better to the rubber. For LCP, the monofilaments were heated using the heating rollers at a temperature of 200 ° C to 250 ° C for 0.1 seconds. The adhesion results are listed in Table 6. This example clearly demonstrates that the Type 70642 finish is not as effective as the finish of the invention in improving the rubber adhesion characteristics of the LCP monofilament.

TABLE 6 EXAMPLE 7 Example 5 was repeated except that in this case the heat treated monofilaments were coated with the type finish 70642, after the surface was treated with 72096 in the spinning stage as is. Similar to example 5, the objective was to improve the surface characteristics including adhesion to the rubber. The adhesion results are listed in table 7. This example demonstrates that the application of finishing type 70642 on the finish of the invention does not have a great impact on the characteristics of adhesion to the rubber.

TABLE 7 EXAMPLES OF THREAD EXAMPLE 8 A sample of "VECTRA ™ A" LCP was spun into filaments of dpf (denier-per-filament) by extrusion at 310 ° C through a spinner of forty (40) holes. A finish was applied consisting of pentaerythritol tetrapelargonate diluted to a concentration of 20% by weight in perchlorethylene. The finish was applied to both sides of the filaments at a level of 0.50% by weight using commercially available double dosed finishing applicators. The filaments were taken at a speed of 668.8 mpm (meters per minute). The filaments were then stacked to produce a thread of approximately 1600 denier which was then wound onto a metal coil covered with a ceramic batt. The coil was placed in a heating furnace in which a nitrogen atmosphere was maintained. The wire was heated using a temperature program in which the temperature of the furnace was gradually raised, for a time of 6 hours, to a temperature of 250 ° C to 30 ° C below the extrusion temperature of the LCP. In this particular example, the temperature was raised to 280 ° C. Once the maximum temperature was reached, the yarn was maintained at that temperature for 10 hours. The heating was then discontinued and the yarn was allowed to cool to room temperature (15-30 ° C), after which the yarn was folded and stacked into ropes. The characteristics of the resulting yarn are shown in table 8. PET supply material = a thin-film rubber adhesion compound used for adhesion work with PET (polyethylene terephthalate). Supply material GWS = Goodyear wire stock, high modulus rubber supply material.

TABLE 8 Gpd = grams per denier. For a typical LCP, the tenacity of the spun yarn as it stands is approximately 10 gdp. A = test experiments in detachment, 5.0 is the highest value and 1.0 is the lowest value.

EXAMPLE 9 Pentaerythritol tetra-isostearate in perchlorethylene Thread was produced as in Example 1, except that pentaerythritol tetraisostearate such as 20% by weight in perchlorethylene was applied at a level of 0.5% by weight. The properties of the yarn are shown in table 9.

TABLE 9 EXAMPLE 10 Pentaerythritol Tetra-isostearate applied without solvent (pure) Thread was produced as in Example 1, except that pure pentaerythritol tetraisostearate (without solvent) was applied at a level of 0.5% by weight. The properties of the yarn are shown in table 10.

TABLE 10 EXAMPLE 11 Finish of Non-pentaerythritol (null sample) Thread was produced as in Example 1, except that a non-pentaerythritol finishing agent such as 20% by weight in perchlorethylene was applied at a level of 0.5% by weight. It was found that the petaerythritol substances have benefits as finishing agents over the null sample, and in particular to use pentaerythritol tetracarboxylic acid derivatives in which x = 14-20 as finishing agents. Such derivatives can be used pure or diluted with a solvent. It is particularly advantageous to use the pure finishing agent in order to avoid recovery, disposal or problems of emissions to the environment due to the solvent. In addition, larger gains in adhesion can be made through improved finish distribution by applying a solvent finish.

While winding, rigidity and adhesion are influenced by a variety of factors other than adhesion, the data in the tables indicate that using the selection of finishes according to the invention produce rope with superior properties. The tables also indicate that pentaerythritol tetraisostearate is the preferred finish for low denier yarn filaments. In a separate experiment, a total of seventeen (17) samples of low denier yarn were prepared with twelve (12) filaments finished with pentaerythritol tetraisostearate, five (5) with pentaerythritol tetrapelargonate, and in all cases, the samples of low denier yarn using the tetraisostearate samples had better performance than the tetrapelargonate samples. When the yarn is produced according to the invention, the bonding of the yarn on the spools is significantly reduced and less yarn damage occurs when the yarn is unwound. In addition, the average tenacity of the yarn is higher for the tetraisostearate finish than for the tetrapelargonate finish. Combining this fact with the improved conversions for the tetraisostearate allows the production of yarn having a significantly higher tenacity than what was previously possible using the same LCP finish and others.

Claims (10)

NOVELTY OF THE INVENTION CLAIMS

1. - A liquid crystalline polymer filament having improved adhesion properties, said filament comprises a liquid crystalline filament having a finish containing 60% or more of components selected from the group consisting of esters between: (a) pentaerythritol and saturated polyols up to 10 carbon atoms and 2 to 6 hydroxyl groups, and (b) a carboxylic acid of formula CxH2? ..? COOH, where x = 2 to 20, in which 2 to 6 of the hydroxy functions are converted to ester functions.

2. The filaments according to claim 1, wherein x = 14 to 20.

3. The filaments according to claim 1, wherein the finish is applied to the filaments at a level of 0.1 to 5.0%. in weigh.

4. The filaments according to claim 3, wherein the finish is applied to the filaments at a level of 0.3 to 3.0% by weight.

5. A liquid crystalline polymer filament having improved adhesion properties, said filament comprising a liquid crystalline filament having a finish selected from the group consisting of tetraesters formed from pentaerythritol and a carboxylic acid of the formula wherein x = 2 to 20. The filaments according to claim 5, wherein x = 14 to 20. 7. The filaments according to claim 5, wherein the finish is pentaerythritol tetrapelargorate for high denier filaments of dpf larger than 20 grams and pentaerythritol tetraisostearate for lower denier yarn filaments of pfd of less than 20 grams. 8. The filaments according to claim 5, wherein the finish is applied to the filaments at a level of 0.1 to 5.0% by weight. 9. The filaments according to claim 8, wherein the finish is applied to the filaments at a level of 0.3 to 3.0% by weight. 10. The filaments according to claim 1, wherein the finish contains 80% or more of esters formed between (a) and (b).