Curable Compositions Using Metal Complex Catalysts
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Solution Overview
Problem
Current radiation-curable formulations using epoxy- and oxetane-functional resins with cationic photoinitiators are limited by low absorptivity, leading to slow curing speeds and requiring additional components like (meth)acrylate-functional materials for improved mechanical properties and reduced shrinkage.
Innovation Solution
Incorporating polymerizable, ethylenically unsaturated metal complexes into curable compositions containing (meth)acrylate-functional materials and heterocyclic moiety-containing compounds, which accelerates thermal curing and photocuring, eliminating the need for cationic photoinitiators and allowing for the inclusion of ethylenically unsaturated materials with urethane functionality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If cationic photoinitiators are used to cure cyclic ether-functional resins, then the formulation can achieve curing through radiation, but the curing speed is slow due to low absorptivity at long wavelengths
Solution Approach 1:
The patent changes the chemical composition parameters by introducing metal complexes (zinc, calcium, aluminum, boron, or magnesium acetylacetonates, beta-diketonates, or beta-diketamides) combined with (meth)acrylate-functionalized compounds. This compositional parameter change enables the system to achieve both rapid thermal curing and adequate radiation curing without relying on cationic photoinitiators with low absorptivity.
Solution Approach 2:
The patent creates a composite curing system that combines metal complex catalysts with (meth)acrylate-functionalized cyclic ether resins. This composite approach allows the formulation to utilize both thermal and radiation curing mechanisms simultaneously, achieving high productivity through thermal curing while maintaining the benefits of radiation-initiated polymerization.
2Strength
If epoxy- and oxetane-functional resins are incorporated into radiation-curable formulations, then mechanical properties and shrinkage are improved, but the formulation requires additional (meth)acrylate-functional materials and cationic photoinitiators
Solution Approach 1:
The patent makes the (meth)acrylate-functionalized cyclic ether resin serve multiple functions: it acts as both the structural resin providing mechanical properties and shrinkage reduction, and as the radiation-curable component. The metal complex serves dual roles as both catalyst for thermal curing and component of the radiation-curable system, eliminating the need for separate cationic photoinitiators.
Solution Approach 2:
The patent extracts and eliminates the need for cationic photoinitiators from the formulation by using metal complex-catalyzed thermal curing combined with radiation curing of (meth)acrylate groups. This removal simplifies the formulation by reducing the number of required components while maintaining both mechanical performance and curing capability.
3Productivity
If thermal curing is used to cure cyclic ether-functional resins, then the curing speed can be increased, but additional heating equipment and process time are required
Solution Approach 1:
The patent merges thermal curing and radiation curing into a single integrated process. The metal complex-catalyzed thermal curing and the radiation-induced polymerization of (meth)acrylate groups occur simultaneously or in rapid sequence, achieving complete curing of both the cyclic ether resin and the (meth)acrylate-functionalized compounds in one operation, thereby reducing total process time.
Solution Approach 2:
The metal complex is pre-incorporated into the formulation at controlled concentrations (0.1-10 wt% based on total resin), preparing the system in advance for rapid thermal curing response. This preliminary inclusion of the catalyst ensures that when thermal energy is applied, the curing reaction immediately proceeds at high speed without requiring additional activation steps.
4Productivity
If polymerizable, ethylenically unsaturated metal complexes are included in the curable composition, then thermal curing is accelerated and production rate is enhanced, but metal leaching may occur
Solution Approach 1:
The patent optimizes the concentration parameter of metal complexes within the range of 0.1-10 wt% based on total resin content. This parameter control balances the need for sufficient catalytic activity to achieve rapid curing with the need to minimize metal content to reduce leaching risks. The specific selection of metals (zinc, calcium, aluminum, boron, magnesium) also considers their相对较低 leaching tendencies compared to other metal options.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enables rapid thermal curing and dual interpenetrating polymeric networks, enhancing production rates in applications like 3D printing while reducing metal leaching and allowing for the use of urethane-containing compounds without inhibiting curing.
Implementation Method 1
the metal complex is photopolymerizable (through its ethylenically unsaturated functional groups) along with the other polymerizable, ethylenically unsaturated compounds and the metal center is catalytically active in the photocured network toward the ring-opening polymerization of the heterocyclic moiety-containing compounds
Implementation Method 2
the metal complex is photopolymerizable (through its ethylenically unsaturated functional groups) along with the other polymerizable, ethylenically unsaturated compounds and the metal center is catalytically active in the photocured network toward the ring-opening polymerization of the heterocyclic moiety-containing compounds
Implementation Method 3
the metal complex is photopolymerizable (through its ethylenically unsaturated functional groups) along with the other polymerizable, ethylenically unsaturated compounds
Data Source
AI summary
Heterocyclic-functional resins, such as epoxides, oxetanes, cyclic carbonates, lactides and lactones, are used in radiation-curable formulations along with ethylenically unsaturated materials such as (meth)acrylates to achieve improved mechanical properties and/or lower shrinkage in the cured compositions prepared therefrom as compared to formulations containing the ethylenically unsaturated materials but no heterocyclic-functional resin. Polymerizable, ethylenically unsaturated metal complexes, such as Zn and Ca carboxylates prepared using unsaturated carboxylic acids or anhydrides, may be employed to effect thermal cure of the heterocyclic-functional resin component of such formulations, which are particularly useful in the production of 3D-printed articles and the like.