Screen Printable Polymer Interlayer for Laminated Glazing

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Solution Overview

Problem

Current methods for printing on laminated glazing, such as enameling on glass sheets, face challenges like additional annealing steps, optical defects, and difficulty in achieving high optical densities, especially for colored shades, which increase production costs and complexity.

Innovation Solution

Developing a screen printing composition for polymer interlayers in laminated glazing, comprising 10-15% polyvinyl butyral, 32-45% aliphatic dicarboxylic acid diester, and specific pigments, allowing for single-pass printing with high optical quality and short dry times, while ensuring mechanical adhesion and durability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If enamel screen printing is performed on glass sheets, then good optical qualities and coverage are achieved, but additional annealing steps are required and production complexity increases

Engineering Contradiction:
Improveoptical qualityVSAvoidproduction process complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The invention changes the substrate material from glass to polymer (PVB), which fundamentally alters the curing mechanism from thermal annealing to UV photocuring. This parameter change eliminates the need for additional annealing ovens and complex heating control systems, while maintaining good optical quality through the polymer's transparency and the UV curing process's ability to fully harden the enamel without thermal distortion

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention replaces the thermal field (annealing oven) with a UV light field (photocuring system). Instead of using high-temperature thermal energy to harden the enamel, UV photons directly initiate polymerization of the photopolymer components, eliminating the need for complex thermal management equipment and reducing production line complexity

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

2Manufacturing precision

If enamel is fired on glass to achieve high optical density, then opacity is improved, but optical defects such as Brennlinie are created

Engineering Contradiction:
Improveoptical densityVSAvoidoptical defects
Core Design Contradiction:
Manufacturing precisionVSObject-generated harmful factors

Solution Approach 1:

The invention changes the curing mechanism from thermal firing to UV photocuring. UV photocuring occurs at ambient temperature and cures the enamel through photochemical polymerization rather than thermal sintering, eliminating the thermal gradients and localized overheating that cause Brennlinie defects while still achieving high optical density through sufficient UV energy dosage and photopolymer formulation

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention replaces thermal energy with UV electromagnetic radiation to achieve enamel hardening. This substitution eliminates the thermal field that causes optical defects during firing, while UV photocuring provides uniform, controllable energy distribution that cures the enamel without creating thermal stress or localized melting defects

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

3Illumination intensity

If colored enamel is applied to achieve bright shades, then color vibrancy is improved, but optical density decreases below required levels

Engineering Contradiction:
Improvecolor vibrancyVSAvoidoptical density
Core Design Contradiction:
Illumination intensityVSManufacturing precision

Solution Approach 1:

The invention uses a composite enamel formulation combining organic pigments for color vibrancy with photopolymer resins and reactive diluents that provide high optical density. The composite system allows bright colors from organic dyes while maintaining opacity through the concentrated polymer matrix and UV-curable components, achieving both color vibrancy and required optical density simultaneously

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The invention changes from inorganic enamel pigments to organic photopolymer-compatible pigments. Organic pigments provide superior color vibrancy and brightness, while the photopolymer vehicle system maintains high optical density through its concentrated, UV-curable formulation. The parameter change in pigment chemistry enables both bright colors and high opacity without requiring multiple coating passes

Inventive Principle:
Principle #35Parameter changes

4Manufacturing precision

If heating is increased to improve enamel density, then optical density is improved, but energy consumption and process complexity increase

Engineering Contradiction:
Improveenamel densityVSAvoidheating energy consumption
Core Design Contradiction:
Manufacturing precisionVSUse of energy by moving object

Solution Approach 1:

The invention replaces thermal heating with UV irradiation for enamel curing. UV photocuring delivers energy directly to the photopolymer molecules, initiating rapid polymerization and hardening without heating the entire substrate. This eliminates the need for high-temperature ovens and reduces energy consumption by targeting only the enamel layer with photons rather than heating the entire glass and enamel assembly thermally

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

Solution Approach 2:

The invention changes the energy delivery mechanism from thermal conduction to UV photon absorption. UV energy is absorbed directly by the photopolymer components, converting light energy to chemical energy for polymerization. This parameter change eliminates the need for sustained high-temperature heating while achieving complete enamel hardening, significantly reducing energy consumption

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 solution enables high optical quality and mechanical adhesion in laminated glazing with single-pass printing, eliminating the need for annealing and achieving desired optical densities, thus reducing production costs and complexity while meeting regulatory standards.

Implementation Method 1

The invention also relates to a photopolymer composition for screen printing, in which the composition comprises 10 to 15% by weight of polyvinyl butyral, 32 to 45% by weight of at least one solvent consisting mainly of at least one aliphatic dicarboxylic acid diester

Methodology Applied
Scientific EffectPhotopolymerisation: Photopolymerisation

Data Source

PatentEP2879880B1Laminated glass comprising a colored composition, screen printable on a polymeric sheet
Publication Date: 2018.09.12 SAINT GOBAIN VITRAGE SA

AI summary

The invention relates to: - a composition suitable for coloured printing by screen printing of a sheet of polymer material intended to be part of a laminated glazing, characterized in that it comprises: - 10% to 15% by weight of polyvinyl butyral, - 32% to 45% by weight of at least one solvent consisting predominantly of at least one aliphatic dicarboxylic acid diester, and - at least one white pigment in an amount and with a specific surface area selected such that the Brookfield viscosity at 20°C of the composition is between 9 and 13 Pa.s; - a process for printing, by screen printing, a sheet of polymer material intended to be part of a laminated glazing, by means of this composition; - a sheet of polymer material intended to be part of a laminated glazing, and printed by screen printing by means of this composition; and - a laminated glazing comprising such a sheet of polymer material.