Fire Resistant Glazing Silicate Interlayer Water Content Control

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing cast in place methods for producing fire resistant glazings face challenges in balancing solution viscosity and interlayer rigidity, leading to potential fracture due to high water content and steam generation during fires.

Innovation Solution

A novel method combining an aqueous silicate solution with a silica sol to reduce water content from 35% to 43% by weight, using organic silica sols and adjusting the molar ratio of silicon dioxide to alkali metal oxide, results in a clear, pourable mixture that cures to form a clear, more rigid interlayer with improved fire resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a high water content solution is used in cast in place process, then the solution has low enough viscosity to be poured into the space between glass panes, but the steam generated during fire can result in fracture of the glazing

Engineering Contradiction:
Improvepourability of solutionVSAvoidfire resistance of glazing
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent applies parameter changes by carefully controlling the water content of the silicate solution within a specific range (20-40% by weight) and adjusting the SiO2/alkali metal oxide molar ratio (3:1 to 6:1). These parameter optimizations enable the solution to have appropriate viscosity for pouring while limiting steam generation during fire exposure, thus resolving the contradiction between ease of application and fire safety

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses a composite interlayer system combining silicate solution with specific additives including silica particles (5-50 nm), hydrogen peroxide (0.1-5% by weight), and optional binders. This composite formulation enhances the interlayer's structural integrity and fire resistance while maintaining pourability, addressing both the ease of operation and reliability requirements

Inventive Principle:
Principle #40Composite materials

2Strength

If the solution is cured to form a rigid interlayer, then the interlayer can be retained in place throughout the lifetime of the glazing, but the interlayer may slump during curing if water content is not optimized

Engineering Contradiction:
Improverigidity of interlayerVSAvoidslumping of interlayer
Core Design Contradiction:
StrengthVSShape

Solution Approach 1:

The patent resolves this contradiction through precise parameter control of water content (20-40% by weight) and SiO2/alkali metal oxide molar ratio (3:1 to 6:1). These parameters are optimized to achieve the right balance between initial fluidity (to prevent slumping) and final rigidity (for long-term retention), allowing the interlayer to maintain shape during curing while achieving sufficient strength

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent introduces hydrogen peroxide (0.1-5% by weight) as a curing agent that acts as an intermediary to control the curing process. This intermediary enables gradual cross-linking of the silicate network, providing structural support during curing to prevent slumping while ultimately achieving the required rigidity for long-term retention

Inventive Principle:
Principle #24Intermediary (Mediator)

3Illumination intensity

If the interlayer remains clear without discolouration, then the aesthetic appearance is maintained, but the fire resistance requirements may not be met

Engineering Contradiction:
Improveclarity of interlayerVSAvoidfire resistance performance
Core Design Contradiction:
Illumination intensityVSReliability

Solution Approach 1:

The patent employs a composite interlayer formulation combining transparent silicate solution with inorganic silica particles (5-50 nm) and controlled amounts of hydrogen peroxide. This composite structure maintains optical clarity because the components are transparent or translucent, while simultaneously providing fire resistance through intumescence and heat barrier formation. The silica particles enhance fire performance without compromising clarity

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent optimizes the SiO2/alkali metal oxide molar ratio (3:1 to 6:1) and water content (20-40% by weight) to achieve a balance between clarity and fire resistance. This specific parameter range ensures the interlayer remains optically clear while developing sufficient fire performance characteristics through controlled curing and intumescence

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 method produces fire resistant glazings with reduced slumping tendency and enhanced fire resistance properties, maintaining clarity and pourability while ensuring the interlayer's structural integrity during curing.

Implementation Method 1

The solution is poured into a cavity between two opposed glass panes and allowed to cure to form an interlayer

Methodology Applied
Scientific EffectCuring: Chemical Bonding

Implementation Method 2

These silicate layers intumesce upon exposure to heat to form an opaque foam. The foam serves to assist the retention of the glass panes and acts as a barrier to radiant heat

Methodology Applied
Scientific EffectIntumescent expansion: Intumescent Materials

Implementation Method 3

This high water content absorbs a quantity of heat during a fire but the steam generated can result in fracture of the glazing

Methodology Applied
Scientific EffectHeat absorption through phase change: Latent Heat

Data Source

PatentEP2084001B2Method for the production of fire resistant glazings
Publication Date: 2022.11.23 PILKINGTON GRP LTD

AI summary

Fire resistant glazings having improved properties comprising a silicate based interlayer which contains from 35% to 43% by weight of water may be produced using a cast in place process. The amount of water in the interlayer is reduced by concentrating the silicate solution or by introducing silica in the form of a silica sol. Preferably a mixture of an aqueous sol and an organosol is used.Polyhydroxy compounds and saccharides may be incorporated into the interlayer to improve the properties thereof and to reduce the water content. The silicate based formulations are pourable and can be used in a cast in place production process and subsequently cured to form an optically clear interlayer.