Additive processing of fluoropolymers

Patent metadata

Field	Value
Publication number	US-11230053-B2
Application number	US-201716071819-A
Country	US
Kind code	B2
Filing date	Jan 19, 2017
Priority date	Jan 21, 2016
Publication date	Jan 25, 2022
Grant date	Jan 25, 2022

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.

First claim

The invention claimed is:

1. A method of producing a fluoropolymer article by additive processing in an additive processing device containing at least one energy source, the method comprising
(i) depositing a composition comprising fluoropolymer particles and a polymerizable binder to create a layer of the composition;
(ii) exposing areas of the composition in the layer to the energy source to polymerize and solidify the binder and bind the fluoropolymer particles in the areas exposed to the energy source; and
(iii) repeating steps (i) and (ii) to form successive layers of the fluoropolymer article; wherein the fluoropolymer is selected from the group consisting of
(a) polytetrafluoroethylene, consisting of tetrafluoroethylene homopolymers and tetrafluoroethylene copolymers containing up to 1% by weight of perfluorinated alpha-olefin comonomers; and
(b) tetrafluoroethylene copolymers containing more than 1% by weight and up to 30% by weight based on the weight of the polymer of perfluorinated comonomers, partially fluorinated comonomers and non-fluorinated comonomers.

2. The method of claim 1 wherein the energy source is selected from electromagnetic irradiation.

3. The method of claim 1 wherein the composition comprises fluoropolymer particles having an z-average particle size from about 50 to 500 nm.

4. The method of claim 1 wherein the composition comprises an aqueous dispersion of fluoropolymer particles.

5. The method of claim 1 wherein the fluoropolymer has a melt flow index at 372° C. and 5 kg load of less than 1 g/10 min.

6. The method of claim 1 wherein the fluoropolymer has a melt flow index at 372° C. and 5 kg load of from 1 to 50 g/10 min.

7. The method of claim 1 wherein the fluoropolymer is a tetrafluoroethylene copolymer containing more than 1% by weight and up to 30% by weight based on the weight of the polymer of perfluorinated comonomers, partially fluorinated comonomers and non-fluorinated comonomers and wherein the fluoropolymer has a melting point between 260° C. and 315° C.

8. The method of claim 1 wherein the binder material comprises polymerizable unsaturated bonds.

9. The method of claim 1 wherein the binder material comprises polymerizable groups selected from acrylates and methacrylates.

10. The method of claim 1 further comprising, after step (iii), (iv) at least one heat treatment to remove the binder material.

11. The method of claim 10 , further comprising sintering the fluoropolymer particles during the at least one heat treatment to remove the binder material.

12. The method of claim 10 , further comprising (v) sintering the fluoropolymer particles after step (iv).

13. The method of claim 1 wherein causing the binder material to polymerize and solidify to bind fluoropolymer particles comprises
(i) either (a): directing energy from the energy source of the additive manufacturing device to a selected location of the layer of the composition and causing the binder material to polymerize and solidify to bind fluoropolymer particles; or (b): directing a selected location of the composition to the energy source and causing the binder material to polymerize and solidify to bind fluoropolymer particles, or a combination of (a) and (b);
(ii) either (c) directing the energy source away from the composition or (d) directing the composition away from the energy source, to avoid the binder material polymerizing in the non-selected locations, or a combination of (c) and (d).

Assignees

• 3M Innovative Properties Co

Inventors

• Bartow Jeffrey N
• Franke Carsten
• Wright Robin E
• Zentis Fee
• Hintzer Klaus
• Gottschalk-Gaudig Gabriele H
• Gangnus Bernd
• Korten Malte
• Schechner Gallus
• Neumann Wolfgang

Classifications

• B33Y70/10

  Composites of different types of material, e.g. mixtures of ceramics and polymers or mixtures of metals and biomaterials · CPC title

• B33Y70/00

  Materials specially adapted for additive manufacturing · CPC title

• B29C64/165 Primary

  using a combination of solid and fluid materials, e.g. a powder selectively bound by a liquid binder, catalyst, inhibitor or energy absorber · CPC title

• B33Y30/00

  Apparatus for additive manufacturing; Details thereof or accessories therefor · CPC title

• B29C64/214

  Doctor blades · CPC title