DE2343543C2 - Process for the production of polymeric fibers - Google Patents

Description

The invention relates to a method of manufacture of polymeric fibers of a quality which makes these fibers suitable for the manufacture of paper or similar flow webs.

Various processes for producing such fibers are already known which operate in such a way that a mixture of a synthetic fiber-forming polymer is sprayed in a flash in an evaporating liquid. When the mixture is sprayed in a flash, it is expanded through a nozzle under an increased pressure into a zone with lower pressure, the temperature of the liquid being such before the expansion. that the liquid boils, ie that at least a part of the liquid evaporates under the reduced pressure. Process in which a solution of the polymer in a solvent is carried out with the formation of bevels? Is sprayed like lightning, are described in US-PS 3081519. in GB-PS! 262531 and in DE-OS 1958609. Method, a dispersion of a geschmolzeneti polymers are sprayed in a flash in water at ^r de en embodiment, are the subject of US-PS 3402231 and FR-PS 1350931st

To get a fiber with a quality that is better than the fibers that can be produced by the known processes, a process has been proposed which consists in an emulsion, which contains the polymer, a solvent for the polymer and water, to be sprayed in a flash. In this Connection is to GB-PS 1323174. DE-OS 2144409. DE-PS 2249604 and the Japanese Patent publication JA 7232133 published in CPJ-Basic Abstracts Journal 1972 is noted. In the Carrying out this known emulsion evaporation process, the liquid sprayed like a flash 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 provide a Process for the production of polymeric fibers, in which fibers are obtained which are excellent Way to produce paper with very good properties.

This object is achieved by the invention according to the patent claim.

The invention is based on the knowledge that those Fibers made by spraying an emulsion of polymer, solvent and water are better if the solvent is the continuous phase and water is the disperse phase is, as fibers that are obtained from a system in which water is the continuous phase and the Solvent represents the disperse phase.

A reverse emulsion (water-in-oil) in which Water is the disperse phase. is generally more difficult to make than the emulsions which normally are can be used in emulsion technology, which are oil-in-water emulsions. It has been found that it is possible to use water-in-oil emulsions to produce and to spray in a flash that contain a polymer, the spraying of a such reverse emulsion results in very good fibers.

It is surprising that when a water-in-oil emulsion containing a polymer is sprayed, the product obtained consists of relatively discrete fibers and not of continuous strands. The known Processes tend to form continuous strands which siuii as a fibrous product used for Production of nonwoven webs is to be used, not suitable.

The method according to the invention counts first to form a mixture, the 1. a polymer and 2. a organic liquid which is able to dissolve or swell the polymer and which contains 3. water, and spray the mixture at a temperature which is at least that high. that the polymer is swollen by the liquid, the spraying off a zone of increased pressure takes place in a zone of lower pressure. The organic liquid evaporates in the process and the polymer precipitates in the form of fibers which are relatively easily frayed and made into paper webs according to conventional methods Methods can be processed. A characteristic of the method according to the invention is the fact that the water mixes with the polymer and the organic liquid in such a way is that the water is dispersed in the form of droplets in a continuous phase that emerges from the Polymers and the organic liquid.

The polymer is preferably dissolved in the liquid, so that the mixture formed in the first process stage is formed, and which is sprayed in the second stage of the process, consists of an emulsion, in which the water is the disperse phase and the solution is the continuous phase.

The polymer is preferably a thermoplastic polymer. In particular, can apply the invention to the manufacture of fibers from a polyolefin.

For reasons that cannot be explained at the present time, those produced by the process according to the invention have Fibers have superior properties compared to fibers obtained by spraying a comparable mixture in which the polymer solution is the dispersed phase in water.

The properties are compared in more detail below, but it should be noted that im Compared to fibers that have been produced in such a way that a comparable mixture is sprayed, in which water represents the continuous phase produced by the process according to the invention Fibers have a larger surface area, a higher drainage factor and higher strength, whereby sheets of paper are obtained, which are also

ίο characterized by improved properties. These improved Fiber properties are not only surprising, but also very remarkable because such fiber properties are essential to satisfactory papermaking pulp. Gives a larger surface the fiber a greater degree of whiteness and a higher gloss as well as better adsorption properties. Improved strength properties, for example improved breaking strength, tear resistance, pick resistance etc. also contribute to the fact that this bevel ·, η in competition with natural cellulose pulps can be even stronger.

Furthermore, according to the invention. procedure Fibers are obtained which have a relatively low content of polymer lumps and fiber bundles.

A low content of polymer lumps and fiber bundles is essential in connection with the use of the fibers in the manufacture of some types of paper, for example printing papers, as roller printing can cause the paper making process to that these lumps and bundles give transparent spots in the paper.

The polymer that is used to carry out the invention Process is used, is preferably a thermoplastic fiber-forming polymer (under the The term "fiber-forming" is to be understood as meaning a polymer which, in compliance with the usual spinning methods, produces fibers can form). It is preferable to use crystalline or partially crystalline polyolefins, for example Low pressure (Ziegler-Natta) -Polyäthjien. isotactic or partially isotactic polypiopylei. s ^ like ethylene; Propylene copolymers. Polybutenes and polymethylpentene are further 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 given above or with other polymers can also be used. The preferred polyolefins are those that have a Have an Instrinsic viscosity of approximately 7 cm 'g. Polyethylene corresponds to a viscous agent of the Molecular weight from about 30,000 to 40,000.

The polymers used to carry out the process according to the invention can be in the form of a dried powder or in the form of pellets, but they are preferably used in the form 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 may be substituted or unsubstituted aliphatic, aromatic or cyclic hydrocarbon that is a solvent for the polymer at elevated temperatures and pressures and is relatively inert than organic under working conditions Liquid for carrying out the

are used according to the method, this hydrocarbon preferably having a boiling point Has atmospheric pressure which is less than the softening point of the polymer and that with water is immiscible or forms a polymer solution that is immiscible with water. The solvent can be liquid or gaseous at room temperature and atmospheric pressure. Preferably it is at standard temperature printing conditions liquid, as otherwise the system after the spray zone will be pressurized got to. Examples of solvents that can be used are aromatic hydrocarbons, such as benzene, Toluene, aliphatic hydrocarbons, for example Butane, pentane, hexane, heptane, octane and 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 of the present invention can do either Water concentration can be established by one of several methods. One method can be from a solution of the polymer in one Run out of solvent, like these in a solution polymerization process occurs, either with the same concentration of the polymer in the solvent, in diluted or concentrated form, after which the water is added to the solution or vice versa is proceeded. In general, hot water is used in carrying out such a method, to prevent precipitation of the polymer. Alternatively, one can choose from a slurry of polymer particles run out in the solvent as they would when performing a slurry polymerization method is generated by adding the appropriate amount of water to the slurry or vice versa is proceeded. Another alternative is from a dry polymer powder or granules or run out of a wet cake, such as that found in the solvent removal step in a polymer plant is obtained, with the appropriate amounts of solvent and water to the dry polymer can be added in any order.

As will be clarified below. Ut it advantageous if the solvent is present before the addition of the water, there is 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 then important. if one uses such an amount of water that the limit of an inversion occurs sew, 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 considerable below the borderline at an occurring reversal, in particular below 30 percent by volume on the mixture, then any suitable mixing method or order of addition of the materials can be used applied or complied with.

The polymer concentration relative to the solvent is not critical. The solvent is present in an amount. which is greater than 100% by weight of the polymer and is sufficient to set a viscosity at the maintained dissolution temperature, that a simple one Handling is possible, d. H. a viscosity of less than 50 Pa s. In general, the polymer concentration will vary from 2 to 30% by weight of the solvent plus polymer and is preferably between 5 and 15%.

One of the functions of water is to control the temperature of the fibrous mass in the zone called "i directly connected to the nozzle. The addition of water increases the overall vapor pressure of the system so that its boiling point is decreased.

For practical reasons, however, water should be in an amount of at least 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 will increase the temperature of the fibrous mass when sprayed is formed is reduced. In this way the properties are related to the phases obtained improved for use in papermaking.

Another function of the water is to be ais Carrier for a hydrophilic water dispersing agent! to act for the fibers to be formed. It was found, that it is very beneficial to use a water dispersant to be used during spraying and precipitation of the fa ^ rous polymer. Even if that Presence of the water dispersant has a beneficial effect on the after the invention If the fibers are produced by the process, the best agents are those used for a water-in-oil emulsion considered unsuitable. Nonetheless, however, hydrophilic water dispersants are becoming preferred in the mixture before spraying. An equivalent amount of the same agent that added at a later point in time to the fibers already formed does not result in the same extent the friability of the fibers. Therefore, the water should be present in an amount sufficient to to carry that amount of the hydrophilic agent which is used to give the fibrous polymer the desired level of water dispersibility. preferably as a solution thereof. additional Water in excess of such a minimum amount required to support the composition can be used to give the aqueous solution or the dispersant a suitable viscosity, i.e., the aqueous solution of the water dispersant should not be so viscous as to cause problems with Handling or mixing into the polymer solution may occur as a dispersed phase. The water can also help to reduce the viscosity of the mixture to a level below that of the polymer solution lies alone, so that higher polymer concentrations can be used possible are. In general, the viscosity of the aqueous solution and / or mixture should be approximately 50 Pa s at de; maintained temperature no.

Another function of water is that. Energy (enthalpy) to be made available to to aid in evaporation of the solvent during spraying, however, the amount of water SQ should not be large, that unnecessary amounts of heat to achieve the desired spray temperature are consumed.

The amount of water that is required for this. to the above To fulfill the specified functions is always below the amount which, when used, results in a conversion takes place, d. h .. at which water must become the continuous phase of the mixture. A condition that

is 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% then it is very difficult to make a water-in-oil emulsion to build. Even with slightly smaller amounts of water, for example with an excess of 60% water, any common mixing method tends to have one Create oil-in-water emulsion. As the amount of water decreases, it becomes easier to create a water-in-oil emulsion to build. For the preparation of mixtures in which the water tends to act as a continuous phase To be more stable, it is convenient to use special mixing methods to make water the less stable discontinuous phase becomes. Corresponding methods are and are known in emulsion technology for example in Volume 8 of Kirk-Othmer's "Encyclopaedia of Chemical Technology", 2nd edition.

A preferred method that is used to prepare a water-in-oil emulsion in which the amount of water sufficient for either the water or the organic liquid to form the continuous phase can be, consists in adding the water to the liquid slowly, so slowly that even at the point of addition no local excess of water compared to the organic liquid and the already formed emulsion is present. The mixture is stirred so that the water drops into droplets his addition is broken. You can meter the addition of water in such a way that the electrical conductivity of the organic liquid is measured, after which the conductivity is monitored to determine the rate of addition to be adjusted with stirring so that the conductivity is less than twice the initial value Conductivity is.

It is advisable to use such mixing methods, when they are carried out, the water makes up 30 percent by volume or more of the mixture. Is the If the amount of water used is 30 percent by volume or more, it is then expedient to first use a solution of the polymer and to form the solvent and then add the water to this solution with vigorous stirring. In this context, the term "polymer solution" is intended to mean the swollen or dissolved mixture to be understood when mixing the solvent with the polymer, usually at increased Temperature. It is also useful to keep the whole mass of the mixture continuously both during as well as stirring after adding the water. The mixing vessel or the mixing device can be in the Be designed in such a way that even and vigorous stirring is possible, with a corresponding vessel design, Guide plates and corresponding stirring methods should be mentioned. That way, posts can with little agitation, which can cause a phase inversion, can be avoided.

This mixing is preferably carried out when both the water and the polymer solution are relatively hot. The polymer solution should expediently be at a temperature above the dissolution temperature lie. The water to be added should have a temperature which is so high that the mixture remains above the dissolution temperature during or after the addition of water. This method helps to prevent phase reversal 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 a phase reversal can take place. It is therefore advisable to move the water at such a speed add, through which a phase separation is avoided, during and after the addition of the Water is vigorously stirred for the same purpose. As previously mentioned, the water preferably becomes gradual added at such a rate that it quickly mixes evenly with the polymer solution will. The water should therefore not be added faster than it is in the form of droplets in the continuous polymer solvent phase is dispersed.

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

When carrying out Examples 1 to 6 described below, in which the water concentration is only 16%, no special mixing methods were used. When performing trial 1 According to Example 7, where the water concentration is 40%, the water gradually became the solution added. Water concentrations on the order of 40 6is 50% are used when performing the The method according to the invention is preferred, but care must be taken. that the water the discontinuous phase is.

When performing a continuous spray, in which part of the mixture thus formed is sprayed through a nozzle further amounts of polymer solutions and water continuously while stirring the remaining mixture in the above given corresponding Quantities are added in order to maintain the water as a discontinuous phase of the mixture.

One of the features of the invention is that it is not necessary. to form a stable emulsion, so that the need is eliminated. Use emulsifier. However, the invention contemplates use of agents in the mixture, with the help of which the water dispersibility of the formed during spraying fibrous polymers is improved. These agents are preferably water-soluble or partially water-soluble high molecular weight materials. However, they can also be materials that are H-soluble in the solution or are partially soluble. Some of these agents can technically be classified as emulsifiers, however, they are only used in an amount sufficient to achieve the required degree of dispersibility and not in amounts generally required to form a stable emulsion. Since the water dispersants must be somewhat hydrophilic, they are not of the type that would normally be used is used to form a water-in-oil type emulsion, i.e. one would normally use a hydrophobic (lipophilic) emulsifier with a relatively low HLB value (value of the hydrophilic-lipophilic Compensation) to form a water-in-oil emulsion use. The amount of water dispersing agent used can be between 0.1 and 15% by weight Polymers and preferably vary between 0.1 and 5 wt .-%. The preferred water dispersing agent

is a polyvinyl alcohol with a degree of hydrolysis of more than approximately 77% and preferably of more than 85% and a viscosity (in a 4% aqueous solution at 20 ^° C.) of more than 2 mPa.s. The polyvinyl alcohol is preferably added with the water added at the time the mixture is formed. Examples of other water dispersants that can be used are cationic guar gum, cationic starch, potato starch, methyl cellulose and a styrene / maleic acid copolymer.

The ingredients of the mixture can be placed in any suitable vessel which has an elevated Temperature can be heated and pressurized. An autoclave is generally used. It is important, however, that the vessel used is equipped with mixing or stirring means which able to keep the mixture in a constant state of agitation, otherwise no stable emulsion is formed and the mixture quickly separates into two distinct and separate phases when standing.

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 dissolution temperature of the polymer in the solvent used. The dissolving temperature is the temperature at which the polymer forms a completely liquid phase with the solvent. There is an excess of solvent. then the dissolving temperature is the temperature at which the polymer dissolves in the solvent, i.e. it is the same as the dissolving temperature. However, there is little solvent present. then is the dissolving temperature the melting point of the polymer lowered by the presence of the solvent which is in the molten one Dissolves polymers. Therefore, the dissolving temperature includes the two situations described as well the area in between.

The 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 wt .-%) in the solvent filled into a vial will. The temperature of the oil bath is slowly increased (for example at 10 ° C / h) until the last traces of polymer disappear. This temperature is the dissolving temperature. In some cases it may be useful to to work at a temperature below the dissolution temperature. In these cases the polymer should at least are in a swollen state.

The maximum temperature maintained should be below the critical temperature of the solvent and / or the decomposition temperature of the polymer. However, it is preferable to maintain slightly lower temperatures. In the case of polyethylene and polypropylene, it is preferable to operate between 120 ° C and 180 ⁰ C and in particular between 130 ⁰ C and 160 ⁰ C.

The pressure set in the vessel containing the heated mixture is preferably the intrinsic pressure. Pressures that are significantly higher than self-pressures are not required. For a given nozzle configuration higher pressures can result in poor fiber formation. It may be useful to use an inert gas, such as nitrogen, to be used during spraying to reduce the speed of the Keep mixture through the nozzle at a fairly constant value. The spraying is preferably carried out through a nozzle that is elongated and not through a sharp-edged opening, which by definition has no longitudinal dimension, since it has been found that it is very useful to shear the mixture to give (in particular the polymer component of the mixture), namely immediately before spraying. Such a shear action favors fiber formation and improves the fiber properties with respect to the Papermaking. The nozzle can have a circular or non-circular cross-section. For example it can be a ring.

The spraying is carried out in such a way that the mixture of polymer, solvent and water is sent through the nozzle into a zone of lower pressure. Preferably the pressure of the zone is with lower pressure at atmospheric pressure or below, since with increasing pressure the temperature of the fibrous Product increases in its formation. The pressure of the emulsion should be applied before spraying into a Zone of lower pressure are below 3.5 bar and preferably below 1.0 bar.

The spraying is carried out adiabatically.

During the spraying process, the polymer is precipitated in the form of fiber-like "noodles". With these noodles it is loose fiber aggregations that are sometimes continuous.

According to a preferred embodiment of the invention, low-pressure steam (less than 1.4 kg / cm ² ) is fed to the fibrous noodles in the post-spray zone in order to strip off 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 these vessels allow the evaporated solvent to be separated off.

When carried out on a technical scale The fibrous noodles are mixed with water to a suitable consistency of less than 5% and preferably less than 2% by weight and then diluted in the form of an aqueous slurry through a disc refiner sent to transform the fibers into a shape, which is optimal for papermaking. The defibration of the fibrous noodles has the separation of discrete fibers and can also be used to control the length of the fibers. Multiple Passages through the refiner are generally convenient. A treatment of the fibrous However, pasta in a disc refiner is not required.

After defibering, the fibers can be thinned to a suitable consistency and made synthetic Paper webs are processed, either alone or in admixture with conventional cellulosic papermaking fibers. Optionally, the fibers can be dewatered, compressed into bales, stored and sent to the end user sent.

Although a batch process has been described above. in its execution the mixture of polymer, solvent and water is prepared in a suitable vessel, so it is also possible to produce the mixture continuously in such a way that the polymer solution with superheated Water continuously in a device connected in series immediately before spraying the nozzle is mixed.

A determination of whether the water is considered discontinuous

Phase or a continuous phase can be carried out as follows. The mixture is formed under the conditions normally observed with regard to temperature, pressure and degree of agitation. Electrodes made of two conductive metals separated by a distance of about 12 mm or more are immersed in the liquid mixture. The electrodes are connected to the poles of a battery. The generated signals are recorded by a recording device connected in series with the electrodes. The generated signal is directly proportional to the conductance of the mix. A trace amount of an ionizable material such as sodium chloride can be present in the water to increase its conductivity. Is water the '! discontinuous phase, then a very low conductance Ss or a zero-reference value is found, ie ungeii ferry the same conductivity as the polymer / solvent medium ϊ-phase of the mixture.

"To produce the desired mixture in which:. Water is present as a discontinuous phase, the l 'stirring speed of the mixture in an appropriate \ manner must be high enough to keep the conductivity of the mixture Jj on the level of conductivity of the polymer solution to £ hold. Similarly, it should be used in the manufacture

'·} Of those mixtures in which the water concentration is expediently so high that a system favors

u is Stigt, upstream in the water as the continuous phase

is, the water of the polymer solution with such overall speed k are added so that the conductivity

J; of the mixture at the level of the conductivity of the

Polymer solution phase is maintained. Other suitable

fc, methods of determining whether an oil-in-water or

I "water-in-oil-like emulsion has been obtained, are

'{J the on pages 146 and 147 in volume 8 of the Kirk-

Jj Othmar Encyclopedia of Chemical Technology, 2nd over-

\ worked edition. 1965. described.

i ;: Example 1

f The one used to complete this example

The dissolution vessel is a glass-lined 3O4ö-liter tank with baffles and a centrally arranged 5.5 KW stirrer with two turbine-like stirrer elements attached to it with four blades. The lower turbine is located at a height of 686 mm (peak to peak) and the upper turbo f. Bine at a height of 483 mm (peak to peak). The stirrer is allowed to run continuously during the experiment. 228 l of water containing 1% by weight of polyvinyl alcohol with a viscosity of 40 to 60 Pas and a degree of hydrolysis of 87.7-89%, based on the weight of the polyethylene to be used, are added to the tank, whereupon the Addition of 45.4 kg of high-density polyethylene with an intrinsic viscosity of 1.4 dl / g and a melt index of 5.5 follows. The vessel is sealed, whereupon 11401 η-hexane are added. The water: hexane volume ratio in the mixture is 1: 5 and the polyethylene concentration is 40 g per liter of hexane. The contents of the vessel are then heated to 130 to 135 ° C and put under a pressure of 8.4 bar. A valve in the bottom part of the vessel is then opened, whereupon the mixture is fed through a 127 mm long 76 mm line to a Valtek angle control valve 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 an annulus with the wall of the opening. The valve is operated in about a quarter of the open position. The mixture flows through the annulus. which forms the spray nozzle, at a rate of 180 g of polyethylene per minute. The mixture is sprayed into a pipe with a diameter of 50 mm. At a distance of approximately 152 mm after the nozzle, low pressure steam at a pressure of 0.7 bar is introduced into the 25 mm line in order to strip off the solvent which has not previously been stripped from the fibrous noodles. At a distance of about 5.4 m from the nozzle, the 25 mm pipe opens into a steam separation vessel, from which the vapors are drawn off at the top. Hot dilution water at a temperature of 85 ° C is introduced at the top of the steam separation kettle at a rate of approximately 19 liters per minute. The water as well as the fibrous noodles fall to the bottom of the steam separation vessel and are at a temperature of 80 to 90 C as well

X one consisten? about 1% fed to a Jones twin disk refiner (305 mm disks) equipped with brush type plates. The disks are operated at 2117 rpm with a play of 0.1 mm + 0.1 mm. The fibers are sent through the refiner a total of four times, with the second to fourth passes taking place at a material temperature of 40 to 50 ° C. Additional polyvinyl alcohol is added to the material tank in an amount of 1% by weight, based on the weight of the polyethylene, and the material is then sent through the refiner a fifth time. The plates are set to 25 + 0.1 mm. The polyethylene fibers have the following fiber distribution when tested according to the TAPPI standard test T 233 su 64.

35

Table 1 A

40 mesh

Weight percent

to 0.8 mm
to 0.5 mm
to 0.23 mm
to 0.1 mm
to 0.05 mm
through 0.05 mm

10.3

33.8

23.8

17.4

5.0

9.7

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

A portion of the fibers obtained is processed according to TAPPI Standard Test T-205 m-58 under modified wet pressing (28 bar and subject to a thermal bonding stage 121 ⁰ C at minimal pressure) to a sample sheet. Another part of the fibers is mixed with a bleached Alder Kraft pulp (50/50) with a Canadian standard degree of freedom of 410 ecm, after which hand sheets are produced by the same method. The hand sheets obtained are tested and the following results are determined:

Table 1B

characteristic

100%

50% blend

Weight per unit area g / m ² 61.2 61.2 Density, g / ccm 0.36 0.48 Opacity,% 83.4 78.9 Gloss,% (Elrepho No. 8) 88.9 84.4 Fracture length, m 139 2416

characteristic 100% 50% blend Tensile force absorption (= Toughness), kg-cm / cm ² 0.06 34.3 Inner bond, Scott- units 14th 90 Tear Strength, g / sheet 6th 28

Another part of the polyethylene fibers is bleached with a bleached Adler Kraft pulp with a Canadian Standard degree of freedom of 410 ecm to produce an entry mixed with 40% by weight of polyethylene fibers and contains 60% by weight kraft fibers. The mixture obtained is shredded by means of a Jordan. To this Way we received an entry with a Canadian standard grind of 250 ecm, which is based on a Paper machine is processed into a paper. The paper machine is operated in such a way that at A thermal bond in two stages (107 and 135 ° C on the Bow) takes place. The paper webs obtained have the following; Characteristics:

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

method T-220 determined. In the case of the leaves that are on a paper machine, the basis weight 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 determined. The tensile strength, the elongation, the tensile energy absorption as well as the breaking length of both the Both hand sheets and machine-made sheets were prepared using the TAPPI standard method T-494 determined). The stiffness of both blades was determined according to the TAPPI standard method T-489-70. The Elrepho No. 8 gloss of both sheets was according to the TAPPl-

! 5 Standard method T-525 determined. The smoothness became insane Trap of both leaves determined by TAPPI routine comparison method # 285. The oil absorption was determined for both films using TAPPI routine comparison method 26 (9166). The opacity as well the scattering coefficients were for b ^ 'dp foils; mh; »n <i der TAPPI Standard Method T-425 determined.

Other tests come from the machine that is used to run the tests, all of which Tests are known in the paper industry. The drainage factor closely related to the hydrodynamic surface of the fibers and an even closer relationship to the drainage properties the fibers used to make paper, than the gas absorption surface, was determined essentially according to TAPPI test method T 221 OS-63 determined, whereby the calculation method has been subjected to a slight modification.

Approximately 10 grams of the fiber sample was weighed and dispersed in water. The slurry then became converted to the standard sheet shape, after which water was added. The slurry was made through four Stir up and down movements of the standard stirrer, which is then removed. The water temperature in the shape was measured, whereupon the drainage

valve has been 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, using the temperature and the drainage time must be noted. The dewatering factor in seconds per gram is then as follows calculated:

Γθ + 0.3 (y- Ij (D-4) l-jrf + 0.3 (y- \\ (i / -4) 1 DF =

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,

Bemerkun ^Vy ~ ^viscous i ^{ty of the} water at the temperature T = WS-wire side; MD = machine direction; FS = FiIz- ^{ω W =} Ψ ^% ^{1 ά} * ™ ^{Carrying out the test venven} "side; AO = cross machine direction; Thickness = that. Deten basern, g
the particular under a pressure using. \
a particular device is determined. The amount I 1 1 is in the above-described

Bsi the implementation of the above example as well as

In the following examples, the basis weight, benen TAPPI test T 221 OS-63 were tabulated.

the thickness, the tensile strength, the folding and this amount is multiplied by 0.3. This value

Density of the hand sheets according to the TAPPI standard was determined empirically for the fibers present.

Example 2

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

a) The Polyäthylux concentration is 80 g / l,

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

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 mm;

2) the 2nd to 6th pass takes place at 40 to 50 ° C with a plate spacing of 0.1 mm.

No further polyvinyl alcohol is added. The fibers obtained show the following fiber distribution:

Table 2A Masöhen size

Wt%

to 0.8 mm 6.4 to 0.5 mm 33.5 to 0.23 mm 292 to 0.1 mm 17.4 to 0.05 mm 6.3 through 0.05 mm 7.2

characteristic

Heat bonding temperature 107 ⁰ C 135 ° C

5 Strain, % MD 1.6 1553 1.7 XD 3.5 3.8 Tensile energy absorption MD 0.019 0.020 (= Toughness), kg-cm / cm ² XD 0.025 0.032 Convolution (MIT) MD 3 7th 10 XD 2 3 Stiffness, g / cm (Taber) MD 1.17 0.96 XD 0.46 0.45 Inside Scott Tie kg-cm / cm ² χ 10 " ³ 152 285 15th Smoothness, cc / min. (Sheffield) WS 328 327 FS 352 293 Porosity, ccm / min. 259 278 (Sheffield) Oil absorption,% 45 32 20th Sugar coloring, sec. WS 0 2.1 FS 0 1.6 Shine (Elrepho No. 8) 85.4 80.9 Opacity,% 80.4 69.1 Fracture length, m MD 3155 3714 25th XD 1900

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 a group of a 50/50 blend with the bleached Alder Kraft pulp described in Example 1 will be produced. The characteristics are as follows:

Table 2 B 100% 30% mixture characteristic 63.5 63.4 Basis weight, g / m ² 0.36 0.44 Density, g / ccm 90.3 84.7 Opacity,% 92.2 86.0 Gloss,% (Elrepho No. 8) 145 2036 Fracture length, m Tensile energy absorption 0.06 29.8 (= Toughness), g-cm / cm ² Iptiere bond, 25th 82 Scott units 3 30th Tear Strength, g / sheet

Example 3

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

a) The polyethylene concentration is 80 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 a plate spacing of 0.05 + 0.1 mm;

2) the second to the sixth pass take place at 20 ^Q C with a plate spacing of 0.05 + 0.1 mm.

No further polyvinyl alcohol is added. The fibers obtained have the following fiber distribution:

Some of the fibers are mixed with the bleached Alder Kraft fibers according to Example 1 (40% by weight of polyethylene fibers. 60% by weight of Kraft fibers) and form one Paper web processed on a paper machine in compliance with two thermal bonding temperatures. the Properties of the webs obtained are as follows:

Table 2 C

Table 3 A Mesh size

characteristic

Thermal bond temperature 107 ^{0 C 135T}

Basis weight, g / m ² thickness, mm density, g / ccm tear strength, g / sheet

Tensile strength, kg / 15 mm

MD XD MD XD

66.6 0.132 0.504

23

26 2.93 1.49

63.3 0.11 0.573

24

27 3.11 1.70

Weight!- %

to 0.8 mm to 0.5 mm to 0.22 mm to 0.1 mm to 0.05 mm through 0.05 mm

The drainage factor Sec./g.

2.3
21.2
32.7
26.2

9.0

8.6

the fiber is 1.10

Hand sheets are produced according to the method described in Example 1, one group containing 100% polyethylene fibers and one group consisting of a 50/50 Mixture with the bleached Alder Kraft fibers according to Example 1 is produced. The following properties are found:

Table 3B characteristic

100% 50/50 blend

Basis weight, g / m ² 62.2 62.3

Density, g / ccm 0.41 0.50

Opacity,% 93.7 88.2

Gloss,% (Elrepho # 8) 93.7 88.4

Length of fracture, m 305 2534

Tensile energy absorption

(= Toughness, kg-cm / cm ² ) 2.4 47.6

Inner bond,

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 1 (40% by weight Polyethylene fibers, 60 wt .-% Kraft fibers) mixed and formed into a paper web on a paper machine in processed two heat bonding stages according to Example 1.

MD Thermal bonding 1543 135 ⁰ C Table 3 C XD temperature 59.9 MD 107 ⁰ C 0.118 characteristic XD 60.3 0.504 MD 0.130 31 Basis weight, g / m ² XD 0.461 36 Thickness, mm MD 31 3.65 Density, g / ccm XD 33 1.80 Tear resistance. g / sheet MD 2.85 1.7 XD 1.39 3.5 Tensile strength, kg / 15 mm MD 1.6 0.025 XD 3.8 0.034 Strain. % 0.019 12th 0.027 7th Tensile energy absorption WS 5 1.1 (= Toughness), kg-cm / cm ² FS 2 0.56 Convolution (MIT) 1.2 0.51 466 Stiffness, g / cm (Taber) 363 WS 147 346 Inside Scott Tie FS 329 400 kg-cm'cm ² χ 10 " ^J 325 Smoothness. ccm / min. (Sheffield) 265 35 14.6 Porosity. ccm / min. 53 16.9 (Sheffield) 0 79.5 Oil absorption. % 0 65.4 Sugar coloring, sec. 87.4 4068 85.9 2108 Shine. % (Elrepho No. 8) MD 3152 Opacity. % XD Fracture length, m

The bottom of the kettle is attached to the shaft remotely while a high shear propeller is positioned approximately 87.5 mm below the turbine. The vessel is provided with four equally spaced vertical baffles. The vessel is then fitted with an electrode which consists of a piece of metal wire which is passed through one end of a short glass tube in a sealing manner. The other end of the wire is passed through a stainless steel tube with an outer diameter of 6.2 mm by a length of 300 mm, whereupon the glass tube and the metal tube are connected using a pipe fitting. 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 n * j: of the battery. The stainless steel sleeve, which is separated from the wire by insulation along its entire length with a gap between them of approximately 15 mm, is connected to the other Po! tied together. It is found that the signal for pure salt water is approximately 140 mV, while the signal for pure fr-hexane is found to be 0 to 1.0 mV. Starting from the bottom of the vessel, an 18.7 mm tube with a ball valve extends 15 mm below the bottom of the vessel. A nozzle is attached immediately next to the ball valve. The nozzle consists of a brass plug with a length of 104 mm with a centrally mounted hole with a diameter of 3.5 mm. The nozzle plug is inserted into the 18.7 mm pipe, which extends to a distance of 300 mm adjacent to the nozzle and protrudes into the atmosphere. The vessel is filled with 500 ml of water. 2500 ml «-hexane, 100 g polyethylene (described in Example 1). 2 g of polyvinyl alcohol and 20 drops of a 25% strength aqueous sodium chloride solution are charged, sealed and flushed with nitrogen, whereupon the contents are heated to a temperature between 145 and 150 ° C. The stirrer is operated at 650 rpm. The contents are at 145 to 150 ° C. for 1 and 1 \ hours to ensure complete dissolution of the polymer. The conductivity of the mixture is between 0.4 and 1.2 mV.

«Is continuous phase. The ball valve will then opened, whereupon the mixture is sent through the nozzle will. The pressure in the vessel is reduced by the Supply of nitrogen kept constant. The fibrous product is made by dropping it on a

so collected wire mesh screen. The fibers are frayed in a manner that they can be kept at room temperature be sent through a Sprout Waldron single disc refiner with 300 mm plates, this disc refiner operates at 2800 rpm with a plate spacing of 0.05 mm. There are a total of four rounds.

The fiber distribution of the fibers obtained is as follows:

Example 4

To carry out this example, a 3.8 liter reactor is used as the vessel used to prepare the mixture for spraying, which is provided with a 10.5 kg / cm ² water vapor jacket, an inlet and outlet for nitrogen and a centrally arranged air-driven drive shaft with a mechanical seal . A blade turbine with six stepped blades with a diameter of 100 mm is approximately 125 mm from the

Table 4A Mesh size

Wt%

to 0.8 mm
to 0.5 mm
to 0.23 mm
to 0.1 mm
to 0.05 mm
through 0.05 mm

2.2

18.8

35.3

24.6

9.5

9.6

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 others made from a 50/50 blend using the bleached Alder Kraft fibers described in Example 1 will be produced. The characteristics are as follows:

Table 4 B 100% 50/50 mix characteristic 58.6 63.3 Basis weight, g / m ² 0.35 0.55 Density, g / ccm 95.3 89.5 Opacity,% 95.3 88.4 Gloss,% (Elrepho No. 8) Tensile energy absorption 0.009 0.06 (= Toughness), g-cm / cm ² Inner scott tie, 76.7 271.0 kg-cm / cm ² ν 10 " ³ 8.8 29.6 Tear resistance. g / fjh »u 0.54 3.4 Tensile strength, kg / 15 mm 3.4 3.7 Strain. %

Example 5

Example 4 is repeated with the exception that the polyvinyl alcohol is omitted from the mixture. The conductivity of the mixture is the same as in Example 4. The stirring is briefly interrupted in order to exercise the electrode. check. The conductivity increases quickly to around 100 mV ar, from which a phase separation can be recognized. When stirring is resumed, the viscosity quickly returns to 0.4 to 1.2 mV. The mixture is kept at 140 ° C. for half an hour and then passed through the nozzle under a constant pressure of 11.5 kg / cm ² . The fibers produced cannot be shredded or made into handsheets unless they are treated with 15% by weight, based on the fibers, of polyvinyl alcohol by mixing in an aqueous slurry. After the treatment, the fibers are defibrated as in Example 4 and have the following fiber distribution:

Table 5A Wt% Mesh size 0.8 to 0.8 mm 11.7 to 0.5 mm 34.1 to 0.23 mm 31.4 to 0.1 mm 14.0 to 0.05 mm 8.0 through 0.05 mm

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

Hand sheets are produced according to the method described in Example 1, one group being made from 100% polyethylene fibers and the other from a 50/50 blend with the bleached Alder Kraft fibers according to Example 1. The properties are like fnliTl:

Table 5 B characteristic

100% 50/50 blend

Thickness, μ 137 104 Weight per unit area, kg / 279 m ² 16.5 16.4 Density, g / ccm 0.43 0.57 Opacity,% 94.8 89.4 Gloss,% (Elrepho No. 8) 94.3 89.0 Tensile energy absorption, ¹⁰ ft-lb / ft ² 1.85 2.98 Inner bond, Scott units 60 102 Tear Strength, g / sheet 16.0 33.0 Tensile strength, kg / 25 mm 1.43 4.81 ¹⁵ elongation,% 6.0 3.4 Fracture length, m 955 3255 ²⁰ Example 6

The example! The procedure described in 4 is repeated, using polypropylene with an intrinsic viscosity of 1.7 dl / g. When carrying out an experiment, the mixture contains 500 ml of water, 2500 ml of η-hexane, 200 g of polypropylene and 2 g of Gelvatol 20-30 polyvinyl alcohol. The mixture is heated to 140 ⁰ C and maintained at this Tempeutur during a period of one hour prior to spraying. A second experiment, which is identical to the first experiment, is carried out with the exception that polypropylene is used in an amount of 100 g. A third attempt that is identical to the two attempts. is carried out with the exception that the temperature of the mixture is heated to 175 to 180 "C prior to spraying. In all cases a fibrous product is obtained.

Example 7 (comparison with "! Jiel)

Two attempts are made to find the fibrous Products that have been produced according to the invention (experiment 1) with the fibrous product compare that has been made under equivalent fiber-making conditions. however, one Spray mixture is used in which water is the continuous phase (Experiment 2).

To carry out these two experiments, a 10-liter vessel that is covered with a steam jacket is used is used, which has an inlet and an outlet for nitrogen, an electrode for measuring the Conductivity and a centrally arranged vertical Rühi shaft with a mechanical seal. An upward pumping blade turbine with a diameter of 100 mm becomes 50 mm on the shaft attached away from the bottom of the vessel. Two straight-vane propellers with a diameter of 100 mm are attached to the shaft 150 or 250 mm above the bottom of the vessel. One pumping down Turbine with a diameter of 100 mm and a downward pumping turbine with a diameter of 75 mm are attached to the shaft 350 or 450 mm above the bottom of the vessel. Three vertical baffles are attached in radial positions with equal spacing on the inside of the vessel wall.

This configuration enables the whole mixture to be stirred and avoids places where only one there is little agitation. These bodies could be the

Favor setting a continuous water phase.

A tube with a diameter of 18.7 mm protrudes from the bottom of the vessel, the one 18.7 mm Has ball valve, which is located 50 mm below the boiler bottom. Immediately next to the ball valve there is a nozzle made of a brass plug with a length of 28 mm with a centrally drilled through Hole with a diameter of), 78 mm. The nozzle plug is inserted into a tube with an inner diameter of 18.7 mm and a length of 240 cm. This pipe extends into a spray tank, which is kept under atmospheric pressure.

The materials used to make the spray mix to carry out the two experiments are the same, namely 4800 ml of n-hexane, 384 g of polyethylene with an intrinsic viscosity of 2.0, 3200 ml Water and 7.7 g polyvinyl alcohol (88% hydrolyzed, molecular weight 10,000). The type of formulation however, this spray mixture of these materials is different when carrying out the two experiments.

To carry out the experiment 1 (erfvndungsgemäßes example), the vessel is first charged with the solvent and the polymer and then aogedichtet and purged with nitrogen and the contents heated to about 144 ⁰ C and is maintained at this temperature while the stirrer at 1000 RPM rotates for a period of approximately 2 hours to ensure complete polymer dissolution. Then the PVA is dissolved in the water in a separate vessel. This solution is heated ^{to approximately 144 ° C.} The heated solution is then introduced under pressure into the barrel containing the heated polymer solution at a rate of approximately 500 ml per minute. This slow and gradual rate of addition has the consequence that the water passes into the dispersed phase in the mixture and remains as such a phase. While the water containing PVA is being added, the stirrer in the vessel containing the Pohmer solution is kept at 1000 rpm. Stirring of this mixture is continued for a period of 15 minutes, whereupon the conductivity of the

Table 7A

Mixture is measured and averaged to about 0 mV. This shows that the water is discontinuous Phase is present in the mixture.

To carry out experiment 2 (comparative example), the spray mixture is formed according to the method described in example 4, that is, the vessel used to carry out experiment 1 is filled with all materials at room temperature, whereupon this mixture is classified under the experiment 1 is heated and stirred to effect the polymer dissolution and dispersion of the PVA-containing water. After stirring between 110 and 140 ^° C. for a period of 2 hours, the conductivity of this mixture is measured and found to be more than 100 mV, which shows that the water is the continuous phase and the polymer solution is the discontinuous phase.

When performing each of Experiments 1 and 2 the mixture formed in the manner described is then heated to 144 "C and at this temperature as well as under a pressure of. -i, 2 bar in the manner described in Example 4 sprayed. That sprayed Material is fiberized using the apparatus described in Example 4 with the exception that the refiner plates used had a Sprout Waldron Master P-29-76-B. The fraying is at a consistency in water of approximately 3%. The settings between the panels are like follows: 1st passage 6.4 mm, 2nd passage 0.6 mm,

3rd pass 0.3 mm, 4th and further passages 0.05 mm. The sprayed material, which is obtained from each test, is defibrated in this way until the fibrous product has reached a classified fiber length (CFL) of approximately 1.2 mm. Part of the product from each experiment is then further defibrated using this method in order to obtain a fibrous product with a classified fiber length (CFL) of 0.8 mm. The properties of these fiber-like products as well as the properties of Hano leaves produced from these products (see Example 1) are measured and compared, the following results being obtained.

characteristic

Fiber properties Products with approximately 0.8 mm CFL Trial 1 Trial 2

(original (comparative)

according to) attempt)

Products with approximately 1.2 mm CFL Trial I Trial 2

(invented (compar

according to) attempt)

Classified fiber length (CFL), mm 0.78 0.88 1.17 1.16 Fiber fractions % Mesh size to 0.8 mm 1.6 08 14.9 6.9 % Mesh size to 0.5 mm 21.0 25.4 31.6 41.3 % Mesh size to 0.1 mm 23.0 17.8 14.2 12.2 Roughness, decidrex 12.6 10.9 13.7 19.5 Surface area, m ² / g 9.48 8.64 8.94 8.64 Drainage factor, sec./g 31.6 9.2 16.2 6.7

CSF = Canadian standard grind

A comparison of the fiber properties and the hand (test 1) are clearly superior to the products that

sheet properties of the fiber products according to the 65 obtained by spraying a comparable mixture

look for 1 and 2, which have essentially been classified in the same class as the water in which the continuous

fied fiber length z-rfibert clearly show the phase represents (experiment 2). The drainage

that the fiber products produced according to the invention factor that of the fiber-like products produced according to the invention

Products is noticeably larger, the same goes for that Strength properties of handsheets made from such fiber products. Bundle of fibers

and polymer lumps in such products are also at acceptably low levels before.

Table 7 B

Leaflets from CFL properties of CFL Comparison hand sheets Hand sheets off 100% polyethylene Leaflets from Hand sheets off 50% polyethylene fibers with approximately 100% polyethylene 50% polyethylene fibers with approximately 0.8 mm < fibers with approximately speed with about 1.2mm CT /. Ver 1.2 mm ι Ver 0.8 mm CFI. and 50% bleached search 2 * search 2 " and 50% bleached ten Alder force 0.407 0.38! ten Alder force Fibers Ver 22.4 23.2 Fibers Ver seeks· XSQ Ver 758 Vcr- Ver such I such 2 * characteristic 0.484 9.5 search I * 8.6 such I * such 2 ·· 0.539 0.518 Density, g / ccm 48.0 0.042 0.416 0.029 0.604 0.549 48.8 35.2 Tear resistance. g / sheet ISSS 47.2 40.8 35.2 2763 2505 18.8 105 1346 110 2914 2621 3.0 3.4 Strain. % 0.169 13.0 3.6 3.6 0.036 0.036 Tensile energy absorption, kg-cm / cm ² 0.087 0.044 0.04 Inner bond. Scott units 153 173 172 (metric) 102 171 169

* = according to the invention;

Comparison attempt

Claims (12)

Patent claims: 1. Process for the production of polymeric fibers by spraying a mixture containing water, a synthetic fiber-forming polymer and an organic solvent containing the polymer able to dissolve or swell through a nozzle from a zone of increased pressure to a zone of lower pressure, the organic solvent ι ο evaporates and the polymer is precipitated in the form of fibers due to the lightning-like expansion, characterized in that a "water-in-oil" emulsion is used in which water is in the form of droplets in a continuous phase of the polymer and the organic solvent. 2. The method according to claim 1, characterized in that the »water-in-ec emulsion used by dispersing the water in a solution of the polymer is formed in the organic solvent. 3. The method according to claim 1 or 2, characterized in that water in the "water-in-oil" - Emulsion in an amount less than 30 percent by volume. based on the mixture is. 4. The method according to claim 2, characterized in that the »water-in-ec emulsion is formed is made by stirring a solution of the polymer in the organic solvent while water is in an amount of 30 to 70 vol .-%, based on the mixture, is added. 5. The method according to any one of the preceding claims, characterized in that the »water in-oil «emulsion also has at least one partially water-soluble dispersant for the Fibers in an amount of 0.1 to 15% by weight. based on the polymer. 6. The method according to claim S, characterized in that the dispersant used is predominantly hydrophilic. 7. The method according to claim 6, characterized in that the dispersant used from a polyvinyl alcohol with a degree of hydrolysis of more than 77% and a viscosity in one 4% aqueous solution at 2OX of more than 2 mPa s. 8. The method according to any one of the preceding claims, characterized in that the included so set polymers is an at least partially crystalline polymer and in an amount between 2 and 30 Wt%. based on the solvent plus polymer. 9. The method according to claim 8, characterized in that the polymer is a polyolefin. preferably a polyethylene or polypropylene which has an intrinsic viscosity of more than 7 cm ³ g and in an amount between 5% and 15% by weight. based on the solution, & o 10. 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 Has lower pressure which is lower than the melting range of the polymer. 11. The method according to any one of claims 9 and 10. characterized in that the emulsion is sprayed at a temperature above the dissolution temperature of the polyolefin, this temperature being below the critical temperature of the Solvent and below the decomposition temperature of the polyolefin, and furthermore the Spraying is carried out under a higher pressure. 12. The method according to any one of the preceding claims, characterized in that a) the "water-in-oil" emulsion by adding of water in an amount between 30 and 70 vol .-%, based on the mixture, at a Temperature above the dissolution temperature to form a solution of an at least partially crystalline polyolefin in 70 to 98% of an organic solvent for the polyolefin, the solvent with water is unmixable and the percentages by weight are based on the total weight of the solution refer to polyolefin and solvent, while the solution to such an extent is stirred so that the water is dispersed in the form of a discontinuous phase, and b) the "water-in-oil" formed in this way Emulsion with stirring & at a temperature above the dissolution temperature and above the Intrinsic pressure is maintained until the emulsion passes through a nozzle into the zone of lower pressure is directed.