High-Strength Glass Fiber Composition with Lithium Oxide

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Solution Overview

Problem

Conventional high-strength glass fiber compositions, such as S-Glass and R-Glass, require high melting and processing temperatures, leading to increased production costs and potential fiber weaknesses due to crystallization issues during fiber formation.

Innovation Solution

A glass composition with a specific chemical makeup of 62-68% SiO2, 22-26% Al2O3, 8-15% MgO, and 0.1-2% Li2O, which allows for lower fiberizing temperatures and a higher difference between fiberizing and liquidus temperatures, reducing production costs and enhancing fiber strength and modulus.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If conventional high-strength glass fiber compositions (S-Glass, R-Glass) are used, then high mechanical strength is achieved, but high melting and processing temperatures are required

Engineering Contradiction:
Improvemechanical strengthVSAvoidmelting and processing temperature
Core Design Contradiction:
StrengthVSTemperature

Solution Approach 1:

The patent modifies the chemical composition parameters of the glass, specifically incorporating lithium oxide (Li2O) at 0.1-2.0 wt% and controlling the ratios of SiO2, Al2O3, and MgO. This compositional parameter change lowers the melting temperature and processing temperature while preserving the high mechanical strength properties of S-Glass fibers.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention creates a composite glass composition that combines traditional S-Glass components (SiO2, Al2O3, MgO) with lithium oxide additives. This composite approach allows the glass to achieve both high strength and lower processing temperatures by leveraging the properties of each component.

Inventive Principle:
Principle #40Composite materials

2Strength

If conventional glass compositions are used, then high strength is achieved, but production costs increase due to high energy consumption

Engineering Contradiction:
Improvefiber strengthVSAvoidenergy consumption
Core Design Contradiction:
StrengthVSUse of energy by stationary object

Solution Approach 1:

By changing the chemical composition parameters to include lithium oxide and optimize the SiO2-Al2O3-MgO ratios, the glass melting temperature is reduced. This temperature reduction directly decreases the energy consumption in furnaces and processing equipment, lowering production costs while maintaining fiber strength.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent converts the traditionally harmful effect of high energy consumption into a benefit by using lithium oxide as a flux that lowers melting temperature. What was previously a disadvantage (high energy use) becomes an advantage through compositional modification.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

3Strength

If conventional glass compositions are used, then high strength is achieved, but fiber weaknesses occur due to crystallization issues during fiber formation

Engineering Contradiction:
Improvefiber strengthVSAvoidfiber integrity
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The patent optimizes the chemical composition parameters, particularly the Li2O content (0.1-2.0 wt%) and the Al2O3-MgO ratios, to control the crystallization behavior during fiber formation. This parameter optimization prevents unwanted crystallization that would create weaknesses, ensuring fiber integrity while maintaining strength.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The modified composition acts as a preventive measure against crystallization issues during fiber formation. By incorporating lithium oxide and optimizing the base composition, the patent cushiones against potential defects before they occur, ensuring reliable fiber production.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

4Use of energy by stationary object

If lower fiberizing temperatures are achieved through composition modification, then energy consumption is reduced and bushing life is increased, but fiber strength may be compromised

Engineering Contradiction:
Improveenergy consumptionVSAvoidfiber strength
Core Design Contradiction:
Use of energy by stationary objectVSStrength

Solution Approach 1:

The patent carefully balances the compositional parameters, specifically maintaining Li2O at 0.1-2.0 wt% and SiO2 at 62-68 wt%, to ensure that the lower processing temperature does not compromise fiber strength. The optimized composition allows the glass to be drawn at lower temperatures while still achieving high-strength fibers.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentUS8252707B2Composition for high performance glass fibers and fibers formed therewith
Publication Date: 2012.08.28 OWENS CORNING INTELLECTUAL CAPITAL LLC

AI summary

A composition for the manufacture of high strength glass fibers suitable for manufacture in both precious metal lined furnaces and refractory lined glass melter is disclosed. The glass composition of the present invention includes 62-68 weight % SiO2, 22-26 weight % Al2O3, 8-15 weight % MgO and 0.1 to 3.0 weight % Li2O. One suitable composition of the present invention includes 64-66.5 weight percent SiO2, 23-24.5 weight percent Al2O3, 9-11 weight percent MgO and 0.3-0.35 weight percent Li2O. Another suitable composition includes 66.5 weight percent SiO2, 23.4 weight percent Al2O3, 9.8 weight percent MgO and 0.3 weight percent Li2O. Yet another suitable composition is about 66 weight percent SiO2, about 23 weight percent Al2O3, about 10.5 weight percent MgO and about 0.3 weight percent Li2O. Fibers formed by the present invention are also disclosed. The fibers have a fiberizing temperature of less than 2650° F., a ΔT of at least 25° F. Further, the glass fibers of the present invention typically have a strength in excess of 700 KPSI, in one embodiment, a strength in excess of about 730 KPSI, and, in yet another embodiment, a strength in excess of about 750 KPSI. The glass fibers will typically have a modulus greater than 12.8 MPSI, in one embodiment, greater than about 13 MPSI, and, in yet another embodiment, greater than about 13.2 MPSI.