Method for producing a cross-linkable polymer with the formation of oxazolidinones

Patent metadata

Field	Value
Publication number	US-11905360-B2
Application number	US-201816754561-A
Country	US
Kind code	B2
Filing date	Oct 12, 2018
Priority date	Oct 13, 2017
Publication date	Feb 20, 2024
Grant date	Feb 20, 2024

Abstract

The invention relates to a method for producing a polymer comprising the following steps: (A) depositing a radically cross-linkable resin, obtaining a radically cross-linked resin; and (B) treating the radically cross-linked resin under conditions which are sufficient to trigger a chemical reaction that is different from the radical cross-linking in the radically cross-linked resin. The radically cross-linkable resin comprises a curable component, in which there are NCO groups, olefinic C═C double bonds and epoxide groups, and the chemical reaction in the radically cross-linked resin that is different from the radical cross-linking is the reaction of NCO groups and epoxide groups to form oxazolidinone groups.

First claim

The invention claimed is:

1. A process for producing a polymer, comprising:
Step A) depositing a free-radically crosslinkable resin to obtain a free-radically crosslinked resin; and
Step B) treating the free-radically crosslinked resin under conditions sufficient to trigger a chemical reaction different than free-radical crosslinking in the free-radically crosslinked resin,
wherein the free-radically crosslinkable resin comprises a curable component in which NCO groups, olefinic C═C double bonds, and epoxide groups are present, and
wherein the chemical reaction in the free-radically crosslinked resin different than free-radical crosslinking is a reaction of NCO groups and epoxide groups to form oxazolidinone groups.

2. The process as claimed in claim 1 , wherein the curable component comprises a curable compound that contains epoxide groups and olefinic C═C double bonds.

3. The process as claimed in claim 1 , wherein the curable component comprises a curable compound that contains NCO groups and olefinic C═C double bonds.

4. The process as claimed in claim 1 , characterized in that the free-radically crosslinkable resin further comprises a free-radical initiator and/or a Lewis acid catalyst.

5. The process as claimed in claim 1 , wherein treating the free-radically crosslinked resin under conditions sufficient to trigger a chemical reaction different than free-radical crosslinking in the free-radically crosslinked resin comprises heating at a temperature of ≥60° C.

6. The process as claimed in claim 1 , wherein the free-radically crosslinkable resin is applied as a coating to a substrate.

7. The process as claimed in claim 1 , wherein the process is an additive production process and wherein the polymer is in the form of an object formed from a precursor, wherein in step A) the free-radically crosslinked resin is the precursor and the treating in step B) results in obtaining the object.

8. The process as claimed in claim 7 , wherein the depositing in step A) comprises:
I) depositing the free-radically crosslinked resin on a carrier to obtain a ply of build material joined to the carrier that corresponds to a first selected cross section of the precursor;
II) depositing the free-radically crosslinked resin onto the ply of build material to obtain a further ply of build material that corresponds to a further selected cross section of the precursor that is joined to the previously applied ply;
III) repeating step II) until the precursor is formed;
wherein depositing the free-radically crosslinked resin at least in step II) further comprises exposure and/or irradiation of a selected region of the free-radically crosslinkable resin corresponding to the respectively selected cross section of the precursor and
the treating in step B) comprises:
IV) treating the precursor obtained in step III) under conditions sufficient for reaction of NCO groups and epoxide groups to form oxazolidinone groups.

9. The process as claimed in claim 8 , further comprising:
lowering the carrier by a predetermined distance before each step II) so that a layer of the free-radically crosslinkable resin forms above the uppermost ply of build material viewed in the vertical direction, and
exposing and/or irradiating the selected region of the layer of the free-radically crosslinkable resin corresponding to the respectively selected cross section of the precursor with an energy beam in step II),
wherein the carrier is positioned inside a container and is vertically lowerable in the direction of gravity, and
wherein the container contains the free-radically crosslinkable resin in an amount sufficient to cover at least the carrier and crosslinked resin deposited on the carrier.

10. The process as claimed in claim 8 , further comprising:
raising the carrier before each step II) by a predetermined distance so that a layer of the free-radically crosslinkable resin forms below the lowermost ply of build material viewed in the vertical direction,
providing the free-radically crosslinkable resin to the carrier from the container, and
simultaneously exposing and/or irradiating the selected region of the layer of the free-radically crosslinkable resin corresponding to the respectively selected cross section of the precursor with a plurality of energy beams in step II),
wherein the carrier is positioned inside a container and is vertically raisable counter to the direction of gravity.

11. The process as claimed in claim 8 , further comprising:
applying the free-radically crosslinkable resin from one or more print heads in step II) in accordance with the respectively selected cross section of the precursor and subsequently exposing and/or irradiating the respectively selected cross section of the precursor with an energy beam.

Assignees

• Covestro Deutschland Ag
• Stratasys Inc

Inventors

• Achten Dirk
• Buesgen Thomas
• Wagner Roland
• Stempfle Florian
• Tomczyk Christoph

Classifications

• C08G18/8125 Primary

  having two or more isocyanate or isothiocyanate groups · CPC title

• B33Y70/00

  Materials specially adapted for additive manufacturing · CPC title

• C08G18/003 Primary

  with epoxy compounds having no active hydrogen (with epoxy resins containing active hydrogen C08G18/58) · CPC title

• C08G18/225

  of alkali or alkaline earth metals · CPC title

• C08G85/002

  Post-polymerisation treatment · CPC title