DE1729183A1 - Process for the production of molding trains consisting of concentrically arranged layers of polytetrafluoroethylene - Google Patents
Process for the production of molding trains consisting of concentrically arranged layers of polytetrafluoroethyleneInfo
- Publication number
- DE1729183A1 DE1729183A1 DE19671729183 DE1729183A DE1729183A1 DE 1729183 A1 DE1729183 A1 DE 1729183A1 DE 19671729183 DE19671729183 DE 19671729183 DE 1729183 A DE1729183 A DE 1729183A DE 1729183 A1 DE1729183 A1 DE 1729183A1
- Authority
- DE
- Germany
- Prior art keywords
- strands
- inserts
- layers
- press
- polytetrafluoroethylene
- 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
Classifications
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C43/00—Compression moulding, i.e. applying external pressure to flow the moulding material; Apparatus therefor
- B29C43/006—Pressing and sintering powders, granules or fibres
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C43/00—Compression moulding, i.e. applying external pressure to flow the moulding material; Apparatus therefor
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
- B29C48/022—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor characterised by the choice of material
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
- B29C48/03—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor characterised by the shape of the extruded material at extrusion
- B29C48/04—Particle-shaped
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
- B29C48/03—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor characterised by the shape of the extruded material at extrusion
- B29C48/05—Filamentary, e.g. strands
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
- B29C48/03—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor characterised by the shape of the extruded material at extrusion
- B29C48/06—Rod-shaped
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
- B29C48/03—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor characterised by the shape of the extruded material at extrusion
- B29C48/09—Articles with cross-sections having partially or fully enclosed cavities, e.g. pipes or channels
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
- B29C48/15—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor incorporating preformed parts or layers, e.g. extrusion moulding around inserts
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
- B29C48/15—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor incorporating preformed parts or layers, e.g. extrusion moulding around inserts
- B29C48/151—Coating hollow articles
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
- B29C48/16—Articles comprising two or more components, e.g. co-extruded layers
- B29C48/18—Articles comprising two or more components, e.g. co-extruded layers the components being layers
- B29C48/21—Articles comprising two or more components, e.g. co-extruded layers the components being layers the layers being joined at their surfaces
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
- B29K2027/00—Use of polyvinylhalogenides or derivatives thereof as moulding material
- B29K2027/12—Use of polyvinylhalogenides or derivatives thereof as moulding material containing fluorine
- B29K2027/18—PTFE, i.e. polytetrafluorethene, e.g. ePTFE, i.e. expanded polytetrafluorethene
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
- B29K2105/00—Condition, form or state of moulded material or of the material to be shaped
- B29K2105/25—Solid
- B29K2105/251—Particles, powder or granules
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Extrusion Moulding Of Plastics Or The Like (AREA)
- Casting Or Compression Moulding Of Plastics Or The Like (AREA)
Description
Verfahren zum Ilerstellen von aus Ivonzentrisch zueinander angeordneten Schichten aus Polytetrafluoräthylen bestehenden Formsträngen Die Erfindung bezieht sich auf ein Verfahren zum Herstellen von aus konzentrisch zueinander angeordneten Schichten aus Polytetrafluoräthylen bestehenden Formstrangen, insbesondere von mit solchen Schichten isolierten Drahten, Litzen oder Kabeln, wobei einzelne Schichten Zusätze, vorzugsweise in Form von Füllstoffen, enthalten. Method for the production of ivons which are arranged centrically to one another Layers of molded strands consisting of polytetrafluoroethylene The invention relates refers to a method for producing from concentric to one another Layers of polytetrafluoroethylene existing molding strands, in particular with such layers insulated wires, strands or cables, with individual layers Contain additives, preferably in the form of fillers.
Bei dem Verfahren wird zuerst das pulverformige Polymerisat mittels einer Presse zu zylindrischen Formkörpern gepreßt und diese werden danach in einer Kolbenstrangpresse zu Formsträngen verpreßt.In the process, the powdery polymer is first by means of a press pressed into cylindrical shaped bodies and these are then in a Piston extruder pressed into shaped strands.
Bekanntlich wird Polytetrafluoräthylen bei Erwärmung nicht plastisch, sondern wandelt sich bei ungefhähr 325 C in eine geleeartige, nicht fließende Masse um, die nicht mit Schneckenpressen verarbeitet werclen kann. Zur Herstellung von Formsträngen werden daller aus dem kristallinen pulverformigen Polymerisat zuerst zylindrische Formkörper gepreßt, die anschließend in einer Kolbenstrangpresse zu Formsträngen verpreßt werden. Vor dem Pressen der Formkorper wird das pulverförmige Polymerisat mit einem Schmiermittel und weiteren Zusätzen - beispielsweise Asbest-oder Glasfasern, Farbpulver, Graphit, Molybdän-Disulfid oder sonstige Metallpulver, je nach Anwendungszweck der Formstränge - vermischt. Das Pressen zum Formkörper nann sowohl in der Rolbenstrangpresse, die zum Verpressen der Formkörper zu Formsträngen benutzt wird, als auch, uncl (lies ist aus wirtschaftlichen Griinden günstiger, in einer zweiten Presse erfolgen.It is known that polytetrafluoroethylene does not become plastic when heated, but at about 325 C it changes into a jelly-like, non-flowing mass that cannot be processed with screw presses. For production of Molded strands are then made from the crystalline powdery polymer first Cylindrical moldings are pressed, which are then closed in a piston extruder Form strands are pressed. Before pressing the moldings, the powdery Polymer with a lubricant and other additives - for example asbestos or Glass fibers, colored powder, graphite, molybdenum disulfide or other metal powder, each according to the application of the molded strands - mixed. Pressing to form the molded body is possible both in the roller extruder, which is used for pressing the shaped bodies into shaped strands is used, as well as, uncl (read is for economic reasons cheaper to do in a second press.
In vielen Fällen werden Formstränge gewünscht, die über ihren Querschnitt eine bestinunte sicyndernde Beschaffenheit hinsichtlich physikalischer, mechanischer oder elektrischer Eigenschaften aufweisen, so beispielsweise Formstränge mit einem bestimmten Farbüberzug, Formstränge mit einem Kern aus Polytetrafluoräthylen und einer Außenschicht beispielsweise aus einer Polytetrafluoräthylen-Molybdändisulfid-rIischung fiir selbstschmierende Achsen oder mit umgekehrtem Aufbau für Zahn-, Lauf-oder Reit) räder, die in ihren Achsbohrungen eine selbstschmierende Schicht auefweisen sollen, Drähte, Litzen oder Kabel mit einer Isolatinn aus Polytetrafluoräthylen und einer leitenden Amßenschicht, beispielsweise aus einer Polytetrafluoräthylen-Graphit-Mischung etc. Die Herstellung solcher Formstränge geschah bisher so, daß für jede Schicht eine Kolbenstrangpresse eingesetzt wurde-kontinuierliche Fertigung-oder der Formstrang entsprechend der Anzahl der Schichten mehrmals eine Kolbenstrangpresse durchlief-difskontinuierliche Fertigung. Die so erhaltenen Formstränge haben jedoch den Nachteil, daß die einzelnen Schichten nicht fest miteinander verbunden sind ; sie eignen sich daher nur in bestimmten Fällen zur Weiterverarbeitung zu Achsen, Zahnrädern etc.. Darüber hinaus ist eine solche Fertigung sehr teuer und aufwendig.In many cases, molded strands are desired that extend beyond their cross-section a certain sicyndendent nature in terms of physical, mechanical or have electrical properties, such as molded strands with a certain color coating, molded strands with a core made of polytetrafluoroethylene and an outer layer made of, for example, a polytetrafluoroethylene-molybdenum disulfide mixture for self-lubricating axles or with the reverse structure for tooth, running or riding) wheels that should have a self-lubricating layer in their axle bores, Wires, strands or cables with a polytetrafluoroethylene insulation and a conductive outer layer, for example made of a polytetrafluoroethylene-graphite mixture etc. The production of such molded strands has been done so that for each layer A piston extruder was used - continuous production - or the molding strand Depending on the number of layers, a piston extruder ran through a dif-continuous one several times Production. The molding strands obtained in this way, however, have the disadvantage that the individual Layers are not firmly bonded together; they are therefore only suitable in certain areas Cases for further processing into axles, gears etc .. In addition, a such production is very expensive and time-consuming.
Die Erfindung zeigt nun einen einfachen Weg zur Herstellung derartiger Formstränge und Isolierungen, die diese Nachteile nicht aufweisen und die einfach und billig gefertigt werden können. Das erfindungsgemäße Verfahren besteht darin, daß vor dem Einfüllen des pulverförmigen Polymerisats in die Presse diese -ensprechend der Anzahl der Schichten-durch rohrförmige, koaxial zur Pressenachse angeordnete Einsätze unterteilt wird, danach in die einzelnen, durch die Einsätze gebildeten Räume das pulverförmige, gegebenenfalls mit Zusätzen vermischter Polymerisat geschüttet wird, hierauf die Einsätze entfernt werden und schließlich das Pulver zu einem zylindrischen Formkörper gepreßt wird. Dieser Formkörper wird nun, soweit er sich nicht bereits in der Kolbenstrangpresse befindet, in diese eingesetzt und in bekannter Weise zu Formsträngen verpreßt. Durch das erfindungsgemäße Verfahren wird somit ein kontinuierlich verlaufender Herstellprozeß für Formstränge geschaffen, die aus konzentrisch zueinander angeordneten, fest miteinander verbundenen Schichten aus Polytetrafluoräthylen mit und ohne Zusätzen bestehen. Aus den Formsträngen können dann durch einfache spanabhebende Bearbeitung die gewünschten Teile, wie Achéen, Zahnräder, Lauf-oder Reibräder oder ähnliches, gefertigt werden.The invention now shows a simple way of producing such Form strands and insulation that do not have these disadvantages and that are simple and can be manufactured cheaply. The method according to the invention consists in that before the powdered polymer is poured into the press, this -speaking the number of layers-by tubular, coaxial to the press axis arranged stakes is divided, then into the individual, by the stakes spaces formed the powdery, optionally mixed with additives is poured, then the inserts are removed and finally the powder is pressed into a cylindrical shaped body. This shaped body is now so far it is not already in the piston extruder, inserted into it and pressed in a known manner to form strands. By the method according to the invention a continuous manufacturing process for molded strands is thus created, those made up of concentrically arranged, firmly connected layers consist of polytetrafluoroethylene with and without additives. From the molded strands can then through simple machining the desired parts, such as Achéen, Gears, running or friction wheels or the like can be manufactured.
In gleicher Weise ist es mit dem erfindungsgemäßen Verfahren möglich, Drähte, Litzen und auch Kabel mit s@lchen Schichten zu isolieren ; hierzu ist es nur erforderlich, daß die Kolbenstrangpressen zum Durchführen der Drähte, Litzen oder Kabel entsprechend ausgebildet sind.In the same way it is possible with the method according to the invention To insulate wires, strands and cables with small layers; this is what it is only required that the piston extrusion to pass through the wires, strands or cables are designed accordingly.
Beim Herausziehen der Einsätze ist daauf zu achten, daß das in den einzelnen, durch die rohrförmigen Einsätze gebildeten Räume befindliche, und mindestens teilweise mit Zusätzen verselme Polymerisatpulver an den Grenzflächen keinen großen Schubkräften ausgesetzt wird, da sonst an den Grenzflächen eine Vermischung der verschiedenen Pulver auftritt und damit eine klare Trennung der einzelnen Schichten nicht mehr gegeben ist. Dies kann insbesondere dann auftreten, wenn die Durchmesserverminderung von Formkörpern zum Formstrang relativ groß ist, also Formstränge kleiner Durchmesser, vie es beispielsweise bei Isolationsschichten für Drähte und Litzen der Fall ist, aus. Formkörpern großer Durchmesser verpreßt werden. Eine Vermischung der verschiedenen Pulver an ihren Grenzflächen würde dann einen Formstrang ergeben, der nicht mehr beispielsweise zevei Schichten aufweist, sondern nur noch eine, aus den beiden Schichten entstandene Mischsechicht. Um eine solche Vermischung zu vermeiden, wird daher am zweckmäßigsten der Einsatz langsam und mit gleichförmiger Geschwindigkeit herausgezogen.When pulling out the inserts, make sure that it is in the individual spaces formed by the tubular inserts, and at least Partly with additives, do not mix up a large polymer powder at the interfaces Shear forces is exposed, otherwise a mixing of the interfaces at the interfaces different powder occurs and thus a clear separation of the individual layers is no longer given. This can occur especially when the diameter reduction from molded bodies to the molded strand is relatively large, i.e. molded strands with a small diameter, as is the case, for example, with insulation layers for wires and strands, the end. Moldings of large diameter are pressed. A mix of the different Powder at their interfaces would then result in a molded strand that is no longer for example, has two layers, but only one of the two layers resulting mixed layer. In order to avoid such mixing, therefore, on Most appropriate the insert is withdrawn slowly and at a steady rate.
Bei der Verwendung mehrerer Einsätze, also bei der Herstellung aus mehreren zueinander angeordneten Schichten bestehenden Formsträngen empfiehlt es sich, die einzelnen Einsätze an der Einschüttseite durch eine oder mehrere Streben miteinander zu einer Einheit zu verbinden. Dies hat den Vorteil, daß alle Einsätze auf einmal aus der Presse gezogen werden können und zudem eine Zentrierung der Einsätze in der Presse erleichtert wird. Letztere kann beispielsweise dadurch geschehen, daß ein rohrformiger, einen Außendurchmesser entsprechend dem Innendurchmesser der Presse besitzenden Einsatz vorgesehen ist, der mit den anderen Einsätzen über Streben verbunden ist.When using several inserts, i.e. when producing from It recommends molding strands consisting of several layers arranged in relation to one another the individual inserts on the pouring side by one or more struts to connect with each other into one unit. This has the advantage that all stakes can be pulled out of the press at once and also a centering of the inserts is facilitated in the press. The latter can happen, for example, by that a tubular, an outer diameter corresponding to the inner diameter of the Press-owning insert is provided, which is connected to the other inserts via struts connected is.
Der Abstand der einzelnen Einsätze voneinander bzw. bei Verwendung nur eines einzigen Einsatzes - bei einem zweischichtigen Formstrang-vder Abstand des Einsatzes von der Pressenwand ist in einem enstprechenden Verhältnis v zu den gewiinschten Schichtdicken zu wählen. Dieses Verhältnis wird im allgemeinen empirisch ermittelt werden, da es stark von der Pressenform und der Form des Preßkolbens abhangt.The distance between the individual inserts or when used only a single insert - with a two-layer molded strand-v the spacing of the use of the press wall is in a corresponding ratio v to the to choose the desired layer thickness. This relationship generally becomes empirical can be determined, as it depends heavily on the shape of the press and the shape of the plunger.
Zur Erläuterung der Erfindung sei auf zwei Figuren hingewiesen, die in zum Teil schematischer Darstellung ein Ausführungsboispiel eines mit dem erfindungsgemä#en Verfahren hergestellton Formstranges und einer mit Einsätzen versehenen Presse beinhalten. In Figur 1 ist ein Querschnitt durch einen aus zwei konzentrischen Schichten bestehenden Formstrang gezeichnet. Die Schichten sind init 1 iind 2 bezeichnet.To explain the invention, reference is made to two figures which in a partly schematic representation, an exemplary embodiment of one with the one according to the invention Methods include making a molding strand and an inset press. In Figure 1 is a cross-section through one consisting of two concentric layers Form strand drawn. The layers are denoted by 1 and 2.
Die Figur 2 zeigt einen Querschnitt durch eine Presse 3 mit drei darin befindlichen Einsatzen 4, 5 und 6. Hierbei dient der rolirförmige Einsatz 6, der einen Außendurchmesser entsprechend dem Innendurchmesser der Presse besitzt, als Zentriermittel. Die drei Einsätze sind an der Einschüttseite durch Streben 7 miteinander verbunden.FIG. 2 shows a cross section through a press 3 with three therein Located inserts 4, 5 and 6. Here, the roll-shaped insert 6, the has an outer diameter corresponding to the inner diameter of the press, than Centering means. The three inserts are connected to one another on the pouring side by means of struts 7 tied together.
Claims (3)
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DEK0064028 | 1967-11-28 |
Publications (2)
Publication Number | Publication Date |
---|---|
DE1729183A1 true DE1729183A1 (en) | 1971-06-03 |
DE1729183B2 DE1729183B2 (en) | 1974-11-28 |
Family
ID=7231419
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
DE1729183A Pending DE1729183B2 (en) | 1967-11-28 | 1967-11-28 | Method for insulating an electrical conductor by extrusion molding of polytetrafluoroethylene and device for carrying out the method |
Country Status (1)
Country | Link |
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DE (1) | DE1729183B2 (en) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO1991000887A1 (en) * | 1989-07-12 | 1991-01-24 | Mather Seal Company | Composite sintered polymeric material |
EP2174779A2 (en) * | 2008-10-06 | 2010-04-14 | General Electric Company | Processes for Producing Multilayer Polytetrafluoroethylene Articles and Articles Formed Therefrom |
-
1967
- 1967-11-28 DE DE1729183A patent/DE1729183B2/en active Pending
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO1991000887A1 (en) * | 1989-07-12 | 1991-01-24 | Mather Seal Company | Composite sintered polymeric material |
EP2174779A2 (en) * | 2008-10-06 | 2010-04-14 | General Electric Company | Processes for Producing Multilayer Polytetrafluoroethylene Articles and Articles Formed Therefrom |
EP2174779A3 (en) * | 2008-10-06 | 2010-07-07 | General Electric Company | Processes for Producing Multilayer Polytetrafluoroethylene Articles and Articles Formed Therefrom |
Also Published As
Publication number | Publication date |
---|---|
DE1729183B2 (en) | 1974-11-28 |
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