EP0053242A1 - Fibrids and fibrils from vinylidene fluoride polymers - Google Patents

Fibrids and fibrils from vinylidene fluoride polymers Download PDF

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Publication number
EP0053242A1
EP0053242A1 EP81108023A EP81108023A EP0053242A1 EP 0053242 A1 EP0053242 A1 EP 0053242A1 EP 81108023 A EP81108023 A EP 81108023A EP 81108023 A EP81108023 A EP 81108023A EP 0053242 A1 EP0053242 A1 EP 0053242A1
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Prior art keywords
fibrids
fibrils
vinylidene fluoride
polymers
water
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German (de)
French (fr)
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EP0053242B1 (en
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Robert Dr. Büning
Volker Dr. Rossbach
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Huels Troisdorf AG
Dynamit Nobel AG
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Huels Troisdorf AG
Dynamit Nobel AG
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    • D—TEXTILES; PAPER
    • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
    • D01F—CHEMICAL FEATURES IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS; APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OF CARBON FILAMENTS
    • D01F6/00—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof
    • D01F6/02—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from homopolymers obtained by reactions only involving carbon-to-carbon unsaturated bonds
    • D01F6/08—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from homopolymers obtained by reactions only involving carbon-to-carbon unsaturated bonds from polymers of halogenated hydrocarbons
    • D01F6/12—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from homopolymers obtained by reactions only involving carbon-to-carbon unsaturated bonds from polymers of halogenated hydrocarbons from polymers of fluorinated hydrocarbons
    • D—TEXTILES; PAPER
    • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
    • D01D—MECHANICAL METHODS OR APPARATUS IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS
    • D01D5/00—Formation of filaments, threads, or the like
    • D01D5/40—Formation of filaments, threads, or the like by applying a shearing force to a dispersion or solution of filament formable polymers, e.g. by stirring
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
    • D21H5/00—Special paper or cardboard not otherwise provided for
    • D21H5/12—Special paper or cardboard not otherwise provided for characterised by the use of special fibrous materials
    • D21H5/20—Special paper or cardboard not otherwise provided for characterised by the use of special fibrous materials of organic non-cellulosic fibres too short for spinning, with or without cellulose fibres

Definitions

  • the present invention relates to fibrids and fibrils based on polymers of vinylidene fluoride. These fibrids and fibrils are a special form of fibers that have special physical properties
  • Fibrids and fibrils made from polyolefins or polyamides are known. Their manufacture is e.g. described in the journal “Angewandte Chemie", 90 (1978), pp. 833-926 or in GB-PSs 14 91 050, 15 30 522 and 15 52 313. These known fibrids are mainly used as substitute products of pulp, e.g. in papermaking.
  • Polyvinylidene fluoride has excellent dielectric properties, while the polymer from which the fibrids are obtained has reduced dielectric properties.
  • the new fibrids can therefore be used in special areas in the electronics industry; for example, they can be embedded in media with a higher modulus of elasticity, so that the piezoelectric effect is enhanced.
  • the new fibrids made of polyvinylidene fluoride can also be excellently used in filters for aggressive substances, even at higher temperatures of e.g. Use 120 0, e.g. in the filtration of nitric acid, where the known polyolefin fibrids cannot be used.
  • PVDF polyvinylidene fluoride
  • the new fibrids have a very large surface area, which can be up to 130 m / g.
  • the high absorption capacity for water is surprising.
  • PVDF - both in powder form and as a shaped body - has practically an adhesive property for water, the new fibrids contain more than 90% by weight of water after their production. Other liquids also adhere equally well to the new fibrids. This property is also retained when the new fibrids are dried and then treated with water with the addition of small amounts of surface-active substances.
  • the new fibrids of the PVDF can be produced on the one hand analogously to the production of fibrids from polyamides: the polymer is dissolved in a suitable water-miscible solvent and the polymer precipitates in water under shear-inducing conditions. Suitable shear-inducing conditions are mentioned in the references mentioned above.
  • PVDF powder can nevertheless be dissolved in acetone if the dissolving process is carried out just below the boiling point of acetone or if the PVDF powder is treated with acetone under pressure at temperatures above 52 ° C.
  • up to 10% solutions of PVDF in acetone can be produced, which are stable at 20 ° C and, depending on the concentration, have a service life of between 10 and 24 hours at this temperature. Fibrids made of PVDF can be produced from these solutions in a manner known per se.
  • solvents are the higher homologues of acetone, provided they are liquid * at room temperature. If necessary, the PVDF powder must be dissolved in these solvents in the same way as when using acetone. Ethylene and propylene carbonate, ⁇ -butyrolactone, dimethylacetamide, tetramethylurea and dimethyl sulfoxide are also suitable as solvents. Depending on the choice of solvent, fibrids with different contents of crystal form I are obtained under the same precipitation conditions.
  • the polymer may also contain small amounts (up to 10 wt .-%) copolymerized further monomers * and miscible with water contains or grafted on.
  • the melt flow index (MFJ according to DIN 53 735) should be between 0.1 and 200.
  • PVDF with small amounts of copolymerized comonomers and or compounded additional polymers has further advantages: PVDF with copolymerized tetrafluoroethylene or other monomers from fluorinated olefins, with the same shear forces and the same solvents, give fibrids with a larger surface area and a higher PVDF content of the crystal form I. It has been shown that if the same solvents are used, the content of fibrids of crystal form I is directly dependent on the surface of the fibrids: the larger the surface, the greater the content of crystal form I.
  • Crystal form I is understood to mean the crystal form which has the excellent dielectric properties (cf. J.Polym.Sc.:Part A, Vol. 3, pp. 4263-4278 (1965)). It is therefore possible to produce fibrids with defined dielectric properties by varying the shear forces and the polymerized second monomer.
  • the fibrid content of crystallization form I can also be determined by varying the PVDF content in the solutions to be precipitated; the higher this is, the higher the content of crystallization form I.
  • PVDF is compounded with other olefinic polymers in amounts of up to about 15% by weight, it is still possible to convert the new fibrids to one second way of producing:
  • the compounds are processed into oriented films and these oriented films are mechanically crushed.
  • fibrids of crystallization form I are also obtained.
  • a highly crystalline PVDF (which likewise predominantly consists of crystallization form II) which is compounded with 0.5 to 10% by weight of an isotactic polypropylene is preferably used for the type of production.
  • the production and orientation of the films from such a compound is carried out in a manner known per se, e.g. by extruding, then quenching and stretching in two directions perpendicular to each other.
  • the mechanical stretching of the stretched film takes place at temperatures between -20 and -60 ° C.
  • the shear-induced precipitation of PVDF fibrids from acetone solution is carried out as follows: Varying amounts of water are pumped through a nozzle with an inside diameter of 2 mm and an outside diameter of 3 mm.
  • the o free-falling water jet has a constant length of 50 cm. After 50 cm the water jet hits a water surface of constant height; the height is maintained by means of an appropriate overflow. The is via an annular nozzle
  • Example 2 acetone solution according to Example 1 applied to the water jet at constant pressure.
  • the ring nozzle ends about 1 mm above the water outlet.
  • Table 1 shows the results for a ring nozzle with a gap width of 0.8 mm, the water pressure being varied by changing the throughput speed. The higher the water pressure, the greater the shear-inducing forces.
  • Example 5 is repeated with an annular nozzle which has a gap width of 0.4 mm. This measure increases the shear-inducing effect. Fibrids are obtained, the specific surface area of which has risen to 105 and the content of crystal form I was 75%.
  • Tetrafluoroethylene used. Fibrids with a specific surface area of 85 and a crystal form 1 content of 85% are obtained.
  • Example 3 The procedure of Example 3 is repeated with the difference that a 7.5% solution of a polyvinylidene fluoride with an MFJ of 20 in dimethyl sulfoxide (dissolving temperature 75 ° C.) is used. Fibrids with a specific surface area of 50 are obtained. These differ from those of Example 3 in that they have practically the pure crystal form I in the crystalline phase, which has been proven by IR absorption and X-ray diffraction.
  • the biaxially stretched film thus obtained contains 75% crystal form I in the crystalline system of polyvinylidene fluoride.
  • This film is cooled to -50 ° C. and then split with rapidly rotating knives. Fine-fiber polyvinylidene fluoride fibrils with a specific surface area of 95 are obtained.
  • the crystal form I remains fully preserved after this process.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Textile Engineering (AREA)
  • Dispersion Chemistry (AREA)
  • Mechanical Engineering (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • General Chemical & Material Sciences (AREA)
  • Compositions Of Macromolecular Compounds (AREA)
  • Manufacture Of Macromolecular Shaped Articles (AREA)
  • Artificial Filaments (AREA)
  • Laminated Bodies (AREA)

Abstract

1. Fibrids and fibrils based on polymers of vinylidene fluoride with a polyvinylidene fluoride content of at least 90% by weight, characterised in that the polyvinylidene fluoride in them is present predominantly in the crystalline structure I.

Description

Gegenstand der vorliegenden Erfindung sind Fibride und Fibrillen auf Basis von Polymeren des Vinylidenfluorids. Diese Fibride und Fibrillen sind eine spezielle Form von Fasern, die besondere physikalische Eigenschaften besitzenThe present invention relates to fibrids and fibrils based on polymers of vinylidene fluoride. These fibrids and fibrils are a special form of fibers that have special physical properties

Fibride und Fibrillen aus Polyolefinen oder Polyamiden sind bekannt. Ihre Herstellung wird z.B. beschrieben in der Zeitschrift "Angewandte Chemie", 90 (1978), S. 833-926 ode in den GB-PSs 14 91 050, 15 30 522 und 15 52 313. Diese bekannten Fibride werden hauptsächlich als Substitutionsprodukte von Zellstoff eingesetzt, wie z.B. bei der Papierherstellung.Fibrids and fibrils made from polyolefins or polyamides are known. Their manufacture is e.g. described in the journal "Angewandte Chemie", 90 (1978), pp. 833-926 or in GB-PSs 14 91 050, 15 30 522 and 15 52 313. These known fibrids are mainly used as substitute products of pulp, e.g. in papermaking.

Es wurde nun gefunden, daß auch Polymere auf Basis von Vinylidenfluorid in Fibride überführbar sind. Dabei stellt sich überraschenderweise heraus, daß diese Fibride desIt has now been found that polymers based on vinylidene fluoride can also be converted into fibrids. It surprisingly turns out that these fibrids of

Polyvinylidenfluorids ausgezeichnete dielektrische Eigenschaften besitzen, während das Polymere aus dem die Fibride gewonnen werden,verminderte dielektrischen Eigenschaften besitzt. Die neuen Fibride können demzufolge auf Spezialgebieten in der Elektronik-Industrie eingesetzt werden; so lassen sie sich beispielsweise in Medien mit höherem E-Modul einbetten, so daß eine Verstärkung des piezoelektrischen Effekts erreicht wird.Polyvinylidene fluoride has excellent dielectric properties, while the polymer from which the fibrids are obtained has reduced dielectric properties. The new fibrids can therefore be used in special areas in the electronics industry; for example, they can be embedded in media with a higher modulus of elasticity, so that the piezoelectric effect is enhanced.

Weiterhin lassen sich die neuen Fibride aus Polyvinylidenfluorid (PVDF) auch vorzüglich in Filter für aggressive Substanzen, selbst bei höheren Temperaturen von z.B. 120 0 einsetzen, wie z.B. bei der Filtration von Salpetersäure, wo die bekannten Fibride aus Polyolefinen nicht verwendbar sind.Furthermore, the new fibrids made of polyvinylidene fluoride (PVDF) can also be excellently used in filters for aggressive substances, even at higher temperatures of e.g. Use 120 0, e.g. in the filtration of nitric acid, where the known polyolefin fibrids cannot be used.

Die neuen Fibride besitzen eine sehr große Oberfläche, die bis zu 130 m/g betragen kann. Überraschend ist das hohe Absorptionsvermögen für Wasser. Obwohl PVDF - sowohl in Pulverform als auch als Formkörper - praktischteine Adhäsionseigenschaften für Wasser besitzt, enthalten die neuen Fibride nach ihrer Herstellung über 90 Gew.-% Wasser Auch andere Flüssigkeiten haften gleich gut an den neuen Fibriden. Diese Eigenschaft bleibt auch erhalten, wenn man die neuen Fibride trocknet und anschließend mit Wasser unter Zusatz von geringen Mengen an oberflächenaktiven Substanzen behandelt.The new fibrids have a very large surface area, which can be up to 130 m / g. The high absorption capacity for water is surprising. Although PVDF - both in powder form and as a shaped body - has practically an adhesive property for water, the new fibrids contain more than 90% by weight of water after their production. Other liquids also adhere equally well to the new fibrids. This property is also retained when the new fibrids are dried and then treated with water with the addition of small amounts of surface-active substances.

Die Herstellung der neuen Fibride des PVDF kann einerseits analog der Herstellung von Fibriden aus Polyamiden erfolgen: Man löst das Polymere in einem geeigneten, mit Wasser mischbaren, Lösungsmittel und fällt das Polymere unter scherinduzierenden Bedingungen in Wasser aus. Geeignete scherinduzierende Bedingungen sind in den oben genannten Literaturstellen genannt.The new fibrids of the PVDF can be produced on the one hand analogously to the production of fibrids from polyamides: the polymer is dissolved in a suitable water-miscible solvent and the polymer precipitates in water under shear-inducing conditions. Suitable shear-inducing conditions are mentioned in the references mentioned above.

Bei der Herstellung von Fibriden aus PVDF trat jedoch die Schwierigkeit auf, ein geeignetes Lösungsmittel zu finden, das die gewünschten Eigenschaften besitzt. In den meisten gängigen Lösungsmitteln gilt PVDF als unlöslich, oder dies Lösungsmittel sind mit Wasser nicht mischbar. (Vgl. Gnamm/ Fuchs "Lösungsmittel, Weichmachungsmittel", Bd. 1, 8. Auflage (1980), S. 358-361).When producing fibrids from PVDF, however, the difficulty arose in finding a suitable solvent that has the desired properties. In most common solvents, PVDF is considered to be insoluble, or these solvents are immiscible with water. (See Gnamm / Fuchs "solvents, plasticizers", vol. 1, 8th edition (1980), pp. 358-361).

Es wurde nun überraschenderweise gefunden, daß sich PVDF-Pulver dennoch in Aceton lösen läßt, .wenn man den Lösevorgang kurz unterhalb des Siedepunkts von Aceton durchführt oder wenn man das PVDF-Pulver unter Druck bei Temperaturen über 52 °C mit Aceton behandelt. Es lassen sich auf diese Weise bis zu 10 %ige Lösungen von PVDF in Aceton herstellen, die bei 20 °C stabil sind und, je nach Konzentration, bei dieser Temperatur Standzeiten zwischen 10 und 24 Stunden besitzen. Aus diesen Lösungen lassen sich Fibride aus PVDF in an sich bekannter Weise herstellen.It has now surprisingly been found that PVDF powder can nevertheless be dissolved in acetone if the dissolving process is carried out just below the boiling point of acetone or if the PVDF powder is treated with acetone under pressure at temperatures above 52 ° C. In this way, up to 10% solutions of PVDF in acetone can be produced, which are stable at 20 ° C and, depending on the concentration, have a service life of between 10 and 24 hours at this temperature. Fibrids made of PVDF can be produced from these solutions in a manner known per se.

Andere geeignete Lösungsmittel sind die höheren Homologen des Acetons, sofern sie bei Raumtemperatur flüssig*sind. Gegebenenfalls muß in diesen Lösungsmitteln das PVDF-Pulver in gleicher Weise wie beim Einsatz von Aceton gelöst werden. Als Lösungsmittel eignen sich weiterhin noch Äthylen- und Propylencarbonat, γ-Butyrolacton, Dimethylacetamid, Tetramethylharnstoff und Dimethylsulfoxid. Je nach Wahl des Lösungsmittels erhält man bei gleichen Fällbedingungen Fibride mit unterschiedlichem Gehalt an der Kristallform I.Other suitable solvents are the higher homologues of acetone, provided they are liquid * at room temperature. If necessary, the PVDF powder must be dissolved in these solvents in the same way as when using acetone. Ethylene and propylene carbonate, γ-butyrolactone, dimethylacetamide, tetramethylurea and dimethyl sulfoxide are also suitable as solvents. Depending on the choice of solvent, fibrids with different contents of crystal form I are obtained under the same precipitation conditions.

Zur Herstellung der Fibride und Fibrillen eignet sich sowohl hochkristallines als auch weniger kristallines Polyvinylidenfluorid. Das Polymere kann auch geringe Mengen (bis zu 10 Gew.-%) weitere Monomere einpolymeri- * und mit Wasser mischbar siert oder aufgepfropft enthalten. Der Schmelzflußindex (MFJ gemäß DIN 53 735) sollte zwischen 0,1 und 200 liegen.Both highly crystalline and less crystalline polyvinylidene fluoride are suitable for producing the fibrids and fibrils. The polymer may also contain small amounts (up to 10 wt .-%) copolymerized further monomers * and miscible with water contains or grafted on. The melt flow index (MFJ according to DIN 53 735) should be between 0.1 and 200.

Der Einsatz von PVDF mit geringen Mengen an einpolymeri- sierten comonomeren und oder eincompoundierten zusätzlichen Polymeren hat noch weitere Vorteile: PVDF mit einpolymerisiertem Tetrafluoräthylen oder anderen Monomeren aus fluorierten Olefinen ergeben bei gleichen Scherkräften und gleichen Lösungsmitteln Fibride mit größerer Oberfläche und höherem Gehalt an PVDF der Kristallform I. Es hat sich nämlich gezeigt, daß bei Verwendung gleicher Lösungsmittel der Gehalt an Fibriden der Kristallform I direkt abhängig von der Oberfläche der Fibride ist: Je größer die Oberfläche, um so größer ist der Gehalt an der Kristallform I.The use of PVDF with small amounts of copolymerized comonomers and or compounded additional polymers has further advantages: PVDF with copolymerized tetrafluoroethylene or other monomers from fluorinated olefins, with the same shear forces and the same solvents, give fibrids with a larger surface area and a higher PVDF content of the crystal form I. It has been shown that if the same solvents are used, the content of fibrids of crystal form I is directly dependent on the surface of the fibrids: the larger the surface, the greater the content of crystal form I.

Weiterhin hat sich herausgestellt, daß der Gehalt an PVDF der Kristallform I um so größer ist, je größer die einwirkenden Scherkräfte bei der Ausfällung sind. Unter der Kristallform I ist dabei jene Kristallform zu ver- stehen, die die ausgezeichneten dielektrischen Eigenschaften besitzt (vgl. J.Polym.Sc.:Part A, Vol. 3, S. 4263-4278 (1965)). Man hat es demzufolge in der Hand, durch Variation der einwirkenden Scherkräfte und des einpolymerisierten zweiten Monomeren Fibride mit definierten dielektrischen Eigenschaften herzustellen.Furthermore, it has been found that the PVDF content of crystal form I is greater, the greater the shear forces acting during the precipitation. Crystal form I is understood to mean the crystal form which has the excellent dielectric properties (cf. J.Polym.Sc.:Part A, Vol. 3, pp. 4263-4278 (1965)). It is therefore possible to produce fibrids with defined dielectric properties by varying the shear forces and the polymerized second monomer.

Der Gehalt an Fibriden der Kristallisationsform I kann auch noch durch Variation des Gehalts an PVDF in den auszufällenden Lösungen bestimmt werden; je höher dieser liegt, desto höher wird der Gehalt an der Kristallisationsform I.The fibrid content of crystallization form I can also be determined by varying the PVDF content in the solutions to be precipitated; the higher this is, the higher the content of crystallization form I.

Wenn das PVDF mit weiteren olefinischen Polymeren in Mengen bis zu etwa 15 Gew.-% compoundiert vorliegt, hat man weiterhin die Möglichkeit, die neuen Fibride auf eine zweite Art herzustellen: Die Compounds werden zu orientierten Folien verarbeitet und diese orientierten Folien werden mechanisch zerkleinert. Dabei werden überraschenderweise ebenfalls Fibride der Kristallisationsform I erhalten. Vorzugsweise wird für die Herstellungsart ein hochkristallines PVDF eingesetzt (das ebenfalls überwiegend aus der Kristallisationsform II besteht) das mit 0,5 bis 10 Gew.-% eines isotaktischen Polypropylens compoundiert ist.If the PVDF is compounded with other olefinic polymers in amounts of up to about 15% by weight, it is still possible to convert the new fibrids to one second way of producing: The compounds are processed into oriented films and these oriented films are mechanically crushed. Surprisingly, fibrids of crystallization form I are also obtained. A highly crystalline PVDF (which likewise predominantly consists of crystallization form II) which is compounded with 0.5 to 10% by weight of an isotactic polypropylene is preferably used for the type of production.

Die Herstellung und Orientierung der Folien aus einem solchen Compound erfolgt auf an sich bekannte Weise, z.B. durch Extrudieren, anschließendem Abschrecken und Verstrecken in zwei senkrecht zueinander stehenden Richtungen. Das mechanische Zerkleinern der so gestreckten Folie erfolgt bei Temperaturen zwischen -20 und -60 °C.The production and orientation of the films from such a compound is carried out in a manner known per se, e.g. by extruding, then quenching and stretching in two directions perpendicular to each other. The mechanical stretching of the stretched film takes place at temperatures between -20 and -60 ° C.

Beispiel 1example 1

Herstellung einer acetonischen PVDF-Lösung.Preparation of an acetone PVDF solution.

In einem Rührkolben werden in 925 cm3 reinem Aceton 75 g Polyvinylidenfluorid (MFJ=20) kurz unterhalb des Siedepunkts unter Rühren gelöst. Die Lösung wird auf 20 °C abgekühlt. Die Lösung muß innerhalb von 8 Stunden bearbeitet werden, weil sie sonst zu gelieren beginnt.75 g of polyvinylidene fluoride (MFJ = 20) are dissolved in 925 cm 3 of pure acetone in a stirred flask just below the boiling point with stirring. The solution is cooled to 20 ° C. The solution must be processed within 8 hours, otherwise it will start to gel.

Beispiel 2 bis 5Examples 2 to 5

Die scherinduzierte Fällung von PVDF-Fibriden aus acetonischer Lösung wird wie folgt vorgenommen: Durch eine Düse mit einem Innendurchmesser von 2 mm und einem Außendurchmesser von 3 mm werden wechselnde Mengen Wasser pro Minute gepumpt. Derofreifallende Wasserstrahl hat eine konstante Länge von 50 cm. Nach 50 cm prallt der Wasserstrahl auf eine Wasseroberfläche mit gleichbleibender Höhe; die Höhenkonstanz wird mittels eines entsprechenden Überlaufs aufrechterhalten. Über eine Ringdüse wird dieThe shear-induced precipitation of PVDF fibrids from acetone solution is carried out as follows: Varying amounts of water are pumped through a nozzle with an inside diameter of 2 mm and an outside diameter of 3 mm. The o free-falling water jet has a constant length of 50 cm. After 50 cm the water jet hits a water surface of constant height; the height is maintained by means of an appropriate overflow. The is via an annular nozzle

acetonische Lösung gemäß Beispiel 1 mit konstantem Druck auf den Wasserstrahl aufgebracht. Die Ringdüse endet etwa 1 mm oberhalb des Wasseraustritts.acetone solution according to Example 1 applied to the water jet at constant pressure. The ring nozzle ends about 1 mm above the water outlet.

In der Tabelle 1 sind die Ergebnisse für eine Ringdüse mit einer Spaltbreite von 0,8 mm wiedergegeben, wobei der Wasserdruck durch Änderung der Durchlaufgeschwindigkeit variiert wurde. Je höher der Wasserdruck, um so größer wurden die scherinduzierenden Kräfte.

Figure imgb0001
Table 1 shows the results for a ring nozzle with a gap width of 0.8 mm, the water pressure being varied by changing the throughput speed. The higher the water pressure, the greater the shear-inducing forces.
Figure imgb0001

Beispiel 6Example 6

Beispiel 5 wird wiederholt mit einer Ringdüse, die eine Spaltbreite von 0,4 mm besitzt. Durch diese Maßnahme wird die scherinduzierende Wirkung vergrößert. Es werden Fibride erhalten, deren spezifische Oberfläche auf 105 angestiegen ist und deren Gehalt an Kristallform I bei 75 % lag.Example 5 is repeated with an annular nozzle which has a gap width of 0.4 mm. This measure increases the shear-inducing effect. Fibrids are obtained, the specific surface area of which has risen to 105 and the content of crystal form I was 75%.

Beispiel 7Example 7

Es wird in gleicher Weise wie Beispiel 6 gearbeitet. Als Lösung wird jedoch eine 7,5 %ige Lösung in Aceton eines Polyvinylidenfluorids mit 6 Gew.-% einpolymerisiertemThe procedure is the same as in Example 6. As a solution, however, a 7.5% solution in acetone of a polyvinylidene fluoride with 6% by weight is polymerized

Tetrafluoräthylen verwendet. Es werden Fibride mit einer spezifischen Oberfläche von 85 und einem Gehalt an Kristallform 1 von 85 % erhalten.Tetrafluoroethylene used. Fibrids with a specific surface area of 85 and a crystal form 1 content of 85% are obtained.

Beispiel 8Example 8

Die Arbeitsweise des Beispiels 3 wird wiederholt mit dem Unterschied, daß eine 7,5 %ige Lösung eines Polyvinylidenfluorids mit einem MFJ von 20 in Dimethylsulfoxid (Lösetemperatur 75 °C) verwendet wird. Es werden Fibride mit einer spezifischen Oberfläche von 50 erhalten. Diese unterscheiden sich von denen des Beispiels 3 dadurch, daß sie in der kristallinen Phase praktisch die reine Kristallform I aufweisen, was durch IR-Absorption und Röntgenbeugung bewiesen wurde.The procedure of Example 3 is repeated with the difference that a 7.5% solution of a polyvinylidene fluoride with an MFJ of 20 in dimethyl sulfoxide (dissolving temperature 75 ° C.) is used. Fibrids with a specific surface area of 50 are obtained. These differ from those of Example 3 in that they have practically the pure crystal form I in the crystalline phase, which has been proven by IR absorption and X-ray diffraction.

Beispiel 9Example 9

95 Teile Polyvinylidenfluorid (MFJ=20) und 5 Teile isotaktisches Polypropylen werden bei 255 °C und bei einem Druck von 100 kg/cm2 zu einer Bahn mit 0,5 mm Dicke schmelzverpreßt. Die Bahn wird sofort in kaltem Wasser abgekühlt. Dann wir die Bahn bei 50 °C um das 4fache verstreckt und anschließend bei 100 °C um das 6fache verstreckt und zwar senkrecht zur ersten Streckrichtung.95 parts of polyvinylidene fluoride (MFJ = 20) and 5 parts of isotactic polypropylene are melt-pressed at 255 ° C. and at a pressure of 100 kg / cm 2 to form a sheet with a thickness of 0.5 mm. The web is immediately cooled in cold water. Then the web is stretched 4 times at 50 ° C and then stretched 6 times at 100 ° C, perpendicular to the first stretching direction.

Die so erhaltene biaxial verstreckte Folie enthält im kristallinen System des Polyvinylidenfluorids 75 % Kristallform I. Diese Folie wird auf -50 °C abgekühlt und anschließend mit schnell rotierenden Messern gespalten. Es werden feinfaserige Polyvinylidenfluorid-Fibrillen mit einer spezifischen Oberfläche von 95 erhalten. Die Kristallform I bleibt nach diesem Prozeß voll erhalten.The biaxially stretched film thus obtained contains 75% crystal form I in the crystalline system of polyvinylidene fluoride. This film is cooled to -50 ° C. and then split with rapidly rotating knives. Fine-fiber polyvinylidene fluoride fibrils with a specific surface area of 95 are obtained. The crystal form I remains fully preserved after this process.

Claims (6)

1. Fasern auf Basis von Polymeren des Vinylidenfluorids, dadurch gekennzeichnet , daß sie in Form von Fibriden oder Fibrillen vorliegen.1. Fibers based on polymers of vinylidene fluoride, characterized in that they are in the form of fibrids or fibrils. 2. Fibride und Fibrillen aus Polymeren des Vinylidenfluorids, dadurch gekennzeichnet, daß sie eine spezifische Oberfläche zwischen 5 und 130 m2/g besitzen..2. Fibrids and fibrils made from polymers of vinylidene fluoride, characterized in that they have a specific surface area between 5 and 130 m 2 / g. 3. Fibride und Fibrillen gemäß Anspruch 1 oder 2, dadurch gekennzeichnet, daß in ihnen das Polyvinylidenfluorid überwiegend in der Kristallstruktur I vorliegt.3. Fibrids and fibrils according to claim 1 or 2, characterized in that the polyvinylidene fluoride is predominantly present in the crystal structure I in them. 4. Verfahren zur Herstellung von Fibriden oder Fibrillen von Polymeren des Vinylidenfluorids gemäß einem der Ansprüche 1 bis 3, dadurch gekennzeichnet, daß man Lösungen der Polymeren des Vinylidenfluorids in einem mit Wasser mischbaren Lösungsmittel unter scherinduzierend Bedingungen in Wasser oder wasserhaltigen Medien einbringt.4. A process for the preparation of fibrids or fibrils of polymers of vinylidene fluoride according to one of claims 1 to 3, characterized in that solutions of the polymers of vinylidene fluoride are introduced in a water-miscible solvent under shear-inducing conditions in water or aqueous media. 5. Verfahren zur Herstellung von Fibriden oder Fibrillen gemäß Anspruch 4, dadurch gekennzeichnet, daß man eine acetonische Lösung der Polymeren des Vinylidenfluorids einsetzt.5. A process for the production of fibrids or fibrils according to claim 4, characterized in that an acetone solution of the polymers of vinylidene fluoride is used. 6. Verfahren zur Herstellung von Fibriden oder Fibrillen von Polymeren des Vinylidenfluorids gemäß einem der Ansprüche 1 bis 3, dadurch gekennzeichnet, daß man orientierte Polyvinylidenfluoridfolien, die 0,5 bis 10 Gew.-% isotaktisches Polypropylen enthalten, mechanisch, gegebenenfalls unter Kühlung, zerkleinert.6. A process for the production of fibrids or fibrils of polymers of vinylidene fluoride according to one of claims 1 to 3, characterized in that oriented polyvinylidene fluoride films containing 0.5 to 10% by weight of isotactic polypropylene are mechanically comminuted, optionally with cooling .
EP81108023A 1980-12-02 1981-10-07 Fibrids and fibrils from vinylidene fluoride polymers Expired EP0053242B1 (en)

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DE19803045333 DE3045333A1 (en) 1980-12-02 1980-12-02 "FIBRIDS AND FIBRILLES MADE OF VINYLIDENE FLUORIDE POLYMERS"
DE3045333 1980-12-02

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EP2906615A4 (en) * 2012-10-12 2016-04-13 Evan Koslow High dielectric compositions for particle formation and methods of forming particles using same
US9353229B2 (en) 2012-08-14 2016-05-31 Gabae Technologies Llc Compositions incorporating dielectric additives for particle formation, and methods of particle formation using same
US9449736B2 (en) 2013-05-21 2016-09-20 Gabae Technologies Llc High dielectric compositions for particle formation and methods of forming particles using same

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DE9014598U1 (en) * 1990-10-22 1991-01-03 Krahmer, Gerhard M., 5064 Rösrath Hair implant made of synthetic threads
DE4130356C2 (en) * 1991-09-12 1995-01-26 Bitterfeld Wolfen Chemie PTFE fiber material and process for its manufacture

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FR1465427A (en) * 1964-08-14 1967-01-13 Grace W R & Co Striated films and mixtures of fibrils made up of two incompatible thermoplastic polymers, and their manufacturing process
US3693851A (en) * 1965-06-05 1972-09-26 Polymer Processing Res Inst Method for fibrillating stretched film
DE2407359A1 (en) * 1973-03-12 1974-09-19 Solvay METHOD OF MANUFACTURING DISCONTINUOUS FIBRILS
DE2646332A1 (en) * 1976-10-14 1978-04-20 Basf Ag PROCESS FOR THE PRODUCTION OF FIBRILS FROM POLYMERIZES

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FR1465427A (en) * 1964-08-14 1967-01-13 Grace W R & Co Striated films and mixtures of fibrils made up of two incompatible thermoplastic polymers, and their manufacturing process
US3693851A (en) * 1965-06-05 1972-09-26 Polymer Processing Res Inst Method for fibrillating stretched film
DE2407359A1 (en) * 1973-03-12 1974-09-19 Solvay METHOD OF MANUFACTURING DISCONTINUOUS FIBRILS
DE2646332A1 (en) * 1976-10-14 1978-04-20 Basf Ag PROCESS FOR THE PRODUCTION OF FIBRILS FROM POLYMERIZES
FR2367838A2 (en) * 1976-10-14 1978-05-12 Basf Ag PROCESS FOR THE PRODUCTION OF FIBRILLES FROM POLYMERS

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9353229B2 (en) 2012-08-14 2016-05-31 Gabae Technologies Llc Compositions incorporating dielectric additives for particle formation, and methods of particle formation using same
EP2906615A4 (en) * 2012-10-12 2016-04-13 Evan Koslow High dielectric compositions for particle formation and methods of forming particles using same
US9796830B2 (en) 2012-10-12 2017-10-24 Gabae Technologies Inc. High dielectric compositions for particle formation and methods of forming particles using same
US9449736B2 (en) 2013-05-21 2016-09-20 Gabae Technologies Llc High dielectric compositions for particle formation and methods of forming particles using same

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EP0053242B1 (en) 1984-09-19
DE3166192D1 (en) 1984-10-25
JPS57121609A (en) 1982-07-29
DE3045333A1 (en) 1982-07-01

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