Vat resin with additives for thiourethane polymer stereolithography printing

Patent metadata

Field	Value
Publication number	US-11427718-B2
Application number	US-201816170342-A
Country	US
Kind code	B2
Filing date	Oct 25, 2018
Priority date	Oct 27, 2017
Publication date	Aug 30, 2022
Grant date	Aug 30, 2022

Abstract

A vat resin for three-dimensional stereolithography printing of a thiourethane polymer part comprising a liquid mixture including a first type of monomer, a second type of monomer, a photolatent base decomposable upon exposure to a light to form a non-nucleophillic base catalyst having a pKa greater than 7, an anionic step-growth polymerization reaction inhibitor having an acidic group configured to form an acid-base pair with the non-nucleophillic base and a light absorber having an absorbance in the liquid mixture that is greater than an absorbance of the photolatent base at a wavelength of the light used for the exposure. Methods of preparing the vat resin and three-dimensional stereolithography printing a thiourethane polymer part using the vat resin are also disclosed.

First claim

What is claimed is:

1. A vat resin for three-dimensional stereolithography printing of a thiourethane polymer part comprising:
a liquid mixture including:
a first type of monomer including two or more thiol functional groups,
a second type of monomer including two or more isocyanate functional groups,
a photolatent base, wherein the photolatent base is decomposable upon exposure to a light to form a non-nucleophillic base catalyst having a pKa greater than 7;
an anionic step-growth polymerization reaction inhibitor, the inhibitor having an acidic group configured to form an acid-base pair with the non-nucleophillic base; and
a light absorber having an absorbance in the liquid mixture that is greater than an absorbance of the photolatent base at a wavelength of the light used for the exposure.

2. The vat resin of claim 1 , wherein the vat resin is substantially free of water.

3. The vat resin of claim 1 , wherein a mole ratio of the photolatent base to the anionic step-growth polymerization reaction inhibitor is in a range from about 5:1 to 15:1.

4. The vat resin of claim 1 , wherein the anionic step-growth polymerization reaction inhibitor is a strong organic acid and is non-oxidizing with respect to oxidize the thiol functional groups of the first type of monomer in the liquid mixture.

5. The vat resin of claim 1 , wherein the anionic step-growth polymerization reaction inhibitor includes one or more of octanoic acid, methanesulfonic acid, trifluoromethanesulfonic acid or carboxlic acid.

6. The vat resin of claim 1 , wherein the anionic step-growth polymerization reaction inhibitor includes p-toluenesulfonic acid has a concentration in the liquid mixture in a range from about 0.001 to 0.2 wt %.

7. The vat resin of claim 1 , wherein the light absorber in the liquid mixture has an absorbance that is at least about 1 percent higher than the absorbance of the photolatent base at the wavelength of the light that the vat resin is exposed to.

8. The vat resin of claim 1 , wherein the light absorber in the liquid mixture has molar extinction coefficient of at least about 10000 M −1 cm −1 at the wavelength used to activate the photolatent base.

9. The vat resin of claim 1 , wherein the light absorber in the liquid mixture has a concentration of 1 mM or less and an absorbance of at least about 1 at a wavelength of the light used for the exposure.

10. The vat resin of claim 1 , wherein the light absorber in the liquid mixture has a concentration that is in a range from about 0.001 to 1 wt %.

11. The vat resin of claim 1 , wherein the light absorber in the liquid mixture includes 2,2′-(2,5-thiophenediyl)bis(5-tert-butylbenzoxazole.

12. The vat resin of claim 1 , wherein the photolatent base is or includes 5-(2′-(methyl)thioxanthone)-1,5-diazabicyclo[4.3.0]non-5-ene tetraphenylborate.

13. The vat resin of claim 1 , wherein first type of monomer includes one of more of: 2,2′-(ethylenedioxy)diethanethiol, decanedithiol, hexanedithiol, glycol dimercaptoacetate, glycol dimercaptopropionate, thiobisbenzenethiol, xylene dithiol, pentaerythritol tetramercaptoacetate, pentaerythritol tetramercaptopropionate, dipentaerythritol hexamercaptopropionate, trimethylolpropane trimercaptoacetate, trimethylolpropane trimercaptoacetate, or tris[2-(3-mercaptopropionyloxy)ethyl] isocyanurate.

14. The vat resin of claim 1 , wherein second type of monomer includes one of more of: hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, diisocyanatooctane, isophorone diisocyanate, xylene diisocyanate, toluene diisocyanate, phenylene diisocyanate, bis(isocyanatomethyl)cyclohexane, 4,4′-methylenebis(phenyl isocyanate), 4,4′-methylenebis(cyclohexyl isocyanate), or tris(6-isocyanatohexyl)isocyanurate.

15. The vat resin of claim 1 , wherein the light absorber in the liquid mixture has an absorbance in a range of about 5 to 10 percent higher than the absorbance of the photolatent base at the wavelength of the light that the vat resin is exposed to.

16. The vat resin of claim 1 , wherein the light absorber in the liquid mixture has an absorbance in a range of about 10 to 20 percent higher than the absorbance of the photolatent base at the wavelength of the light that the vat resin is exposed to.

Assignees

• Univ Texas
• Adaptive 3D Tech

Inventors

• Ellson Gregory T
• Lund Benjamin R
• Voit Walter

Classifications

• B33Y70/00

  Materials specially adapted for additive manufacturing · CPC title

• C08G18/73

  acyclic · CPC title

• C08G18/089

  Reaction retarding agents · CPC title

• C08G18/7621

  being toluene diisocyanate including isomer mixtures · CPC title

• C08G18/2063

  having two nitrogen atoms in the condensed ring system · CPC title