Classifications

• • D—TEXTILES; PAPER
  • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
  • D01F—CHEMICAL FEATURES IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS; APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OF CARBON FILAMENTS
  • D01F2/00—Monocomponent artificial filaments or the like of cellulose or cellulose derivatives; Manufacture thereof
• • D—TEXTILES; PAPER
  • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
  • D01F—CHEMICAL FEATURES IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS; APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OF CARBON FILAMENTS
  • D01F2/00—Monocomponent artificial filaments or the like of cellulose or cellulose derivatives; Manufacture thereof
  • D01F2/24—Monocomponent artificial filaments or the like of cellulose or cellulose derivatives; Manufacture thereof from cellulose derivatives
  • D01F2/28—Monocomponent artificial filaments or the like of cellulose or cellulose derivatives; Manufacture thereof from cellulose derivatives from organic cellulose esters or ethers, e.g. cellulose acetate
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/29—Coated or structually defined flake, particle, cell, strand, strand portion, rod, filament, macroscopic fiber or mass thereof
  • Y10T428/2913—Rod, strand, filament or fiber
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/29—Coated or structually defined flake, particle, cell, strand, strand portion, rod, filament, macroscopic fiber or mass thereof
  • Y10T428/2913—Rod, strand, filament or fiber
  • Y10T428/2933—Coated or with bond, impregnation or core
  • Y10T428/2964—Artificial fiber or filament
  • Y10T428/2965—Cellulosic

Definitions

• the invention relates to fibers of cellulose derivatives and fibers of cellulose. regenerated from these derivatives.
• cellulose derivatives is understood here to mean the compounds formed, following chemical reactions, by substitution of the hydroxyl groups of the cellulose, these derivatives also being called substitution derivatives.
• Cellulose means regenerated "a cellulose obtained by a regeneration treatment carried out on a cellulose derivative.
• the invention relates more particularly to cellulose formate fibers and cellulose fibers regenerated from this formate, as well as methods for obtaining them such fibers.
• Fibers made of cellulose formate and fibers of cellulose regenerated from this formate have especially been described in the international patent application WO 85/05115 (PCT / CH85 / 00065), filed by the applicant, or in the patents equivalents EP-B-179 822 and US-A-4 839 113.
• These documents describe obtaining spinning solutions based on cellulose formate, by reaction of the cellulose with formic acid and phosphoric acid. These solutions are optically anisotropic, that is to say, they have a liquid crystal state.
• These documents also describe the cellulose formate fibers obtained by spinning these solutions, using the so-called "dry-jet-wet spinning” technique, as well as cellulose obtained after a regeneration treatment of these formate fibers.
• the cellulose fibers of application WO 85/05115 are characterized by a structure much more orderly, due to the liquid-crystal nature of the spinning solutions from which they come. They thus have very high mechanical properties in extension, in particular very high values of tenacity and modulus, but, in counterpart, are characterized by rather low elongation at break values, these values being on average between 3% and 4%, and not exceeding 4.5%.
• the primary purpose of the invention is to provide cellulose formate fibers as well as regenerated cellulose fibers which, compared to the fibers of the WO application 85/05115, present a significantly improved elongation at break, as well as high energy properties at break.
• the second object of the invention is to obtain the above improvements without reducing the tenacity of the fibers, which is a major advantage of the invention.
• Another object of the invention is to obtain regenerated cellulose fibers from cellulose formate, the fatigue resistance of which, in particular in tires, is significantly improved compared to that of regenerated cellulose fibers of the WO 85/05115 cited above.
• Ds being the degree of substitution of the cellulose for formate groups (in%)
• Te being its toughness in cN / tex
• Mi being its initial modulus in cN / tex
• Ar being its elongation at break in%.
• Er being its energy at break in J / g.
• D S being the degree of substitution of the cellulose for formate groups (in%)
• T E being its toughness in cN / tex
• M I being its initial modulus in cN / tex
• a R being its elongation at break in%.
• E R being its energy at break in J / g.
• the cellulose formate fiber and the above regenerated cellulose fiber are both obtained through new and specific processes which constitute other objects of the invention.
• the spinning process of the invention to obtain the cellulose formate fiber from the invention, consisting in spinning an optically anisotropic solution of cellulose formate in a solvent with phosphoric acid base, according to the spinning method called "dry-jet-wet spinning", is characterized in that the fiber coagulation step and the neutral washing step of the coagulated fiber are both made in acetone.
• the regeneration process of the invention to obtain the regenerated cellulose fiber of the invention, consisting in passing a cellulose formate fiber according to the invention through a regenerating medium, washing it and then drying it, is characterized in that the medium regenerating agent is an aqueous sodium hydroxide solution (NaOH), the concentration of sodium hydroxide, denoted Cs, is greater than 16% (% by weight).
• the medium regenerating agent is an aqueous sodium hydroxide solution (NaOH)
• the concentration of sodium hydroxide, denoted Cs is greater than 16% (% by weight).
• the degree of polymerization is noted DP.
• the DP of the cellulose is measured so known, this cellulose being in powder form, or previously transformed into powder.
• IV The inherent viscosity (IV) of the cellulose in solution is first determined, according to Swiss standard SNV 195 598 of 1970, but at different concentrations which vary between 0.5 and 0.05 g / dl.
• the intrinsic viscosity [ ⁇ ] is then determined by extrapolation to concentration none of the inherent viscosity IV.
• DP (M w ) / 162, 162 being the molecular weight of the elementary motif of cellulose.
• the solution is first coagulated with water in a dispersing device. After filtration and washing with acetone, a powder is obtained which is then dried in a vacuum oven at 40 ° C for at least 30 minutes. After isolating the formate, the cellulose is regenerated by treating this formate at reflux with normal sodium hydroxide. The cellulose obtained is washed with water, dried and the DP is measured as described above.
• the degree of substitution of cellulose for cellulose formate is also called degree of formylation.
• the degree of substitution determined by the method described here gives the percentage of alcohol functions of the cellulose which are esterified, that is to say transformed into formate groups. This means that a 100% degree of substitution is obtained if the three alcohol functions of the cellulose motif are all esterified, or that a degree of substitution of 30%, for example, is obtained if 0.9 alcohol function out of three, in medium, is esterified.
• the degree of substitution is measured differently depending on whether one characterizes cellulose formate (formate in solution, or fibers in formate) or fibers in cellulose regenerated from cellulose formate.
• this formate is first isolated from the solution as indicated previously in paragraph I-1. If measured on formate fibers, cut beforehand these fibers in pieces 2 to 3 cm long.
• cellulose formate thus prepared is weighed with precision and introduced into an Erlenmeyer flask. 40 ml of water and 2 ml of normal sodium hydroxide are added (NaOH 1 N). The mixture is heated at 90 ° C. at reflux for 15 minutes under nitrogen. We thus regenerates the cellulose by retransforming the formate groups into groups hydroxyl. After cooling. excess soda is titrated back with a decinormal hydrochloric acid solution (0.1 N HCl), and the result is degree of substitution.
• a decinormal hydrochloric acid solution 0.1 N HCl
• the degree of substitution is noted Ds when it is measured on cellulose formate fibers.
• D S degree of substitution
• the isotropy or optical anisotropy of the solutions is determined by placing a drop of solution to study between crossed linear polarizer and analyzer of a microscope polarization optics, then by observing this solution at rest, that is to say in the absence of dynamic stress, at room temperature.
• an optically anisotropic solution is a solution which depolarizes the light, that is to say which presents, thus placed between polarizer and crossed linear analyzer, light transmission (colored texture).
• a optically isotropic solution is a solution which, under the same conditions observation, does not have the above depolarization property, the field of microscope remaining black.
• fibers is meant here multifilament fibers (also called “spun”), made up in a known manner of a large number of elementary filaments of low diameter (low titer). All the mechanical properties below are measured on fibers having been subjected to a preliminary conditioning. By “conditioning prior”means the storage of fibers for at least 24 hours, before measurement, in a standard atmosphere according to European standard DIN EN 20139 (temperature 20 ⁇ 2 ° C; humidity ⁇ 65 ⁇ 2%).
• the titer of the fibers is determined on at least three samples, each corresponding at a length of 50 m, by weighing this length of fiber. The title is given in tex (weight in grams of 1000 m of fiber).
• the mechanical properties of the fibers are measured in a known manner using a tensile machine ZWICK GmbH & Co (Germany) type 1435 or type 1445.
• the fibers after have received a small preliminary protection twist (helix angle of approximately 6 °), undergo traction over an initial length of 400 mm at a speed of 200 mm / min (or at a speed of 50 mm / min only when their elongation at the failure does not exceed 5%). All results given are an average of 10 measures.
• the tenacity (force-breaking divided by the title) and the initial modulus are indicated in cN / tex (centinewton per tex - reminder: 1 cN / tex equal to approximately 0.11 g / den (gram per denier)).
• the initial module is defined as the slope of the linear part of the curve Force-Elongation, which occurs just after the standard pretension of 0.5 cN / tex.
• the elongation at break is indicated as a percentage.
• the energy at break is given in J / g (joule per gram), that is to say per unit mass of fiber.
• Cellulose formate solutions are made by mixing cellulose, formic acid, and phosphoric acid (or an acid-based liquid phosphoric), as indicated for example in the aforementioned application WO 85/05115.
• Cellulose can be in various forms, in particular in the form of a powder, prepared for example by spraying a plate of crude cellulose. Of preferably, its initial water content is less than 10% by weight, and its DP included between 500 and 1000.
• Formic acid is esterification acid, phosphoric acid (or liquid based on phosphoric acid) being the solvent for cellulose formate, called “solvent” or “spinning solvent” in the description below. -after.
• the phosphoric acid used is orthophosphoric acid (H 3 PO 4 ), but it is possible to use other phosphoric acids, or a mixture of phosphoric acids.
• the phosphoric acid can, depending on the case, be used solid, in the liquid state, or dissolved in formic acid.
• the water content of these two acids is less than 5% by weight: they can be used alone or possibly contain, in small proportions, other organic and / or mineral acids, such as acetic acid, sulfuric acid or acid hydrochloric for example.
• the concentration of cellulose in the solution can vary widely measure; C concentrations between 10% and 30% (% by weight of cellulose - calculated on the basis of non-esterified cellulose - on the total weight of the solution) are for example possible, these concentrations being in particular a function of the degree of cellulose polymerization.
• the weight ratio (formic acid / acid phosphoric) can also be adjusted within a wide range.
• cellulose formate When making cellulose formate, the use of formic acid and phosphoric acid makes it possible to obtain both a high degree of substitution in cellulose formate, generally greater than 20%, without excessive reduction in the degree initial polymerization of cellulose, as well as a homogeneous distribution of these formate groups, both in the amorphous zones and in the crystalline zones of the cellulose formate.
• Kneading means suitable for obtaining a solution are known from those skilled in the art: they must be able to knead, knead properly, preferably cellulose and acids at an adjustable speed until the solution is obtained.
• solution means here, in known manner, a homogeneous liquid composition in which no solid particle is visible to the naked eye.
• Mixing can be carried out for example in a mixer with Z-shaped arms, or in a screw mixer continuously.
• These mixing means are preferably equipped with a device vacuum evacuation and a heating and cooling device allowing adjust the temperature of the mixer and its contents, for example to speed up dissolution operations, or to control the temperature of the solution being training.
• the spinning solutions thus obtained are ready to spin, they can be transferred directly, for example by means of an extrusion screw placed at the outlet of the mixer, to a spinning machine to be spun there, without further processing than usual operations such as degassing or filtration for example.
• the spinning solutions are spun according to the so-called “dry-jet-wet-spinning” technique: this technique uses a non-coagulating fluid layer, generally air, placed in outlet of the die, between the die and the coagulation means.
• the spinning solution is transferred to the spinning block where it supplies a spinning pump. From this pump spinning, the solution is extruded through at least one die, preceded by a filter. It is during the journey to the sector that the solution is gradually brought to the desired spinning temperature, generally between 35 ° C and 90 ° C, depending on the nature of the solutions, preferably between 40 ° C and 70 ° C. So we mean by "spinning temperature” means the temperature of the spinning solution at the time of its extrusion through the die.
• Each die can include a variable number of extrusion capillaries, which number can vary for example from 50 to 1000.
• the capillaries are generally of cylindrical shape, their diameter possibly varying for example from 50 to 80 ⁇ m (micrometers).
• a liquid extrudate made up of a variable number of elementary liquid veins.
• Each elementary liquid vein is stretched (see below spinning factor) in a non-coagulating fluid layer, before enter the coagulation zone.
• This non-coagulating fluid layer is in generally a layer of gas, preferably air, the thickness of which can vary from a few mm to several tens of mm (millimeters), for example from 5 mm to 100 mm, depending on the specific spinning conditions; in known manner, by thickness of the non-coagulating layer the distance between the underside of the channel, arranged horizontally, and the entrance to the coagulation zone (surface of the coagulating liquid).
• the coagulating medium used is acetone.
• Tc The temperature of the coagulating medium. noted Tc, is not a critical parameter for the implementation of the invention. For example, for spinning solutions containing 22% by weight of cellulose, it was observed that a variation in temperature Tc, in the entire temperature range from -30 ° C to 0 ° C, had practically no of incidence on the mechanical properties of the fibers obtained.
• a negative temperature Tc that is to say less than 0 ° C, will be chosen, and even more preferably less than -10 ° C.
• the temperature Tc will be chosen as much lower than the concentration C of the spinning solution will be lower.
• the level of spinning solvent in the coagulating medium is preferably stabilized at a level below 15%, even more preferably below 10% (% in weight of coagulating medium).
• the coagulation means to be used are known devices, composed by example of baths, pipes and / or cabins, containing the coagulating medium and in which the fiber circulates during formation.
• a coagulation bath is preferably used arranged under the die, at the outlet of the non-coagulating layer. This bath is generally extended at its base by a vertical cylindrical tube, called “spinning tube", in which passes the coagulated fiber and circulates the coagulating medium.
• the depth of the coagulating medium in the coagulation bath measured from the inlet of the bath up to the entry of the spinning tube, can vary from a few millimeters to a few centimeters for example, according to the specific conditions of realization of the invention, in particular according to the spinning speeds used.
• the coagulation bath can be extended if necessary by additional coagulation devices, by example by other baths or cabins, placed at the outlet of the spinning tube, by example after a horizontal reference point.
• the fiber is left in contact with the coagulating medium until a substantial part of the spinning solvent is extracted from the fiber.
• the invention will preferably be implemented so that the following two relationships are verified: Rs ⁇ 50%; ⁇ c ⁇ 2 cN / tex.
• the fiber is taken up on a device drive, for example on motorized cylinders.
• the speed of the spun product, on this drive device is called “spinning speed” (or call speed or training): this is the speed of travel of the fiber through the installation of spinning, once the fiber is formed.
• spinning speed or call speed or training: this is the speed of travel of the fiber through the installation of spinning, once the fiber is formed.
• FEF spinning stretch factor
• neutral washing we means any washing operation allowing all or almost all of the fiber to be extracted spinning solvent.
• patents or patent applications EP-B-220642, US-A-4,926,920, WO 94/17136, as in the aforementioned application WO 85/05115 page 72, examples II-1 and below
• the Applicant has found that the acetone used as a washing medium, despite a washing power which is, in known manner, significantly weaker than that of water, leads to fibers which, once completed (i.e. washed until neutral, then dried), properties very clearly improved, firstly with regard to their elongation at break, when compared to the fibers described in application WO 85/05115.
• the step of coagulating the fiber and the neutral washing step of the coagulated fiber must both be carried out in acetone.
• the temperature of the washing acetone is not a critical parameter of the process. he goes However, it is obvious that too low temperatures will be avoided in order to favor the washing kinetics.
• the temperature of the washing acetone denoted T1
• T1 will be chosen positive (by this is meant a temperature equal to or greater than 0 ° C), and even more preferably greater than + 10 ° C.
• uncooled acetone can be used, i.e. acetone at temperature ambient, the washing operation then preferably being carried out in an atmosphere controlled.
• washing means can be used, for example consisting of baths containing the washing acetone and in which the fiber to be washed circulates.
• the times of washing in acetone can vary, typically, from a few seconds to a few tens of seconds, depending on the specific conditions of implementation of the invention.
• the washing medium as well as the coagulating medium may contain all two of the constituents other than acetone, without the spirit of the invention being modified, provided that these other constituents are present only in minor proportion; the total proportion of these other constituents will preferably be less than 15%, more preferably less than 10% (% by total weight of coagulating medium or washing medium). More particularly, if water is present in the acetone of coagulation or washing, its content will preferably be less than 5%.
• the cellulose formate fiber is dried by any suitable means, in order to remove the washing acetone.
• the level of acetone leaving the drying means is adjusted to a rate less than 1% by weight of dry fiber.
• a drying temperature at least equal to 60 ° C. is used, more preferably between 60 ° C and 90 ° C.
• the method of the invention can be implemented in a very wide range of speeds of wiring, which can vary from several tens to several hundred meters at the minute, for example at 400 m / min or 500 m / min or more.
• the spinning speed is at least equal to 100 m / min, more preferably at least equal to 200 m / min.
• the washing step will preferably be carried out so that the rate residual spinning solvent in the finished fiber, i.e. washed and dried, does not exceed 0.1% to 0.2% by weight, relative to the weight of dry fiber.
• the cellulose formate fiber thus spun can also be sent directly to the means of regeneration, online and continuously, in order to prepare a fiber in regenerated cellulose.
• a process for regenerating a fiber into a cellulose derivative consists in treating this fiber in a regenerating medium so as to eliminate the almost all of the substituent groups (so-called saponification treatment), to wash the fiber thus regenerated and then dried, these three operations being in principle carried out in continuous on the same treatment line called "regeneration line".
• the regenerating medium usually used is a weakly concentrated aqueous sodium hydroxide solution (sodium hydroxide NaOH), do not containing only a few% soda (% by weight), for example from 1 to 3% (see par example PCT / AU91 / 00151).
• the filaments of the cellulose formate fibers (whether these are conforming or not to the invention) underwent partial, superficial dissolution, as soon as that the sodium hydroxide concentration reached and exceeded approximately 6% by weight, the medium regenerating then becoming a true solvent for cellulose formate.
• partial, superficial dissolution is completely detrimental to the mechanical properties of the fiber: presence of bonded filaments, drop in resistance of the attacked filaments, fiber washing difficulties, etc.
• the process of the invention for obtaining a regenerated cellulose fiber in accordance with the invention, by regeneration of a cellulose formate fiber, is characterized in that that the regenerating medium is a highly concentrated aqueous sodium hydroxide solution, of which the sodium hydroxide concentration, denoted Cs, is greater than 16% (% by weight).
• the regenerating medium is a highly concentrated aqueous sodium hydroxide solution, of which the sodium hydroxide concentration, denoted Cs, is greater than 16% (% by weight).
• a Cs concentration greater than 18% is used, and still more preferred, a concentration of between 22% and 40%; we have indeed found that such concentration ranges were, as a rule, more particularly beneficial to the elongation of the regenerated fiber, the area with an optimal concentration of between 22% and 30%.
• a cellulose formate fiber according to the invention having in particular an elongation at break Ar greater than 6%.
• the regeneration line consists concretely, and in a classic way, of regeneration means, followed by washing means, themselves followed by means of drying. All these devices are not critical for the implementation of the invention, and those skilled in the art will be able to define them without difficulty.
• the means of regeneration and washing may consist in particular of baths, pipes, tanks, cabins, in which circulate the regenerating medium or the washing medium. Cabins, for example, each with two cylinders can be used motorized around which the fiber to be treated is wound, this fiber then being showered with the liquid medium used (regenerating or washing).
• the residence times in the regeneration means will of course have to be adjusted so as to regenerate the formate fibers substantially, and thus to verify the following relationship on the final regenerated fiber: 0 ⁇ D S ⁇ 2.
• residence times which, depending on the conditions particular implementation of the invention, may vary for example from 1 to 2 seconds up to 1 to 2 tens of seconds.
• the washing medium is preferably water. Indeed, after the operation of above regeneration, the cellulose fiber can be washed with its swelling medium natural. that is to say with water, the latter having the best washing. Water is used at room temperature, or at a higher temperature, if necessary, to increase the washing kinetics. At this wash water can be possibly added a neutralizing agent for the soda not consumed, by example of formic acid.
• the drying means may consist, for example, of heated tunnels ventilated through which the washed fiber circulates, or in heating cylinders on which the fiber is wound.
• the drying temperature is not critical, and may vary over a wide range, in particular from 80 ° C to 240 ° C or more, depending on the specific conditions for implementing the invention, in particular according to the speeds of passage on the regeneration line. Preferably a temperature not exceeding 200 ° C.
• the fiber is taken from a take-up reel, and controls its residual humidity level.
• the conditions of drying temperature and time
• the humidity residual is between 10% and 15%, even more preferably in the range of 12% to 13% by weight of dry fiber.
• washing and drying times required vary by a few seconds to a few tens of seconds, depending on the means used and the conditions particular embodiments of the invention.
• the voltage constraints at the input of the regeneration means, washing means and drying means will preferably be chosen lower at 10 cN / tex. and even more preferably less than 5 cN / tex.
• the regeneration speed (denoted Vr), that is to say the speed of passage of the fiber to across the regeneration line, can vary from several tens to several hundred meters per minute, for example up to 400 or 500 m / min or more; so advantageous, this speed Vr is at least equal to 100 m / min, more preferably at least equal to 200 m / min.
• the regeneration method of the invention is preferably implemented in line and continuously with the spinning method of the invention, so that the entire production chain. from the extrusion of the solution through the die to drying of the regenerated fiber, or uninterrupted.
• test described below can either be tests in accordance with the invention, or tests not in accordance with the invention.
• a total of 14 spinning tests of cellulose formate fibers are carried out, according to the spinning method of the invention, and in particular conforming to the indications provided in paragraphs II-1 and II-2 above.
• the coagulation step and the neutral washing step of the coagulated fiber are all two carried out in acetone.
• Table 1 gives both the specific conditions for carrying out the process of the invention, and the properties of the fibers obtained.
• the DP of the cellulose in the solution is between 400 and 450, which shows in particular a weak depolymerization after dissolution.
• the values of Ds are between 25 and 50%.
• they are all between 30 and 45%: in practice, they are identical to substitution degree values measured on spinning solutions corresponding.
• their elongation at break Ar is greater than 7% (examples A-4 to A-6), even more preferably greater than 8% (examples A-5 and A-6).
• the neutral washing step of the coagulated fiber is carried out with water (as in WO 85/05115 cited above), and not with acetone.
• This water from washing is industrial water, at a temperature close to 15 ° C.
• the fibers contain 250 to 1000 filaments.
• Table 2 gives both the specific conditions for carrying out the process of the invention, and the properties of the fibers obtained.
• the abbreviations and the units used in this table 2 are the same as for the previous table 1.
• these fibers of table 2 may have characteristics quite interesting tenacity and initial modulus; in particular, after a stage of conventional regeneration according to the prior art (aqueous NaOH solution weakly concentrated), they can be transformed into regenerated fibers having very high toughness (110 to 120 cN / tex, or even more) combined with very high initial modulus values (3000 to 3500 cN / tex, or even more).
• a total of 23 regeneration tests of cellulose formate fibers are carried out, according to the regeneration process of the invention, according to the indications provided in paragraph II-3 above.
• the regenerating medium is an aqueous sodium hydroxide solution, the concentration Cs is in any case greater than 16%.
• Table 3 gives both specific conditions for carrying out the process of the invention, and the properties of the fibers obtained.
• their elongation at break A R is greater than 7% (examples C-4 to C-11, C-13 to C-16, C-19 and C-20), even more preferably greater than 8% (example C-4).
• the filamentary title (title of the fiber T I divided by the number N of filaments) is equal to approximately 1.8 dtex (decitex) (most common filamentary title for cellulosic fibers)
• the latter can vary to a large extent, for example from 1.4 dtex to 4.0 dtex, or even more, by adjusting the spinning conditions in known manner.
• the regenerated fibers of tests C-19 and C-20 have, respectively, a filamentary titer of 2.9 dtex and 3.6 dtex.
• an increase in elongation at break A R has been observed, combined with a decrease in the tenacity TE and in the initial modulus M I , when the filamentary title increases.
• a total of 9 regeneration tests of cellulose formate fibers are carried out. (referenced from D-1 to D-9), according to a regeneration process not in accordance with the invention.
• the regeneration conditions are the same as those used for the fibers in accordance with the invention of table 3 above, with one exception: the environment regenerating agent is an aqueous sodium hydroxide solution whose concentration of sodium hydroxide Cs is at most equal to 16%.
• Table 4 gives both the specific conditions for carrying out the process of the invention, and the properties of the fibers obtained.
• the abbreviations and the units used in this table 4 are the same as for the previous table 3.
• test C-12 the process of the invention made it possible to very significantly improve the toughness values (18% increase), elongation at break (33% increase), energy at break (55% increase), without any significant change in the initial module value.
• each filament is constituted at least in part by layers nested one in the others surrounding the axis of the filament; we also note that in each layer, general, the optical direction and the crystallization direction vary almost periodically along the axis of the filament.
• band structure is described commonly in the literature under the name of "band structure”.
• the fibers of regenerated cellulose of the invention have many other advantages when compared to the fibers described in basic application WO 85/05115 aforementioned on the one hand, to conventional fibers of the rayon type on the other hand.
• the fibers of the invention in particular have a very high fatigue strength appreciably improved, both in laboratory test and in pneumatic rolling.
• the fatigue resistance can be analyzed by submitting assemblies of these fibers in various known laboratory tests, including the fatigue test known as the "Disc Fatigue Test" (see for example US 2,595,069, standard ASTM D885-591 revised 67T).
• the fibers of the invention compared to the fibers of the basic application WO 85/05115, systematically show markedly improved endurance in the "Disc Fatigue Test".
• fibers according to the invention having an elongation at preferential breaking greater than 7% were assembled to form plied (type "A” and "B", respectively) having the same formula 180x2 (tex) 420/420 (t / m).
• such a formula means that each ply consists of two yarns (multifilament fibers), each having a count of 180 tex before twisting, which are first of all twisted individually at 420 rpm in one direction during a first step, then twisted the two together at 420 rpm in the opposite direction during a second step.
• the fatigue resistance of the regenerated fibers of the invention is therefore significantly improved - by a factor of two to three on average - compared with the regenerated fibers of the initial application WO 85/05115.
• the ability of technical fibers to reinforce tires can be analyzed, in a known manner, by reinforcing a sheet of rubber with twists of the fibers to be tested, previously glued, incorporating the fabric thus formed in a tire structure, for example in a carcass ply reinforcement, and then subjecting the tire as well reinforced with a rolling test.
• Such rolling tests are widely known to those skilled in the art, they can for example be implemented on automatic machines allowing to vary a large number of parameters (pressure, load, temperature ...) during driving. After rolling, the twists are extracted of the tire tested, and their residual breaking strength is compared to that control plies extracted from control tires which have not undergone the rolling.
• the fibers of the invention when used for reinforce a radial tire carcass, show endurance which is significantly improved compared to fibers according to WO 85/05115.
• the fibers of the invention (devious type "A” above) showed almost no lapse, even after tens of thousands of kilometers.
• the regenerated fibers of the invention have other characteristics quite apart from advantageous fact. compared to conventional rayon fibers.
• the moisture resistance of cellulosic fibers can be analyzed using various known tests, a simple test consisting for example of soaking the fibers completely in a water bath, for a determined time, then measure the breaking strength of the fibers in the wet state, by pulling them immediately out of the water bath after simply having them drained.
• the breaking strength in the wet state for the fibers of the invention, represents 80 to 90%, depending on the case, of the nominal breaking force (ie in the dry, measured as indicated in paragraph 1-4.).
• the nominal breaking force ie in the dry, measured as indicated in paragraph 1-4.
• rayon fibers it now only represents around 60% of the nominal breaking force.
• the fibers of the invention are therefore much less sensitive to moisture than conventional rayon fibers, they have better dimensional stability in a humid environment.
• the fibers of the invention can be assembled, as described previously, to form reinforcement assemblies at high or very high mechanical properties, in particular plies whose construction can be adapted to a very large extent depending on the intended application.
• an increase in torsion i.e. of the helix angle
• increases its elongation at break while being however detrimental to its toughness and its extension module.
• the fibers of the invention in the twisted state, have a toughness which is still greater than the toughness of fibers radiates not twisted.
• the toughness of the plies according to the invention are generally much greater than toughness on plies obtainable from rayon type fibers whose toughness hardly exceeds, in a known manner, 45-50 cN / tex before twisting. We can therefore use them in smaller quantities in articles usually reinforced with conventional rayon fibers.
• the fibers of the invention have an initial modulus which remains all very high (for example approximately 1500 to 2600 cN / tex in Table 3), in all cases very clearly superior to that of rayon fibers conventional (approximately 1000 cN / tex, in known manner).
• the improvement brought by the invention does not consist in a simple displacement towards another optimum of a given combination [tenacity-elongation at break], with an energy at break remaining substantially the same (total surface under the curve of Force-Elongation traction remaining substantially constant); it actually consists of a very noticeable improvement in any combination [toughness-elongation at rupture], allowing in a way to "extend" the Force-Elongation curves obtained for the fibers of the initial application WO 85/05115, and thus to obtain a very markedly improved energy at break (increased surface area under the curve Force-Elongation).
• cellulose formate used in this document covers cases where the hydroxyl groups of the cellulose are substituted by groups other than the formate groups, in addition to these, for example ester groups, in particular acetate groups, the degree of substitution of cellulose for these other groups being preferably less than 10%.
• the additional constituents can be for example plasticizers, sizes, dyes, polymers other than cellulose which may be esterified during the making of the solution. It can also be various additives making it possible, for example, to improve the spinability of spinning solutions, properties of use of the fibers obtained, the adhesiveness of these fibers to a matrix of rubber.
• the invention also covers the cases where a chain consisting of one or more is used.
• a chain consisting of one or more is used.

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• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• General Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Textile Engineering (AREA)
• Artificial Filaments (AREA)
• Tires In General (AREA)
• Yarns And Mechanical Finishing Of Yarns Or Ropes (AREA)
• Polysaccharides And Polysaccharide Derivatives (AREA)
• Chemical Or Physical Treatment Of Fibers (AREA)

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• 1995
  • 1995-08-10 FR FR9509905A patent/FR2737735A1/fr active Pending
• 1996
  • 1996-08-05 ES ES96927680T patent/ES2156619T3/es not_active Expired - Lifetime
  • 1996-08-05 DE DE69612863T patent/DE69612863T2/de not_active Expired - Fee Related
  • 1996-08-05 AT AT96927680T patent/ATE201241T1/de not_active IP Right Cessation
  • 1996-08-05 WO PCT/EP1996/003444 patent/WO1997006294A1/fr active IP Right Grant
  • 1996-08-05 EP EP96927680A patent/EP0848767B1/fr not_active Expired - Lifetime
  • 1996-08-05 US US09/011,423 patent/US6093490A/en not_active Expired - Lifetime
  • 1996-08-05 CA CA002226305A patent/CA2226305C/fr not_active Expired - Fee Related
  • 1996-08-05 AU AU67419/96A patent/AU701914B2/en not_active Ceased
  • 1996-08-05 BR BR9610076A patent/BR9610076A/pt not_active IP Right Cessation
  • 1996-08-05 JP JP50811997A patent/JP3941836B2/ja not_active Expired - Fee Related
  • 1996-08-05 CN CN96197243A patent/CN1077614C/zh not_active Expired - Fee Related
  • 1996-08-05 RU RU98103987/04A patent/RU2169217C2/ru not_active IP Right Cessation
• 2000
  • 2000-04-05 US US09/544,249 patent/US6261689B1/en not_active Expired - Lifetime
• 2006
  • 2006-11-28 JP JP2006320139A patent/JP4034808B2/ja not_active Expired - Lifetime

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