Gelatin Binder Demoldability via Adhesion Reducer
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Solution Overview
Problem
The use of agar as a binder in metal or ceramic powder injection molding results in dimensional variations of sintered products due to water vaporization at high temperatures, and gelatin-based compositions exhibit poor demoldability leading to broken products during removal from molding dies.
Innovation Solution
A plastic molding composition containing gelatin as a binder, a polar solvent, and an adhesion reducer with a HLB value ranging from 10 to 20, which reduces adhesion and improves demoldability, allowing for the removal of molded products from molding dies without breaking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If agar is used as a binder and the composition is heated to 80°C or more to achieve flowability, then the composition can be molded, but water vaporizes causing dimensional variations in sintered products
Solution Approach 1:
The invention changes the solation temperature parameter of the binder from high (agar requiring 80°C or more) to low (gelatin solating at 10-50°C). This parameter change allows the composition to achieve flowability at lower temperatures where water vaporization is minimized, thereby maintaining dimensional accuracy in the final sintered product
Solution Approach 2:
The invention uses gelatin, a biodegradable and water-soluble binder, that can be easily removed during sintering without requiring complex degreasing processes. The binder serves its temporary purpose during molding and then decomposes cleanly, leaving no harmful residues that would affect product quality
2Manufacturing precision
If gelatin is used as a binder to achieve flowability at low temperature, then dimensional accuracy is improved, but demoldability deteriorates due to excessive adhesion to the molding die
Solution Approach 1:
The invention introduces a release agent as an intermediary substance between the gelatin-based composition and the molding die. This release agent prevents excessive adhesion during molding while allowing easy removal of the molded product, solving the demoldability problem without compromising the low-temperature processing benefits of gelatin
Solution Approach 2:
The invention modifies the surface properties of the molding die by applying a release agent, changing the adhesion parameters between the gelatin and the die surface. This allows the composition to maintain good adhesion during injection while enabling easy demolding afterward
3Strength
If a large amount of binder resin is used to ensure binding strength, then the molded product can be formed, but a degreasing process is required before sintering
Solution Approach 1:
The invention uses gelatin, a biodegradable binder that decomposes completely during sintering, replacing persistent binder resins that require separate degreasing processes. The gelatin binder serves its binding function during molding and then naturally decomposes without requiring additional process steps
Solution Approach 2:
The invention utilizes the phase transition properties of gelatin, which transitions from a gel state during molding to complete decomposition during sintering. This natural phase transition eliminates the need for separate degreasing processes required by conventional binder resins
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 composition enables the production of sintered products with reduced dimensional variations and improved demoldability, ensuring the molded products can be removed intact and subsequently sintered into predetermined shapes.
Implementation Method 1
When gelatin is heated to a temperature, higher than the solation temperature, gelatin is solated. Therefore, compared to when agar is used, the composition can have flowability at a lower heating temperature by using gelatin and water as a binder.
Implementation Method 2
water, which is used as a solvent for the agar, vaporizes easily at this temperature. Therefore, water contained in the composition vaporizes during a process where the composition is prepared and during a process where the composition is injected in a molding die to form a molded product.
Implementation Method 3
an adhesion reducer. The adhesion reducer reduces adhesion of the gelatin so that a molded product, which is molded from the composition with a molding die, is removed from the molding die without being broken.
Data Source
AI summary
A plastic molding composition includes a powder, gelatin, a polar solvent, and an adhesion reducer. The powder contains at least one of a ceramic particle and a metal particle. The adhesion reducer reduces adhesion of the gelatin so that a molded product, which is molded from the composition with a molding die, is removed from the molding die without being broken. The adhesion reducer is a water-soluble or water-dispersible compound. The adhesion reducer has a HLB value, calculated by Griffin's method, ranging from 10 to 20.