Stilbene Brightener and Polyvinyl Alcohol Aqueous Solutions
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Solution Overview
Problem
Papermakers face inefficiencies in preparing brightened, coated papers as they need to separately add polyvinyl alcohol to the coating slip to enhance optical brightener performance, complicating the process.
Innovation Solution
Storage-stable aqueous solutions are developed, consisting of stilbene optical brighteners and polyvinyl alcohol, which can be directly used or diluted for coating compositions, improving the whiteness of coated papers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If polyvinyl alcohol is added separately to the coating slip to enhance optical brightener performance, then the whiteness of coated papers is improved, but the process complexity and preparation time increase
Solution Approach 1:
The patent combines polyvinyl alcohol and optical brightener into a single pre-mixed aqueous solution. This merging eliminates the need for separate addition of polyvinyl alcohol to the coating slip, thereby reducing process complexity while maintaining the whiteness enhancement effect. The combined solution is applied directly to the coating composition, streamlining the manufacturing process.
Solution Approach 2:
The patent prepares the optical brightener and polyvinyl alcohol in advance as a stable aqueous solution before application to the coating slip. This preliminary action of pre-mixing the components resolves the technical contradiction by eliminating the need for separate addition during the coating process, thus reducing process complexity while preserving the whiteness improvement.
2Illumination intensity
If polyvinyl alcohol is added separately to the coating slip, then optical brightener performance is enhanced, but the preparation time and efficiency decrease
Solution Approach 1:
By merging polyvinyl alcohol and optical brightener into a single pre-mixed aqueous solution, the patent eliminates multiple addition steps during coating slip preparation. This merging directly improves productivity by reducing the number of operations required, while the combined solution maintains the whiteness enhancement capability.
Solution Approach 2:
The pre-preparation of the optical brightener and polyvinyl alcohol as a stable aqueous solution before application to the coating slip eliminates the need for separate addition steps during the coating process. This preliminary action significantly reduces preparation time and improves efficiency while preserving the whiteness improvement effect.
3Productivity
If a stable aqueous solution of optical brightener and polyvinyl alcohol is prepared, then process efficiency is improved, but the solution stability and storage requirements become critical
Solution Approach 1:
The patent optimizes parameters of the aqueous solution including pH (adjusted to alkaline conditions using ammonia or alkali metal hydroxides), concentration ratios, and temperature conditions to ensure stability. By carefully controlling these parameters, the patent achieves both high process efficiency through the pre-mixed solution and long-term storage stability, resolving the contradiction between productivity and composition stability.
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 solutions provide a simplified process for producing high-whiteness coated papers by allowing direct use or dilution of the brightener solutions, resulting in enhanced whiteness and process efficiency.
Implementation Method 1
the whiteness and thereby the attractiveness of coated papers can be improved by the addition of optical brighteners
Implementation Method 2
aqueous solutions of stilbene optical brighteners with polyvinyl alcohols which can be directly used by the papermaker
Data Source
AI summary
The instant invention relates to storage stable aqueous solutions of stilbene optical brighteners with polyvinyl alcohols which can be directly used by the papermaker in that they may be diluted with water and/or be metered directly into a coating composition, to provide coated papers of a particularly high whiteness.