BE658802A - - Google Patents

Description

  

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   The present invention relates generally to synthetic linear spinnable polyamides, and more particularly to molten blends of these polyamides, and to a process for the production of such blends.



   Although threads formed from polyamides such as
 EMI1.1
 polyhexamethylene adipamide and poly-opsilonn-capro-amide are produced for many textile and industrial applications, they have only limited utility in other important applications, due to properties such as their relatively low dimensional stability , their low modulus and their significant permanent elongation. It is known, for example, that these properties contribute directly to "flattened spots", a phenomenon which occurs when conventional polyamide yarns are used for making tire reinforcement cords.

   It was also recognized that any noticeable reduction in the depth of these flattened places would practically eliminate this inconvenience.
 EMI1.2
 deny the use, moreover very advantageous, of polyamide yarns in tire cards. In this regard, a reduction in the depth of the flattened places from about 5-5.3 mm for poly- ropes.
 EMI1.3
 hexylmethylene adipnmide and about 6.35mm for polycaproamide cords, less than 4.06mm, in a tire, 8.50 x 14, will allow satisfactory behavior provided there is no loss appreciable in other properties such as tenacity and elongation of filaments in the cord.

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   The main object of the invention is to provide a melt-blended polyamide yarn having better dimensional stability, higher modulus and reduced permanent elongation, and which, when used for making fabric. tire cords, causes a noticeable reduction in flattened areas.



   Another object of the invention is to provide a process for the production of such mixed polyamides in the molten state.



   According to the invention, with these objects in mind, the polyamide filaments are prepared from a molten mixture of two distinct polyamides, the first having a Tg equal to or less than 120 C, the second having a cicada Tg or greater than 140 C. This molten mixture is produced by mixing the two starting polyamides in determined proportions, heating and mixing so as to obtain a homogeneous molten mixture, and maintaining the molten mixture at a temperature of at least 1 C above the melting point of the mixture, but not exceeding 350 C, for a minimum period of time.

   Typically, the molten mixture is then spun into filaments, and stretched
Due to the mutual exchange which takes place between amides at melting temperatures, it is believed that the molten mixture of polyamides according to the invention is, at least in part, a block copolymer, in which the segments of each component polymer have a relatively high molecular weight.



   The temperature (above 0 ° C.) at which the greatest loss of mechanical work occurs is referred to herein as Tg, and this is a property of the polymer which depends on the structure and molecular arrangement. The

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 way in which this temperature is related to the greatest loss of macanic work is indicated in "Die Physik der Hochpolmeren", by AS Staverman and F. Schwarzl, Band IV, Springer-Berlag, Berlin 1956, chapter I. The measurements are carried out at 0.1 cycles per second, with an amplitude of the deformations of:!:. 0.8%. The "tangent delta" of the publication corresponds to the Tg of the present description.



   The symbol Tg used herein represents a temperature well known in the polymer art, and commonly referred to as "glass transition temperature". Physically, it is the temperature at which a polymer changes from a glassy or brittle state to a liquid or rubbery state. More generally, it is at this temperature that the viscous mechanism of deformation is most apparent, and for example, at this temperature, there is a change in the slope of the curve connecting the coefficient of é. lasticity and temperature, and also a change in the slope of the curve relating the coefficient of expansion to temperature.



   It has already been recognized on this subject (flory, "Principles of Polymer Chemistry", Cornell University Press, Ithaca, New York, (1953), page 53 and Tobolsky, "Properties and Structure of Polymers", John Wiley and Sons Inc., New York 1960, Pages 69-70), that the numerical value obtained for Tg in any one case depends very much on the method of determination.



  In this regard, the values reported herein are determined by measuring the temperature at which the greatest loss of work occurs when a filament is subjected to cyclic stresses.

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   The "permanent deformation" S of a cord is a viscoelastic property which can be related to a flattened area of a tire, and which is masked by a test simulating the existence of flattened places. In this test the changes in length of two initially identical cords were measured when subjected to different tensions and / or different temperatures. The different voltages and temperatures simulate changes in the deformed and undeformed portions of a tire. The algebraic difference between changes in length is the permanent deformation, and it is expressed as a percentage.



   To determine the permanent set, a sample of yarn is shaped as a drawn yarn measuring 840 denier, which is then given a Z twist of 480 turns per meter. Two ends are bundled and twisted at a rate of 480 turns per meter of twist S. The compound rope is hot drawn at a temperature not more than 30 ° C. below the melting point of the yarn with a tension of 0.9 to 1.8 kg, for a period of 60 seconds. To measure the permanent deformation, a machine is used which is designed to measure the variations in length of a filament or a cord when the tensions and / or temperatures are varied. During the test, it is advantageous to keep the ropes at a low relative humidity (less than 10% relative humidity).



   The detailed procedure to be used to measure the permanent deformation of a rope when it is subjected to a particular cycle of temperatures and tensions is as follows: 1 Release the rope at 160 C for 10 minutes (which simulates the vulcanization of the tire );

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2 Fit soft ropes in the test fixture; apply a load of 0.8 g per denier and hold at 77 ° C for 1 hour (this preconditions the strings);
3 Bring the temperature of the strings to 25 C and maintain at 0.6 g per denier for at least 30 minutes;
4 Measure the lengths of the two ropes (La and Lb); . these are the starting lengths for the two strings;

   
5 Pass the load of 0.8 g per donier, bring the cords to 77 C, and hold for 30 minutes;
6 Pass the load on the corda b to 0.25 g per danier;
7 After 15 minutes, bring the strings to a temperature of 25 C;
8 After 5 minutes, pass the load on rope a at 0.6 g per denier;
9 After 30 minutes, measure the length of the string a;
10 Immediately after, pass the load on the string b at 0.6 g per denier and measure the length after exactly 1 minute (Lb, 1 minute);
11 Calculate at La and # Lb in%, comparing the initial and final lengths;

   the algebraic difference between # La and # Lb is the permanent deformation at the various times in%.



   The depth of the flattened places for an 8.50 x 14 tire (the greatest radial distance between the normal periphery of a tire and the geometric chord presented by a flattened place, expressed in millimeters, can be predicted , as a function of the value of the permanent deformation, according to the following equation:

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 EMI6.1
 Depth of flattened places 1 2.16 S 1.6J.



  As a general rule, the pQc i.de of the mixture ..,; w; , is a polyamide lending itself well to ttlTr ;; i having good strength and good strength, and, qu ;; suitable for most end uses. It is referred to herein as polyamide A. Each polyamide A has a Tg of 120 ° C or less, and should have a permanent set of 1.20% or more.

   The polyamide sucond of the mixture has at least
 EMI6.2
 an aromatic or cyclo-aliphatiquo nucleus in the skeleton of at least one of its meshs - For all reason, co polyamido is of a rigid structure, it is more difficult to treat in the form of homofilamont because of its viscositd farta the molten state, it has a Tg of 140 C or more, a permanent set of 1.00% or less, and it will be designated under the no!
 EMI6.3
 of polyamide B.

   When the polyamides A,, q .; one hundred mixtures in the molten state in accordance with the peratoiros conditions xpecified here t used for the 40 cordas do pnou-, matiquos, the latter have a permanent set of less than 1.07%, which corresponds to a back depth. Flattened areas less than 4.06 mm. In addition, other properties
 EMI6.4
 late tees. rope <, tees of the wire and the davent rope '' bj, one eiU-oures.



  "'t"' 'Each polyamide A has the following p., W çt.J.las: t' t 'v
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 R1 to R15 denote hydrogen or alkyl radicals
 EMI7.1
 (1 to 4) 'D and E are divalent unsubstituted aliphatic, cyclo-aliphatic or aromatic radicals (when D is an unsubstituted divalent cyclo-aliphatic or aromatic radical, E must be a divalent aliphatic radical, and vice- versa), and F is a divalent aliphatic radical.



  Polyamide A can be, for example, any
 EMI7.2
 that of the following: polytetramethylene-suberamido; polyhaxamethyâhesubdram.de polyhexam, thylene-adipaniide-, polyhexamethyl-, lene-ebaçamide; poly-epsilonn-caproamidej poly-n-lieptylamide; , polyaùprylamide; polypelargonamide! palyddcanaam.de; poly- '- undecanoamide; poly '* metaxylylenQ'-adipamide; polymetaxylylene "pimelam14e; po.ymtax;, r.ylne suberamide: polymetaxylylene-adZam.da; polymdtaxyly.ene sebaçam3, de. It can be a homopolymer, an ordinary copolymer, a PIQ @ o4 copolymer, a mixture of polymers.



  Polymetaxylylene adipamid is somewhat different from other Group A materials in that although it has a Tg less than about 120 0, it exhibits a permanent strain of about 1.00%. Thus, it can be used, under
 EMI7.3
 homofilament shape, for making a tire that is barely acceptable with regard to flat spots. This-. However, when it is melt-mixed according to the process of the invention, better behavior with regard to the flattened places is obtained.



   Each polyamide B has the following mesh:
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 G and I are divalent aliphatic, aromatic or cycloaliphatic radicals (but which cannot both be divalent aliphatic radicals). As a practical limitation, the polyamide B should also have a block melting point of less than 350 ° C., since above this temperature excessive degradation occurs which prevents melt spinning.



   Polyamide B can be, for example, any
 EMI8.1
 than polymers prepared from: metaphonylenodiamine and adipic acid, pimelic acid or au- beric acid, 1,3-diamino-cyclohexane (150nref3 m61ang, jv) and adipic acid, paraphenylene.-dian, ine and az61ic acid or seb.cic acid; bis (4-aminocyc: lohexyl) -methane (liquid mixture dtiso'Ùres, for example 80 of cis, trans and 20% of cis, cis) and oxalic acid or isophthalic acid; bis (4-aQ \ ino-cyclohe: {'! l) -methane (solid mixture of isomers, for example 50-55% trans, trans it .- $ f7N of ci3, trans) and the acid az6lafque or sebaciquti acid; bis (4-aminophenyl) - methane and adipic acid; 4,6-dimethyl-methaphenylenediamine and suberic acid, az41a-acid or sebacic acid;

   2, ± -ditnfi; tiiyl-mltaphônylénc-dia; ine and 4,6-dimethyl-metaphenylene-diamine (eg. 50/50) with suberic, azelaic or sebacic acid; 1,3-diaminonropana and isophthalic acid; 1,4-diaminc-butane and isophthalic acid; 1,5-diaminopentane and isophthalic acid; 1,6-diaminohexane and isophthalic acid; 2-methyl-hexamethy-
 EMI8.2
 lene diamine and terephthalic acid; vietaxylylene diamine and isophthalic acid or hexahy.ro-p-xylylene-dia "1ine (mixed isomers) and adipic acid or isophta- acid
 EMI8.3
 lique. It can be a honopolymer, a block copolymer or

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 normal crystallizable, or a mixture of polymers.



   In general, the molten blends of the present invention, as well as the filaments spun from such blends, will contain from about 12 to about 80, and preferably from about 12 to about 50 parts of B , and from about 88 to 20 (preferably at least 50) parts of A.



   It is believed that the cords produced from the yarns according to the invention owe their exceptional stability to the fact that the crystallinity of the yarn can normally be developed. a much higher degree than is possible with ordinary copolymers having the same constituents and the same composition. However, there are some combi-. polymers A and B for which the constituents crystallize; it from the molten mixture to form a mixed crystal. These constituents, like ordinary copolymers, exhibit the properties of isomorphic polymers, in that they have a melting point versus composition curve without a net eutectic.

   These isomorphic components prevent the development of maximum crystallicity in the filaments of molten mixtures of these components at operating temperatures.



   Thus, an additional condition to be taken into account in choosing suitable pairs of polyamides, A and B, is their tendency to isomorphic. In many cases, this can be predicted from the mesh sizes, determined by x-ray measurements. A convenient estimate of this trend can result from a comparison between the numbers of chain atoms in the mesh. of each homopolymer. When these numbers are the same, the polymers chosen are likely to syncrystallize and be less valuable for the purposes of the invention.

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  For polymers A of the type PMylon 66n, which crystallize from the molten state QfJ, I11'3 3.Q 6VOÙMQ hexagonal, then transform to more bacae t * npàr4yU # o (vîyo 140 * C) in a another system <c'ùi> t-à-4iTe lo VQtêP1P frÍlliniquo), the polynture * B must 6trc non iHOtnorpho do.ne te eystëmo hll1xn, onl.



  We find a more unequivocal criterion of the compatibility of the combinations of A, B dntis the rulaiihn between the melting point and In compJition due to co) olymr'o oi'4Lnn1rù5 of A ot 3 When the points of uiion do these copolymers are notably more hna than soft dc; each of its constituent parts, A ot a are "> 1> tix isomoruhcs, -> .. 'orH, t ... L t is therefore uno coribiiiaison prcH'ér60.



  A! \ UtN cond l ticn ost quo lu raélllngo do polyem1.doB A, B is of a weight m, Jl <scul <, ir <filablù (by exempta au-dos.uS 'd 10.0JO), although' It does not always include: 3alrl3 that the individual constituents so tr, ottyoilt 4qn> 'intorval1e of molecular weights The highest iolec4laro weight usable for each constituent will generally give
 EMI10.2
 
 EMI10.3
 the millQurQ $ propri6to à la ribro.



  The mixtures of potYll "1idol5 melted according to the invention, were prepared by mixing and mixing the polyamides A and B in proportions such that at least (4 S2 + 24 S 2 ¯ 2, + 8) parts of p0yt!) Id9 B for 100 parts of SA and bB as the per- Ktcncntes n4foMations of polyamides A and B. When polyamide B is pre-
 EMI10.4
 are in a proportion lower than the minimum percentage
 EMI10.5
 specified above, it is usually mpo5tblo to arrive gas a (, deformation p;, rrL, .int) ritc inferior 6 3-f0? t or 4 a proton- dor of the flattened places lower than 4t06 MM for a tire - matiquc 8.50 x 14 faiiriqu3 in normal cundit-iona of preparation and vulcanication dl.f. tires.

   When he

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 EMI11.1
 there is a certain tendency towards isomorphism, higher proportions of the polyamide, B. Thus, in the above expression, the quantity z S <. 2 + 24 S - 2 is decreased by up to mild units when the polyamides A ut t are not isomorphic, and it is increased by up to 6 units, when there is a tendency to isomorphic. 'The strongest propor-
 EMI11.2
 permissible ration of Polymer B is 0%! preferably, however, a proportion greater than 50% is not used.
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  Lo m6lango is heated and stirred in such a way as to obtain a hontogeneous molten molangc, that is to say that one heats up to the melting point of the time during which the nwt: is maintained in the molten state should be kept as short as possible, so that there is the minimum of mutual exchange of amide between polymers A and B, maintaining the longest possible length for the blocks. Cos conditions are met
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 if the molten mixture is heated to a temperature which is at least 1 ° C above the melting point of the mixture, but does not exceed
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 Saint pas 3500C, for a period of 0 to 120 30 minutes. Preferably, the temperature to which we heat is above 5 to 40 C the melting point of the
 EMI11.6
 mixture, and the corresponding period is between 0 and 60 '' & 2. minutes.

   In these last expressions, T
30 denotes the temperature at which to heat, in C. The above pressure for the upper limit applies to polyamides of normal spinnable molecular weight. The presence of the acid or water catalyzes the mutual exchange of amides, so that shorter periods will be used when abnormal proportions of such reactants.

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 EMI12.1
 are present. Also, catalysts (eg polyanidization catalysts) can increase Vi! <. (J83e de-
 EMI12.2
 changes and inhibitors can reduce it,
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 An effective blend of Polymers A and B is required to give the yarn the properties of the yarn. can use mechanical telephones.

   After completion of the melt-blending, the polyamide blend spun into yarns and underwire.



  The content of polynmidia A and B can be effected in any suitable operation, eg by mixing with flakes, molten materials or colutiona.



  Preference is given to the mixture of flakes or melted intltiètres. The mixed product in the molten state can be converted into yarn by wet, dry or melt spinning, the latter method being preferred.



  The coMportcnt of the filanents from the point of view -, the first deformation and the flat places can uclquoroi6: Ctro improve by a trueness at high temperature or annealing (example XXI), 0 the durài nci-, s2airo rather one energy reduced. , or tei, ipératux> e .bai & iaéQ, pf'r treating oV \ ', 1C a plasticizer such as 1 ,,, val) uur oru or a blowing agent ;.



  The compounds ::; it;!. O / 1: .i pr6 ± erC! (H3 for formalin "Io fila- mont of the invention tiont dUD trilangom in the molten state of polyhexamethylenic4-adipttmidu (66) and dQ polyhoxnm6thylôhu-isophià- ¯ lamido (61), no more due to 50% of 61. Loarac "µri u <s co-blend block copolymer has been established by different medium extraction of formic acid at varying concentrations. , a physical melanro of 66 and 61 can be separated using the difference in solubility of these polo
 EMI12.4
 amides in Mixtures of Fornic acid and water on 66

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 EMI13.1
 being soluble in 76-78% fornic acid and 61 in 96 mg / g% acid.

   An ordinary copolymer is more soluble than. homopolyiiterc 61, while block polymers have intermediate solubility, the exact behavior being determined by the size of the blocks.



   82% formic acid (in water) has been found to be an excellent solvent for distinguishing those melt mixtures of 66 and 61 which provide filaments satisfactory for the purposes of the invention. from those who do not provide such filaments. In the latter, the mutual exchange of amides and / OR of initial low molecular weight reduced
 EMI13.2
 the loosening of the blocks of 61 to such an extent that they are not sufficiently effective in stabilizing the wire against the formation of flattened spots in the tire.

   It has been found (example 16) that the filament 66-61 according to the invention does not
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 containing not more than $ 0% 61 * is at least about 12% insoluble in 82% formic acid. The soluble fraction, obviously, includes the 66 for (not having undergone an exchange
 EMI13.4
 mutual) ot the blocks 66-61 having undergone more strongly the mutual exchange (that is to say naked bringing closer to the ordinary copolymers).



     Using amide exchange rate constants from a study of typical compounds, one can deduce that the block copolymer component produced by the desired degree of mutual exchange has a length of
 EMI13.5
 moyonnb dihu minus 10 stitches of 61.

   Coci matches the 'lod l.i blocks, for effective results; longer blocks are preferable. It is evident that a higher degree of mutual exchange of amides is permissible when using
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 dc di.ltteès b1 with high viscosity (long chains), or

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 when high percentages of component 61 are used, as long as at least about 12% remains insoluble in 82% formic acid.



   Polyamide filaments according to the invention. not only useful for the production of tire cords of exceptional thermal stability, they are also useful as reinforcements for fire hoses, straps, industrial rubber articles and in the form of threads. industrial in general, as well as in textile yarns due to their exceptionally high modulus. These yarns, in the form of filaments, mches, staple fibers or the equivalent, are useful in carpets, pile fabrics, twill fabrics, taffeta, and, in general, in woven and knitted fabrics. .



   The mixtures of molten polymers according to the invention can contain customary additives for polyamides, in particular delustrers such as those described in US Pat. No. 2,205,722 dated November 4, 1936, anti-oxidants such as those described in. U.S. Patent No. 2,510,777 dated December 30, 1946, or light stabilizers such as those described in U.S. Patent No. 2,887,462 dated January 26, 1955.



   In the examples which follow, the compositions are given by weight, unless otherwise indicated. The inherent viscosities are determined in a solution of 0.5 g of polymer in 100 cm 3 of m-cresol.



   Flattened areas in tires are produced in the laboratory by inflating the tire to 1.55 kg / cm2
8.50 x 14 test, heating it to 77 C, then loading it to 492 kg until the tire has cooled

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 at room temperature. Radial strain, in mm, is the depth of flattened places, or flattening.



   As previously specified, the filaments of the present invention are prepared from a molten blend of two separate polyamides, and were characterized by the difference in Tg between the two constituent polyamides. We have also described how the Tg is determined.

   Representative values for the Tg of the polyamides described here are as follows:
 EMI15.1
 Polyhexamethylene-adipamide 80 ±
 EMI15.2
 
<tb> Polycaproamide <SEP> 75 C
<tb>
<tb> Polymetaxylylene-adipamide <SEP> 115 C
<tb>
 
 EMI15.3
 Poly-2-methyl-haxamethylene-terephthalamide 14600 Poly-2, @ / @, 6-dimethylmetap? Enylene-
 EMI15.4
 
<tb> sebaçamide <SEP> 180 C
<tb>
<tb> Polyamide <SEP> repaired <SEP> to <SEP> from <SEP> of <SEP> bis- (4-amino-
<tb>
 
 EMI15.5
 cyclohaxy1 -methane (solid mixture
 EMI15.6
 
<tb> of <SEP> and <SEP> isomers of <SEP> azelaic <SEP> 175 C
<tb>
<tb> Polymetaphenylene adipamide <SEP> 160 C
<tb>
<tb> Polyhexamethylene-isophthalamide <SEP> 142 C
<tb>
 Example I
 EMI15.7
 Polyhaxamethylene adipamide flakes having an inherent viscosity of 1.0 are mixed.

  1 with polymetaphenylene adipamide flakes having an inherent viscosity of 0.46. The ratio between the weights of mixed polyamidos is 65/35. After mechanical mixing, the flakes are melted in a 1.27 cm screw pipe, and the molten mixture is passed to a die. The temperature in the extruder rises in the direction of flow and, after the extrusion end, the molten polymer at a temperature of 297 ° C. The holding time at 297 ° C. is 5 minutes.

   The

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      mixture is spun into a bundle of 5 filaments having a total count of 230 denier, which is stretched at a rate of 5.5 on a spindle at 80 C and a serial plate at 180 C
Toughness, elongation at break, initial modulus, cold-relaxed permanent elongation and permanent set are measured, and the predictable kurtosis is calculated. The tensile strength properties are conventionally measured using an Instron Tester. The cold-relaxed permanent elongation is determined from the measured elongation of a strand of known length at which a load of 1.0 g per denier has been suspended for 30 minutes.

   Permanent cold elongation includes not only the instantaneous elongation (first half minute) under the given load, but also the elongation that occurs during the remainder of the 30 minutes of the test period. Prior to testing, samples are released for 48 hours at 55% relative humidity and 25 C. The samples are then released for up to 5 minutes at the temperatures indicated, and the values found are therefore referred to as "standby values". relaxed state ". The results are reported in Table I.

   By way of comparison, this table also gives the results obtained with a 90/10 mixture, with the polyhexamethylene-adipamide and polymetaphenylene-adipamido homopolymers, and with the ordinary copolymer (which can be obtained, for example, from mixtures polymers containing similar proportions of the homopolymers, but after being held at a high temperature for a time sufficient to form an ordinary copolymer).

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   Example II
Polyhexamethylene adipamide flakes having an inherent viscosity of 1.1 are mixed with polyhexamethylene adipamide flakes.
 EMI17.1
 metaphenylene adipamide having an inherent viscosity of 015.



   The ratio between the weights of the mixed polyamides is 70/30. After mechanical mixing, the flakes are melted in a 1.27 cm screw extruder, and the molten mixture is passed to a die. The temperature at the extruder end of the extruder is 209 C. The residence time is 5 minutes. The blend is spun into a 5-filament bundle having a total count of 145 denier. The beam is stretched at a rate of 5.0 on a 70 ° C spindle and a plate. 180 C placed in series downstream of the spindle. The results are reported in Table I.
 EMI17.2
 

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    TABLE I
 EMI18.1
 Mixtures of polvhexamethylene adipamide and polY] etapt> enylene adipamide
 EMI18.2
 
<tb> I <SEP> II <SEP> III <SEP> IV <SEP> ordinary
<tb>
 
 EMI18.3
 6: 35 70/30 75/25 80/20 90/10 80 120 100/0 0/100
 EMI18.4
 
<tb> Tenacity, <SEP> grams <SEP> per
<tb> denier <SEP> 8.7 <SEP> 7.0 <SEP> 7.1 <SEP> 7.6 <SEP> 3.1 <SEP> 8.5
<tb> Elongation, <SEP>% <SEP> 17 <SEP> 10 <SEP> 12 <SEP> 13 <SEP> 15 <SEP> 16
<tb> Initial <SEP> module, <SEP> grams
<tb> by <SEP> denier <SEP> 100 <SEP> 70 <SEP> 75 <SEP> 68 <SEP> 46 <SEP> 49
<tb> Elongation <SEP> permanent <SEP> to <SEP> cold
<tb> to <SEP> <SEP> state released, <SEP>% <SEP> 1.4 <SEP> 2.3 <SEP> 2.6 <SEP> 3.7 <SEP> 5.7 < SEP> 3.7
<tb>
 
 EMI18.5
 Permanent deformation,% 0.64-0.56 0 ± 68 1.04 1lt5 2 s3 1.7 0.41
 EMI18.6
 
<tb> Flattening, <SEP> mm,

   <SEP> tire-
<tb>
 
 EMI18.7
 matic ci, 50 x 14 3.12 2.97 3, z3 3.99 -, $ 3 5.68 5.33 2, at%
 EMI18.8
 
<tb> Tg, <SEP> C <SEP> 80 <SEP> 160
<tb>
 

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Example III
Polyhexamethylene adipamide flakes having an inherent viscosity of 1.1 are mixed with polymetaphenylene adipamide flakes having an inherent viscosity of 0.5. The ratio between the weights of the mixed polyamides is 75/25. After mechanical mixing, the flakes are melted in a 1.27 cm screw extruder and the molten mixture is passed to a die. The temperature at the extrusion end of the extruder is 308 ° C. The residence time in the extruder / die part is 5 minutes.



  The mixture is spun into a bundle of 5 filaments having a total count of 172 denier. The beam is stretched at a rate of 6.1 over an 80 C spindle and an 185 C plate arranged in series. The results are reported in Table I.



   Example IV
Polyhexamethylene adipamide flakes having an inherent viscosity of 1.1 are mixed with poly-metaphenylene adipamide flakes having an inherent viscosity of 0.5.



  The ratio between the weights of the mixed polyamides is 80/20.



  After mechanical mixing, the flakes are melted in a 1.27 cm screw extruder, and the molten mixture is passed to a die. The temperature at the extrusion end of the extruder is 306-308 ° C. The residence time in the die extruder part is 5 minutes. The mixture is spun into a bundle of 5 filaments having a total count of 170 denier. The beam is stretched at a rate of 5.2 on a spindle at 80 C and a plate at 170 C. The results are reported in Table I.

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    Example V
Polyhexamethylene-adipamide flakes having an inherent viscosity of 1.1 are mixed with polyhexamethylene-isophthalamide flakes having an inherent viscosity of 0.45. The weight ratio of the mixed polyamides is 50/50. After mechanical mixing, the flakes are melted in a yarn press. At the extrusion end, the molten polymer has a temperature of 300 ° C. The residence time in the die extruder part is 15 minutes. The mixture is spun into a bundle of 5 filaments having a total weight of 90 denier. The beam is stretched at a rate of 5.0 on a spindle at 80 ° C. and a plate is streaked at 170 C. The results are shown in Table II.



   Example. VI
Polyhexamethylene-adipamide flakes having an inherent viscosity of 1.1 are mixed with polyhexamethylene-isophthalamide flakes having an inherent viscosity of 0.45. The ratio of the mixed polyamide back weights is 60/40. After mechanical mixing, the flakes are melted in a spinning press. At the extrusion end, the molten polymer has a temperature of 295 ° C. In the die, the temperature is 296 ° C. The residence time in the extruder / die part is 15 minutes. The mixture is spun into a bundle of 5 filaments grading a total of 125 doniers.



  The beam was drawn at a rate of 5.0 over an 80 ° C spindle and a 170 ° C plate arranged in series. The results are shown in Table II.

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    TABLE II
 EMI21.1
 Mixtures of polhex =, nihy3ene-a-pice and p3.yhea.acthylene-àsenhtalide
 EMI21.2
 v VI SPEED ... o. z1Qù 50/50 60LliJ 7QhJQ 1 'M? t'! ' 5 5hk "2ll #> 'lE'J: l' # U l & .: L: lE ...: .. I.1": ":" - -, r; fodided.n: i: td.a1. . 78a .. -; "7% ± #.
 EMI21.3
 
<tb>



  Permanent <SEP> elongation <SEP> to cold <SEP>
<tb> to <SEP> released <SEP> state, <SEP>.% <SEP>
<tb>
 
 EMI21.4
 Permanent deformation,% o, 89 0.93 o, Ê6 o * 57 Flattening, mm, pneumatiaue 8.50 x z4 3.66 3.76 3.6l 2 ... 97
 EMI21.5
 
<tb> Tg. <SEP> C <SEP> 142
<tb>
 

 <Desc / Clms Page number 22>

 
Example VII
Polyhexamethylene-adipamide flakes having an inherent viscosity of 1.1 are mixed with polyhexamethylene-isophthalamide flakes having an inherent viscosity of 0.51. The ratio of the weights of the mixed polyamides is 70/30. After mechanical mixing, the flakes are melted in a 2.54 cm screw extruder, and the molten mixture is passed through a die.

   The temperature at the extrusion end of the extruder is 307 ° C. The residence time in the die extruder part is 3 minutes.



   The mixture is spun into a bundle of 34 filaments totaling 1100 denier. The beam is stretched at a rate of
5.4 on an 80 C spindle and 150 C plate in series. The results are shown in Table II.



   Example VIII
Polyhexamethyleno-adipamide flakes having an inherent viscosity of 1.1 are mixed with flakes of an ordinary 48/52 copolymer of the 2,4 and 4.6 isomers of polydimethyl-metaphenylene-suberamide having inherent viscosity. of 0.40. The ratio between the weights of polyhexamethylene adipamide and polydimethylmetaphenylene suberamide is 70/30 After mechanical mixing, the flakes are melted in a 2.54 cm screw extruder, and the molten mixture is brought to a pathway. The temperature at the extrusion end of the extruder is 300 ° C. The residence time in the extruder-die part is 5 minutes.

   The mixture is spun into a bundle of 34 filaments totaling 1210 denier. The beam was stretched at a rate of 5.5 on a brocho at 120 ° C. and a plate at 200 ° C. in a series. The results are shown in Table III.

 <Desc / Clms Page number 23>

 



  Example IX
 EMI23.1
 Flakes of polyhexamethylene adipamide having an inherent viscosity of 1.1 are mixed with flakes of an ordinary 48/52 copolymer of the 2,4 and 4.6 isomers of polydimethylmethylmetaphenylene suberamide having a viscosity
 EMI23.2
 inherent in Oe4O. The ratio of the weights of polyhexamethylene adipamide to polydimethylmetaphenylene suberamide is 80/20. After mechanical mixing, the flakes are melted in a 2.54 cm screw pipe, and the molten mixture is passed to a die. The temperature at the extrusion end of the extruder is 300 ° C. Time to
 EMI23.3
 stay in the boudinouscifilière part is 5 minutes. The mixture is spun into a bundle of 34 filaments grading a total of 1210 denier.

   The beam was stretched at a rate of 5.5 over a 120 ° C spindle and 200 ° C plate in series. The results are shown in Table III.



   TABLE III Mixtures of polyhexamethylene adipamide and poly-2,4 / 4,6'-
 EMI23.4
 dimethyl-metaphenylene-suberamide (48/52)
 EMI23.5
 
<tb> VIII <SEP> IX
<tb>
<tb> 70/30 <SEP> 80/20
<tb>
<tb>
<tb>
<tb> Tenacity <SEP> 5.5 <SEP> 7.1
<tb>
<tb>
<tb> Elongation <SEP> 13 <SEP> 14
<tb>
<tb>
<tb> Module <SEP> initial <SEP> 85 <SEP> 84
<tb>
<tb>
<tb> Elongation <SEP> permanent <SEP> to <SEP> cold <SEP> to
<tb>
 
 EMI23.6
 relaxed state,% 3.0 3.6
 EMI23.7
 
<tb> Permanent <SEP> deformation, <SEP>% <SEP> 0.85 <SEP> 1.04
<tb>
<tb>
<tb> Flattening, <SEP> mm, <SEP> pneumatic
<tb>
<tb> 8.50 <SEP> x <SEP> 14 <SEP> 3.58 <SEP> 3.91
<tb>
<tb>
<tb>
<tb>
<tb> - <SEP> 24 <SEP> -
<tb>
 

 <Desc / Clms Page number 24>

 
EXAMPLE
Polymetaxylylene adipamide flakes having an inherent viscosity of 0,

  8 with flakes of poly-metaphenylene adipamide having an inherent viscosity of 0.5.



  The weight ratio of the mixed polyamides is 80/20. After mechanical mixing, the flakes are melted in a 1.25 cm screw sausage and the molten mixture is sent to a die. The temperature at the extrusion end of the extruder is 302-310 ° C. The residence time in the filière section is 5 minutes.



  The mixture is spun into a bundle of 5 filaments totaling 200 denier. The beam was stretched at a rate of 5 on an 80 ° C spindle and 170 ° C plate in series. The results are shown in Table IV.



   EXAMPLE XI
Polyhexamethylene sebacamid flakes having an inherent viscosity of 1.1 are mixed with polymetaphenylene adipamide flakes having an inherent viscosity of 0.6. The ratio between the weights of the mixed polyamides is 75/25. After mechanical mixing, the flakes are melted in a 1.27 cm screw extruder, and the molten mixture is passed to a die. The temperature at the extrusion end of the extrusion is 305 ° C. The residence time in the extrusion die part is 5 minutes.



  The mixture is spun into a bundle of 5 filaments totaling 160 denier. The beam was stretched at a rate of 5.3 over an 80 ° C spindle and 170 ° C plate in series. The results are shown in Table IV.



   EXAMPLE XII
Polyhexamethylene flakes are mixed

 <Desc / Clms Page number 25>

 adipamide having an inherent viscosity of 1.1 with polytrimethyleno-isophthalamide flakes having an inherent viscosity of 0.6. The ratio between the weights of the mixed polyamides is 80/20. After mechanical mixing, the flakes are melted in a 1.27 cm screw extruder and the molten mixture is passed to a die. The temperature at the extrusion extremity of the extruder is 305-310 C. The residence time in the extruder-die part is 5 minutes.



  The mixture is spun into a bundle of 5 filaments totaling 160 denier. The beam was drawn at a rate of 5.0 on an 80 ° C spindle and a 10 ° C plate in series. The results are shown in Table IV.



   EXAMPLE XIII
Polyhexamethylene adipamide flakes having an inherent viscosity of 1.1 are mixed with flakes of
 EMI25.1
 polymetaphenylene adipartdo having an inherent viscosity of 5. The weight ratio of mixed polyamides is 75/25. After mechanical mixing, the flakes are melted in a 1.27 cm screw pipe, and the molten mixture is sent to a die. The temperature at the extrusion end of the extruder is 308 C. The residence time in the boudincusc-die part is 5 minutes. The mixture is spun into a bundle of 5 filaments totaling 172 deniors. The beam was stretched at a rate of 5.5 over an 80 ° C spindle and 185 ° C plate in series.

   The material is boiled, released in water for 30 minutes, and then subjected to dry measurements on an Instron Tester.



  The results are shown in Table IV. The high modulus of 46 for an elongation of 28 makes this yarn particularly suitable for textile applications.

 <Desc / Clms Page number 26>

 



   XTV example
Polycaproamide flakes having an inherent viscosity of 1.0 were mixed with polymetaphenylene adipamide flakes having an inherent viscosity of 0.6. The ratio of the weights of the mixed polyamides is 70/30.



  After mechanical mixing, the flakes are melted in a 1.27 cm screw extruder and the melted mixture is passed to a die. The temperature in the extruder rises in the direction of flow, and at the extrusion end the molten polymer is at a temperature of 275 C. The residence time in the coil / die part is 5. minutes. The mixture is spun into a bundle of 5 filaments totaling 304 denier. The beam is stretched at a rate of 5.0 on a 70 C spindle. The permanent deformation is 0.79% and the flattening is 3.45 mm, instead of 2.1% and 6.35 mm for a control yarn on polycaproamide. These results are shown in Table IV.



   Table IV
 EMI26.1
 
<tb> x <SEP> XI <SEP> XII <SEP> XIII <SEP> XIV
<tb>
<tb>
<tb> 80/20 <SEP> 75/25 <SEP> 80/20 <SEP> 75/25 <SEP> 70/30
<tb>
<tb>
<tb>
<tb>
<tb>
<tb> Tenacity <SEP> 3.3 <SEP> 4.7
<tb>
<tb>
<tb>
<tb> Elongation <SEP> 26 <SEP> 15 <SEP> 20
<tb>
<tb>
<tb>
<tb>
<tb> Module <SEP> initial <SEP> 65 <SEP> 51 <SEP> 46
<tb>
<tb>
<tb>
<tb> Permanent elongation <SEP>
<tb>
<tb> to <SEP> cold <SEP> to <SEP> the <SEP> state released
<tb>
<tb>
<tb> che, <SEP>% <SEP> 3.1 <SEP> 2.2 <SEP> 2.0
<tb>
<tb>
<tb>
<tb> Deformation <SEP> perma-
<tb>
 
 EMI26.2
 nent,% 0.70 0.59 0.64 0.79
 EMI26.3
 
<tb> Flattening, <SEP> mm, <SEP> tire-
<tb>
<tb> mati <SEP> que <SEP> 8.50 <SEP> x <SEP> 14 <SEP> 3.25 <SEP> 3.02 <SEP> 3.12 <SEP> 3,

  45
<tb>
 

 <Desc / Clms Page number 27>

 
Example XV
Yarns of various compositions are spun and drawn under conditions substantially as described in Example X. The percent compositions, and "pormanent deformations" of the individual components, are shown in the following table.
 EMI27.1
 

 <Desc / Clms Page number 28>

 



    TABLE V
 EMI28.1
 
<tb> Polymer <SEP> A <SEP> Polymer <SEP> B
<tb>
 
 EMI28.2
 Exchange- "'' '" ############# * "#######' # '
 EMI28.3
 
<tb> tillon <SEP> Quantity <SEP> Deformation <SEP> Quotity <SEP> Deformation
<tb> permanent <SEP> Relevant <SEP> quantity
permanent <tb>
<tb>
 
 EMI28.4
 XV 63% polycaproamide (6) 2.1 35% polyhexamethylene-
 EMI28.5
 
<tb> isophthalamide <SEP> (61) <SEP> 0.57
<tb> XVI <SEP> 85% <SEP> of <SEP> 66 <SEP> 1.7 <SEP> 15% <SEP> of <SEP> polytetramethylene-
<tb>
 
 EMI28.6
 ## iso htalaraide ::

  iTII 70% poly (m-xylylene adipamide) 1.0 30% of 61 0.57
 EMI28.7
 
<tb> XVIII <SEP> 74% <SEP> of <SEP> 66 <SEP> 1.7 <SEP> 26% <SEP> of <SEP> 61/66 <SEP> (1)
<tb> XIX <SEP> 75% <SEP> of <SEP> 66 <SEP> 1.7 <SEP> 25% <SEP> of <SEP> 61 / 6T <SEP> (2)
<tb>
 
 EMI28.8
 XX 75% of 66 1.7 25 of 61 / 6T (3) XXI 75% of 66 1.7 25 of poly (2) -mlthjlhexmethylene-terephthalamide 0.48
 EMI28.9
 
<tb> (1) <SEP> Ordinary <SEP> Copolymer <SEP> of <SEP> 95% <SEP> of <SEP> 61 <SEP> and <SEP> 5 <SEP>% <SEP> of <SEP> 66, <SEP> viscosity <SEP> inh <SEP> annuity <SEP> 0.56
<tb>
 
 EMI28.10
 (2) Ordinary copolymer of 70 /.

   of 61 and 3J of 6T, inherent viscosity 0.50 (3) ordinary copolymer of 95% of 61 and 5 Sl of 6T, inherent viscosity tu ,, 5

 <Desc / Clms Page number 29>

 
The filaments are put in the form of cords, and the permanent deformations are determined, according to the results shown in Table VI. This table also shows the flattening of tires containing the strings.
 EMI29.1
 

 <Desc / Clms Page number 30>

 



    TABLE VI Sample
 EMI30.1
 
<tb> xv <SEP> XVI <SEP> XVII <SEP> XVIII <SEP> XIX <SEP> XX <SEP> XXI
<tb> Tenacity, <SEP> grams / deny <SEP> 7.0 <SEP> 4.6 <SEP> 5.8 <SEP> 4.0
<tb> Elongation, <SEP>% <SEP> 12.0 <SEP> 12.0 <SEP> 12.0 <SEP> 10.0
<tb> Modulus, <SEP> grams / denier <SEP> 62 <SEP> 79 <SEP> 60 <SEP> 70
<tb> Permanent <SEP> deformation, <SEP>% <SEP> 1.07 <SEP> 0.78 <SEP> 0.64 <SEP> 0.98 <SEP> 0.92 <SEP> 0.88 < SEP> 1.70
<tb> Flattening, <SEP> mm <SEP> 2.54 <SEP> 3.43 <SEP> 3.12 <SEP> 3.86 <SEP> 3.73 <SEP> 3.66 <SEP> 5, 41
<tb>
 

 <Desc / Clms Page number 31>

 
It is interesting to note the effect of isomorphism in sample XXI.

   While one could have predicted, from the composition formula given above and in conjunction with Table VIII, a suitable flattening behavior for this mixture A, B with a content of also B. low than 15%, these polymers tend to be isomorphic. Thus, even with 25% B, the flattening is about the same as for homopolymer A alone. However, when the string of Example XXI is annealed lengthwise. constant temperature for three hours at 230 C, permanent set is reduced to approximately 1.00%.



   Likewise, the use of copolymer constituents in polyamide B which are individually isomorphic with polymer A is not as effective as one would expect. For example, increasing the proportion of 6T in copolymer B from 5% in sample XX to 30% in sample XIX does not produce a change in the value of the permanent set. in proportion to its very rigid mesh, since 6T is isomorphic with 66, the polymer A used in these examples.



  Likewise, higher proportions of 6T in copolymer B formed from 61 and 6T produce completely isomorphic blends with 66, and a corresponding increase in tire flattening.



   ExampleXVI
This example demonstrates the utility of 82% formic acid solubility as a criterion for establishing the suitability of melt-blended polyamide filaments for the purposes of the invention. Polyamide filaments are prepared in the manner described in Example VII.

 <Desc / Clms Page number 32>

 comprising 80% 66 and 20% 61. The melt mixing temperature is 295 ° C in each case. Different lengths of stay are used. The percent "permanent deformation" was determined as well as the flattening produced in 8.50 x 14 tires containing these cords The results are shown in Table VII.



   Each sample is tested, according to the following procedure, to determine the fraction soluble in 82% formic acid.



   A 1 g sample is dissolved in 10 cm3 of 98% formic acid, and the solution is thoroughly mixed with 75 g of sand passing through a sieve having a mesh size of 0.045 mm. The resulting mixture is dried at 35 ° C. in vacuo to remove the formic acid which served as the solvent. The sample is then placed in a glass column, and subjected to extraction (at room temperature) with 82% aqueous formic acid. The extraction is continued until no more polymer is extracted.



   The amount of polymer extracted is determined by evaporation of the solvent.



   TABLE VII
 EMI32.1
 
<tb> Sample <SEP> XXII <SEP> XXIII <SEP> XXIV <SEP> XXV
<tb>
<tb>
<tb>
<tb>
<tb> Duration <SEP> of the <SEP> stay, <SEP> minutes <SEP> 4.7 <SEP> 7.1 <SEP> 13.6 <SEP> 21.2
<tb>
<tb>
<tb>
<tb>
<tb> Permanent <SEP> deforantion,% <SEP> 0.88 <SEP> 0.92 <SEP> 0.94 <SEP> 1.05
<tb>
<tb>
<tb>
<tb> Flattening, <SEP> mm <SEP> 3.66 <SEP> 3.73 <SEP> 3.78 <SEP> 4.01
<tb>
<tb>
<tb>
<tb>
<tb>% <SEP> soluble <SEP> in <SEP> acid
<tb>
<tb> formic <SEP> to <SEP> 82% <SEP> 54 <SEP> 27 <SEP> 19 <SEP> 15
<tb>
<tb>
<tb>
<tb>
<tb>% <SEP> estimated exchange <SEP>
<tb>
<tb>
<tb> mutual <SEP> of <SEP> amides <SEP> 0.8 <SEP> 1.2 <SEP> 3.5 <SEP> 5.5
<tb>
 
It should be noted that Sample XXV, which is about 15% insoluble in 82% formic acid falls within the scope of the invention, exhibiting a kurtosis of 4,

  01 mm

 <Desc / Clms Page number 33>

 
The lower limit for the percentage of polyamide B in the mixture was represented here by the expression (4 SA2 + 24 SB2 - 2, + 8). The values of the expression 4 SA2 + 24 SB2 were calculated for each example, and are shown below.



   TABLE VIII
 EMI33.1
 
<tb> 1-IV <SEP> 16.0 <SEP> XI <SEP> 21.67 <SEP> XV <SEP> 25.42 <SEP> '<SEP>
<tb>
<tb> V-VII <SEP> 19.4 <SEP> XII <SEP> 11.66 <SEP> XVII <SEP> 11.82
<tb>
<tb> VIII-IX <SEP> 15.07 <SEP> XIII <SEP> 15.65 <SEP> XXI <SEP> 17.12
<tb>
<tb> X <SEP> 8.05 <SEP> XIV <SEP> 21.65
<tb>
 
As previously indicated, a tire cord can ultimately be prepared from polymetaxylylene adipamide homofilaments, but better flattening behavior is obtained when the homopolymer is melt mixed in accordance with the present invention. As would be expected, the value (8.05) of the expression 4S A2 + 24 SB2 for the mixture of Example X is lower than normal.



   It goes without saying that modifications can be made to the embodiments which have just been described, in particular by substitution of equivalent technical means without thereby departing from the scope of the present invention.

 

Claims (1)

CLAIMS. 1.- Filament which comprises a mixture of a first poly- {Imide having a T less than or equal to 120 C and a second polyamide having a Tg greater than or ± equal to 140 C, the second polyumide having a point of fusion less than 350 C. 2 .'- Filament according to claim 1, characterized in that the second polyamide is an aromatic polyamide. 3.- Filament according to one or 1'nuire of claims 1 and 2, characterized in that the second polyamide is present in an amount of 12 to 50% of the mixture. 4.- Filament according to one or the addition of claims 1 and 2, characterized in that the second polyamide is present at EMI34.1 resulting in (4 S + 24S - 2) at 80% of the mixture, SA and SB stain the permanent deformations of yarns obtained by spinning the first and the second polyamides, respectively. 5.- Filament according to one or the other of claims 1 to 4, characterized in that the first polyamide is poly- EMI34.2 hexumethylene-Lldipllmide. polyhexvm6thylene-sebacLJmide, polycapro-umide or polym6taxylylene-'f'dipmide, and the second polyamide is polyn1! 3tuph6nyleneadipumide, polyhexamethylen-isophtcalcamide, poly2, J / t, 6-. -mCtaphdnylène subertimide, polytrirnethylane-isophthalumide, polytetrumethylene-iaophtiJlJr, iide and ordint copolymers, ires uyont one of these uromltic polyamides as main constituent. 6. Filument according to claim 5, cl'ructri6é in that the mixture is partially insoluble in a solvent of the first polyamide, EMI34.3 7. Filament according to claim 6, c IJr / lct6riaé in that the first polyamide is palyhexamthyl: ne-td3p, mide, the second polyamide is polyhextim6thyl, no-isophtzltimidop and <Desc / Clms Page number 35> the mixture is at least 12% insoluble in 82% aqueous formic acid. 8. Filament according to claim 7, characterized in that the molten mixture is a block copolymer, the insoluble fraction of which consists of blocks having an average length of at least 10 polyhexamethylene-isophthalamide meshes. 9. A filament according to claim 1, in substance as described above, in particular in the examples. 10.- Cord for tires, manufactured from a certain number of filaments according to one or the other of claims 1 to 9. 11.- 'Process for preparing the filaments according to either of claims 1 to 9, which consists in mixing a first polyamide having a Tg less than or equal to 120 C with the second polyamide having a Tg greater than or equal to 140 C and a melting point less than 350 C, heating the mixture to the melting point of the mixture, then heating it to a temperature between 1 C above the melting point of the mixture and 350 C , and maintaining it at this temperature for a period ranging from 0 to 120 1/2 T-250/30 minutes, T representing the temperature at which the mixture is stirred and then spinning the molten mixture into filaments. 12. A method according to claim 11, characterized in that the filaments are stretched. 13.- Process according to one or the other of claims 11 and 12, characterized in that the polyamides are mixed in proportions such that there is (4 SA2 + 24 SB2 -2) to 80% of the second polyamide in the blend, S2 and SB being the permanent deformations of yarns obtained by spinning the first and second polyamide respectively. <Desc / Clms Page number 36> 14. A process for producing filaments, in substance, as described above, in particular in Examples I to XVI. 15.- Filaments obtained by the process according to any one of claims 11 to 14. 16. A cord for tires made up of filaments obtained by the process according to one or more of claims 11 to 14.