Bio-based binder system for foundry molds
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Solution Overview
Problem
Conventional phenolic-urethane binders used in the foundry industry contain organic solvents and free formaldehyde/phenol, leading to unpleasant odors and potential health issues, and can prematurely react with gaseous catalysts, reducing the flowability and strength of molds and cores.
Innovation Solution
A bio-based binder system comprising a polymerizable hydroxyl-containing component (PHCC) from saccharides, an isocyanate component, and a tertiary amine catalyst, which can be used in solvent-diluted systems with foundry aggregates like sand, eliminating volatile organic compounds (VOCs) and free formaldehyde/phenol, and allowing for controlled curing in cold-box or no-bake processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional phenolic-urethane binders are used in the cold-box process, then the molds and cores can be cured, but the binders contain organic solvents and free formaldehyde/phenol which cause unpleasant odors and health issues
Solution Approach 1:
The patent changes the chemical composition parameters of the binder system by replacing phenolic resin with a polymerizable hydroxyl-containing component (PHCC) that reacts with isocyanate to form polyurethane. This substitution eliminates the need for organic solvents and free formaldehyde/phenol, thereby resolving the harmful factors while maintaining curing functionality
Solution Approach 2:
The patent creates a composite binder system combining PHCC and isocyanate components that work synergistically. The PHCC provides hydroxyl groups for polymerization while isocyanate provides crosslinking capability, forming a composite material system that achieves both environmental benefits and mechanical performance
2Strength
If phenolic-urethane binder components are mixed with sand to form foundry mix, then the binder can strengthen molds and cores, but the components may prematurely react prior to curing which reduces flowability and strength
Solution Approach 1:
The patent divides the binder system into separate components (PHCC and isocyanate) that are mixed with sand but do not react until the curing stage. This segmentation prevents premature reaction while maintaining the ability to strengthen molds and cores upon curing, thereby resolving the contradiction between strength and flowability
Solution Approach 2:
The patent prepares the foundry mix with pre-mixed PHCC and sand, but delays the isocyanate addition until just before curing. This preliminary preparation maintains flowability during mixing and shaping operations, while ensuring strength development occurs at the appropriate curing stage
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
The bio-based binder system provides environmentally attractive solutions with improved flowability and strength of molds and cores, reducing VOC emissions and health hazards while maintaining or exceeding the performance of conventional phenolic-urethane binders.
Implementation Method 1
a catalyst, and preferably tertiary amine catalyst, component adapted to catalyze the polymerization of a) and b)
Implementation Method 2
catalyze the polymerization of a) and b)
Data Source
AI summary
A bio-based binder system for use in preparing foundry molds. In a preferred embodiment, the system includes the use of a) a polyermizable hydroxyl-containing component comprising a saccharide, b) an isocyanate component, and c) a catalyst, and preferably amine catalyst, component adapted to catalyze the polymerization of a) and b), in the presence of a foundry aggregate such as sand. The system can be used in any suitable manner, including in either a cold box process or no bake process as described herein.