Supported Dolomite Stabilizer for PVC Thermal Stability
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Solution Overview
Problem
Existing thermal stabilizers for polyvinyl chloride (PVC) fail to provide adequate long-term stability at lower temperatures, leading to discoloration and degradation of motor vehicle components, especially when exposed to varying light and elevated temperatures, and are hindered by the use of perchlorate salts which pose explosion risks and incompatibility issues.
Innovation Solution
A stabilizer system comprising a thermal stabilizer and supported, at least partly calcined dolomite, specifically combining an aqueous metal perchlorate salt solution with calcined dolomite to create a safer, more effective stabilizer composition that enhances the long-term thermal stability of PVC, particularly when used with polyurethane-backfoamed components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If existing thermal stabilizers (calcium-zinc, barium-zinc, organotin, lead) are used to stabilize PVC at processing temperatures, then adequate stabilization at elevated processing temperatures is achieved, but inadequate stabilization at lower temperatures over prolonged periods occurs
Solution Approach 1:
The stabilizer system is segmented into two distinct functional components: a primary thermal stabilizer (calcium-zinc, barium-zinc, organotin, or lead-based) that operates at high processing temperatures, and a secondary long-term stabilizer (hydrotalcite-supported metal perchlorate) that provides sustained protection at lower service temperatures. This segmentation allows each component to be optimized for its specific temperature range without compromise.
Solution Approach 2:
The invention merges two previously separate stabilizing functions into a single integrated stabilizer system. The primary thermal stabilizer and the secondary long-term stabilizer work synergistically, with the hydrotalcite support structure enabling both components to coexist and function simultaneously, providing comprehensive protection across the full temperature spectrum from processing to service.
2Reliability
If perchlorate salts are used to improve long-term thermal stability, then stabilization performance is enhanced, but explosion risks and incompatibility issues arise
Solution Approach 1:
Hydrotalcite serves as an intermediary carrier that holds the metal perchlorate in a stable, dispersed state. The layered double hydroxide structure of hydrotalcite physically confines the perchlorate ions, preventing their direct interaction and eliminating explosion risks while maintaining the stabilizing function. This intermediary approach allows the use of highly effective perchlorate stabilizers without their inherent safety concerns.
Solution Approach 2:
The metal perchlorate is not used in bulk form but is locally distributed as supported species on the hydrotalcite surface and within its interlayer spaces. This local distribution creates isolated active sites that provide stabilizing function while preventing the accumulation of hazardous concentrations that would lead to explosion risks or incompatibility issues.
3Adaptability or versatility
If polyurethane backfoaming is applied to PVC components, then functional properties are improved, but discoloration and degradation occur due to amine interaction
Solution Approach 1:
The stabilizer system applies preliminary anti-action by providing preemptive protection against amine-PVC interactions before degradation can occur. The metal perchlorate components react with and neutralize the amine groups in the polyurethane foam structure, preventing them from attacking the PVC polymer chains and causing discoloration or degradation, thereby preserving both the functional and aesthetic properties of the backfoamed components.
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 provides improved long-term thermal stability and safety by eliminating explosion risks and incompatibility issues, resulting in a more stable and durable PVC composition suitable for motor vehicle components.
Implementation Method 1
the resin can be degraded with autocatalytic release of hydrogen chloride
Implementation Method 2
a stabilizer system comprising a thermal stabilizer and a supported, at least partly calcined dolomite
Implementation Method 3
improve the performance of metal stabilizers such as calcium-zinc, barium-zinc, organotin and lead stabilizers
Implementation Method 4
improve the long-term stability of motor vehicle components made of polyvinyl chloride at moderately elevated temperatures
Data Source
AI summary
The invention relates to a stabilizer system comprising a thermal stabilizer and a supported, at least partly calcined dolomite of the formula Mt1X1*CaX2 where Mt1=Mg or Zn; X1=O or (OH)2; X2=O; (OH)2 or CO3, wherein the calcined dolomite has been supported with a metal perchlorate of the formula Mt2(ClO4)m*nH2O where Mt2=Li, Na, K, Mg, Ca, Ba, Zn, Al, La, Ce; m=1, 2 or 3, m being selected so as to compensate for the charge of the metal ion Mt2; n=0 to 3 and wherein the stabilizer system does not comprise any of the compounds selected from the group consisting of (B) and (C) when Mt1 is Mg, and wherein (B) at least one nitrogen-containing organic compound is selected from the group consisting of (B1) and (B2), (B1) being a tert-alkanolamine and (B2) being an enaminone or a urea, and (C) an alkaline earth metal aluminohydroxocarbonate of the formula (C) (M1−xZnx)yAl2(OH)4+2y CO3* zH2O (C) where M=magnesium or/and calcium; x=0 to 0.5; y=2 to 8 and z=0 to 12. The invention further relates to compositions and articles comprising the stabilizer system, to the use thereof and to processes for production of the supported dolomite.