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Additive Processing of Fluoropolymers

IP.com Disclosure Number: IPCOM000249472D
Publication Date: 2017-Feb-28

Publishing Venue

The IP.com Prior Art Database

Abstract

Provided are methods for making shaped fluoropolymer by additive processing using a polymerizable binder. Also are 3D printable compositions for making shaped fluoropolymer articles and articles comprising a shaped fluoropolymer.

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Additive Processing of Fluoropolymers

ABSTRACT

Provided are methods for making shaped fluoropolymer by additive processing using a

polymerizable binder. Also are 3D printable compositions for making shaped fluoropolymer articles and

articles comprising a shaped fluoropolymer.

BACKGROUND

Fluoropolymers are widely used as raw materials for their chemical inertness, in particular for

articles requiring low friction properties and /or inertness to chemicals and heat. Perfluorinated polymers

are particularly inert.

Fluoropolymers are typically classified into thermoplastics and elastomers (sometimes also

referred to as fluororubbers).

Fluorothermoplastics can be processed by conventional melt shaping methods, such as injection

molding and extrusion. Fluorothermoplastics typically are copolymers of tetrafluoroethylene (TFE) with

one or more other perfluorinated, partially fluorinated or non-fluorinated comonomers. Copolymers of

TFE and perfluorinated alkyl or allyl ethers are known in the art as PFA’s (perfluorinated alkoxy

polymers). Copolymers of TFE and hexafluoropropylene (HFP) with or without other perfluorinated

comonomers are known in the art as FEP’s (fluorinated ethylene propylene). Copolymers of TFE, HFP

and vinylidenefluoride (VDF) are known in the art as THV. Other types of melt-processable

fluoropolymers are based on vinylidenefluoride homo- or copolymers, known in the art as PVDF.

Copolymers of TFE and ethylene are known as ETFE.

Certain types of thermoplastics, have a very high melt viscosity (low melt flow index (MFI) and

are termed in the art as “non-melt processable”. Non-melt processable fluoropolymers include

homopolymers of TFE or copolymers of TFE with other copolymerizable perfluorinated monomers,

wherein the amount of comonomers is limited to less than 1 %wt. Such TFE homo-and copolymers are

referred to in the art as PTFE. PTFE has such a high melt viscosity that it cannot be processed by

conventional melt processing techniques such as extrusion, injection molding or blow molding.

Homopolymers of tetrafluoroethylene (TFE) or copolymers of TFE with other copolymerizable

perfluorinated monomers, wherein the amount of comonomers is limited to less than 1 % by weight based

on the weight of the polymer, are referred to in the art as polytetrafluoroethylene (PTFE). PTFE and other

comonomers of tetrafluoroethylene with a comparable high melt viscosity (low melt flow rate) cannot be

shaped by conventional melt processing techniques such as extrusion, injection molding or blow molding.

PTFE articles typically are formed by ram extrusion, or by press-sintering PTFE particles into billets that

are then machined into the desired shape. These are subtractive methods where material is removed to

shape articles.

In WO2007/133912 A2 an additive manufacturing process for special thermoplastic

fluoropolymers (PVDF and PCTF) are described but examples are not provided. In CN103709737 A and

CN 105711104 A methods for 3D printing are described w...