Optical Brightener Formulation for Papermaking Brightness and Retention
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Solution Overview
Problem
Conventional optical brighteners (OBAs) face limitations in achieving higher brightness in papermaking due to cost constraints and inefficiencies in retention and stability, with tetra-sulfonated stilbene OBA causing sheet yellowing and hexa-sulfonated OBA being expensive, and current carriers like polyvinyl alcohol requiring costly cooking processes.
Innovation Solution
A formulation combining polyvinyl alcohol, glucomannan, carboxymethyl cellulose, and sorbitol as carriers to optimize OBA retention, reducing dosage rates and enhancing brightness and whiteness while minimizing the need for external heating and water addition, using low viscosity polyvinyl alcohol and konjac glucomannan for improved dispersion and cohesion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If tetra-sulfonated stilbene OBA is used to improve brightness, then brightness is improved, but sheet yellowing and over-greening occur due to overdosing
Solution Approach 1:
The patent uses a carrier system comprising polyvinyl alcohol and glucomannan as intermediary substances to deliver the OBA to the paper. This mediator approach allows controlled release and distribution of the OBA, preventing localized overdosing that causes yellowing while maintaining overall brightness enhancement.
Solution Approach 2:
The patent changes the physical and chemical parameters of the OBA delivery system by using a carrier formulation with specific molecular weights and ratios of polyvinyl alcohol to glucomannan. This parameter optimization enables better retention and uniform distribution of OBA, avoiding the yellowing effect associated with conventional direct addition methods.
2Illumination intensity
If hexa-sulfonated stilbene OBA is used to achieve higher brightness, then brightness is improved, but cost increases significantly
Solution Approach 1:
The carrier system acts as an efficient delivery mechanism that maximizes the utilization of tetra-sulfonated stilbene OBA, extracting maximum brightness performance from this more cost-effective compound and reducing the need to use expensive hexa-sulfonated alternatives.
Solution Approach 2:
The patent employs a cost-effective carrier formulation using readily available polyvinyl alcohol and glucomannan materials, creating an economical system that achieves high brightness without requiring expensive specialty chemicals.
3Reliability
If polyvinyl alcohol carrier is used to improve OBA retention, then OBA retention is improved, but costly cooking processes are required
Solution Approach 1:
The patent merges polyvinyl alcohol with glucomannan in a carrier formulation, creating a synergistic system where glucomannan enhances the OBA retention capability while the combination allows for simplified processing that reduces or eliminates the need for expensive cooking operations.
Solution Approach 2:
The carrier is formulated as a composite material combining polyvinyl alcohol and glucomannan, leveraging the properties of both components to achieve superior OBA retention without requiring the high-energy cooking process traditionally needed for polyvinyl alcohol alone.
4Illumination intensity
If OBA addition dosage is increased to satisfy higher brightness demand, then brightness is improved, but water retention capability deteriorates
Solution Approach 1:
The carrier system serves as an intermediary that binds OBA molecules, preventing them from interfering with the water retention mechanisms in the paper. This mediated approach allows high OBA concentrations for brightness enhancement without the negative impact on water retention that would occur with direct high-dosage OBA addition.
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 formulation achieves significant brightness gains with reduced OBA addition rates, improved whiteness, and enhanced water retention, while minimizing cost and environmental impact, and provides resistance to light-induced aging and color aberrations.
Implementation Method 1
The formulation includes the optical brightener, polyvinyl alcohol, glucomannan, carboxymethyl cellulose, and sorbitol. These complementary elements gives noticeable retention power to OBA
Implementation Method 2
using low viscosity polyvinyl alcohol and konjac glucomannan for improved dispersion and cohesion
Implementation Method 3
When observed under light, OBAs can absorb invisible ultraviolet light and re-emit visible blue light back, giving viewers the visual perception of a brighter sheet
Implementation Method 4
using low viscosity polyvinyl alcohol and konjac glucomannan for improved dispersion and cohesion
Implementation Method 5
The formulation includes the optical brightener, polyvinyl alcohol, glucomannan, carboxymethyl cellulose, and sorbitol. These complementary elements gives noticeable retention power to OBA, yielding significant OBA dosage reduction along with other benefits such as lower additive viscosity and reinforced bonding to the sizing/coating medium
Data Source
AI summary
This invention relates to a formulation of optical brightener, polyvinyl alcohol, glucomannan, carboxymethyl cellulose, and sorbitol which can be used on the sizing or coating application of papermaking. This composition yields high whiteness and brightness on the product paper.