DE2109082A1 - Process for the non-destructive degradation of polytetrafluoroethylene - Google Patents
Process for the non-destructive degradation of polytetrafluoroethyleneInfo
- Publication number
- DE2109082A1 DE2109082A1 DE19712109082 DE2109082A DE2109082A1 DE 2109082 A1 DE2109082 A1 DE 2109082A1 DE 19712109082 DE19712109082 DE 19712109082 DE 2109082 A DE2109082 A DE 2109082A DE 2109082 A1 DE2109082 A1 DE 2109082A1
- Authority
- DE
- Germany
- Prior art keywords
- polytetrafluoroethylene
- sintered
- solid
- degradation
- destructive degradation
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- -1 polytetrafluoroethylene Polymers 0.000 title claims description 16
- 229920001343 polytetrafluoroethylene Polymers 0.000 title claims description 16
- 239000004810 polytetrafluoroethylene Substances 0.000 title claims description 16
- 238000000034 method Methods 0.000 title claims description 7
- 230000015556 catabolic process Effects 0.000 title claims description 5
- 238000006731 degradation reaction Methods 0.000 title claims description 5
- 230000001066 destructive effect Effects 0.000 title claims description 4
- 239000007787 solid Substances 0.000 claims description 5
- 239000002245 particle Substances 0.000 claims description 4
- 239000000463 material Substances 0.000 description 4
- 239000000843 powder Substances 0.000 description 4
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 2
- 238000002845 discoloration Methods 0.000 description 2
- 230000005865 ionizing radiation Effects 0.000 description 2
- 239000007788 liquid Substances 0.000 description 2
- 238000002844 melting Methods 0.000 description 2
- 230000008018 melting Effects 0.000 description 2
- 238000005245 sintering Methods 0.000 description 2
- 239000002699 waste material Substances 0.000 description 2
- 101100286286 Dictyostelium discoideum ipi gene Proteins 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- 229910002092 carbon dioxide Inorganic materials 0.000 description 1
- 239000001569 carbon dioxide Substances 0.000 description 1
- 238000004140 cleaning Methods 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000008020 evaporation Effects 0.000 description 1
- 238000001704 evaporation Methods 0.000 description 1
- 239000010419 fine particle Substances 0.000 description 1
- XUCNUKMRBVNAPB-UHFFFAOYSA-N fluoroethene Chemical group FC=C XUCNUKMRBVNAPB-UHFFFAOYSA-N 0.000 description 1
- 239000000314 lubricant Substances 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 229920000642 polymer Polymers 0.000 description 1
- 230000005855 radiation Effects 0.000 description 1
- 239000011347 resin Substances 0.000 description 1
- 229920005989 resin Polymers 0.000 description 1
- 230000003068 static effect Effects 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 229920001169 thermoplastic Polymers 0.000 description 1
- 239000004416 thermosoftening plastic Substances 0.000 description 1
- 238000009423 ventilation Methods 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
- C08J3/00—Processes of treating or compounding macromolecular substances
- C08J3/28—Treatment by wave energy or particle radiation
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
- C08F8/00—Chemical modification by after-treatment
- C08F8/50—Partial depolymerisation
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
- C08J2327/00—Characterised by the use of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a halogen; Derivatives of such polymers
- C08J2327/02—Characterised by the use of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a halogen; Derivatives of such polymers not modified by chemical after-treatment
- C08J2327/12—Characterised by the use of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a halogen; Derivatives of such polymers not modified by chemical after-treatment containing fluorine atoms
- C08J2327/18—Homopolymers or copolymers of tetrafluoroethylene
Landscapes
- Chemical & Material Sciences (AREA)
- Health & Medical Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Medicinal Chemistry (AREA)
- Polymers & Plastics (AREA)
- Organic Chemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Processes Of Treating Macromolecular Substances (AREA)
- Treatments Of Macromolecular Shaped Articles (AREA)
- Cephalosporin Compounds (AREA)
Description
Patentanwalt . PatentanwältePatent attorney. Patent attorneys
757 Baden-Baden Balg DIpI.-J ng. Ralf M. Kern 757 Baden-Baden Balg DIpI.-J ng. Ralf M. Kern
Γ ΠΓ Π
P las tomer Corporation Ab 16.9.70 neueP las tomer Corporation New from 9/16/70
Newtown, PaM V.St.A.Newtown, Pa M V.St.A.
Telefon - Nr. 66 31 97Telephone number 66 31 97
Die Erfindung betrifft ein Verfahren zum zerstörungsfreien Abbau von Polytetrafluoräthylen mit dem Ziel, es als Feststoff leicht zerteilbar zu machen.The invention relates to a method for the non-destructive degradation of polytetrafluoroethylene with the aim of converting it as a solid easy to divide.
Polytetrafluoräthylen ist bekanntlich ein weisses thermoplastisches Pulver, das bei 3270C schmilzt. Es zeichnet sich durch hohe Verwendungstemperaturen, chemische Inaktivität, ausgezeichnete elektrische Eigenschaften und einen niedrigen Reibungskoeffizienten aus. In der vom Hersteller gelieferten Form neigt dieses Material jedoch zum Verklumpen und muss während der Verarbeitung bei mindestens 3270C gesintert werden. So wird beispielsweise Typ 7-Polytetrafluoräthylen-Pulver im allgemeinen unter Druck zur gewünschten Form verpresst und danach in einem Ofen bei einer Temperatur von normalerweise etwa 371° bis etwa 3990C gesintert. Typ 1, 5 und 9-Pulver andererseits werden unter Druck vorgeformt und ebenfalls unter Druck zwischen etwa 3^3° und etwa 399°C gesintert. Typ 6-Pulver wird mit einem Schlüpfrigmacher wie Naphtha oder dergleichen vermischt, vorgeformt, unter hohem Druck zu gewünschter Form strangverpresst, vom Schlüpfrigmacher durch Verdampfen desselben befreit und schliesslich normalerweise bei einer Temperatur von etwa 371°Polytetrafluoroethylene is known to be a white thermoplastic powder, melting at 327 0 C. It is characterized by high usage temperatures, chemical inactivity, excellent electrical properties and a low coefficient of friction. In the form supplied by the manufacturer, however, this material tends to clump and must be sintered at at least 327 ° C. during processing. For example, Type 7 polytetrafluoroethylene powder is generally compressed under pressure into a desired shape and then sintered in a furnace at a temperature of normally about 371 ° to about 399 0 C. Type 1, 5 and 9 powders, on the other hand, are preformed under pressure and also sintered under pressure between about 3 ^ 3 ° and about 399 ° C. Type 6 powder is mixed with a lubricant such as naphtha or the like, preformed, extruded under high pressure to the desired shape, de-lubricated by evaporation and finally usually at a temperature of about 371 °
109849/1609 "2 "109849/1609 " 2 "
POSTZENTRALE: 8 München 90, Eduard-Schmid-Str. 2POST CENTER: 8 Munich 90, Eduard-Schmid-Str. 2
bis etwa 649°C gesintert. Keines dieser gesinterten Materialien kann leicht feinteilig zerkleinert werden; man kommt beispielsweise bei gesintertem Polytetrafluoräthylen selbst bei Hochleistung-Stossvermahlung nur bis zu Teilchengrössen zwischen 0,149 und 0,074 mm und erreicht dies auch nur durch gleichzeitig angewendete Kühlung durch z.B. flüssiges Kohlendiöxyd oder flüssigen Stickstoff.sintered to about 649 ° C. None of these sintered materials can easily be crushed into fine particles; one comes for example with sintered polytetrafluoroethylene, even with high-performance impact grinding, only up to particle sizes between 0.149 and 0.074 mm and only achieves this through Simultaneously applied cooling by e.g. liquid carbon dioxide or liquid nitrogen.
In der amerikanischen Patentschrift 3 4^2 5II wird ein Verfahren zum Abbau von gesintertem oder nicht gesintertem Polytetrafluoräthylen beschrieben, bei dem man das Polymer auf eine Temperatur oberhalb seines normalen Sinterbereichs und bis auf etwa 47I0G erhitzt. Da nun aber bei jedem Erhitzen von Polytetrafluoräthylen über 2O4°C besondere Entlüftungsmassnahmen erforderlich sind und bei über dem Sinterbereich liegenden Temperaturen möglicherweise eine Verfärbung des normalerweise weissen Materials auftritt, besteht das Bedürfnis nach einem Verfahren zum Abbau von gesintertem und ungesinterteiü Polytetrafluoräthylen ohne Hitzeanwendung, mit dem man es in Form feinverteilter Partikel gewinnen kann, die sich leicht dispergieren lassen und nicht zum Verklumpen neigen.In the American patent 3 4 ^ 2 5II a process for the degradation of sintered or unsintered polytetrafluoroethylene is described in which the polymer is heated to a temperature above its normal sintering range and up to about 47I 0 G. However, since special ventilation measures are required every time polytetrafluoroethylene is heated above 2O4 ° C and, at temperatures above the sintering range, there may be discoloration of the normally white material, there is a need for a method for breaking down sintered and unsintered polytetrafluoroethylene without the use of heat it can be obtained in the form of finely divided particles that are easy to disperse and do not tend to clump.
Die Erfindung beruht nun auf der unerwarteten Erkenntnis, dass man gesintertes oder nicht gesintertes Polytetrafluoräthylen durch Einwirkung einer kritischen Dosis von ionisierender Strahlung in ein Material umwandeln lässt, das sich ohne schädliche thermische Nebenwirkungen zu Mikrokomgrösse zerkleinern und in dieser Form leicht in verschiedenen Medien dispergieren lässt. Diese Teilchen besitzen überdies den für Polytetrafluoräthylenharz typischen, äusserst niedrigen Reinigungskoeffizienten. Der erfindungsgemässe Strahlungsdosisbereich liegt dabei generell zwischen etwa 5 un<3 etwa 25 und vorzugsweise zwischen etwa 10 und 25 Megarad.The invention is based on the unexpected finding that sintered or unsintered polytetrafluoroethylene can be converted by exposure to a critical dose of ionizing radiation into a material that can be broken down to micro-grain size without harmful thermal side effects and easily dispersed in this form in various media. These particles also have the extremely low cleaning coefficient typical of polytetrafluoroethylene resin. The radiation dose range according to the invention is generally between about 5 and < 3 about 25 and preferably between about 10 and 25 megarads.
1098Λ9/18091098Λ9 / 1809
besteht die Erfindung aus einem festen Polytetrafluorethylen, das thermisch nicht abgebaut ist und eine Teilehengrösse unter etwa 11,1 /u sowie einen Reibungskoeffizienten im Bereich von 0,04 bis 0,15 besitzt.the invention consists of a solid polytetrafluoroethylene, which is not thermally degraded and a part size below about 11.1 / u and a coefficient of friction in the range of 0.04 to 0.15.
Nachstehend wird die Erfindung an Hand einiger bevorzugter Ausführungsbeispiele näher erläutert, ohne auf sie beschränkt zu sein.The invention is explained in more detail below with reference to a few preferred exemplary embodiments, without being restricted to them to be.
Die Beispiele wurden in der Weise durchgeführt, dass -auf 3,2 bis 1,6 mm vorzerkleinerte- Proben aus einerseits nicht gesintertem und andererseits gesintertem Abfall-Polytetrafluoräthylen in nachstehend tabellierten Dosen der ionisierenden Strahlung eines 3MeV-Van de Graff-Beschleunigers unterworfen wurden und anschliessend zu der entsprechenden, ebenfalls tabellierten Korngrösse zerkleinert wurden. Die Korngrösschenbestimmung erfolgte dabei gemäss ASTMB-330-Vorschrift mittels Fisher Sub Sieve Sizer.The examples were carried out in such a way that -to 3.2 up to 1.6 mm pre-shredded samples made from, on the one hand, not sintered and on the other hand, sintered waste polytetrafluoroethylene in the doses of ionizing radiation tabulated below a 3MeV Van de Graff accelerator and were then crushed to the corresponding, also tabulated grain size. The grain size determination was carried out in accordance with ASTMB-330 regulation using a Fisher Sub Sieve Sizer.
fluoräthylen dauer (Sek.)Polytetra irradiation
fluoroethylene duration (sec.)
Me garaddose
Me garad
KorngrösseMedium
Grain size
Abfallsintered 12.5
waste
109849/16109849/16
Bei diesen Bestrahlungen stieg die Temperatur des Polytetrafluoräthylens niemals über etwa 1210C an, und es trat auch praktisch keine Produktverfärbung ein. Sämtliche Produkte besassen folgende typische Eigenschaften, die nach der jeweils angegebenen ASTM-Vorschrift hergestellt wurden.During this irradiation, the temperature of the polytetrafluoroethylene never rose above about 121 ° C., and there was also practically no discoloration of the product. All products had the following typical properties, which were manufactured according to the specified ASTM specification.
Schmelzpunkt ·Melting point
Farbe weiss oder grauColor white or gray
öpez. Gewicht 2,10-2,15 (D-792-6OT)öpez. Weight 2.10-2.15 (D-792-6OT)
Härte (Durometer D) 5C - 65 (D-1706-59T)Hardness (Durometer D) 5C - 65 (D-1706-59T)
Durchschlagsfestigkeit 50C - 1500 V/25,4 ,u (D-149-55T)Dielectric strength 50C - 1500 V / 25.4, u (D-149-55T)
Wasserabsorption keine (D-57O-54T)Water absorption none (D-57O-54T)
Entflammbarkeit nicht entflammbar (D-635-5ÖT)Flammability non-flammable (D-635-5ÖT)
Re ibungs koeffizientFriction coefficient
(statisch oder kinetisch) 0,04 - 0,15(static or kinetic) 0.04-0.15
- 5 109849/1609 - 5 109849/1609
Claims (1)
Nevj to wn, Pa., V. J t. A. Plastorner Corporation
Nevj to wn, Pa., V. J t. A.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US3989470A | 1970-05-22 | 1970-05-22 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| DE2109082A1 true DE2109082A1 (en) | 1971-12-02 |
Family
ID=21907917
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| DE19712109082 Pending DE2109082A1 (en) | 1970-05-22 | 1971-02-25 | Process for the non-destructive degradation of polytetrafluoroethylene |
Country Status (4)
| Country | Link |
|---|---|
| CA (1) | CA941331A (en) |
| DE (1) | DE2109082A1 (en) |
| FR (1) | FR2091707A5 (en) |
| GB (1) | GB1282410A (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6228428B1 (en) | 1991-10-28 | 2001-05-08 | The Gillette Company | Coating cutting edges with fluorocarbon polymers |
| US5263256A (en) * | 1992-04-17 | 1993-11-23 | The Gillette Company | Method of treating razor blade cutting edges |
-
1971
- 1971-02-25 DE DE19712109082 patent/DE2109082A1/en active Pending
- 1971-03-15 CA CA107,769A patent/CA941331A/en not_active Expired
- 1971-04-19 GB GB21277/71A patent/GB1282410A/en not_active Expired
- 1971-05-17 FR FR7117823A patent/FR2091707A5/fr not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| FR2091707A5 (en) | 1972-01-14 |
| CA941331A (en) | 1974-02-05 |
| GB1282410A (en) | 1972-07-19 |
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