Патент USA US2411474код для вставки
Patented Nov. ‘19, 1946’ ‘ 2,411,474 ‘UNITED STATES2,411,474PATENT OFFICE vMETHOD 0F IMPROVING FILAMEN TS 0F HYDROLYZED OLEFlN/YINYL ns'rnn rN'rERroLYMERs ORGANIC Halsey B. Stevenson, Brandywine- Hundred, Del., assignor to E. I. du P ont de Nemours & Com pany, Wilmington, D_el.,'a corporation of Dela ware No Drawing. Application October 18, 1944, , 559,231 5 Claims. (Cl. .8—130.1) Serial No. ‘This invention relates to improved hydrolyzed resultant stretched ?lament in and at a temperature within the‘range of v:from ole?n/vinyl organic ester interpolymer, ?laments and, more particularly,_ to a new process for im- I proving the properties of ?laments derived from 102° C. to 104° C. within the range of from 102° C. to'104° hydrolyzed ole?n/vinyl organic ester interpoly- " mers. The following examples, in which proportions " are in parts by weight unless This invention has as an of oriented ?laments of hydrolyzed ethylene/vinyl otherwise: speci?ed, 10 I , ‘ Ewample I ' , L V ' An interpolymer oi’?ethylen-e and vinyl acetate having a molar ratio oi‘ 2.6/1 of ethylene to vinyl of ethylene at about 1000 atmospheres pressure . and at about 65° C. to vinyl acetate containing a small amount of benzoyl peroxide. The ethyl ene/vinyl acetate interpolymer' was hydrolyzed in a benzene-methanol solution with excess caus tic and the interpolymer was isolated and the a temperature within the range of from 80° C’. to 100° C. in a medium containing H2O a ?lament of C., a substantially completely hydrolyzed interpoly mer of ethylene with a vinyl ester of a mono elongation and a ' carboxylic acid having the general formula . _ 30 when immersed for 5 minutes approximately 100° C. RCOOH drawn yarn was wound-on a metal wherein R is of the slight. tension and heat treated by atoms and hydrocarbon radicals, said acid being steam in an autoclave at 104° for 5v DJ til minutes,’ the yarn had a tenacity of 4.4' g./d. at 16% elong ,tion and had a shrinkage of only 8.5% when immersed in boiling. water for‘ 5 minutes. Example’ If ‘A'melt-spun' yarn of a substantially completely 40 hydrolyzed ethylene/vinyl acetate interpolymer having a molar ratio of ethylene-vinyl acetate of 2.8/1 was drawn in steam at 99-100° g. at a draw ratio of 5.3/1 to give an oriented yarn having a 101°‘ C. to 106° 0., in a taut condition, with a medium comprising H2O‘ at a temperature within 45 tenacity of\3.7‘ g./d. at 175% elongation and hav- " the range of from 101° C‘. to 106° C. ing a shrinkage of 27% whenvheated in water to 100° C. This yarn was heat A preferred embodiment of this invention 'com treated in steam for ‘ ‘prises drawing, at a temperature within the range about 5 minutes atl0l3° " of from 90° C‘. to 100° C. in steam at a tempera ture‘within the range of from 90° (1110 100° 0., 50 v a ?lament of a substantially completely hydro-_ lyzed interpolymer of ethylene with vinyl acetate, C‘. When the above yarn was set at 100° C. in steam under otherwise identical conditions, the heat-set yarn had a tenacity of 3.7 g./d. at 20% elongation but had a shrinkage of 13% 55 Jected to water at 100° C. 2,411,474 ' , . 3 4 ' ' drolyzed ethylene/vinyl organic‘ ester interpoly ~ mer or by- spinning from a solution of the inter Example III _ A hydrolyzed ethylene/vinyl-acetate interpoly mer of molar ratio of ethylene/vinyl acetate of approximately 2.4/1 was dissolved in a trichloro ethylene-ethanol mixture and ?laments obtained polymer with ‘subsequent evaporation of the sol vent. Suitable solvents are trichloroethylene ethanolewater mixtures, primary aliphatic alcoe hols boiling above 75°, primary and secondary aliphatic amines and mixtures of aromatic hy by “dry-spinning" the solution. The yarn was drocarbons with such alcohols and amines. oriented by drawing in steam at 99° C. at a draw As hereinbefore stated, it is essential that the ratio of 8.11/1 to give a yarn having a tenacity 10 ?lament should be drawn in a medium compris of 3.9 g./d. at 12% elongation. The yarn was ing water at a. temperature within the range of \set in steam at 102° C. to give ?laments having from 80° C. to 100° C. Furthermore, the time a tenacity of 3.8 g./d. at 19% elongation. The of travel of the ?lament through the drawing . heat-set yarn had a shrinkage ‘of 12% when medium must be such that said ?lament is heated treated in water at ‘100° C. When the unset or 15 to a temperature within said range. While ap which had not been subjected preciable effects are obtained when'drawing is untreated yarn to the steam treatment was placed in boiling wa effected at ‘a temperature as low as 80° C., ter, the yarn was so water-sensitive'that it broke. markedly improved ?laments are produced when The process of this invention is applicable to the temperature of the aqueous medium and the any ‘?lament of a hydrolyzed interpolymer of 20 filament during the drawing step is within the‘ ethylene with a vinyl ester of an organic acid range of from 90° C. to 100° C. While the me having the general formula RCOOH, wherein R dium comprising H2O in which thedrawing .of ' is of the group consisting of hydrogen atoms and / the ?lament is effected may be a bath of liquid hydrocarbon radicals, said acid being free from water, said drawing is carried out most readily unsaturated linkages between acyclic'carbon at 25 and conveniently and with the production ‘of ?la oms and any carbon atom alpha to the carbon ment products having optimum properties when atom in‘ the carboxyl group of said acid being attached to at least one but not more than three said medium comprises steam. The drawing or orientation of the ?lament as described above is therefore preferably carried out in steam, or steam and air, at a temperature within the range of from 90° Cfto 100°C. Drawing can be con ‘carbon atoms, provided the mol ratio of ethylene - to vinyl/organic ester in said interpolymer prior to hydrolysis was within the range of from 1/1 to 5/ 1. Included among examples of said inter polymers are interpolymers of ethylene with vinyl formate, with vinyl acetate,‘ with vinyl propi onate, with vinyl butyrate, with vinyl stearate, 35 with vinyl benzoate, with vinyl cyclohexanoate, with vinyl isobutyrate, with vinyl palmitate, with vinyl myristate, with vinyl toluate, with vinyl ' naphthoate and thevlike. On account of supe rior products had therewith, I prefer to employ 40 interpolymers of ethylene with a vinyl ester of an‘ organic acid having the general ‘formula _ CnH2n+1COOH, wherein n is a positive integer within the range of from 1 to 3.‘ Inasmuch as ' ‘ the acid group of the vinyl ester is removed by 45 hydrolysis, it is usually most economical to use veniently effected by passing the ?lament from the snubbing roll‘ to the drawing roll through a vertical tube open at both. ends and to which steam‘ is admitted. By maintaining a speed dif-_ . ferential betweenthe drawing roll and the snub bing roll, the ?lament is stretched and oriented, the tension on the drawing roll being su?icient'to effect stretching but insufficient to cause break _ By passing steam in the ver ing of the ?lament. which the ?lament is passed tical tube through during the drawing operation, it may be heated / readily to the desired temperature. The use of steam alone usually provides a temperature with while tem in the range ‘of from 99° C. to 100°C.C.,are attained peratures of from 80° C. to 99° an interpolymer of- ethylene with vinyl acetate I by mixing air with, the steam before it is in which is the most readily available vinyl ester. troduced into the tube. Such- heating prevents Appreciable effects are had when the mol ratio local over-heating of the ?lament and avoids the of ethylene to vinyl organic ester in the inter~ tendency to form broken ?laments. Less-pref’ polymer prior to hydrolysis is as low as 1/ 1, and 50 erable, although operable, is the employment of a liquid water bath heated to a temperature‘ within ' also.when it isas high as 5/1. However, the ?la ments obtained according to the process of this the range of from 80° C. to 100° C. The use of invention have markedly superior resistance to hot ' such baths necessitates guides for the filaments water and substantially ‘improved dye receptivity ' and ‘these may bring about breakage of the ?la of ethylene to vinyl organic 55 ments. Instead of baths of substantially pure when the mol ratio hydrolysis is liquid water, there may be employed baths of ester in said interpolymer prior to aqueous solutions, e. g., aqueous salt solutions within the range of from 2/ 1 to 4/ 1. Example I, interpolymeriza_ heated to ‘the desired temperature. However, As indicated in ' aqueous baths of substantially pure liquid water tion of the vinyl ester with ethylene can‘ be car ried out under super-atmospheric pressure in the to provide ?laments having higher tenacities than are obtained through the employment of baths of aqueous solutions; while highest tenacities are drolyzed either in a lower aliphatic alcohol solu obtained when the medium employed in the draw tion or aromatic hydrocarbon-alcohol solution by \ ing operation 'is steam, either substantially‘pure treatment with alkali hydroxide. For preparing 65 'or admixed with air. _ rawing temperatures presence of a peroxygen-type polymerization cat alyst. The resulting interpolvmei' may be hy ?laments the. resulting hydrolyzed interpolymer , above 100° C. cannot be used. Below 80° C., the ?lament is softened insuf?ciently for good draw _ ably substantially completely hydrolyzed. ing and lower drawing ratios with lowertenaci-_., The‘ heat stability and water resistance of the 70 'ties (poorer ?nal properties) ‘are obtained. should be-at least 80% hydrolyzed and prefer ?bers had in accordance with this invention are _ In general the time of travel of'the ?lament improved if the hydrolyzed ethylene/vinyl ester through the‘ drawingmedium is 1 to 5 seconds, although usually .1 to 3 seconds are preferred. The time is related to ?lament size, drawing me interpolymer is subjected to an extraction‘ with hot methanol prior to formation of the‘?bers. As shown in the examples, the ?laments may 75 dium and drawing temperature.‘ With regardto ' be obtained by either melt spinning of the hy I 9,411,474 time of travel. the output or a drawing unit de- ' pends on the drawing speed and high‘ speeds may - require longer tubes or baths for theheating. It is to be understood that, duringthe drawing . operation, any draw ratio short of the breaking. point of the ?lament may be employed. How-' ever. on account of the superior products thereby obtained, I prefer to employ draw ratios ‘within ?xed length or under a slight‘ tension to prevent shrinkage during the operation. In’ practice, it is convenient to wind the ?lament on a'Iheat-re sistant bobbin or similar member to maintain said ?lament at a ?xedlength during‘ the setting op ' oration. The low shrinkage in ‘boiling water (5% to the range of from 4.5/1 to 8.5/1, i. e. to draw the I 10%) 01' the ?laments obtained in accordance ?lament to a length within the range of'from 10 with this invention as compared to the‘ shrink‘ 450% to 850% of its original length. _ ~ ~ age of from 15% to 60% of hydrolyzed ethyl- ' Best results have been obtained by orienting or ' drawing of the ?lament which has ?rst been brought into equilibrium with water at room tem perature. Filaments containing less than about carried out at elevated temperatures. The ?la ments'as obtained by the process of this inven tion have improved dye receptivity and increased It seems probable that equilibrium of the ?lament ‘ elongation. ,Said ?laments are particularly use with the water cannot be reached rapidly enough 20 ful in the production of fabrics such as hosiery. ?lter cloths, battery separators, tents and the during the short time of passage 01' yam through 2-3% moisture draw more poorly in steam or wa ter than ?laments which have been ?rst brought into equilibrium withwater at room temperature. the drawing medium. - like. : ‘ After the ?lament has been drawn, and thereby This setting is brought ' ments of this invention may be made without de ' oriented, it must be set. - about according to the .process of this invention ‘ As many apparently'widely different embodi parting from the spirit and scope thereof, it is ' by contacting the drawn ?lament in taut condi tion with a medium comprising H2O ata tem-, perature within the range of from 101° C. to 106° 25 to be understood that I do not limit myseli_ to C. Although the medium comprising H20 may Having described the present invention, the the speci?c embodiments thereof except as de ?ned in the appended claims. ' ' I be liquid water at a temperature of from 101° C. 30 following is claimed as new and useful: 1,. The process for obtaining an improved hy 'to 106° 0., it is more convenient to use steam. Furthermore, when said medium is steam, ?la drolyzed ethylene/vinyl organic ester interpoly moved from the steam bath it may be dried quick. hydrocarbon radicals, said acid being free from , mer ?lament, which comprises drawing at a tem ments having markedly superior properties re perature within therange 01’ from 80° C. to 100°. sult. The heat transfer from steam is better than from liquid Water'and the ?lament‘ attains the 85 C. in a medium containing H2O at a temperature within the range of from 80° C. to 100° C., a ?la required temperature within the range of from ment of a hydrolyzed interpolymer‘of ethylene 101° C.‘ to 106° C. more'rapidly and with better with a vinyl ester of a monocarboxylic acid hav control. Equipment adapted for treatment of ing the-general formula RCOOH, wherein R is the ?lament ,with steam,‘ e. g., an autoclave, is readily available and..when the‘?lament is re 40 of the group consisting 01' hydrogen atoms and, ly. It is preferred that the time of heat treat ment in steam should not exceed 20 minutes since heating times in” excess of 20 minutes result in degradation of the ?laments. In general, opti mum results are had when the?lament is cori tacted with steam’ at from 102° C. to 104° C. for a period of time within the range of from 5 min; ‘ utes to 20 minutes, although when the ?lament is treated in the form of thick packages of yarn, 50 sumcient time must be allowed to obtain equilib rium temperature throughout the package. unsaturated linkages between acyclic carbon atoms and any carbon atom alpha to the carbon atom in the carboxyl group of said acid being attached to at least one but not more than three carbon atoms, the mo] ratio of ethylene to vinyl organic ; ester in said interpolymer prior to hydrolysis hav ing been Within the .range of from 1/1 to 5/1, and thereafter heating the resultant [stretched ?lament at a temperature within the range of from 101° C. to 106° C. in a taut condition in contact with a, medium comprising H2O at a temperature within the range 01’ from 101° C(to ,Setting temperatures in excess of 106° C. are 106° C. - > ‘ to be avoided since such high temperatures usu 2. The process/for obtaining an improved hy ally‘ cause some degradation of the ?lament with 55 idrolyzed ethylene/vinyl organic ester interpoly resulting loss of "tenacity and other properties. mer ?lament, which comprises drawing at a tem On the other hand, when setting temperatures‘ perature within the range of from 90° C. to 100° C. of less than 101° C. are employed, the resultant ?lament is not protected against subsequent] in a medium comprising H2O at a temperature shrinkage in boiling water. The subsequent tem 60 within the range of from 90° ment of a hydrolyzed interpolymer of ethylene perature employed within the heat-setting range with a vinyl ester of a monocarboxylic acid hav of from 101° C. to 106° C. may vary with the particular hydrolyzed‘ interpolymer depending ing the general formula CnHZn-i-ICOOH, wherein n is a positive integer within the range of from 1 upon the molecular weight of said interpolymer and the ratio of ethylene to vinyl organic ‘ester 65 to 3, the mol ratio of ethylene to vinyl organic ester in said interpolymer prior to hydrolysis hav originall'y'present in said interpolymer prior to hydrolysis. The exact setting temperature for \ing been within the range of from 1/1 to 5/1, and thereafter heating the resultant stretched maximum properties of any given ?lament can ?lament at a temperature within" the range of readily be determined. This determination may be readily carried out by a few preliminary ex~ 70 from 101° C. to 106° C. in a taut condition in contact with a medium comprising H20 at a tem aerlnients to ?nd the optimum conditions. perature within the range of from 101° C. to The setting or heat treatment in the medium 106° C. ‘ :omprising H2O at a. temperature within the range 3. The process for obtaining an improved hy-I )1’ from 101° C. to 106° 0. must be carried out vith the ?lament in a taut condition, 1. e., at a 75 drolyzed ethylene/vinyl acetate interpolymer ?la ment, which comprises drawing for a period of 2,411,474 7 the range of from 1/1 to 5/1, and thereafter con from 1 to 5 seconds in a medium comprising steam at a temperature within the range of from 90° C. to 100° C., a ?lament of a‘ substantially com tacting the resultant stretched ?lament in a taut condition for a period of from 5 to 20 minutes with steam at a temperature within the range of 7“ pletely hydrolyzed interpolymer of ethylene with from 102° C. to 104° C. vinyl,acetate,. the mol ratio of ethylene to vinyl acetate in said interpolymer prior to hydrolysis _ 5. The'process for obtaining an improved hy drolyzed; ethylene/vinyl acetate interpolymer ?la having been within the range of from 1/1 to 5/1, ment, which comprises drawing for a period of and thereafter contacting the resultant stretched from 1 to 5 seconds in steam at a temperature ?lament in a taut condition for a period of from 10 within the range of from 90° C. to 100° C., a ?la 5 to 20 minutes with amedium comprising steam ment of a substantially completely hydrolyzed at a temperature within the range of from 101° interpolymer of ethylene‘ with vinyl acetate, the mol ratio of ethylene to vinyl acetate in said C. to 106° C. 4. The process for obtaining an improved by interpolymer prior to ‘hydrolysis having been ‘with drolyzed ethylene/vinyl acetate interpolymer ?la- in the range of from 2/1 to 4/1, and thereafter contacting the resultant stretched ?lament in a taut condition for a period of from 5 to 20 min utes with steam at a temperature within the range ment, which comprises drawing for a period of from 1 to 5 seconds in steam at a temperature within the range of from 90° C. to 100° C., a ?la ment of a substantially completely hydrolyzed interpolymer of ethylene with vinyl acetate; the ' mol ratio of ethylene to vinyl acetate in said in terpolymer prior to hydrolysis having been within of from 102° C. to 104° C. 20 HALSEY B. STEVENSON. . '