Mineral Insulation Pore Control via Surfactant
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Solution Overview
Problem
Mineral insulation elements produced using aluminum blowing methods often exhibit non-homogeneous porosity distribution and large pores, which hinder achieving low thermal conductivity below 0.045 W/mK and high mechanical strength simultaneously.
Innovation Solution
The use of platelet-like aluminum particles with tetrafunctional polysiloxanes as blown pore inhibitors, which attach to solid particle surfaces, preventing agglomeration and forming smaller, uniform pores, thereby controlling porosity and thermal conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of stationary object
If aluminum blowing is used to produce mineral insulation elements, then bulk density is reduced, but porosity distribution becomes non-homogeneous and thermal conductivity cannot be reduced below 0.045 W/mK
Solution Approach 1:
The patent applies preliminary action by adding a surfactant to the aluminum paste before the blowing process. This surfactant pre-treats the aluminum particles to control their behavior during hydrogen bubble formation, ensuring uniform pore distribution from the outset rather than allowing non-homogeneous porosity to develop naturally during aluminum blowing.
Solution Approach 2:
The patent changes the chemical parameters of the aluminum paste by incorporating a surfactant, which modifies the surface properties of aluminum particles. This parameter change controls the bubble formation process, leading to more uniform pore sizes and distribution while maintaining the desired bulk density reduction.
2Quantity of substance
If aluminum particles are used as pore formers, then porosity is increased, but large pores are formed which prevent achieving low thermal conductivity
Solution Approach 1:
The surfactant acts as an intermediary substance between the aluminum particles and the water in the suspension. It mediates the bubble formation process by controlling how hydrogen bubbles nucleate and grow on aluminum particle surfaces, preventing excessive bubble coalescence that would lead to large pores.
Solution Approach 2:
The patent changes the physical-chemical parameters of the blowing process by introducing a surfactant, which affects surface tension and bubble formation dynamics. This parameter change enables better control over pore size, maintaining high porosity while preventing the formation of excessively large pores that would increase thermal conductivity.
3Manufacturing precision
If finer aluminum particles are used to create smaller pores, then pore size is reduced, but particles agglomerate strongly before reaction leading to even larger pores
Solution Approach 1:
The surfactant serves as an intermediary that prevents direct agglomeration of fine aluminum particles. It adsorbs onto the particle surfaces, creating a steric or electrostatic barrier that maintains particle dispersion stability in the suspension, allowing fine particles to remain separated until the blowing reaction occurs.
Solution Approach 2:
The patent changes the colloidal parameters of the aluminum particle suspension by adding a surfactant, which modifies the inter-particle forces and prevents agglomeration. This parameter change enables the use of finer aluminum particles without the harmful agglomeration effect, maintaining both particle dispersion and achieving smaller pore sizes.
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 process achieves insulation elements with bulk densities between 75 to 110 kg/m3 and thermal conductivities as low as 0.040 to 0.041 W/mK, while maintaining adequate mechanical strength, by inhibiting bubble formation and ensuring a high percentage of small pores.
Implementation Method 1
the reaction with water which forms hydrogen bubbles
Implementation Method 2
an affinity of aluminum particles or small aluminum particle agglomerates present in the aluminum products to the solid particle surface in the suspension of the fresh composition being produced and a certain degree of bonding being effected
Implementation Method 3
pores which have been blown to a different extent occur in the cast fresh compositions with decreasing distance from the surface as a result of the decreasing hydrostatic pressure
Data Source
AI summary
A mineral, aluminum-blown insulation element, in particular insulation slab, comprising calcium silicate hydrates as framework and blown pores surrounded by the framework, wherein more than 40% by volume, in particular more than 50% by volume, of the blown pores have a diameter of less than 1 mm and more than 75% by volume, in particular more than 85% by volume, of the blown pores have a diameter of less than 2 mm and the thermal conductivity λ10dr is preferably less than 0.045 W/mK.