Method for preparing fibers of polyethylene-1,2-diphenoxyethane-4,4{40 -dicarboxylate

Abstract

Abstract Stretched synthetic fibers are prepared by spinning polyethylene-1,2-diphenoxyethane-4,4''-dicarboxylate which has been obtained by copolymerizing comonomer(s) containing one or more metal salts of strong acid having a pKa value of 3.5 or less and has the residual carboxyl groups in the polymer of 20 gramequivalents or less per 106 g at a high winding speed of 1,500 to 5,000 m/min, and continuously or discontinuously 5 to 50 percent stretching the thus obtained fibers. The stretched fibers have a good strength, a good boiling water shrinkage and a good bending and wearing strength. The textile plain-woven from the stretched fibers has a good wrinkling resistance. This invention relates to a method for high speed spinning, and more particularly to a method for preparing fibers of polyethylene-1,2-diphenoxyethane-4,4''-dicarboxylate containing a high speed spinning step, characterized by using a copolymer of polyethylene-1,2-diphenoxyethane-4,4''-dicarboxylate. According to the conventional method for preparing fibers by melt spinning, a polymer is melted, and extruded through nozzles; the thus obtained filamentary products are once wound up; said unstretched filaments having a low strength, a low degree of crystallization and a low degree of orientation are led to a stretching and twisting step to effect the stretching; the orientation and crystallization are also effected thereby; and thus fibers sufficiently durable as yarns are obtained. That is, good physical properties as good yarns are endowed only by passing the materials through the two steps such as spinning step and the stretching-and-twisting step. The conventional method is obviously not preferable from the economical point of view as well as in view of various properties of yarns, for example, uniformity, because it requires the discontinuous two steps. In order to overcome the above-mentioned disadvantage, several attempts have been made to endow various physical properties required as fibers to yarns by eliminating stretching step and effecting orientation and crystallization in a spinning step where material is extruded through nozzles, solidified and wound up. For example, a high speed winding of the filaments high speed winding of the filaments extruded through nozzles at 3,000-5,200 yd/minute or more has been proposed, as seen in Japanese Patent Publications Nos. 3104/60 and 6768/56. However, the thread prepared by the conventional direct spinning method based on such high speed winding has actually had a relative high residual percentage stretching, a low yield point strength and particularly a poor stretching recovery. Other disadvantage is a devitrification. That is, it has been very difficult to endow sufficient physical properties and transpaRency to the yarns obtained by the direct spinning method. An object of the present invention is to provide a method for preparing fibers of polyethylene-1,2-diphenoxyethane-4,4''dicarboxylate by direct spinning method based on the high speed winding, quite free of said various disadvantages. As a result of a wide range of researches on homopolymers or copolymers of polyester or polyamide in connection to the direct spinning method, the present inventors have found polyethylene1,2-diphenoxyethane-4,4''-dicarboxylate as a polymer composition suitable for the direct spinning method, which is prepared by copolymerizing a comonomer or comonomers containing one or more metal salts of strong acid having a pKa value of 3.5 or less, and have established the method of the present invention. The present method is to prepare fibers having a good transparency and good physical properties by effecting a high speed winding at 1,500 m to 5,000 m/minute, using polyethylene1,2-diphenoxyethane-4,4''-dicarboxylate prepared by copolymerizing a comonomer or comonomers containing one or more metal salts of strong acid having pKa of 3.5 or less and having residual carboxyl group in the polymer of 20 gram-equivalents/106 g polymer or less in effecting the direct spinning, and effecting a 5 to 50 percent stretching of the thus obtained fibers of the said polymer having a birebriengence of 0.010 to 0.25. The amount of residual carboxyl group, as referred to above is determined according to a method of H.A. Pohl, Anal. Chem. 26 1614 (1954) using benzyl alcohol as a solvent, chloroform as a dispersing liquid and phenol red as an indicator, where the titration is effected with caustic soda in a benzyl alcohol solvent. When the amount of residual carboxyl group in the polymer exceeds 20 gram-equivalents/106 g, a decrease in the yield point strength is observed. The reduced viscosity of the polymer is preferably 0.5-1.5. When it is less than 0.5, the strength is reduced, and only insufficient physical properties as yarns are thereby endowed. On the contrary, when the reduced viscosity exceeds 1.5, the spinnability is lowered, and the filaments are often broken at the spinning. Thus, the reduced viscosity of over 1.5 is not preferable. The reduced viscosity, as referred to above, is a viscosity of a polymer having a polymer concentration of 0.5g/100cc of a solvent mixture of tetrachloethane and phenol at a mixing ratio of the former to the latter of 2:1 by weight, determined at 35*C. The metal salt of strong acid, as referred to above, is a comonomer or comonomers containing sulfinate group, sulfonate group, phosphonate group, etc. in the form of metal salt. Examples of these monomers include, as the phosphonates, disodium 3,5-dicarbomethoxybenzenephosphonate, sodium 4carbomethoxyphenyl-4''-tolylphosphonate, disodium gamma carbomethoxypropanephosphonate; as the sulfinates, sodium pcarboxy-1,2-diphenoxyethane-p''-sulfinate, sodium 3,5dicarbomethoxybenzenesulfinate, sodium p-carboxy-1,2diphenoxyethane-p''-sulfinate, sodium 0-( Beta carbomethoxyethyl)benzenesulfinate; as the sulfonate, disodium p, p''-dicarbomethoxy-1,2-diphenoxyethane-m,m''-disulfonate, sodium pcarboxy-1,2-diphenoxyethane-p''-sulfonate, sodium m,m''dicarbomethoxy-1,2-diphenoxyethane-p''-sulfonate, sodium mcarbomethoxy-1,2-diphenoxyethane-p''-sulfonate, sodium p-( Beta gamma -epoxypropoxy) benzenesulfonate, etc., but are not limited thereto. More important factor of these monomers is a compatibility between these polar monomers and a polymerization reaction system. In general, these metal salts have a low compatibility and accordingly their copolymerizabilities become lower. Thus, the phase separation is inevitable and in the case of very insoluble comonomer, the filaments inevitably tend to have a white turbidity. In view of these facts, a monomer having such a unit structure as is preferable. In copolymerizing these comonomers, the addition of the comonomers may be effected in any step prior to the condensation polymerization reaction of polyethylene-1,2-diphenoxyethane-4,4''dicarboxylate. That is, the comonomers can be added during, before or after the esterification reaction of 1,2-bis(p-carboxyphenoxy) ethane and ethyleneglycol, or during, before or after the ester interchange reaction of 1,2-bis(p-carbomethoxyphenoxy) ethane with ethyleneglycol. The amount of monomers used in the copolymerization is 0.1-10 percent by mole, preferably 5 percent by mole or less on the basis of 1,2-bis(p-carboxyphenoxy)ethane or 1,2-bis(pcarbomethoxy phenoxy)ethane. In the case of less than 0.1 percent by mole, such effect can hardly be obtained. On the other hand, in the case of more than 10 percent by mole, a decrease in spinnability is observed. The spinning result of using a copolymer of polyethylene-1,2diphenoxyethane-4,4''-dicarboxylate having a reduced viscosity of 0.8 is given in Table 1. The comonomer used is sodium-p,p''carbomethoxy-1,2-diphenoxyethane-m-sulfonate. The copolymer is melted at 285*C and extruded through nozzles of 0.5 mm, and their spinnability is investigated with respect to the maximum winding speed, filament breakage and winding speed which brings about devitrification, and its result is listed in Table 1.

Inventors

• 👤 Hidehiko Kobayashi
• 👤 Kiichiro Oimachi Sasaguri
• 👤 Kazuya Neki
• 👤 Noboru Tanimura

Bibliographic Details