High Modulus Glass Strands for Composite Reinforcement

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Solution Overview

Problem

Existing glass strands used in composites have a relatively low specific Young's modulus, making them inadequate for applications requiring high mechanical strength and stability, especially under dynamic conditions, and their fiberizing conditions are often costly and constraining, limiting their practicality.

Innovation Solution

Developing glass strands with a composition of 50-65% SiO2, 12-23% Al2O3, 1-10% CaO, 6-12% MgO, and 1-3% Li2O, which allows for direct fiberizing under conditions with a liquidus temperature of at most 1250°C, improving mechanical properties and fiberizability while reducing production costs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If E-glass or R-glass strands are used to reinforce composites, then mechanical strength is improved, but the specific Young's modulus remains relatively low (around 33 MPa/kg/m3)

Engineering Contradiction:
Improvespecific Young's modulusVSAvoidmechanical performance under dynamic conditions
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The patent modifies the chemical composition parameters of the glass strands by incorporating specific amounts of Al2O3 (12-23%), MgO (6-12%), CaO (1-10%), and Li2O (1-3%), while maintaining SiO2 content between 50-65%. This parameter optimization achieves a specific Young's modulus exceeding 36.5 MPa/kg/m3, resolving the contradiction between mechanical strength and specific modulus by finding the optimal compositional balance.

Inventive Principle:
Principle #35Parameter changes

2Strength

If R-glass is used to achieve high specific Young's modulus (around 33.5 MPa/kg/m3), then mechanical properties are improved, but melting and fiberizing conditions become more constrictive and costly

Engineering Contradiction:
Improvespecific Young's modulusVSAvoidfiberizing conditions and production cost
Core Design Contradiction:
StrengthVSEase of manufacture

Solution Approach 1:

The patent adjusts the glass composition parameters to achieve a liquidus temperature of at most 1250°C, which is lower than conventional R-glass. This is accomplished by optimizing the ratio of network modifiers (MgO, CaO, Li2O) to network formers (SiO2, Al2O3), thereby improving fiberizing conditions and reducing production costs while maintaining high specific Young's modulus.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite glass system combining multiple oxide components (SiO2, Al2O3, MgO, CaO, Li2O) in specific proportions. This composite composition synergistically achieves both high mechanical properties and favorable processing conditions, resolving the contradiction between performance and manufacturability.

Inventive Principle:
Principle #40Composite materials

3Strength

If glass composition is optimized for high mechanical strength, then specific Young's modulus improves, but fiberizability and processing conditions deteriorate

Engineering Contradiction:
Improvespecific Young's modulusVSAvoidfiberizability
Core Design Contradiction:
StrengthVSEase of operation

Solution Approach 1:

The patent identifies and optimizes critical compositional parameters: SiO2 (50-65%), Al2O3 (12-23%), MgO (6-12%), CaO (1-10%), and Li2O (1-3%). This multi-parameter optimization simultaneously achieves high specific Young's modulus (>36.5 MPa/kg/m3) and good fiberizability by controlling viscosity and devitrification behavior during the fiberizing process.

Inventive Principle:
Principle #35Parameter changes

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 new glass strands achieve a higher specific Young's modulus of over 36.5 MPa/kg/m3, enhanced mechanical properties, and improved fiberizability, making them a cost-effective alternative to R-glass with reduced fiberizing temperatures and improved resistance to water and alkali.

Implementation Method 1

the glass used having to be able to be drawn into the form of filaments a few microns in diameter using the process indicated above... a liquidus temperature of at most 1250° C.

Methodology Applied
Scientific EffectMelting: Melting

Implementation Method 2

the process that consists in mechanically attenuating streams of molten glass that flow out of orifices located in the base of a bushing

Methodology Applied
Scientific EffectMechanical attenuation:

Data Source

PatentUS8476175B2Glass strands and composites having an organic and/or inorganic matrix containing said strands
Publication Date: 2013.07.02 OWENS CORNING INTELLECTUAL CAPITAL LLC

AI summary

The invention relates to glass strands especially for the production of composites having an organic and/or inorganic matrix, the composition of which strands comprises the following constituents in the limits defined below, expressed as percentages by weight:SiO250-65%Al2O312-23%SiO2 + Al2O3  >79%CaO 1-10%MgO 6-12%Li2O 1-3%, preferably 1-2% BaO + SrO 0-3%B2O3 0-3%TiO2 0-3%Na2O + K2O  <2%F2 0-1%Fe2O3  <1%.These strands are made of a glass offering an excellent compromise between its mechanical properties, represented by the specific Young's modulus, and its melting and fiberizing conditions.