Screen Printing Composition for Polyvinyl Butyral Interlayers
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Solution Overview
Problem
Current screen printing processes for laminated glazing units, particularly on glass surfaces, face issues such as additional annealing steps, optical defects, and the need for differentiated heating, which increase costs and affect optical density, and are challenging to apply on curved surfaces.
Innovation Solution
Screen printing is adapted to be performed on polyvinyl butyral interlayer sheets within the laminated glazing unit, using a composition of 11-13% polyvinyl butyral, 35-40% aliphatic dicarboxylic acid diester, and specific black pigments, achieving a Brookfield viscosity of 9-13 Pa·s, allowing for a single pass with short touch-dry times and ensuring high optical quality and adhesion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If screen printing is performed on glass surfaces, then good coverage and opacity are achieved, but additional annealing steps are required and production complexity increases
Solution Approach 1:
The patent introduces polyvinyl butyral interlayer as a mediator substrate for screen printing. Instead of printing directly on glass which requires annealing, the printing composition is applied to the flexible polyvinyl butyral interlayer that is already part of the laminated glazing unit structure. This intermediary approach eliminates the need for separate annealing furnaces while maintaining printing quality.
Solution Approach 2:
The patent combines the printing function with the existing polyvinyl butyral interlayer that is already required for the laminated glazing unit. By merging the printing substrate function with the safety interlayer function, the process eliminates additional equipment while maintaining both the structural safety requirements and the printing quality requirements.
2Ease of manufacture
If enamel is screenprinted on glass face 2, then printing is achieved, but physical contact during bending causes bonding defects and requires additional annealing
Solution Approach 1:
The polyvinyl butyral interlayer serves as a protective intermediary between the printing composition and the glass surface during bending operations. The interlayer prevents direct physical contact between the printed glass surfaces, eliminating bonding defects while allowing the printing process to proceed on the interlayer itself.
3Ease of manufacture
If heating is applied to enameled zones, then curing is achieved, but differentiated heating is required for each configuration increasing process complexity
Solution Approach 1:
The patent makes the heating process universal by applying it to the entire laminated glazing unit assembly rather than requiring differentiated heating for specific enameled zones. The autoclave heating cures both the polyvinyl butyral interlayer and any printing composition simultaneously, eliminating the need for configuration-specific heating protocols.
4Manufacturing precision
If black enamel is applied to achieve optical density of 3, then coverage is achieved, but increased thickness is required which affects transparency
Solution Approach 1:
The patent changes the chemical composition parameters of the printing material by using a specialized printing composition formulated for polyvinyl butyral that contains high pigment concentration. This allows achieving the required optical density of 3 or more with a thin layer that does not adversely affect the overall transparency of the laminated glazing unit.
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
This approach eliminates the need for additional annealing, achieves high optical density without pinholes, and satisfies mechanical and aesthetic standards, ensuring compatibility with in-line processes and durability, while maintaining mechanical strength and resistance to aging and UV radiation.
Implementation Method 1
35% to 40% by weight of at least one aliphatic dicarboxylic acid diester
Implementation Method 2
achieve a Brookfield viscosity of 9-13 Pa·s and allow for a single pass with short touch-dry times
Implementation Method 3
at least one black pigment in an amount and with a specific surface area that are selected so that the Brookfield viscosity of the composition at 20° C. is between 9 and 13 Pa·s
Data Source
AI summary
The invention relates toa composition suitable for the black printing, via screen printing, of a sheet of polyvinyl butyral intended to be part of a laminated glazing unit, characterized in that it comprises:11% to 13% by weight of polyvinyl butyral,35% to 40% by weight of at least one aliphatic dicarboxylic acid diester, andat least one black pigment in an amount and with a specific surface area that are selected so that the Brookfield viscosity of the composition at 20° C. is between 9 and 13 Pa·s;a process for printing, via screenprinitng, a sheet of polyvinyl butyral intended to be part of a laminated glazing unit, using this composition;a sheet of polyvinyl butyral intended to be part of a laminated glazing unit, and printed, via screen printing, using this composition; anda laminated glazing unit comprising such a sheet of polyvinyl butyral.