Crosslinked Cellulose Hydrate Membrane for Sterile Filtration
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Solution Overview
Problem
Existing cellulose hydrate membranes for filtration lack mechanical stability, are prone to shrinkage and swelling, and are not suitable for sterile filtration due to high brittleness and 'start-of-roll/end-of-roll effects', requiring reinforcement which can introduce particles into the filtrate.
Innovation Solution
A crosslinked unreinforced cellulose hydrate membrane is produced using at least two different diepoxide compounds as crosslinking agents in an alkaline solution at elevated temperatures, resulting in improved mechanical stability, reduced dimensional change, and excellent pleatability without steam, allowing for reliable sterile filtration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If cellulose hydrate membranes are used for filtration, then hydrophilicity and low protein adsorption are achieved, but mechanical stability is poor and shrinkage/swelling occurs
Solution Approach 1:
The patent applies crosslinking to create a composite network structure within the cellulose hydrate membrane. The crosslinked gel structure combines the hydrophilic properties of cellulose hydrate with enhanced mechanical stability, reducing shrinkage and swelling while maintaining filtration performance.
Solution Approach 2:
The patent modifies the physical and chemical parameters of the cellulose hydrate membrane through crosslinking. By changing the molecular structure through crosslinking reactions, the membrane achieves improved dimensional stability and mechanical strength while retaining its hydrophilic characteristics.
2Strength
If crosslinking is performed to improve mechanical stability, then strength increases, but brittleness increases and pleatability decreases
Solution Approach 1:
The patent optimizes the crosslinking parameters including the type and amount of crosslinking agent, reaction temperature, and reaction time. By carefully controlling these parameters, the membrane achieves sufficient mechanical stability while maintaining flexibility and pleatability required for sterile filtration applications.
Solution Approach 2:
The crosslinking is performed to achieve uniform distribution of crosslinked structures throughout the membrane, creating consistent local properties that balance mechanical strength with flexibility. This uniform crosslinking prevents localized brittleness while maintaining overall structural integrity.
3Strength
If reinforcement is added to improve mechanical stability, then strength increases, but particles may be introduced into the filtrate
Solution Approach 1:
Instead of adding physical reinforcement layers that could shed particles, the patent creates an integrated crosslinked composite structure within the membrane matrix. This internal crosslinked network provides mechanical strength without introducing foreign particles into the filtration stream.
Solution Approach 2:
The patent removes the need for separate reinforcement layers by integrating the strengthening function directly into the membrane structure through crosslinking. This eliminates the harmful effect of reinforcement particles while maintaining the desired mechanical properties.
4Stability of the object's composition
If high degree of crosslinking is performed to reduce shrinkage, then dimensional stability improves, but hydrophilicity is impaired
Solution Approach 1:
The patent optimizes the crosslinking degree and selects crosslinking agents that minimize impact on hydrophilicity. By controlling the crosslinking parameters and using appropriate crosslinking agents, the membrane achieves dimensional stability while preserving the hydrophilic properties necessary for aqueous filtration.
Solution Approach 2:
The crosslinked gel structure creates a composite network that maintains water channels and hydrophilic pathways while providing dimensional stability. The crosslinked framework supports the membrane structure without blocking the hydrophilic properties needed for filtration performance.
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 membrane exhibits high mechanical stability, low plasticizer content, and excellent pleating properties, with minimal dimensional change during swelling and drying, ensuring consistent membrane flow and thickness, and is suitable for sterile filtration applications.
Implementation Method 1
crosslinking of the cellulose hydrate membrane by impregnation with a crosslinker solution and subsequent temperature increase
Implementation Method 2
crosslinking being carried out in an aqueously alkaline solution containing at least two different crosslinking agents
Implementation Method 3
crosslinking being carried out at a temperature of 75° C. to 150° C. for 0.1 to 60 minutes
Data Source
AI summary
The present invention relates to a crosslinked unreinforced cellulose hydrate membrane crosslinked using at least two different crosslinking agents, to a method for the production thereof and to the use of the crosslinked unreinforced cellulose hydrate membrane according to the invention.