THF-Free PVC Adhesive Using Chlorinated Polymer and Dioxolane
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Solution Overview
Problem
The use of tetrahydrofuran (THF) as a solvent in PVC-based adhesives poses health and environmental hazards, and there is a need for a THF-free adhesive that maintains similar or better properties in terms of workability, strength, and temperature resistance.
Innovation Solution
A PVC-based adhesive using CPVC with a chlorine percentage of at least 60 wt% dissolved in 1,3-dioxolane or its derivatives, along with aliphatic compounds having a hydrocarbon ring and ether groups, replacing THF as the solvent.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If THF is used as solvent in PVC-based adhesive, then good dissolving ability and adhesive properties are achieved, but health hazards and environmental risks increase
Solution Approach 1:
The patent changes the chemical parameter of the solvent from THF to 1,3-dioxolane, which has different toxicological properties. This parameter change maintains the solvent's ability to dissolve PVC while reducing health hazards and environmental risks, as 1,3-dioxolane is considered less toxic than THF.
Solution Approach 2:
The patent employs a shorter, more benign solvent molecule (1,3-dioxolane) that can be easily evaporated or degraded. This replacement eliminates the need for complex safety infrastructure and reduces long-term environmental persistence, aligning with the principle of using temporary, less harmful substances.
2Reliability
If THF is used as solvent in PVC-based adhesive, then good dissolving ability is achieved, but environmental risks increase
Solution Approach 1:
The patent changes the chemical parameter of the solvent from THF to 1,3-dioxolane, which has different environmental persistence and toxicity characteristics. This parameter change maintains the solvent's ability to dissolve PVC while reducing environmental risks, as 1,3-dioxolane is considered more environmentally benign than THF.
3Temperature
If CPVC with high chlorine percentage is used, then temperature resistance and bond strength are improved, but solubility in conventional solvents decreases
Solution Approach 1:
The patent changes the parameter of the solvent system by introducing 1,3-dioxolane, which has different solvency characteristics compared to conventional solvents. This parameter change enables CPVC with high chlorine content (60-70%) to remain soluble and processable, while maintaining the desired temperature resistance and bond strength properties.
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 adhesive is less toxic, easier to process, with improved drying properties and shelf-life, and provides a strong, temperature-resistant bond comparable to traditional PVC adhesives, while being safer for health and the environment.
Implementation Method 1
CPVC with a chlorine-percentage of at least 60 wt.%, wherein the CPVC is obtainable by chlorination of a uPVC having a K-value of at most 55, and a solvent comprising 1,3-dioxolane and/or derivatives thereof
Implementation Method 2
Depending on time and temperature, the adhesive dries by evaporation of the solvent in air. After drying, a joint formed by the adhesive is obtained
Data Source
AI summary
The present invention relates to a PVC-based adhesive for bonding of pipes made of PVC, comprising: CPVC with a chlorine-percentage of at least 60 wt.%, wherein the CPVC is obtainable by chlorination of a u PVC having a K-value of at most 55, and a solvent comprising one or more aliphatic compounds having a hydrocarbon ring and at least two ether groups in the ring structure. Further, the present invention relates to the use of said adhesive.