DE2343543A1 - METHOD OF PRODUCING FIBERS - Google Patents

Description

CROWN ZELLERBACH INTERNATIONAL INC., San Francisco, U.S.A.

Process for making fibers

The invention relates to a process for the production of fibers with a quality which these fibers for the production of Makes paper or similar flow paths suitable.

There are already various methods for producing such fibers are known, which work in such a way that a Mixture of a synthetic fiber-forming polymer in .einer vaporizable liquid is sprayed in a flash ("flashing"). When the mixture is sprayed in a flash, it is passed through a nozzle under increased pressure into a zone expands with lower pressure, the temperature of the liquid before the expansion is such that the liquid boils, i.e. at least part of the liquid evaporates under the reduced pressure. Procedure in whose

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Carrying out a solution of the polymer in a solvent to form fibers will be flashed in the U.S. Patent 3,081,519, British Patent 1,262,531 and DT-OS 1,958. Process which, when carried out, results in a dispersion A molten polymer are flashed in water, are the subject of US Pat. No. 3,402,231 and French Pat. No. 1,350,931.

In order to obtain a fiber with a quality that is better than the fibers produced by the known processes A method has been proposed which consists of creating an "emulsion" which is the polymer, a solvent for the polymer and water it contains to flash. In this context, reference is made to GB-PS 1 323 174, DT-OS 21 44 as well as the DT-PS .. .. ... (Patent application P 22 49 604.4 pointed out. When performing this known emulsion flash process the flashed liquid contains water as a continuous phase in which droplets of the solvent are dispersed, which forms a disperse phase.

The object of the invention is to create a method for Manufacture of polymer fibers, which leads to fibers that can be used in an excellent and simple manner for the manufacture of paper suitable, whereby a paper with very good properties is obtained. The invention is based on the knowledge that the fibers, obtained by flashing an emulsion of polymer, solvent and water are better when the solvent is the continuous phase and water is the disperse phase compared to the case where water is the continuous phase Phase and the solvent represents the disperse phase.

A reverse (water-in-oil) emulsion, in which water is the disperse phase, is generally more difficult to prepare than the emulsions normally used in emulsion technology, which are oil-in-water emulsions. It has been found that it is possible to prepare and flash water-in-oil emulsions which contain a polymer, the flashing of such an

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inverted emulsion leads to very good fibers.

It is surprising that when flashing a water-in-oil emulsion, which contains a polymer, the product obtained from relatively discrete fibers rather than continuous strands. The known processes tend to be continuous Strands are formed, which turn out to be a fibrous product that is to be used for the production of flow sheets, not suitable.

The method according to the invention consists in first mixing to form the 1. a polymer and 2. an organic liquid, which the polymer is able to dissolve or swell, and 3. contains water, to form, and to form the mixture at a temperature flash that is at least so high that the polymer is swollen by the liquid, the flashing from a zone increased pressure takes place in a zone of lower pressure. The organic liquid evaporates and the polymer falls in the form of fibers which can be broken up relatively easily and processed into paper webs by conventional methods. The method according to the invention is characterized in that the water with the polymer and the organic liquid is mixed in such a way that the water is dispersed in the form of droplets in a continuous phase, which consists of the polymer and the organic liquid.

Preferably, the polymer is dissolved in the liquid so that the mixture formed in the first process stage and which is flashed in the second stage of the process, consists of an emulsion in which the water is dispersed Phase and the solution represents the continuous phase.

The polymer is preferably a thermoplastic Polymer. In particular, the invention can be used for the production of fibers from a polyolefin.

For reasons that cannot yet be explained, the after

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the fibers produced according to the invention are superior Properties compared to fibers obtained by flashing a comparable mixture in which the polymer solution is the dispersed phase in water.

In the following, the properties are compared in more detail, However, it should be noted that compared to fibers that have been produced in this way that a comparable Mixture is flashed, in which water represents the continuous phase, according to the method according to the invention produced fibers have a larger surface, a higher drainage factor and higher strength, whereby paper sheets are obtained, which also improved through Characteristics distinguish. These improved fiber properties are not only surprising but also very remarkable as such fiber properties are essential to satisfactory papermaking pulp. A bigger one The surface gives the fiber a greater degree of whiteness and gloss as well as better adsorption properties. Improved Strength properties, for example improved breaking strength, tear resistance, pick resistance, etc. also contribute contributes to the fact that these fibers are in even stronger competition with natural ones Cellulose pulps.

Furthermore, fibers can be obtained by the process according to the invention which have a relatively low content of polymer lumps and fiber bundles. A low level of Polymer lumps and fiber bundles are essential in connection with a use of the fibers for the production of some types of paper, such as printing papers, as roller printing in the papermaking process, these clumps and bundles can cause transparent stains in the paper result.

The polymer which is used to carry out the process according to the invention is used, is preferably a thermoplastic fiber-forming polymer (under the term "fiber-forming" is to understand a polymer that, in compliance with the usual spinning

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methods to form fibers). It is preferable to be crystalline or to use partially crystalline polyolefins, for example low-pressure (Ziegler-Natta) polyethylene, isotactic or partially isotactic polypropylene and ethylene / propylene copolymers. Polybutenes and polymethylpentene are others Examples of polyolefins that can be used to practice the invention. Crystalline or partially crystalline Polyamides and polyesters can also be used. Non-crystalline polymers such as polycarbonates, polysulfones, Polyvinyl chloride, polymethyl methacrylate, polyacrylonitrile and polystyrene can be used. Mixtures of the substances noted above or with other polymers can also be used.

The preferred polyolefins are those that have an intrinsic viscosity of about 0.7 dl / g. Polyethylene has a viscosity average molecular weight of approximately 30,000 to 40,000.

The ones used to carry out the process according to the invention Polymers can be used in the form of a dried powder or in the form of pellets, but they will preferably in the form of a wet cake, slurry or solution of the polyolefin in the reaction solvent used, i.e. in a form as it is obtained after the polymerization.

In general, any substituted or unsubstituted aliphatic, aromatic or cyclic hydrocarbon, the is a solvent for the polymer at elevated temperatures and pressures and is relatively inert under the operating conditions is to be used as the organic liquid for carrying out the process according to the invention, this hydrocarbon preferably has a boiling point at atmospheric pressure which is lower than the softening point of the polymer, and which is substantially immiscible with water or which forms a polymer solution which is substantially water

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is not miscible. The solvent can be liquid or gaseous at room temperature and atmospheric pressure. Preferably it is liquid at standard temperature printing conditions, otherwise the system must be pressurized after the flash zone. Examples of solvents that can be used are aromatic hydrocarbons, for example benzene, toluene, aliphatic hydrocarbons, for example butane, pentane, hexane, heptane, octane as well as their isomers and homologues, alicyclic hydrocarbons, for example cyclohexane, chlorinated hydrocarbons, for example methylene chloride, carbon tetrachloride, ethyl chloride and methyl chloride, higher alcohols, esters, ethers,

Ketones, nitriles, amides, fluorinated compounds (for example fluorocarbons, nitromethane and mixtures of these Solvents as well as from these solvents with other solvents.

The polymer / solvent / water mixture according to the invention can can be formed by one of several methods depending on the water concentration. A method can be derived from a solution to the Run out of polymers in a solvent, such as those obtained in a solution polymerization process, either with the same concentration of the polymer in the solvent, in dilute or concentrated form, whereupon the water of the solution is added or the reverse is done. In general, hot water is used in carrying out such a method, to prevent precipitation of the polymer. Alternatively, from a slurry of polymer particles in the Run out of solvent, as is the case when performing a slurry polymerization method is generated ', the corresponding amount of water is added to the slurry or vice versa is proceeded. Another alternative is from a dry polymer powder or granules or a wet cake, as obtained in the step of solvent removal in a polymer plant, the Appropriate amounts of solvent and water can be admixed with the dry polymer in any order.

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_ "7 -

As will be explained below, it is advantageous if the solvent is present before the addition of the water, since the addition of water to the solvent and not the reverse Measure ensures that the solvent or the polymer solution forms the continuous phase of the mixture to be formed, This latter measure is important when you have a such an amount of water is used that approaches the limit of an inversion occurring, i.e. near the point at which the amount of water is that amount which forms the continuous phase. If the amount of water is significantly below the boundary line at a reversal that occurs, in particular below 30 percent by volume, based on the mixture Any suitable mixing method or order of addition of the materials can be used or adhered to.

The polymer concentration relative to the solvent is not critical. The solvent is present in an amount greater than 100% by weight of the polymer and is sufficient to have a viscosity at the maintained dissolution temperature to be adjusted so that simple handling is possible, i.e. a viscosity of less than 5OO poises. In general, the polymeric concentration will vary from about 2 to about 30 weight percent of the Solvent plus polymer and is preferably between about 5 and about 15%. ■

One of the functions of water is temperature to reduce the fibrous mass in the zone immediately adjacent to the nozzle. The addition of water increases the total vapor pressure of the system so that its boiling point is decreased.

However, as a practical matter, water should be in an amount of at least about 1% and preferably above 10%, based on the volume of the mixture of solvent and water, can be used. By lowering the boiling point of the mixture, the temperature of the fibrous mass that is formed during flashing is reduced. In this way-

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the properties of the phase obtained in terms of a Use for paper production improved.

Another function of water is to act as a carrier for a hydrophilic water dispersant for those to be formed Fibers to act. It has been found to be very beneficial to use a water dispersant during flashing and to use the precipitation of the fibrous polymer. Albeit the presence of the water dispersant is a favorable one Influence on those produced by the process according to the invention Exerts fibers, the best remedies are those that are not suitable for a water-in-oil emulsion suitable to be considered. Nevertheless, hydrophilic water dispersants are preferred in the mixture prior to flashing. An equivalent amount of the same agent that was added to the fibers already formed at a later date does not give the same degree of fiber friability. Therefore, the water should be in such an amount that which is sufficient to carry that amount of the hydrophilic agent which is used to remove the fibrous To impart the desired degree of water dispersibility to polymers, preferably as a solution thereof. More water above such a minimum amount required to carry the agent can be used to to impart a suitable viscosity to the aqueous solution or the dispersant, i.e., the aqueous solution of the water dispersant should not be so viscous as to cause problems with handling or incorporation into the polymer solution appear as a dispersed phase. The water can also help reduce the viscosity of the mixture to a level which is below the level of the polymer solution alone, so that higher polymer concentrations are possible. In general the viscosity of the aqueous solution and / or the mixture should be below approximately 500 poises at the Temperature.

Another function of water is to generate energy (enthalpy)

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to make available in order to evaporate the solvent to contribute during the flashing, which is not expedient, to choose the temperature so high, so that enough energy is given up to the solvent alone to cause its complete evaporation. However, the amount of water should not be so be large that excessive amounts of heat must be invested to achieve the desired flash temperature. Do you have that Amount of water determined for a suitable viscosity, then additional water can be used to a certain extent, as it helps to reduce the viscosity of the mixture and to encourage solvent evaporation, but it does so the amount of additional water added need not be large.

The amount of water which is required to fulfill the functions indicated above is always below the amount which, when used, results in a conversion, ie at which water must become the continuous phase of the mixture. One condition necessary to ensure that the organic liquid or solution is the continuous phase is that the amount of water in the mixture is quite low. If the amount of water is more than about 70%, it is very difficult to form a water-in-oil emulsion. Even with somewhat smaller amounts of water, for example with an excess of 60% water, every common mixing method tends to produce an oil-in-water emulsion. As the amount of water decreases, it becomes easier to form a water-in-oil emulsion. To prepare mixtures in which the water tends to be more stable as a continuous phase, it is useful to use special mixing methods so that water becomes the less stable discontinuous phase. Corresponding methods are known in emulsion technology and are described, for example, in Volume 8 of Kirk-Othmer ¹ s "Encyclopaedia of Chemical Technology", 2nd edition.

A preferred method that is used is an i. ^T ater-in-oil

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To produce an emulsion in which the amount of water is sufficient that either the water or the organic liquid is continuous Phase can be, is to slowly add the water to the liquid, so slowly that even no local excess of water compared to the organic liquid and the emulsion already formed at the point of addition is present. The mixture is stirred so that the water is broken up into droplets when it is added. .You can Dose the addition of water in such a way that the electrical conductivity of the organic liquid is measured, whereupon the conductivity is monitored in order to adjust the rate of addition with stirring such that the conductivity is less than twice the initial conductivity.

It is appropriate to use such mixing methods, when carried out, the water about 30 percent by volume or more of the mix. If the amount of water used is approximately 30 percent by volume or more, it is appropriate to do so first to form a solution of the polymer and the solvent and then add the water of this solution with vigorous stirring to add. In this context, the term “polymer solution” is to be understood as meaning the swollen or dissolved mixture which is obtained when the solvent is mixed with the polymer, usually at an elevated temperature. It is also advisable to stir the entire mass of the mixture continuously both during and after the addition of the water. The mixing vessel or the mixing device can be designed in such a way that uniform and vigorous stirring is possible, with a corresponding vessel design, baffles and appropriate stirring methods may be mentioned. In this way, spots with little agitation that cause a phase inversion can be avoided cause can be avoided.

This mixing is preferably carried out when both the water and the polymer solution are relatively hot. Conveniently, the polyite should be dissolved at one temperature lie above the melt release temperature. The water to be added

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water should have a temperature which is so high that the mixture during or after the addition of water above the melt solution temperature remains. This method helps prevent phase inversion during the addition of water.

If the water and polymer solution phases are allowed to separate during or after the addition of the water, then can a phase reversal take place. It is therefore appropriate to add the water at such a rate that phase separation is avoided, with vigorous stirring during and after the addition of the water for the same purpose, As previously mentioned, the water is preferably added gradually at such a rate that it becomes rapidly uniform is mixed with the polymer solution. The water should therefore not be added faster than it is in the form of droplets is dispersed in the continuous polymer / solvent phase.

If the mixture contains about 30% or less water, then preferably a water-in-oil emulsion is formed. It is then it is not necessary to add the water to the organic liquids. At low water concentrations you can even mix the two liquids and then stir them, or the solution (or a slurry of the polymer particles in one organic liquid) to the water.

When carrying out Examples 1 to 6 described below, in which the water concentration is only 16%, were no special mixing methods observed. When carrying out experiment 1 according to example 7, where the water concentration is 40% the water was gradually added to the solution. Water concentrations in the order of 40 to 50% are preferred when carrying out the method according to the invention, however, care must be taken to ensure that the water is the discontinuous phase.

When carrying out a continuous flashing, in which a part of the mixture formed in this way by a

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23A3543

If the nozzle is flashed, additional amounts of polymer solutions and water can be added continuously while stirring the remaining Mixture are added in the appropriate proportions given above in order to maintain the water as a continuous phase of the mixture.

One of the features of the invention is that it is not necessary to form a stable "emulsion" so that there is no need to use emulsifying agents. However, the invention provides for the use of agents in the mixture with the aid of which the water dispersibility of the fibrous polymer formed during flashing is improved. These agents are preferably water-soluble or partially water-soluble high molecular weight materials. However, they can also be materials that are soluble or partially soluble in the solvent. Some of these agents can technically be classified as "emulsifying agents", but they are used only in an amount sufficient to impart the required degree of dispersibility and not in amounts which are generally required to form a stable emulsion. Since the water dispersants must be somewhat hydrophilic, they are not of the type normally used to form a water-in-oil type emulsion, i.e., a hydrophobic (lipophilic) emulsifier with a relatively low HLB (hydrophilic -lipophilic balance) to form a water-in-oil emulsion. The amount of water dispersant employed can vary between 0.1 and about 15 percent by weight of the polymer, and preferably between about 0.1 and about 5 percent by weight. The preferred Wasserdispergierungsmittel is a polyvinyl alcohol having a degree of hydrolysis of more than about 77%, and preferably greater than about 85% and a viscosity (in a 4% aqueous solution at 20 ⁰ C) of more than about 2 centipoises. The polyvinyl alcohol is preferably added with the water at the time the mixture is formed. Examples of other water dispersants used

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are cationic guar gum, cationic starch, Potato starch, methyl cellulose and Lytron 820 (a styrene / maleic acid copolymer).

The ingredients of the mixture can be placed in any suitable vessel which is heated to an elevated temperature and can be pressurized. An autoclave is generally used. It is important, however, that the one used The vessel is equipped with a mixing or stirring device, which keeps the mixture in a constant state of stirring because otherwise no stable emulsion is formed and the mixture quickly turns into two different ones when standing and separates separate phases.

The ingredients are then heated to a suitable temperature and stirred to form a mixture in which water as a discontinuous or dispersed phase within a continuous phase of the polymer solution is present. The temperature maintained is preferably above the melt dissolution temperature of the polymer in the solvent used. The melt dissolution temperature of any polymer in a solvent is determined in such a way that low concentrations of the polymer (for example 0.1 and 1.0% by weight) in the solvent can be filled into a vial, which is then sealed and placed in an oil bath. The temperature of the oil bath is slowly increased (for example at 10 ° C / hour) until the last traces of polymer disappear. This temperature is the melt release temperature. In some cases it can be useful be to work at a temperature below the melt release temperature. In these cases the polymer should at least are in a swollen state.

The maximum temperature maintained should be below the critical one Temperature of the solvent and / or the decomposition temperature of the polymer lie. However, it is preferable keep slightly lower temperatures. In the case of polyethylene and polypropylene, it is preferable between approximately 120 ° C and about 180 ° C and especially between about

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130 ° C and 160 ° C to work.

The one set in the vessel containing the heated mixture Pressure is preferably essentially autogenous pressure. Prints that are significantly higher than your own prints are not necessary. For a given nozzle design, higher pressures can result in poor fiber formation. It may be appropriate to use an inert gas such as nitrogen during flashing to reduce the rate of the mixture through the nozzle at a fairly constant value. The flashing is preferably carried out by a Nozzle which, according to its definition, is designed to be elongated and not by a sharp-edged opening which, by definition does not have a longitudinal dimension as it has been found to be very useful to impart a shear effect to the mixture (especially the polymer component of the blend), and although immediately before flashing. Such a shearing action promotes fiber formation and improves the fiber properties in relation to papermaking. The nozzle can have a circular or non-circular cross-section. For example, it can be a ring.

The flashing is carried out in such a way that the mixture of polymer, solvent and water through the nozzle into a Zone with deeper pressure is sent. Preferably the pressure of the lower pressure zone is substantially atmospheric or below, since as the pressure increases, the temperature of the fibrous product increases as it is formed. In general the pressure of the emulsion should be in a zone before flashing

2 lower pressures below about 3.5 kg / cm (50 psig) and before

2 are preferably below about 1.0 kg / cm (15 psig).

The flashing is essentially done adiabatically, it however, it can be varied somewhat.

During flashing, the polymer becomes fibrous in the form of "Noodles" failed. These noodles are loose

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Fiber aggregations that are sometimes continuous.

According to a preferred embodiment of the invention

2 low pressure water vapor (less than about 1.4 kg / cm) fed to the fibrous noodles in the post-flash zone to Stripping the remaining solvent from the fibrous noodles. This can be done in a tank or preferably in a line that is directly connected to the nozzle.

The fibrous noodles are collected in a suitable receptacle, preferably one of these receptacles Separation of the evaporated solvent permitted.

When carried out on a technical scale, the fibrous Pasta with water to a suitable consistency of less than about 5% and preferably less than 2% by weight diluted and then sent through a disc refiner in the form of an aqueous slurry to form the fibers to transfer that is optimal for papermaking. The shredding of the fibrous noodles has the separation of discrete Fibers and can also be used to control the length of the fibers. Multiple passes through the refiner. are generally appropriate. Treatment of the fibrous noodles in a disc refiner is, however not mandatory.

After defibering, the fibers can be used in a suitable manner Consistency can be diluted and processed into synthetic paper webs, either alone or in a mixture with conventional cellulosic papermaking fibers. Optionally, the fibers can be dewatered, compressed into bales, stored and be sent to the end user.

Although a feasible method has been described above, when carried out the mixture of Polymers ^ solvent and water in a suitable container

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is produced, it is still possible to produce the mixture on a continuous basis in such a way that the Polymer solution with superheated water continuously in a device connected in series immediately before flashing is mixed through the nozzle.

A determination of whether the water is in a discontinuous phase or a continuous phase can be made as follows carry out. The mixture is made under the conditions normally observed in terms of temperature, pressure and extent of stirring. Electrodes made up of two conductive metals that extend over a distance of approximately 12mm or more separated are immersed in the liquid mixture. The electrodes are connected to the poles of a battery tied together. The signals generated are recorded by a recording device that is in rows with the electrodes is switched. The signal generated is directly proportional to the conductance of the mix. A trace amount of an ionizable Materials such as sodium chloride can be used in the water to increase its conductivity. If water is the discontinuous phase, a very low conductance or a zero conductance is determined, i.e. approximately the same conductivity as the polymer / solvent phase of the mixture.

To produce the desired water-discontinuous mixture the agitation speed of the mixture is suitably high enough to reduce the conductivity of the mixture to approximately to maintain the conductivity of the polymer solution phase. Similarly, in the preparation of such mixtures, in which the water concentration is expediently so high that a water-continuous system favors will, the water of the polymer solution at such a rate be added so that the conductivity of the mixture is kept approximately at the conductivity of the polymer solution phase,

Other suitable methods of determining whether a

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Oil-in-water or water-in-oil type emulsion has been obtained is, on pages 146 and 147 in Volume 8 of the Kirk-Othmar Encyclopedia of Chemical Technology, 2nd revised edition, 1965, described.

example 1

The dissolution vessel used to conduct this example is a 3040 liter tank lined with glass and provided with baffles with a centrally located 7.5 HP Stirrer with two turbine-like stirrer elements attached to it, provided with four blades. The lower turbine is located at a height of 686 mm (tip to tip) and the upper turbine at a height of 483 mm (tip to tip). Of the The stirrer is kept running during the experiment. 228 60 gallons (1) water gas 1 wt% polyvinyl alcohol (Monsanto Gelvatol, viscosity of 4 - 6 CP and 87.7 - 89% hydrolyzed), based on the weight of the to be used Polyethylene are added to the tank, followed by the addition of 45.4 kg of a high-density polyethylene with an intrinsic viscosity of 1.4 dl / g and a melt index of 5.5 (Mitsui 22OOP). The vessel is sealed, whereupon 1140 liters (300 gallons) of η-hexane are added. The water: hexane volume ratio in the mixture is 1: 5 and the polyethylene concentration 40 g per liter of hexane. The contents of the vessel are then heated to 130 to 135 ° C and pressurized to 8.4 kg / cm (120 psig). One valve The bottom of the jar is then opened, whereupon the mixture is passed through a 127 mm long 76 mm line to a Valtek angle control valve is fed, which has an opening with a diameter of 9.5 mm and a length of 7 mm. A nipple-shaped plug in the valve opening forms one Annular space with the wall of the opening. · The valve is approximately in the one-quarter open position operated. The mixture flows through the annulus that forms the flash nozzle at one rate of 180 g polyethylene per minute. The mixture

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is flashed into a line with a diameter of 50 mm.

At a distance of about 152 mm after the nozzle, low-

2 pressurized steam at a pressure of 0.7 kg / cm (10 psig) was introduced into the 25 mm line to strip off the solvent that was not previously flashed from the fibrous noodles. At a distance of approximately 5.4 m (18 feet) from the nozzle, the 25 mm line opens into a steam separation kettle from which the vapors are withdrawn at the top. Hot dilution water at a temperature of 85 ° C is introduced at the top of the steam separation kettle in an amount of approximately liters (5 gallons) per minute. The water as well as the fibrous noodles fall to the bottom of the steam separation vessel and are fed to a Jones double disc refiner (305 mm discs) at a temperature of 80 to 90 ° C and a consistency of about 1%, the one with brush-like plates (Jones type 1, 1, 1.5, + 10 °). The disks are operated at 2117 rpm with a clearance of 0.1 mm + 0.1 mm (0.04 + 0.004 inches). The fibers are sent four times in total by the refiner, wherein the second up to 4 passes at a material temperature of 4O to 50 ⁰ C. Additional Gelvatol 20-30 polyvinyl alcohol (based on the weight of the polyethylene) is added to the material tank in an amount of 1% by weight, after which the material is sent through the refiner a fifth time. The plates are set to 25 + 0.1 mm (0.010 + 0.004 inches). The polyethylene fibers have the following fiber fractionation when tested according to the TAPPI standard test T 233 su.

20th Tabel 1A C. • 13th Jewich 35 10.3 Mesh 65 33.8 on 150 23.8 on 270 17.4 on by 27O 5.0 on 9.7 on 4098 12/11

The fibers have a drainage factor of 0.24 sec / g.

Some of the fibers obtained are tested according to the TAPPI standard test

T-205 m-58 modified wet grouting (28 kg / cm (400 psig)) as well as in compliance with a heat binding level (121 ° C at minmalem Print) processed into a test sheet. Another part of the fibers is made with a bleached Alder Kraft pulp (50/50) mixed with a Canadian standard degree of freedom of 410 ecm, after which hand sheets were produced using the same method will. The hand sheets obtained are tested, with the following results being determined:

characteristic

2 weight per unit area g / m density, g / cem
Opacity,%

Gloss,% (Elrepho No. 8) fracture length, m

Tensile energy absorption _ (= toughness), kg-cm / cm

Inner bond, Scott units

Tear Strength, g / sheet

Table 1B 50% blend 100% 61.2 61, 2 0.48 0.36 78.9 83.4 84.4 . 88.9 2416 139

0.06

14th
6th

34.3

90 28

Another part of the polyethylene fibers is bleached with a Alder Kraft pulp with a Canadian standard degree of freedom of 410 ecm blended to produce a feed that Contains 40% by weight of polyethylene fibers and 60% by weight of kraft fibers. The mixture obtained is fiberized by means of a Jordan. This creates an entry with a standard Canadian grind of 250 ecm, which is processed into paper on a paper machine. The paper machine is in operated in such a way that at two stages there is a thermal bond

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(107 and 135 ° C on the arch) takes place. The received paper webs have the following properties:

Tabel characteristic 1C Heat wrap igstemper 107 ° C 135 ° C 2
Basis weight, g / m 66.6 63.3 Thickness, mm 0.132 0.11 Density, g / ccm 0.504 0.573 Tear Strength, g / sheet 23 24 MD 26th 27 Tensile strength, kg / 15 mm XD 2.93 3.11 MD 1.49 1.70 Strain, % XD 1.6 1.7 MD 3.5 3.8 Tensile energy absorption "
(= Toughness), kg-cm / cm XD 0.019 0.020 MD 0.025 0.032 Convolution (MIT) XD 3 7th MD 2 3 Stiffness, g / cm (Taber) XD 1.17 0.96 MD 0.46 0.45 Inside Scott Tie
kg-cm / cm ² χ 10 ~ 3 XD 152 285 Smoothness, cc / min.
(Sheffield) 328
352 327
293 Porosity, ccm / min.
(Sheffield) WS
FS 249 278 oil absorption,% 45 32 Sugar coloring, seconds 0 2.1 WS 0 1.6 Gloss,% (Elrepho No. 8) FS 85.4 80.9 Opacity,% 80.4 69.1 Scattering coefficient 408 253 Fracture length, m 2931 3271 MD 1492 1786 XD

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Remarks:

WS = wire side; MD = machine direction; FS = felt side; XD = cross machine direction; Thickness = the one under a certain pressure using a certain device is determined.

When carrying out the above example and the following examples, the basis weight, the thickness, the tear resistance, the folding and the density of the hand sheets are determined according to the TÄPPI standard method T-220. In the event of of the sheets which have been produced on a paper machine, the basis weight was determined according to the TAPPI standard method T-410, the thickness according to the TAPPI standard method T-411, the Tear strength according to the TAPPI standard method T-410, the folding according to the TAPPI standard method T-511 and the density according to the TAPPI standard method T-426. The tensile strength, the elongation, the tensile energy absorption and the breaking length Both the hand sheets and the sheets produced on the machine were determined according to the TAPPI standard method T-494) . The stiffness of both blades was determined according to the TAPPI standard method T-489-70. The Elrepho No. 8 shine Both sheets were determined according to the TAPPI standard method T-525. The smoothness was postponed in the case of both sheets using TAPPI routine comparison method No. 285. The oil absorption was determined for both films using the TAPPI routine comparison method 26 (9166). The opacity and the scattering coefficient were determined for both films using TAPPI standard method T 42 5 determined.

Other tests emerge from the machine that is used to carry out the tests, all tests in the paper industry are known. The drainage factor closely related to the hydrodynamic surface area of the fibers and has an even closer relationship with the drainage properties of the fibers used in papermaking as to the gas absorption surface, was determined essentially according to TAPPI test method T221 OS-63, the calculation method having been subjected to a slight modification.

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Approximately 10 grams of the fiber sample was weighed and dispersed in water. The slurry was then converted to the standard sheet shape and water was added. The slurry was stirred by four up and down strokes of the standard stirrer, which is then removed. The water temperature the mold was measured and the drain valve opened. The time between the opening of the valve and the first sucking noise is noted. The method is then repeated with only water (no fibers) in the platform, whereby the temperature and the drainage time are noted. The drainage factor in seconds per gram is then as follows calculated:

DF = Fd + 0.3 (.-. - 1) (D

- 4) 7 - / d + 0.3 4 * ¹ > (d - 4) 7 - ' ^{L V} T J

wherein

DF = drainage factor, sec./g

D = drainage time with the pulp in the mold, seconds

d = drainage time with no pulp in the mold, seconds,

V = viscosity of the water at temperature T

W = weight of fibers used to perform the test, g

The amount (^ - 1) is in the TAPPI described above

τ
Test T221 OS-63 listed in a table. This amount is multiplied by 0.3. This value was determined empirically for the present fibers.

Example 2

The procedure described in Example 1 is repeated, but with the following exceptions;

a) The polyethylene concentration is 80 g / l,

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b) the mixture is passed through the nozzle at a rate of 250 g / min, sent,

c) the fiberization conditions are as follows:

1) the first pass takes place at 80 to 90 C with a plate spacing of 0.1 now (0.004 inch),

2) the 2nd to 6th pass takes place at 40 to 50 ° C with a 0.1 mm (0.004 inch) spacing between plates.

No further polyvinyl alcohol is added.

The fibers obtained have the following fiber fractionation:

Table 2A Mesh wt%

on 20 6.4 on 35 33.5 on 65 29.2 to 150 17.4 to 270 6.3 through 270 7.2

The dewatering factor of the fibers is 0.46 sec./g.

Hand sheets are produced as in Example 1, one group containing 100% polyethylene fibers and one group is made from a 50/50 blend with the bleached Alder Kraft pulp described in Example 1. The properties are as follows:

409812/1113

characteristic

Basis weight, g / m density, g / ccm
Opacity,%

Gloss,% (Elrepho No. 8} fracture length, m

Tensile energy absorption ₂ (= toughness), g-cm / cm inner bond, Scott units tear strength, g / sheet

Table 2B 50% blend 100% 63.4 63.5 0.44 0.36 84.7 90.3 86.0 92.2 2036 145 29.8 0.06 82 units 25 30th 3

Some of the fibers are made with the bleached Alder Kraft fibers according to Example 1 (4O wt .-% polyethylene fibers, 6O wt .-% Kraft fibers) are mixed and formed into a paper web on a paper machine processed in compliance with two thermal bonding temperatures. The properties of the webs obtained are as follows:

40981 2/1113

Table 2C

characteristic

Basis weight, g / m thickness, mm
Density, g / ccm Tear Strength, g / sheet

Tensile strength, kg / 15 mm elongation,%

Tensile energy absorption (= toughness), kg-cm / cm

Convolution (MIT) stiffness, g / cm (Taber)

Inner Scott bond kg-cm / cm ^ χ 10 ^ Smoothness, cc / min. (Sheffield)

Porosity, ccm / min. (Sheffield) oil absorption,% sugar coloring, sec.

Gloss (Elrepho No. 8) Opacity,%
Break length, m thermal bonding temperature

135 ° C

63.3

0.11

0.573

3.11

1.70

1.7

3.8

0.020

0.032

0.96

0.45

285

327

293

278

32

2.1

1.6

80.9

69.1

3714

1900

107 ° C 66.6 0.132 0.504 MD 23 XD 26th MD 2.93 XD 1, 49 HD 1.6 XD 3.5 MD 0.019 XD 0.025 MD 3 XD 2 MD 1.17 XD 0.46 152 WS 328 FS 352 259 45 WS 0 FS 0 85.4 80.4 MD 3155 XD 1553

409812/1113

Example 3

The procedure described in Example 1 is repeated with the following exceptions:

a) The polyethylene concentration is 8O g / l,

b) the mixture is sent through the nozzle at 150 g / minute and

c) the fiberization conditions are as follows:

1) the first pass takes place at 80 to 90 ° C with one Plate spacing of 0.05 + 0.1 mm (0.002 + 0.004 inch)

2) the second to the sixth pass are carried out at 20 ° C with a plate spacing of 0.05 + 0.1 mm (0.002 + 0.004 inch). No further polyvinyl alcohol is added.

The fibers obtained show the following fiber fractionation:

Table 3A Mesh weight on 20 2.3 on 35 21, 2 on 65 32.7 to 150 26.2 to 270 9.0 through 270 8.6

The dewatering factor of the fibers is 1.10 sec./g.

According to the method described in Example 1, hand sheets are prepared, one group containing 100% polyethylene fibers and a group of a 50/50 blend with the bleached Alder Kraft fibers according to Example 1 is made. It will found the following properties:

409812/1113

Table 3B
Property TOO% 50/50 mixture

62.2 62.3 0.41 0.50 93.7 88.2 93.7 88.4 305 2534

Weight per unit area _t
Density, g / ccHi
Opacity _r %

Gloss, % (Elrepho No. 8)
Fracture length, m

Train energy loss

(= Toughness, kg-cm / cm ² ) 2.4 47.6

Inner binding, Scott units 20 82

Tear strength, g / sheet 5 29

Some of the fibers are mixed with the bleached Alder Kraft fibers described in Example T (40% by weight polyethylene fibers, 60% by weight Kraft fibers) and processed into a paper web on a paper machine in two heat bonding stages according to Example 1. The properties of the sheet obtained
are as follows;

/, 09812/1113

Table 3C

23435A3

characteristic

2 weight per unit area, g / m thickness, mm
Density, g / ccm Tear Strength, g / sheet

Tensile strength, kg / 15 mm elongation,%

Tensile energy absorption

(= Toughness), kg-cm / cm ²

Convolution (MIT)

Stiffness, g / cm (Taber)

Inner Scott bond kg-cm / cm ² 10 smoothness, ccm / min. (Sheffield)

Porosity, ccm / min. (Sheffield) Oil Absorption,% Sugar Color, Sec.

Gloss,% (Elrepho No. 8) Opacity,%
Break length, m thermal bonding temperature

107 ° C 135 ° C 60.3 59.9 0.130 0.118 0.461 0.504 MD 31 31 XD 33 36 MD 2.85 3.65 XD 1.39 1, 8O MD 1.6 1.7 XD 3.8 3.5 MD 0.019 0.025 XD 0.027 0.034 MD 5 12th XD 2 7th MD 1.2 1.1 XD 0.51 0.56 147 466 WS 329 363 FS 325 346 265 400 53 35 WS 0 14.6 FS 0 16.9 87.4 79.5 85.9 65.4 MD 3152 4068 XD 1543 2108

098 12- / 1.31

Example 4

To carry out this example, a Benco Model 575 is used as the vessel used to prepare the mixture for flashing

2 3.8 liter reactor used with a 10.5 kg / cm (150 psi) Steam jacket, an inlet and outlet for nitrogen and a centrally arranged air-operated drive shaft is provided with a mechanical seal. A blade turbine with six stepped blades with a diameter of 100 mm (Bench Scale Equipment Co.) becomes approximately Mounted on the shaft 125mm from the bottom of the kettle while a high shear propeller positioned approximately 87.5 mm below the turbine. The vessel comes with four equally spaced vertical Provide guide plates. The vessel is then fitted with an electrode equipped, which consists of a piece of metal wire, which is passed through one end of a short glass tube to form a seal is. The other end of the wire is threaded through a stainless steel tube with an outside diameter of 6.2 mm (1/4 inch) 300 mm (ί2 inch) in length, followed by the glass tube and metal tube using a Swagelok tube fitting get connected. The electrode is inserted into the vessel in such a way that the wire is above the Water level of the mixture described below. The wire is connected to a wire of an ohm meter in rows with the battery switched. The stainless steel sleeve held by the wire by insulating it along its entire length separated by a distance of about 15 mm therebetween is connected to the other pole. You can see that that The signal for salt water alone is approximately 140 mV, while the signal for η-hexane alone is approximately 0 to 1.0 mV will. Starting from the bottom of the vessel, an 18.7 mm tube with a ball valve extends 15 mm below of the bottom of the vessel. Directly next to the ball valve there is a nozzle, which consists of a brass plug with a length of 104 mm with a centrally drilled hole with a diameter of 3.5 mm. Of the

Q 9 8 1 2/1 1 1 3

Nozzle plug is inserted into the 18.7 mm pipe, which extends a distance of approximately 300 mm (12 inches) from the nozzle and protrudes into the atmosphere. The vessel is filled with 500 ml of water, 25OO ml of η-hexane, 100 g of polyethylene (Mitsui 22OOP, described in Example 1), 2 g of GeI-vatol 20-30 polyvinyl alcohol and 20 drops of a 25% aqueous sodium chloride solution are charged. The vessel is sealed and purged with nitrogen, whereupon the contents are heated to a temperature between 145 and 150 ° C. It will the stirrer operated at 650 rpm. The contents are kept at 145 to 150 ° C for 1 and 1 1/2 hours in order to be complete Ensure dissolution of the polymer. The conductivity of the mixture is between 0.4 and 1.2 mV, which shows that that water is a discontinuous phase. The ball valve is then opened and the mixture is sent through the nozzle will. The pressure in the vessel is kept constant by supplying nitrogen. The fibrous product is made by Impact collected on a wire mesh screen. The fibers are defibrated in such a way that they pass through at room temperature sent a Sprout Waldron single disc refiner with 300 mm plates (12 inch plates) (Sprout Waldron Pattern C-29-78-B) be, with this disc refiner with 2800 rpm at a Work plate spacing of 0.05 mm (0.002 inch). There are a total of four rounds.

The fiber fractionation of the fibers obtained is as follows:

Tabel Mesh 4A Wt% on 20 2.2 on 35 18.8 on 65 35.3 to 150 24.6 to 270 9.5 through 270 9.6

409812/1113

The dewatering factor of the fibers is 4.3 sec./g.

Hand foils are made as in Example 1, one group containing 100% polyethylene fibers and the other from a 50/50 blend using those described in Example 1 bleached Alder Kraft fibers. The characteristics are as follows:

Table 4B

characteristic

2 weight per unit area, g / m density, g / ccm

Opacity,%

Gloss,% (Elrepho No. 8) Tensile energy absorption (= toughness), g-cm / cm ² Inner Scott bond, kg-cm / cm ² χ 10 ~ ³ Tear strength, g / sheet Tensile strength, kg / 15 mm elongation,%

100%

50/50 mix

58.6 63.3 0.35 0.55 95.3 89.5 95.3 88.4

0.009

0.06

76.7 271.0 8.8 29.6 0.54 3.4 3.4 3.7

Example 5

Example 4 is repeated with the exception that the polyvinyl alcohol omitted from the mix. The conductivity of the mixture is the same as in Example 4. The stirring is briefly interrupted to check the electrode. The conductivity rises quickly to around 100 mV, from which a phase separation can be recognized. After resuming stirring, the conductivity quickly returns to 0.4 back to 1.2 mV. The mixture is kept at 140 ° C for half an hour and then through the nozzle under one

2
steady pressure of 11.5 kg / cm (165 psi) sent. Which he-

098 1 2/1113

The fibers produced cannot be frayed or made into handsheets unless they are mixed with 15% by weight, based on the fibers, of Gelvatol 20-30 polyvinyl alcohol treated in an aqueous slurry. the After the treatment, fibers are defibrated as in Example 4 and have the following fiber fractionation:

Tabel Mesh 5A Wt% on 20 0.8 on 35 11.7 on 65 34.1 to 150 31.4 on 27O 14.0 through 270 8.0

The fibers have a drainage factor of 16.5 sec./g.

Hand sheets are prepared according to the method described in Example 1, one group consisting of 100% polyethylene fibers and the other from a 50/50 blend with the bleached Alder Kraft fibers is prepared according to Example 1. The characteristics are as follows:

. .-- · :: · ^ c 409812/1113 ORIGINAL INSPECTED

no / ο c; /, ο

- 33 -

characteristic

Thickness, / U

Weight per unit area, kg / 279 m Density, g / ccm

Opacity,%

Gloss,% (Elrepho No. 8) Tensile Energy Absorption, ft-lb / ft Inner bond, Scott units tear strength, g / sheet tensile strength, kg / 25 mm Strain, %

Fracture length, m

Tabel 5B 100% 50/50 mix 137 104 16.5 16.4 2 0.43 0.57 94.8 89.4 94.3 89.0 1.85 2.98 -lb / ft ² 60 102 nuances 16.0 33.0 1.43 4.81 6.0 3.4 955 3255

Example 6

The procedure described in Example 4 is repeated, using polypropylene with an intrinsic viscosity of 1.7 dl / g (Hercules Profax 6301) is used. When carrying out an experiment, the mixture contains 500 ml of water, 2500 ml n-hexane, 200 g polypropylene and 2 g Gelvatol 20-30 polyvinyl alcohol. The mixture is heated to 140 ° C and on this Maintained temperature for one hour prior to flashing. A second attempt, the same as the first attempt is identical, is carried out with the exception that polypropylene is used in an amount of 100 g. A third experiment, identical to the two experiments, is carried out with the exception that the temperature of the mixture heated to 175 to 180 ° C before flashing. In all cases a fibrous product is obtained.

40981 2/1113 ^ NAL INSPECTED

2343-43

Example 7 (comparative example)

Two attempts are made to identify the fibrous products, which have been produced according to the invention (experiment 1) to compare with the fibrous product that under equivalents Fibermaking conditions have been established but using a flash mix in which water is the continuous phase (Experiment 2).

To carry out these two experiments, a 10 liter vessel surrounded by a steam jacket is used, which an inlet and an outlet for nitrogen, an electrode for measuring conductivity and a centrally located one has vertical agitator shaft with a mechanical seal. A blade turbine pumping upwards with a diameter of 100 mm (4 inches) is now attached to the shaft 50 from the bottom of the Attached to the tube. Two straight vane propellers with a diameter of 100 minutes (4 inches) are attached to the shaft Attached 150 or 250 mm above the bottom of the vessel. One after below pumping turbine with a diameter of 1OO mm (4 inch) and a 3 inch diameter pumping down turbine are 350 and 450 mm above the shaft, respectively attached to the bottom of the vessel. Three vertical baffles are attached in radial positions equidistant inside attached to the vessel wall. üü

This configuration makes stirring of the whole mixture and avoids i points at which only a slight stirring action "'is present. These points could favor the establishment of a continuous water phase.

A pipe with a diameter of 18.7 mm (3/4 inch) protrudes from the bottom of the vessel, which has a 18.7 mm (3/4 inch) Has ball valve, which is located 50 mm below the boiler bottom. Located immediately next to the ball valve a nozzle made of a brass plug with a length of 28 mm with a centrally drilled hole with a through-

4098 12/1 1 1 3 ORIGINAL INSPECTED

knife of 1.78 mm. The nozzle plug is inserted into a tube with an inner diameter of 18.7 mm (3/4 inch) and a length of 240 cm introduced. This tube extends into a flash tank that is kept under atmospheric pressure.

The materials used to produce the flash mix to carry out the two experiments are the same 48OO ml n-hexane, 384 g polyethylene (Mitsui Hyzex 5000P, intrinsic viscosity 2.0), 3200 ml of water and 7.7 g of Gelvatol 20-30 polyvinyl alcohol (88% hydrolyzed, molecular weight 10,000). The manner in which this flash mixture is formulated from these materials is, however, different when carrying out the two experiments.

To carry out experiment 1 (example according to the invention) the vessel is first charged with the solvent and the polymer and then sealed and flushed with nitrogen, whereupon the contents are heated to and at about 144 C is held while the stirrer is at 1000 rpm approximately 2 hours to ensure complete polymer dissolution. Then the PVA dissolved in the water in a separate vessel. This solution is heated to approximately 144 ° C. The heated solution then becomes introduced under pressure into the vessel containing the heated polymer solution at a rate of approximately 5OO ml per minute. This slow and gradual rate of addition has the consequence that the water is dispersed in the Phase passes over in the mixture and remains as such phase. While the water containing PVA is being added, the stirrer is turned off in the vessel containing the polymer solution to 1000 rpm held. Stirring of this mixture is continued for a period of 15 minutes, followed by conductivity of the mixture is measured and found to be approximately 0 mV. This shows that the water is a discontinuous phase is present in the mixture *.

To carry out Experiment 2 (comparative example), the

40981 2/1113

Formulation of the flash mixture according to that described in Example 4 Method carried out, i.e. that the vessel used to carry out Experiment 1 with all materials at room temperature is filled, whereupon this mixture is heated and stirred under the conditions described in Experiment 1, about the polymer dissolution and dispersion of the PVA containing Effect of water. After stirring between 110 and 140 ° C during a period of 2 hours the conductivity this mixture measured and found to be more than 100 mV, from which it can be seen that the water is the continuous phase and the polymer solution is the discontinuous phase.

When performing each of experiments 1 and 2, the The mixture formed in the manner described is then heated to 144 ° C. and at this temperature and under pressure of 11.2 kg / cm (160 psi) according to that described in Example 4 Way flashed. The flashed material is defibrated using the apparatus described in Example 4 with the Exception that the refiner plates used had a Sprout Waldron pattern P-29-76-B. The fraying will be at a consistency carried out in water of approximately 3%. The settings between the plates are as follows: 1st passage 6.4 mm, 2nd passage 0.6 mm, 3rd passage 0.3 mm, 4th and more Passages 0.05 mm. The flashed material, which is obtained from each attempt, is frayed in this way for as long as until the fibrous product reaches a classified fiber length (CFL) of approximately 1.2 mm. Part of the Product from each experiment is then further defibrated using this method to produce a fibrous product with a classified fiber length (CFL) of 0.8 mm. The properties of these fibrous products as well as the properties of hand sheets made from these products (see Example 1) are measured and compared, with the following results can be obtained.

4098 12/1113

Table 7A

Fiber properties

characteristic

Products with approximately
0.8 mm CFL

Attempt 1 Attempt 2

Products with approximately
1.2 mm CFIL

Attempt 1 Attempt 2

Classified fiber length (CFL), mm

Fiber fractions

% on 20 mesh screen% on 35 mesh screen% through 150 mesh screen

Roughness, Decidrex surface, m ² / g
Drainage factor, sec./g

0.78

0.88

1.6
21, 0
23.0 0.8
25.4
17.8 12.6 10.9 9.48 8.64 31.6 9.2

1.17

1.16

14.9
31.6
14.2 6.9
41.3
12.2 I. 13.7 19.5 U)
"O
I. 8.94
16.2 8.64
6.7

CSF = Canadian standard grind

Table 7B

Properties of handsheets

Hand sheets made from 100% polyethylene fibers with
approximately
0.8 mm CFL

Hand sheets made from 100% polyethylene fibers, approximately 1.2 mm

CPL hand sheets made from% polyethylene fibers with a thickness of approximately 0.8 mm CFL and 50% bleached Aider-Kraft fibers

Hand sheets made from 50% polyethylene fibers, approximately 1.2 mm CFL and 50% bleached Alder-Kraft fibers

O
CO
OO

Property Verr

search 1 search 2

Density,
g / ccm

0.484 0.407

Tear Strength, g / sheet 48.0 22.4

Length of fracture, m 1855 859
Elongation,% 18.8 9.5

Tensile energy absorption,

kg-cm / cm ^

Inner bond,

Scott units
(metric)

0.169 0.042

153

105

Attempt attempt 1 seek

0.416 0.381

47.2 23.2

1346 758

13.0 8.6

0.087 0.029

102

110

Attempt 1

0.604

40.8 2914 3.6

171 attempt

0.549

35.2 2621

3.6

0.044 0.04

169

Try Try 1 try

0.539

173

0.518

48.8 35.2 2763 2505 3.0 3.4

0.036 0.036

172

A comparison of the fiber properties as well as the hand sheet properties of the fiber products according to Experiments 1 and 2, which are defibrated to essentially the same classified fiber length clearly show that the fiber products produced according to the invention (Experiment 1) are clearly superior to the products are obtained by flashing a comparable mixture in which the water is continuous Phase represents (experiment 2) »The dewatering factor of the fiber-like products produced according to the invention is noticeable larger, the same applies to the strength properties of hand sheets, which are made from such fiber products will. Bundles of fibers and lumps of polymer in such products are also at an acceptably low level.

098 1 2/1113

Claims (2)

- 40 claims 1. Process for the production of polymeric fibers, in which Performing first a mixture is formed, the water, the polymer and an organic liquid, which the polymer able to dissolve or swell contains, and then the mixture of a zone of increased pressure is flashed into a zone of lower pressure, whereby the organic liquid evaporates and the polymer in shape is precipitated by fibers, characterized in that the water with the polymer and the organic liquid to disperse the water as droplets in a continuous phase of the polymer and the organic liquid is mixed. 2. The method according to claim 1, characterized in that the polymer is dissolved in the solvent and the water in the solution is dispersed. 3. The method according to claim 1 or 2, characterized in that the mixture water in an amount of less than 3O percent by volume, based on the mixture, is added. 4. The method according to claim 2, characterized in that water of the mixture in an amount of 30 or more percent by volume, based on the mixture, is added, the amount of water being sufficient that the water the continuous phase forms, and a solution of the polymer in the organic liquid is stirred while the water is added to the solution at a slow rate. 5. The method according to any one of the preceding claims, characterized in that the mixture also has at least one partially water-soluble dispersant for the fibers to be formed in an amount of about 0.1 to 15% by weight, based on the polymer, is added. 409812/1113 6. The method according to claim 5, characterized in that the dispersant used is predominantly hydrophilic. 7. The method according to claim 6, characterized in that the dispersant used consists of a polyvinyl alcohol with a degree of hydrolysis of more than about 77% and a viscosity in a 4% aqueous solution at 20 ⁰ C of more than about 2 centipoises. 8. The method according to any one of the preceding claims, characterized in that the polymer used is at least one partially crystalline polymer and in an amount between about 2 and about 3O wt .-%, based on the Solvent plus polymer. 9. The method according to claim 8, characterized in that the polymer is a polyolefin. 10. The method according to claim 9, characterized in that the polyolefin is a polyethylene or polypropylene, the one Has intrinsic viscosity greater than about 0.7 dL / g and in an amount between about 5 and 15 weight percent, based on on the solvent. 11. The method according to any one of the preceding claims , characterized in that the solvent has a boiling point below the pressure of the zone of lower pressure which is lower than the melting range of the polymer. 12. The method according to claims 9 and 10, characterized in that that the mixture is heated to a temperature between about 120 and 160 ° C. 13. The method according to any one of the preceding claims, characterized characterized in that the mixture in the second stage at a temperature above the melt dissolving temperature of the Polyolefin is flashed, this temperature being below 4098 12 / 1113- the critical temperature of the solvent and below is the decomposition temperature of the polyolefin, and furthermore, the flashing under autogenous pressure or under a higher pressure Printing is carried out. 14. The method according to any one of the preceding claims, characterized characterized in that A) a solution is formed which consists of 1) an at least partially crystalline polyolefin and 2) a substantially water-immiscible organic solvent for the polyolefin in an amount between 7O and 98%, based on the total weight Polyolefin and solvent, B) the solution is water at a temperature above the melt dissolution temperature of the polyolefin and in an amount between 3O and 7O % By volume based on the mixture is added while the solution is being stirred to such an extent that that the water is dispersed therein as a dispersed phase, C) the mixture thus formed with stirring a temperature above the melt dissolution temperature and under autogenous pressure or above is maintained and D) the mixture is passed through a nozzle into a zone of lower pressure. 40981 2/1113