Initiator molecule for a non linear absorption reaction, photopolymerisable composition that can be activated by biphotonic absorption and associated 3D printing method

Patent metadata

Field	Value
Publication number	US-12460086-B2
Application number	US-202118004649-A
Country	US
Kind code	B2
Filing date	Jul 8, 2021
Priority date	Jul 9, 2020
Publication date	Nov 4, 2025
Grant date	Nov 4, 2025

Abstract

A polymerization initiator molecule, excitable by two photons and capable of generating polymerization-initiating free radicals, includes two branches grafted onto a central phenyl nucleus. Each branch includes an oligomer of oligophenyleneethynylenyl type or oligo-2,5-dihalogenphenyleneethynylenyl type. A photopolymerizable composition, activatable by two-photon absorption, includes a radically polymerizable resin and a photochemically effective amount of a radical photoinitiator system. The photoinitiator system includes at least one initiator molecule as described above. Moreover, a method and an associated device for two-photon three-dimensional printing are disclosed. The method includes transforming a volume of a photopolymerizable composition including at least one initiator molecule. The transformation includes irradiating the volume of composition with an irradiation light source emitting an irradiation signal having a wavelength L irr of between 1 and 1.5 times, and preferably between 1.1 and 1.25 times, a cut-off wavelength L CutOff of the initiator molecule. Embodiments may apply to submicron-resolution two-photon 3D printing.

First claim

The invention claimed is:

1 . A polymerization initiator molecule, capable of being excited by two photons and of generating polymerization-initiating free radicals, the molecule comprising two branches and a halogen atom grafted onto a central phenyl nucleus respectively at positions 1, 3, and 5, each of the branches comprising an oligomer of oligophenyleneethynylenyl type or oligo-2,5-dihalogenphenyleneethynylenyl type.

2 . The polymerization initiator molecule of claim 1 , wherein each of the branches comprises the oligomer of the oligo-2,5-dihalogenphenyleneethynylenyl type, the dihalogen corresponding to two bromine atoms.

3 . The polymerization initiator molecule of claim 1 , wherein a free end of each of the branches is terminated by a terminal phenylamine.

4 . The polymerization initiator molecule of claim 1 , wherein each of the branches is a branch of
R=-[p-N,N-(dialkyl)aminophenylethynyl](oligophenyleneethynylenyl) or R′=-[p-N,N-(dialkyl)aminophenylethynyl](oligo-2,5-dihalophenyleneethynylenyl) type.

5 . The polymerization initiator molecule of claim 1 , wherein the halogen atom is a bromine atom.

6 . A photopolymerizable composition activatable by two-photon absorption, the composition comprising:
a radically polymerizable resin; and a photochemically effective amount of a radical photoinitiator system, wherein the radical photoinitiator system comprises at least one polymerization initiator molecule of claim 1 .

7 . The photopolymerizable composition of claim 6 , wherein the radically polymerizable resin comprises a main monomer of vinyl monomer type.

8 . The photopolymerizable composition of claim 7 , wherein the main monomer is a multifunctional acrylate monomer.

9 . The photopolymerizable composition of claim 6 , wherein the radically polymerizable resin comprises a solubilizing component comprising one or more of:
a monoacrylate with at least one alkyl chain, a diacrylate with at least one alkyl chain, and a dithiol.

10 . The photopolymerizable composition of claim 6 , wherein the photopolymerizable composition comprises 0.1% to 10% by weight of the radical photoinitiator system.

11 . The photopolymerizable composition of claim 9 , wherein the photopolymerizable composition comprises:
0.1% to 10% by weight of the radical photoinitiator system; and C5% to 60% of the solubilizing component.

12 . A method for two-photon three-dimensional printing, the method comprising:
transforming a volume of the photopolymerizable composition of claim 6 , the transforming comprising irradiating the volume of the photopolymerizable composition with an irradiation source emitting an irradiation signal having a wavelength Lin of between 1 and 1.5 times a cut-off wavelength L CutOff of the at least one initiator molecule, beyond which a molar extinction coefficient of the at least one initiator molecule is less than 1% of a maximum value of the molar extinction coefficient over an absorption band of the at least one initiator molecule.

13 . The method of claim 12 , wherein the irradiation signal results from a laser with a wavelength of between 508 and 578 nm.

14 . The method of claim 12 , wherein irradiating the volume of the photopolymerizable composition with the irradiation source comprises direct writing by a laser-type irradiation source, the direct writing being performed at a speed greater than 50 mm/s.

15 . The method of claim 12 , wherein irradiating the volume of the photopolymerizable composition with the irradiation source comprises parallel projection, of photolithographic type or of holographic projection type, with a number of irradiation sources exceeding ten thousand.

16 . A device for three-dimensional-printing, the device comprising means arranged to implement the method of claim 12 .

17 . The polymerization initiator molecule of claim 3 , wherein the terminal phenylamine is of a dialkylphenylamine type.

18 . The photopolymerizable composition of claim 7 , wherein the main monomer of vinyl monomer type comprises an acrylate monomer or a methacrylate monomer.

Assignees

• Univ Claude Bernard Lyon
• Centre Nat Rech Scient
• Ecole Normale Superieure Lyon

Inventors

• Banyasz Akos
• Monnereau Cyrille
• Baldeck Patrice
• Arnoux Caroline

Classifications

• C09D135/02

  Homopolymers or copolymers of esters (C09D135/06, C09D135/08 take precedence) · CPC title

• C08F2800/20

  as weight or mass percentages · CPC title

• C08F222/1006

  of polyhydric alcohols or polyhydric phenols · CPC title

• C08F2/50

  with sensitising agents · CPC title

• B29K2033/12

  Polymers of methacrylic acid esters, e.g. PMMA, i.e. polymethylmethacrylate · CPC title