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Particulate photoinitiators and uses thereof

a technology of photoinitiators and particles, applied in the field of photoinitiators, can solve the problems of reducing the photoactivity, affecting the overall efficiency of polymerization, and only partially solving the difficulty, and achieve the effect of low water solubility

Pending Publication Date: 2020-07-16
YISSUM RES DEV CO OF THE HEBREWUNIVERSITY OF JERUSALEM LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

The use of these nanoparticles facilitates fast and thorough polymerization in aqueous systems, enhancing the efficiency of 3D printing and coating processes while reducing environmental impact by eliminating solvent use.

Problems solved by technology

This difficulty is only partially resolved by using water-insoluble photoinitiators, in organic solvents, or by using their water-soluble derivatives, typically prepared through tedious synthetic procedures.
Direct manipulation on the photoinitiator structure, rendering it water soluble, often decreases its photo-activity and consequently affects the overall efficiency of polymerization.
However, TPO has very low water solubility (3.13 mgL−1 at 25° C.) and as such cannot be used in aqueous inks.
The use of such dispersions renders unnecessary the need for solvents.

Method used

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  • Particulate photoinitiators and uses thereof
  • Particulate photoinitiators and uses thereof
  • Particulate photoinitiators and uses thereof

Examples

Experimental program
Comparison scheme
Effect test

example 1

on of Photoinitiator Containing Microemulsions

[0084]TPO nanoparticles were prepared by rapid conversion of volatile microemulsions droplets, while using oil-in-water microemulsions containing TPO at various concentrations.

TABLE 1Compositions (in % w / w) of microemulsions of TPO:nBuAc = n-butyl acetate; IPA = isopropyl alcohol;SDS = sodium dodecyl sulfate; PVP =polyvinylpyrrolidone (MW 40,000); TDW = Triple Distilled Water.SampleNo.TPOnBuAcIPASDSPVPTDW102421.07.57.54020.823.221.07.57.54031.722.321.07.57.54042.621.421.07.57.54053.820.321.07.57.54065.019.021.07.57.540

TABLE 2Compositions (in % w / w) of alcohol-water mixtures (SampleNo. 1-4) and microemulsions (Sample No. 5-6) of variousphotoinitiators; nBuAc = n-butyl acetate; IPA = isopropylalcohol; SDS = sodium dodecyl sulfate; PVP = polyvinylpyrrolidone(MW 40,000); TDW = Triple Distilled Water.SamplePhotoinitiatorNo.TypeAmountSDSIPAnBuAcPVPTDW1Ig 1842.522.55000252Ig29592.522.55000253Ig6512.522.55000254Ig9072.522.55000255ITX1.57.52122.5...

example 2

y of TPO Nanoparticles Photoinitiator

[0087]Photoinitiation is the most critical step in a photopolymerization process, which determines the kinetics and properties of the resulting polymerized objects. Rate of photopolymerization is generally proportional to the square root of the rate of initiation (Ri). For photoinitiated polymerization, Ri is directly proportional to the incident light intensity, the concentration of photoinitiator and the intrinsic properties of the photoinitiator. The intrinsic properties of the photoinitiator that influence its utility are the molar extinction coefficient (ε), the quantum yield or cleavage events that occur per photon absorbed, and the photoinitiator efficiency or the ratio of initiation events to radicals generated by photolysis. For efficient polymerization, the initiator should have a large e and good overlapping absorbance spectrum with the emission spectrum of the light sources.

[0088]The molar extinction coefficient of TPO nanoparticles w...

example 3

nt of Photoinitiator Activity

[0092]To determine the polymerization efficiency of TPO nanoparticles, polymerization kinetics of acrylamide in aqueous solutions with TPO nanoparticles was compared to that of aqueous solutions of the commonly used photoinitiator 12959. Fourier Transform Infrared Spectrophotometer, (ALPHA FT-IR Spectrometer, Bruker) was used in conjunction with platinum ATR single reflection diamond accessory (Sample scans 64; Resolution 4 cm−1). The polymerization medium comprised aqueous solutions of 20% w / w monomer (acrylamide) with cross-linking monomer polyethylene glycol 600 diacrylate (5% w / w of the monomer) and photoinitiator (TPO nanoparticles or Igracure 2959 at concentration of 0.5% w / w of the monomer). The resulting aqueous acrylamide solutions had 2.9 mM of TPO and 4.5 mM of 12959. Measurements were performed on ˜200 μl of polymerization solution dropped on the ATR diamond. The UV light was radiated onto the sample through a chamber (at 1.5 cm height) cente...

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Abstract

Provided is a novel class of solid water-dispersible powders, including a plurality of water-insoluble photoinitiators in nanoparticle forms for use in water-based ink formulations.

Description

TECHNOLOGICAL FIELD[0001]The invention generally concerns photoinitiators in particulate form and uses thereof.BACKGROUND[0002]The growing concerns over developing economic and environment friendly coatings, adhesives and printing inks has led attention towards photo-polymerization of aqueous photo-curable systems. Current methods of coating (wood / automotive) result in considerable emission of volatile organic compounds that are harmful to humans and the atmosphere. To prevent or minimize such an emission, new developments in the field focus on formulations with a low solvent content, water based paints, and IR- or UV-curing systems. Among these, developing water borne UV curing systems offers several economical productivity advantages in terms of production time (fast curing / production efficiency), energy consumed (low-temperature processing; no high energy-consuming drying ovens), stability (higher shelf life, no pot-life issues), safety (little or no use of reactive diluents, non...

Claims

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Application Information

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Patent Type & Authority Applications(United States)
IPC IPC(8): G03F7/028G03F7/00G03F7/004C08F2/50
CPCB82Y20/00G03F7/0048G02B2207/101G03F7/028C08F2/50G03F7/0037
Inventor MAGDASSI, SHLOMOLARUSH, LIRAZCOOPERSTEIN, IDOPAWAR, AMOL ASHOK
Owner YISSUM RES DEV CO OF THE HEBREWUNIVERSITY OF JERUSALEM LTD