Green Molded Body Binder Composition for Rapid Degreasing
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Solution Overview
Problem
Existing methods for producing sintered molded bodies using organic binders face issues such as mold deposit, dimensional inaccuracies, and cracking or swelling during degreasing, often requiring special facilities and prolonged heating times.
Innovation Solution
A composition comprising a polyacetal resin, polyolefin resin, and epoxy resin, with specific end amounts of polyoxymethylene units, is used to enhance compatibility and reduce mold adhesion, allowing for rapid degreasing without specialized equipment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a polyacetal resin and an epoxy resin are used together as a binder to increase compatibility and promote uniformity, then the qualities of green molded bodies, degreased bodies, and sintered bodies are improved and the degreasing speed is increased, but specific methods to suppress stain of mold and to improve dimensional accuracy during production of green molded bodies are not disclosed
Solution Approach 1:
The patent applies parameter changes by precisely controlling the total end amount of polyoxymethylene units in the polyacetal resin within 0.1-0.75 mol% and the hemiformal end amount within 0.05-0.20 mol%. These specific parameter ranges optimize the binder's performance to suppress mold deposit while maintaining quality and degreasing speed.
Solution Approach 2:
The patent uses a composite binder system combining polyacetal resin, epoxy resin, and polyolefin resin. This composite material approach leverages the complementary properties of each component: polyacetal for structural integrity, epoxy for compatibility and adhesion, and polyolefin for processability and mold release properties.
2Productivity
If the binder contained in the green molded bodies thermally decompose and gasify in a short period of time, then the degreasing process is faster, but cracks or swells would occur in the molded bodies during the degreasing step
Solution Approach 1:
The patent controls the thermal decomposition behavior by adjusting the end group composition of the polyacetal resin. The specific ranges for total end amount (0.1-0.75 mol%) and hemiformal end amount (0.05-0.20 mol%) regulate the degradation kinetics, enabling gradual binder removal that prevents defects while maintaining efficient degreasing.
Solution Approach 2:
The epoxy resin acts as an intermediary that modifies the thermal decomposition profile of the binder system. It facilitates controlled breakdown of the polyacetal resin, allowing the binder to gasify at a regulated rate that prevents sudden volume changes and associated defects in the molded body.
3Shape
If a polyacetal resin is used together with other polymers as a binder to achieve excellent shape retentionability, then the rigidity inherent to the polyacetal resin improves the shape retentionability of the green molded body, but the production process becomes more complex
Solution Approach 1:
The patent creates a composite binder system where polyacetal resin provides rigidity and shape retentionability, while epoxy and polyolefin resins contribute complementary properties. This combination achieves excellent shape retention without requiring specialized production equipment or complex processing steps.
Solution Approach 2:
The patent ensures homogeneous distribution and compatibility of the binder components through controlled end group chemistry. The specific end amount ranges promote uniform mixing and consistent performance throughout the molded body, simplifying the production process by eliminating the need for specialized handling or processing equipment.
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 rapid degreasing, reduces mold deposit, and suppresses cracking and swelling, resulting in high-quality sintered molded bodies with improved dimensional accuracy.
Implementation Method 1
the method in which green molded bodies are heated to thermally decompose and gasify the binder
Data Source
AI summary
A green molded body is produced by molding a composition for use in sintered molded bodies. The composition includes a sinterable inorganic powder and an organic binder. The organic binder contains at least a polyacetal resin, a polyolefin resin, and an epoxy resin. A total end amount with respect to all polyoxymethylene units in the polyacetal resin is 0.1 mol % or more and 0.75 mol % or less.