Blended Aggregate Mold Moisture Resistance

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Solution Overview

Problem

Conventional molding methods using water-soluble binders like starch or sodium silicate result in molds with poor moisture resistance, leading to potential breakage during transportation or before molten metal solidification due to humidity absorption.

Innovation Solution

A blended aggregate for molding comprising sodium silicate or potassium silicate as a water-soluble binder, lithium silicate as a lithium salt, and a surfactant, which enhances moisture and water resistance by generating foamed bubbles with controlled viscosity and lithium salt distribution.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-generated harmful factors

If water-soluble binders like starch or sodium silicate are used for molding, then unpleasant odor and gas generation are reduced, but the mold strength decreases due to moisture absorption

Engineering Contradiction:
Improveunpleasant odor and gas generationVSAvoidmold strength
Core Design Contradiction:
Object-generated harmful factorsVSStrength

Solution Approach 1:

The invention uses a composite binder system combining water-soluble binder (starch or sodium silicate) with water-insoluble binder (clay or organic binder) to create a mold material that maintains the low odor and gas generation benefits of water-soluble binders while gaining the moisture resistance and strength of water-insoluble binders

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The invention changes the chemical composition parameters of the binder by introducing water-insoluble components (clay with specific particle size distribution or organic binders) to alter the moisture absorption characteristics and strength properties of the mold material

Inventive Principle:
Principle #35Parameter changes

2Temperature

If water-soluble binders are used for molding, then binding power is weakened by heat during casting, but the mold resistance to moisture is insufficient

Engineering Contradiction:
Improveheat resistance during castingVSAvoidmoisture resistance
Core Design Contradiction:
TemperatureVSReliability

Solution Approach 1:

The composite binder system combines the heat-weakening property of water-soluble binders (which aids in molten metal penetration and casting) with the moisture resistance of water-insoluble binders, achieving both casting effectiveness and mold stability

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The invention creates different functional zones within the binder composition where water-soluble components provide heat response characteristics for casting while water-insoluble components provide moisture resistance, with each component performing its specialized function

Inventive Principle:
Principle #3Local quality

3Ease of manufacture

If conventional binder compositions are used, then molding is achieved, but the mold breaks during transportation or before molten metal solidification due to humidity absorption

Engineering Contradiction:
Improvemolding capabilityVSAvoidtransportation and structural integrity strength
Core Design Contradiction:
Ease of manufactureVSStrength

Solution Approach 1:

The blended aggregate combines water-soluble binder with water-insoluble binder components (clay or organic binders) to create a mold material that maintains structural integrity and transportation strength while retaining molding capability

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The water-insoluble binder acts as an intermediary component that bridges the gap between the molding properties provided by water-soluble binders and the structural strength required for transportation and handling

Inventive Principle:
Principle #24Intermediary (Mediator)

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 provides molds with excellent resistance to moisture and water, preventing breakage and maintaining structural integrity under humid conditions, as demonstrated by improved bending strength and reduced moisture absorption in testing.

Implementation Method 1

the mold may be weakened by absorbing moisture

Methodology Applied
Scientific EffectAbsorption: Absorption (physical)

Implementation Method 2

aggregate and the binder are agitated so that the blended aggregate foams, to thereby form a mold

Methodology Applied
Scientific EffectFoaming: Foam

Data Source

PatentEP3466561B1Aggregate mixture for casting mold, and casting mold
Publication Date: 2021.01.27 SINTOKOGIO LTD
  • EP3466561B1 patent drawingFigure 1
  • EP3466561B1 patent drawingFigure 2
  • EP3466561B1 patent drawingFigure 3

AI summary

To provide a binder composition for molding, by which a mold made of aggregate has an excellent resistance to moisture. The binder composition for molding contains a water-soluble binder and at least one kind of lithium salt that is selected from a group of lithium silicate, lithium oxide, lithium hydroxide, lithium carbonate, lithium bromide, lithium chloride, lithium nitrate, and lithium nitrite.