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ADDITIVE PROCESSING OF FLUOROPOLYMERS

IP.com Disclosure Number: IPCOM000249477D
Publication Date: 2017-Feb-28

Publishing Venue

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Abstract

Provided are method of producing a shaped fluoropolymer articles. The methods include subjecting a composition comprising a fluoropolymer to additive processing in an additive processing device. Also provided are articles obtained with the methods and 3D-printable compositions.

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ADDITIVE PROCESSING OF FLUOROPOLYMERS

ABSTRACT

Provided are method of producing a shaped fluoropolymer articles. The methods include

subjecting a composition comprising a fluoropolymer to additive processing in an additive processing

device. Also provided are articles obtained with the methods and 3D-printable compositions.

BACKGROUND

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

articles requiring low friction properties and /or inertness to chemical reactivity, heat, or both.

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. Instead

PTFE articles typically are produced by paste extrusion, or by sintering to produce blocks or billets which

are then shaped into articles. For example by skiving, turning, machining (i.e., substractive 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 where the use of PTFE is mentioned. The materials are

processed by irradiating a polymer powder with infrared or lasers and melting the powder in selected

areas exposed to the IR- or laser irradiation. These methods are known in the art of 3D-printing as laser

melting or laser sintering. In US 7,569,273 B2 a different method is described that is reported to be

suitable for PVDF. Examples are also not provided. The method described in US 7,569,273...