PVC Sealing Membrane with Adipic Polyester and Polyacrylate
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Solution Overview
Problem
Sealing membranes for roofs face challenges with processability and impact strength at low temperatures, as well as inadequate weather resistance due to the use of polymer plasticizers, which are complex and costly to produce, and have high glass transition temperatures leading to brittleness and increased sensitivity to damage.
Innovation Solution
A composition comprising polyvinyl chloride as the base polymer, adipic acid polyester as the polymeric plasticizer, and polyacrylate, with specific weight proportions and processing techniques to produce dry, pre-sintered films that are flexible and resistant to impact and aging, while minimizing the use of low-molecular-weight plasticizers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If polymer plasticizers are used in PVC sealing membranes to replace low molecular weight plasticizers, then health safety is improved, but the glass transition temperature increases leading to poor processability at low temperatures and increased impact sensitivity
Solution Approach 1:
The patent changes the molecular weight parameter of the plasticizer from low molecular weight to high molecular weight (polymer plasticizer with Mn = 5,000 to 8,000), which improves health safety but increases glass transition temperature. This contradiction is resolved by combining the polymer plasticizer with specific polyacrylate copolymers that modify the plasticizer system's overall properties, allowing maintenance of low-temperature flexibility despite using high molecular weight plasticizers.
Solution Approach 2:
The patent creates a composite plasticizer system combining polymer plasticizers (adipic acid polyesters) with polyacrylate copolymers containing carboxyl groups. This composite approach allows the system to benefit from the health safety of polymer plasticizers while the polyacrylate component compensates for the increased glass transition temperature, restoring processability at low temperatures.
2Object-affected harmful factors
If polymer plasticizers are used in PVC sealing membranes, then health safety is improved, but impact resistance decreases due to increased hardness at low temperatures
Solution Approach 1:
The patent modifies the plasticizer system by incorporating polyacrylate copolymers with specific molecular weights and carboxyl content. This changes the rheological and mechanical properties of the plasticizer system, reducing the hardness increase at low temperatures that would otherwise compromise impact resistance, while maintaining the health benefits of polymer plasticizers.
Solution Approach 2:
The patent develops a composite plasticizer system where polymer plasticizers (providing health safety) are combined with polyacrylate copolymers (providing flexibility and impact resistance). The carboxyl groups in the polyacrylate interact with the PVC and polymer plasticizer, creating a synergistic system that maintains both health safety and impact resistance.
3Reliability
If complex rubber-like polymers based on butyl acrylate and multiple components are used to improve weather resistance, then weather stability is improved, but production complexity and cost increase
Solution Approach 1:
The patent extracts and isolates the essential weather-resistant component (polyacrylate copolymer) from complex multi-component rubber-like polymer systems. By using a focused combination of PVC, polymer plasticizer, and polyacrylate copolymer, the patent achieves weather resistance without the production complexity of processing five or more different polymer components.
Solution Approach 2:
Instead of using complex rubber-like polymers as the base and adding PVC and plasticizers, the patent inverts the approach by using PVC as the base polymer and adding polyacrylate copolymers as the weather-resistant modifier. This simplifies the production process while achieving the desired weather stability.
4Object-affected harmful factors
If polymer plasticizers are used in sealing membranes, then health safety is improved, but aging resistance decreases over time as the softening effect diminishes
Solution Approach 1:
The patent creates a composite plasticizer system where polymer plasticizers are combined with polyacrylate copolymers containing carboxyl groups. The polyacrylate component provides long-term stability and prevents the softening effect from diminishing over time, thereby improving aging resistance while maintaining the health benefits of polymer plasticizers.
Solution Approach 2:
The polyacrylate copolymer acts as an intermediary between the PVC base polymer and the polymer plasticizer. The carboxyl groups in the polyacrylate form interactions that stabilize the plasticizer system over time, preventing migration and evaporation of the plasticizer components, thereby improving aging resistance while maintaining health safety.
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 solution results in sealing membranes with improved notched impact strength, aging resistance, and reduced sensitivity to temperature fluctuations, allowing for better processing and increased durability, especially at low temperatures, with enhanced perforation resistance and plasticizer retention.
Implementation Method 1
the use of a polymer as a processing aid... has the advantage that the glass transition temperature of the polymer mixture treated with this plasticizer is relatively high
Implementation Method 2
EP 1 141 055 A1 proposes the use of a complex rubber-like polymer... This can be used to produce roof sealing membranes
Data Source
AI summary
The present invention relates to a composition for the production of a sealing web, comprising a main polymer, a polymer plasticizer and a polyacrylate, wherein the polymer plasticizer is an adipic acid polyester having a mean molecular weight of 3,000 to 12,000. The invention further relates to sealing webs produced from said composition, and to the use thereof.