Aluminoborosilicate Glass Refining for Neutral White Color
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Solution Overview
Problem
Existing borosilicate glasses used in pharmaceutical packaging face challenges in achieving a neutral white color impression while maintaining low bubble content and high chemical resistance, particularly due to the use of CeO2 as a refining agent which causes a yellow color tinge and may lead to lamp ring formation during processing.
Innovation Solution
A glass composition comprising specific proportions of SiO2, B2O3, Al2O3, Na2O, K2O, and CaO, with controlled amounts of Cl and CeO2, optimized to achieve a color position in the CIE 1931 color space and low bubble content, and processed using methods like down draw or overflow fusion to prevent lamp ring formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If CeO2 is used as a refining agent to reduce bubble content, then the number of bubbles decreases, but the glass develops a yellow color tinge
Solution Approach 1:
The patent combines multiple refining agents (CeO2, Cl, and other metal oxides) in specific proportions to achieve effective bubble removal while neutralizing the yellow color tinge that CeO2 alone would cause. This synergistic combination allows the glass to meet both clarity and color neutrality requirements.
Solution Approach 2:
The patent optimizes the concentration parameters of refining agents, specifically limiting CeO2 to 10-2000 ppm, Cl to 75-800 ppm, and controlling the weight ratio of CeO2 to Cl to at most 10. These parameter adjustments ensure effective refining while maintaining neutral white color appearance.
2Manufacturing precision
If Cl-based refining agents are used to reduce bubble content, then the number of bubbles decreases, but lamp rings may form during processing
Solution Approach 1:
The patent precisely controls the concentration of Cl (75-800 ppm) and its ratio to CeO2 (weight ratio at most 10), which optimizes bubble removal efficiency while minimizing lamp ring formation during glass processing. This parameter optimization balances refining effectiveness with processing quality.
3Manufacturing precision
If the proportion of CeO2 is increased to achieve better refining results, then the number of bubbles decreases, but the yellow color tinge increases
Solution Approach 1:
The patent establishes an optimal concentration range for CeO2 (10-2000 ppm) and controls its weight ratio to Cl at at most 10, achieving effective bubble removal while preventing excessive yellow coloration. This balanced parameter selection resolves the trade-off between refining efficiency and color neutrality.
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 glass achieves a neutral white color impression with low bubble content, high hydrolytic resistance, and prevents lamp ring formation, meeting stringent pharmaceutical packaging requirements while being cost-effective.
Implementation Method 1
This is generally achieved by refining. Previously, refining agents comprising oxides of As and/or Sb have been used. For safety reasons new refining agents have been developed, in particular Cl-based refining agents. An alternative refining agent is CeO2.
Implementation Method 2
Furthermore, in particular in the field of pharmaceutical packaging, a neutral white color impression of the glass is desired... can be processed into pharmaceutical containers without development of lamp rings
Data Source
AI summary
An aluminoborosilicate glass with excellent visual appearance, and a method of producing such glass are provided. The use of the glass, in particular for pharmaceutical packaging, for example pharmaceutical containers such as glass vials, glass ampoules, glass cartridges or glass syringes.