Urethane Foam Thermal Conductivity via Composite Particle Orientation
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Solution Overview
Problem
Urethane foam molded products used for sound absorption and vibration damping have low thermal conductivity, leading to heat accumulation around heat-generating components, and existing methods to improve heat dissipation, such as using oriented magnetic particles or high thermal conductivity fillers, either fail to effectively enhance thermal conductivity or compromise other physical properties like sound absorption and cost.
Innovation Solution
Incorporating composite particles with nonmagnetic thermal conductive particles and adhered magnetic particles into the urethane foam, allowing the magnetic particles to orient in a magnetic field during foam molding, creating a heat transfer path without significantly altering the foam's cell structure or physical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If oriented magnetic particles (iron or stainless steel) are used to improve heat dissipation, then heat transfer path is formed, but thermal conductivity remains low due to low thermal conductivity of magnetic particles
Solution Approach 1:
The patent uses composite particles consisting of a thermal conductive core (carbon fiber or graphite) coated with a magnetic layer (iron oxide or similar). This composite structure combines the high thermal conductivity of nonmagnetic materials with the magnetic properties needed for orientation, resolving the contradiction between forming heat transfer paths and maintaining low thermal conductivity of filler materials.
2Temperature
If large amount of carbon fiber is mixed to create heat transfer path, then thermal conductivity is improved, but foam molding is adversely affected and sound absorption properties are diminished
Solution Approach 1:
By using composite particles with magnetic coating, the patent achieves effective heat transfer paths with much smaller filler amounts (0.1-5 wt%). The magnetic coating enables orientation and connection of carbon fiber cores without requiring large quantities, thus maintaining sound absorption properties while improving thermal conductivity.
Solution Approach 2:
The patent changes the physical state and distribution parameters of the filler by using oriented composite particles instead of random mixing. This orientation during foam molding creates efficient heat transfer paths with minimal filler content, avoiding the adverse effects of excessive carbon fiber mixing.
3Temperature
If carbon fiber is used as thermal conductive filler, then thermal conductivity is improved, but orientation is impossible because carbon fiber is nonmagnetic
Solution Approach 1:
The patent creates composite particles by coating carbon fiber or graphite cores with magnetic materials such as iron oxide. This composite structure retains the high thermal conductivity of the carbon-based core while adding magnetic properties that enable orientation in a magnetic field during foam molding, thus resolving the contradiction between thermal conductivity and orientability.
4Ease of manufacture
If iron or stainless steel is used for magnetic particles, then excellent magnetization property is achieved, but thermal conductivity is low
Solution Approach 1:
The patent uses composite particles where a thermal conductive core (carbon fiber or graphite) is coated with a magnetic layer. The magnetic layer provides the necessary magnetization properties for orientation, while the carbon-based core provides high thermal conductivity, thus combining the benefits of both materials without their individual drawbacks.
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 enhances thermal conductivity of urethane foam molded products while maintaining their inherent physical properties, such as sound absorption, and reduces material costs by using a smaller amount of filler, effectively suppressing temperature increases in heat-generating components.
Implementation Method 1
the magnetic particle is adhered to a surface of the thermal conductive particle. Therefore, when a magnetic field is applied during foam molding, the magnetic particle tends to orient itself along magnetic field lines.
Implementation Method 2
the thermal conductive filler is mixed in the base material and oriented to form mutual connections... forms a heat transfer path in the direction of orientation of the magnetic particles
Data Source
AI summary
The present invention provides a urethane foam molded product that has high thermal conductivity with minimal change to its physical properties. A simple method for producing the same is also provided. The urethane foam molded product includes a base material formed of a polyurethane foam, and a thermal conductive filler mixed in the base material and oriented to form mutual connections. The thermal conductive filler is formed of composite particles that include thermal conductive particles formed of a nonmagnetic material, and magnetic particles adhered to the surfaces of the thermal conductive particles. The method for producing the urethane foam molded product includes a raw material mixing process that mixes a foam urethane resin material and the thermal conductive filler to obtain a mixed raw material, and a foam molding process that injects the mixed raw material into a cavity of a foaming die and performs foam molding while a magnetic field is applied so as to substantially uniform a magnetic flux density inside the cavity.