Embossed Interlayer for Laminated Glass De-Airing

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Solution Overview

Problem

The challenge in laminated glass production is achieving efficient air removal and edge sealing during the lamination process, particularly with unplasticized high modulus polymeric interlayers, which can lead to trapped air and visual defects due to their stiffness and susceptibility to dust, requiring specific surface patterns to facilitate de-airing without premature edge sealing.

Innovation Solution

A thermoplastic interlayer sheet or film with an embossed surface pattern featuring relatively uninterrupted channels in two non-parallel directions, spaced 0.1 to 1 mm apart, with depths of 14 to 20 µm and widths of 30 to 300 µm, designed for unplasticized high modulus polymers like ethylene acid copolymers or ionomers, to facilitate efficient de-airing and reduce energy required for compression.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the interlayer surface is made rougher to facilitate de-airing, then air removal efficiency is improved, but the energy required for edge sealing increases

Engineering Contradiction:
Improvede-airing efficiencyVSAvoidenergy for edge sealing
Core Design Contradiction:
ProductivityVSUse of energy by moving object

Solution Approach 1:

The invention applies different surface characteristics to different regions of the interlayer: the central area has a rough surface pattern (with Rz values of 10-50 micrometers) to facilitate de-airing, while the edge regions maintain smoother characteristics to enable efficient sealing. This localized differentiation allows each region to optimize its function without compromising the other.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The interlayer surface is segmented into distinct functional zones: a central de-airing zone with rough patterns and edge sealing zones with smoother surfaces. This segmentation allows independent optimization of each zone's properties, enabling effective air removal in the center while maintaining energy-efficient sealing at the edges.

Inventive Principle:
Principle #1Segmentation

2Ease of manufacture

If the interlayer surface is made smoother to facilitate edge sealing, then sealing efficiency is improved, but air removal efficiency deteriorates

Engineering Contradiction:
Improveedge sealing efficiencyVSAvoidair removal efficiency
Core Design Contradiction:
Ease of manufactureVSProductivity

Solution Approach 1:

The invention applies different surface characteristics to different regions of the interlayer: the central area has a rough surface pattern (with Rz values of 10-50 micrometers) to facilitate de-airing, while the edge regions maintain smoother characteristics to enable efficient sealing. This localized differentiation allows each region to optimize its function without compromising the other.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The interlayer surface is segmented into distinct functional zones: a central de-airing zone with rough patterns and edge sealing zones with smoother surfaces. This segmentation allows independent optimization of each zone's properties, enabling effective air removal in the center while maintaining energy-efficient sealing at the edges.

Inventive Principle:
Principle #1Segmentation

3Productivity

If vacuum de-airing is used to remove air at ambient temperature, then de-airing efficiency is improved, but the complexity of the lamination process increases

Engineering Contradiction:
Improvede-airing efficiencyVSAvoidlamination process complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The interlayer's rough surface pattern is designed to passively facilitate air removal through its own geometric features. The channels and peaks create natural pathways for air to escape during the lamination process without requiring active vacuum systems or complex de-airing equipment, thereby simplifying the overall process while maintaining efficiency.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The invention replaces complex mechanical vacuum de-airing systems with a passive surface geometry solution. The rough embossed pattern on the interlayer surface creates natural channels that allow air to escape through thermal expansion and pressure differentials during heating, eliminating the need for sophisticated vacuum equipment and control systems.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 embossed surface pattern enables effective air removal and edge sealing, reducing the likelihood of trapped air and visual defects, while minimizing energy investment for compression, thus enhancing the quality and durability of laminated glass.

Implementation Method 1

the embossed surface comprises a surface pattern that provides relatively uninterrupted channels for de-airing

Methodology Applied
Scientific EffectDe-airing:

Implementation Method 2

The presence of a gaseous phase within the laminate will take the form of bubbles or pockets of gas between the interlayer and glass interface. These are generally objectionable for end-use applications where the laminate functions as a transparent article... Autoclaving is a step typically utilized in the production of laminated glass using a combination of heat and pressure to hasten the dissolution of any residual air (gaseous component) within the laminate assembly.

Methodology Applied
Scientific EffectDissolution: Solvation

Implementation Method 3

Thermoplastic interlayers are typically heated during the lamination process to soften the interlayer and facilitate adhesion to glass or plastic material.

Methodology Applied
Scientific EffectMelting: Melting

Data Source

PatentEP1965977B1Interlayers for laminated safety glass with superior de-airing and laminating properties and process for making the same
Publication Date: 2015.03.04 EI DU PONT DE NEMOURS & CO
  • EP1965977B1 patent drawingFigure 1A~1C
  • EP1965977B1 patent drawingFigure 2
  • EP1965977B1 patent drawingFigure 3

AI summary

This invention relates to thermoplastic interlayer sheets or films for laminated safety glass with superior vacuum de-airing at elevated temperatures and superior tacking and edge sealing properties. The sheeting has an embossed surface pattern on at least one of the surfaces, which provides relatively uninterrupted channels for de-airing in at least two non-parallel directions, wherein the channels are spaced about 0.1 to about 1 mm apart and have a depth of less than about 25 μm and a width of about 30 to about 300 μm.