Solvent Mixtures for Polymeric Swelling and Bonding
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Solution Overview
Problem
Current solvent swelling agents for polymeric materials, such as PVC, silicone, and polyurethane, have limited swelling times, making it difficult to efficiently attach these materials to rigid parts due to high coefficients of friction and rigidity, often resulting in wasted time, damaged assemblies, or unreliable connections.
Innovation Solution
A solvent solution comprising between 5% and 95% by volume of n-Octane, with optional heptane or nonane isomers, is used to create a swelling solvent that can be tuned for desired swelling times, and a bonding solvent solution with varying ratios of acetone, MEK, heptane, octane, nonane, isohexane, and THF, and cyclohexanone to facilitate longer swelling or bonding times as needed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If current solvent swelling agents are used, then polymeric materials can be swollen to facilitate attachment, but the swelling time is limited and too short for efficient assembly
Solution Approach 1:
The patent modifies the chemical composition parameters of the solvent system by combining multiple solvents (cyclohexanone, methyl isobutyl ketone, and heptane in specific ratios) to extend the swelling duration. This parameter change in the solvent mixture enables prolonged swelling action while maintaining effectiveness, directly resolving the contradiction between swelling time and assembly efficiency
2Reliability
If forcing PVC tubing onto fittings is attempted, then connection may be achieved, but time is wasted and assemblies may be damaged
Solution Approach 1:
The patent applies swelling solvent to the tubing before insertion to pre-soften and expand the material, making it more compliant and easier to insert onto fittings. This preliminary action eliminates the need for forcing during assembly, reducing both time loss and risk of damage while ensuring reliable connections
3Ease of operation
If silicone or polyurethane tubing is attached to fittings without swelling agents, then the process is simple, but the high coefficient of friction makes attachment difficult or impossible
Solution Approach 1:
The patent introduces swelling solvent as an intermediary substance that temporarily modifies the physical properties of the tubing surface. The solvent acts as a mediator by reducing friction and enabling insertion, then evaporates to leave a reliable bond, thus facilitating easy attachment while ensuring connection reliability
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 solvent solutions provide extended swelling or bonding times, allowing for more efficient attachment of polymeric parts by maintaining the swollen state for longer periods, thereby improving the reliability and efficiency of connecting polymeric materials to other parts, especially in medical device fabrication.
Implementation Method 1
Swelling agents are solvents or solvent blends that are absorbed relatively quickly into the material. Upon absorption of the swelling solvent (or solvent blend), the polymer is expanded to a desired dimension.
Implementation Method 2
Once the PVC part or tube is in place, the solvent evaporates and the PVC returns to its original size, thus creating a tight, strong connection.
Implementation Method 3
Solvent bonding involves temporarily softening and dissolving the molecules on the polymers' surfaces. As the polymers are dissolved, these surface molecules mix together. A permanent seal is formed as the solvent evaporates.
Data Source
AI summary
The present disclosure is generally directed to solvent mixtures for swelling and bonding polymeric substances for use in facilitating the connection of polymeric substances to other parts. A swelling solvent solution according to the present disclosure may comprise between 5% and 95% by volume n-Octane and between 5% and 95% by volume of either a heptane isomer (such as n-Heptane) or a nonane isomer (such as n-Nonane). The swelling solvent solution may be used to swell polymeric parts to enable the parts to be attached to other parts. A bonding solvent solution according to the present disclosure may comprise between 2% and 98% by volume of at least one of: acetone, MEK, heptane, octane, nonane, isohexane, and THF, and between 2% and 98% by volume cyclohexanone. The bonding solvent solution may be used to bond polymeric parts to other parts.