HNBR Sealing Gasket Composition for Low-Temperature Compression Set
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Solution Overview
Problem
Existing rubber sealing gaskets for automobile air-conditioning systems exhibit poor compression performance and low-temperature performance, with high compression set rates and early cracking at low temperatures, failing to meet the required mechanical and aging properties.
Innovation Solution
A rubber sealing gasket is developed using hydrogenated nitrile butadiene rubber (HNBR) with specific additives and a dual vulcanization process, incorporating a co-crosslinking agent like triallyl isocyanurate (TAIC) and reinforcing fillers such as carbon black, which improves compression set performance and low-temperature resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional rubber materials and single vulcanization process are used, then manufacturing simplicity is maintained, but compression performance and low-temperature performance are poor
Solution Approach 1:
The vulcanization process is divided into two distinct stages: first vulcanization at 170-175°C for 12-22 min to establish basic crosslinking, and second vulcanization at 150-155°C for 3-5 h to optimize compression performance. This segmentation allows each stage to serve specific functions, resolving the contradiction between performance improvement and process complexity.
Solution Approach 2:
The patent changes vulcanization parameters systematically: temperature is reduced from 170-175°C in first vulcanization to 150-155°C in second vulcanization, while time increases from 12-22 min to 3-5 h. This parameter optimization enables improved compression performance despite increased process complexity.
2Reliability
If conventional rubber formulations are used, then material simplicity is maintained, but compression set rate is high (35-68%)
Solution Approach 1:
The patent uses a composite formulation combining HNBR base rubber with specific additives: carbon black N220 (20-30 parts) and N990 (25-35 parts) as reinforcing fillers, TAIC (4.8-5.2 parts) as co-crosslinking agent, and DCP (4.8-5.2 parts) as vulcanizing agent. This composite approach reduces compression set rate to 24-32%, overcoming the limitation of conventional formulations.
Solution Approach 2:
The formulation provides different functional zones: carbon black N220 contributes to compression resistance, N990 enhances low-temperature flexibility, TAIC improves crosslinking density, and DCP provides vulcanization. Each additive serves a specific local function that collectively resolves the compression set issue.
3Reliability
If conventional rubber materials are used, then material simplicity is maintained, but low-temperature performance is poor with early cracking
Solution Approach 1:
The patent combines HNBR base rubber with carbon black N990 (25-35 parts) which specifically enhances low-temperature flexibility and crack resistance. This composite material approach prevents early cracking at low temperatures while maintaining material composition manageability.
Solution Approach 2:
The patent optimizes the acrylonitrile content parameter of HNBR to 36-38%, which balances oil resistance and low-temperature flexibility. This parameter optimization enables improved low-temperature performance without excessive material complexity.
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 a rubber sealing gasket with enhanced compression performance, improved mechanical properties, and resistance to low-temperature brittleness, meeting the performance requirements for automobile air-conditioning systems by reducing compression set rates and maintaining integrity at extreme temperatures.
Implementation Method 1
a carboxyl-free peroxide vulcanization process is adopted to provide a relatively high decomposition temperature
Implementation Method 2
the co-crosslinking agent TAIC...can significantly improve a crosslinking density
Implementation Method 3
The reinforcing filler is a mixture of carbon black N220 and carbon black N990
Data Source
AI summary
The present disclosure belongs to the technical field of polymer rubber composites, and specifically relates to a rubber sealing gasket with excellent compression performance and low-temperature performance, and a preparation method and use thereof. The rubber sealing gasket is prepared from the following raw materials in parts by mass: a hydrogenated nitrile butadiene rubber (HNBR): 100 parts; a processing aid: 12.3 parts to 13.7 parts; a reinforcing filler: 45 parts to 65 parts; a vulcanizing agent: 4.8 parts to 5.2 parts; and a co-crosslinking agent: 4.8 parts to 5.2 parts. The rubber sealing gasket prepared by the present disclosure has excellent compression performance and low-temperature performance, meets the performance requirements of rubber sealing gaskets for automobile air-conditioning systems, and can be used in sealing components of automobile air-conditioning systems.