Polyurethane Binder Additives for Foundry Sand Strength and Stability
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Solution Overview
Problem
Foundry binder systems face challenges in achieving high initial strength and extended sand lifespan while avoiding chlorine-containing compounds that pose health risks and corrosion issues, and in maintaining storage stability and thermal resistance to reduce surface defects in castings.
Innovation Solution
A mixture comprising methanesulfonic acid, esters of phosphorus-oxygen acids, and silanes is used as an additive in the polyisocyanate component of a two-component binder system, replacing chlorosilanes and acid chlorides, to enhance sand life, storage stability, and thermal resistance without compromising strength or introducing harmful chlorides.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If chlorosilanes and acid chlorides are used as additives in the binder system, then initial strength is improved, but health risks and corrosion issues arise due to chlorine-containing compounds
Solution Approach 1:
The patent removes harmful chlorine-containing compounds (chlorosilanes and acid chlorides) from the binder system while replacing them with alternative additives that provide the necessary strength without the harmful effects. This extraction of the harmful element while maintaining the beneficial function directly resolves the contradiction between initial strength and health/safety concerns.
Solution Approach 2:
The patent converts the previously harmful role of chlorine-containing compounds into a beneficial alternative system using non-chlorine-based additives. By developing a replacement system that achieves the same technical effect (strength enhancement) without the harmful side effects, the invention transforms a harmful approach into a safe one.
2Strength
If the binder system is made more reactive to achieve high initial strength, then sand life is reduced due to premature curing
Solution Approach 1:
The patent employs a multi-component additive system where each component contributes to different aspects of the curing behavior. The synergistic interaction between these components allows dynamic control of the reaction kinetics, enabling high initial strength development while maintaining adequate sand life through balanced reactivity management.
Solution Approach 2:
The invention uses a composite additive system combining multiple substances (alternative to chlorosilanes and acid chlorides) that work synergistically. This composite approach allows optimization of both initial strength and sand life by combining the beneficial effects of different additives while avoiding their individual limitations.
3Duration of action of stationary object
If chlorine-containing compounds are used to extend sand life, then storage stability is improved, but thermal resistance and surface quality deteriorate
Solution Approach 1:
The patent extracts and eliminates chlorine-containing compounds from the binder system, replacing them with alternative additives that extend sand life without causing surface defects. This removal of the harmful element while maintaining the beneficial function (sand life extension) resolves the contradiction between sand life and surface quality.
4Productivity
If fast-curing binder systems are used to achieve high initial strength, then productivity is improved, but sand life is significantly reduced
Solution Approach 1:
The patent uses a dynamically balanced additive system that controls the curing kinetics to achieve fast initial strength development while maintaining adequate sand life. The multi-component additive system allows optimization of the reaction rate profile, providing rapid curing for productivity while preventing premature complete curing that would reduce sand life.
Solution Approach 2:
The invention changes the chemical parameters of the binder system by introducing alternative additives that modify the curing characteristics. These parameter changes enable the system to achieve fast curing speed for improved productivity while simultaneously maintaining adequate sand life through controlled reactivity.
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 solution extends sand life, improves storage stability, and reduces surface defects in castings by maintaining high initial and final strength, while eliminating health hazards and corrosion risks associated with chlorine-containing compounds.
Implementation Method 1
A mixture which can be produced by reacting a premix of (av) 1.0 to 50.0 percent by weight of methanesulfonic acid, (bv) one or more esters of one or more phosphorus-oxygen acids and (cv) one or more silanes
Implementation Method 2
The two components are usually mixed with a molding base material, preferably sand, in the mixture the components react to form a cured polyurethane binder
Implementation Method 3
typically in the presence of catalysts, which ensure rapid conversion and thus a sufficiently short curing time. In addition to other substances such as organometallic compounds, suitable catalysts include primarily tertiary amines
Data Source
AI summary
A mixture is described which can be produced by causing a reaction of a precursor mixture of (av) methanesulfonic acid (bv) one or more esters of one or more phosphorus oxoacids and (cv) one or more silanes. The invention additionally relates to the usage of said mixtures as additives for the polyisocyanate component of a two-component binder system for producing a polyurethane resin. The invention further relates to a solution containing polyisocyanate for usage as a component of a moulding material binder system, to the usage of a solution containing polyisocyanate as the polyisocyanate component of a two-component binder system for producing a polyurethane resin and to corresponding two-component binder systems for producing a polyurethane resin.