Low-Hygroscopicity Glass Wool Composition for Vacuum Insulation
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Solution Overview
Problem
The thermal insulating properties of glass wool and vacuum insulation materials are adversely affected by moisture absorption, with existing solutions focusing on filament diameter and binder type rather than the glass composition, which has a more significant impact on moisture absorption.
Innovation Solution
A glass wool composition with specific ranges of SiO2, Al2O3, Na2O, K2O, MgO, CaO, and B2O3 is developed to reduce moisture absorption, including a high B2O3 content to inhibit hydration reactions and a balanced ratio of Na2O and K2O to minimize moisture adsorption sites, while maintaining suitable viscosity and melting temperature for industrial production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If glass wool is produced using conventional glass compositions (C-glass with high alkaline metal content), then industrial production is facilitated and chemical durability is maintained, but moisture absorption increases and thermal insulating properties deteriorate
Solution Approach 1:
The patent changes the chemical composition parameters of the glass wool, specifically limiting Na2O+K2O to 8-15 wt% and MgO+CaO to 10-20 wt%, while adjusting SiO2 to 55-65 wt% and Al2O3 to 10-20 wt%. This parameter optimization reduces moisture absorption while maintaining industrial producibility through balanced composition ranges
Solution Approach 2:
The patent creates a composite glass composition that combines multiple oxide components in specific proportions, forming a new material system that integrates the benefits of low moisture absorption (through controlled alkaline metals) with good chemical durability (through balanced MgO and CaO content) and industrial manufacturability (through feasible SiO2 and Al2O3 ranges)
2Reliability
If glass composition is optimized to reduce moisture absorption, then thermal insulating properties are improved, but production constraints increase due to limited cullet types
Solution Approach 1:
The patent establishes specific composition ranges that can accommodate variations in cullet types. By setting broad but controlled ranges for each oxide component, the formulation maintains low moisture absorption characteristics while being adaptable to different available cullet sources
Solution Approach 2:
The patent applies local quality control by specifically targeting the alkaline metal oxide content (Na2O+K2O) and alkaline earth metal oxide content (MgO+CaO) as the critical zones for moisture absorption control, while allowing more flexibility in SiO2 and Al2O3 ranges to accommodate cullet variations
3Reliability
If glass composition is adjusted to balance chemical durability and thermal insulation, then physical properties are improved, but selection of constituent components is limited
Solution Approach 1:
The patent simplifies the composition selection process by establishing clear parameter ranges: SiO2 (55-65%), Al2O3 (10-20%), Na2O+K2O (8-15%), MgO+CaO (10-20%), with B2O3 as optional (0-5%). These standardized ranges balance all required properties while reducing selection complexity
Solution Approach 2:
The patent creates a universal glass composition formula that simultaneously achieves multiple functions: thermal insulation, moisture resistance, chemical durability, and manufacturability. This multi-functional composition reduces the need for separate optimizations for each property
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 optimized glass wool composition effectively lowers moisture absorption, maintaining thermal insulating properties and facilitating industrial production, resulting in improved thermal insulation performance and reduced devitrification risks.
Implementation Method 1
including a high B2O3 content to inhibit hydration reactions
Implementation Method 2
a balanced ratio of Na2O and K2O to minimize moisture adsorption sites
Implementation Method 3
Glass wool is widely used as an insulation material... for the purpose of retaining heat
Implementation Method 4
vacuum insulation materials are also known that are obtained by sealing a glass wool core material with an envelope and reducing the pressure inside
Data Source
Figure 1
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AI summary
The present invention provides: a glass wool which has physical properties required for a heat insulation material, can be produced industrially, can have reduced hygroscopicity, and has a novel compounding composition; and a vacuum heat insulation material produced using the glass wool. The present invention relates to a glass wool having the following glass composition: SiO2: 60.0 to 65.0% by mass inclusive, Al2O3: 0.5 to 2.0% by mass inclusive, Na2O and K2O: 13.0 to 17.0% by mass inclusive, MgO and CaO: 8.0 to 12.0% by mass inclusive, B2O3: 5.0 to 12.0% by mass inclusive, and others: a remainder.