Test Background
Compressive stress relaxation refers to the phenomenon that the compressive force decreases with time after applying a constant compressive deformation, expressed as a percentage of the initial force. For rubber products used outdoors, the ambient temperature may cycle between high temperatures (such as 150°C) and low temperatures (such as -40°C). When evaluating the performance and longevity of these rubber products in practical applications, it is important to consider shrinkage at low temperatures.
Rubber will crystallize at low temperatures, which will further increase its shrinkage. For example: rubber hoses and rubber sealing rings used in automobiles can maintain good working condition at normal temperatures, but may leak at low temperatures.
Zhongke Testing Reliability Experiment Center has the capability to test the reliability performance of various vulcanized rubbers or thermoplastic rubbers, and provides professional compressive stress relaxation testing services for vulcanized rubbers or thermoplastic rubbers.
Scope of tests
Vulcanized rubber: flat vulcanizing machine vulcanizing type, vulcanizing tank vulcanizing type, continuous vulcanizing type, special vulcanizing type, etc.
Thermoplastic rubber: polystyrene, polyurethane, polyolefin, polyester, ethylene-vinyl acetate copolymer, ethylene-acrylate copolymer, polyethylene-butyl rubber joint copolymer, etc.
Test method
1. Normal and high temperature test: At the specified test temperature, compress the vulcanized rubber or thermoplastic rubber sample to and maintain a constant strain state, and measure the reduction in compression force.
Method A, compress the specimen at the test temperature and measure all compression forces at the test temperature.
Method B, compress the specimen at standard laboratory temperature and measure all compression forces. The specimen is stored at the test temperature.
2. Cyclic temperature test:
Method A: The test temperature alternates between high and low temperatures at regular intervals. The high-temperature stage evaluates the aging resistance of the rubber material, and the low-temperature stage evaluates the sealing performance of the rubber material.
Method B: The test temperature continuously alternates between high and low temperatures to generate thermal stress inside the rubber material. The compressive force is determined using a continuous measuring system.
Test standard:
GB/T 1685.2-2019 Vulcanized rubber or thermoplastic rubber - Determination of compressive stress relaxation - Part 2: Test at cyclic temperature
GB/T 1685-2008 Determination of compressive stress relaxation of vulcanized rubber or thermoplastic rubber at room temperature and high temperature
ISO 3384-2005 Determination of compressive stress relaxation of vulcanized rubber or thermoplastic rubber at normal and elevated temperatures
ISO 3384-2-2012 Vulcanized rubber or thermoplastic rubber - Determination of compressive stress relaxation - Part 2: Test at cyclic temperatures
