I. Rubber tensile property test Any rubber products are used under certain external conditions, thus requiring that the rubber should have certain physical and mechanical properties, and the performance of the most obvious for the tensile properties, in the quality inspection of finished products, the design of rubber formulations, to determine the technological conditions, and comparison of the rubber aging resistance, media resistance, generally need to be identified through the tensile properties, so the tensile properties of the rubber are important for the Therefore, the tensile property is one of the important routine items of rubber. Tensile properties include the following items: (1) Tensile stress S (tensile stress) sample in tension stress, the value of the applied force and the initial cross-sectional area of the sample ratio. (2) fixed tensile stress Se (tensile stress at a given elongation) working part of the specimen stretched to a given elongation when the tensile stress. Common fixed tensile stress 100%, 200%, 300%, 500% fixed tensile stress. (3) tensile strength TS (tensile strength) specimen stretched to the maximum tensile stress at the time of tearing. In the past has been called tensile strength and tensile strength. (4) elongation rate E (elongation percent) due to stretching the specimen caused by the deformation of the working part of the value of the incremental elongation with the initial length of percent ratio. (5) fixed stress elongation Eg (elongation at a given stress) specimen at a given stress elongation. (6) tearing elongation Eb (elongation at break) sample in the tearing of the elongation. (7) rip permanent deformation of the specimen will be stretched to break, and then subjected to its self out of the state, recovery of a certain period of time (3min) after the remaining deformation, the value of the working part of the incremental elongation and the initial length of percent ratio. (8) Tensile strength at break TSb (tensile strength at break) The tensile stress of the tensile specimen at break. If, after the yield point, the specimen continues to elongate and is accompanied by a decrease in stress, then the values of TS and TSb are not the same, and the value of TSb is less than that of TS. (9) Yield point tensile stress Sy (tensile stress at yield) Stress stress corresponding to the first point on the stress-strain curve at which there is a further increase in strain and no increase in stress. (10) Yield point elongation Ey (elongation at yield) The strain (elongation) corresponding to the first point on the stress-strain curve at which there is a further increase in strain without an increase in stress. Second, the determination of rubber compression permanent deformation Some rubber products (such as sealing products) are used in compression, its compression resistance is one of the main properties affecting product quality, rubber compression resistance is generally used to constant amount of compression permanent deformation. Rubber in compression, will inevitably occur physical and chemical changes, when the compression force disappears, these changes prevent the rubber to return to its original state, so the compression permanent deformation. The magnitude of the compression permanent deformation depends on the temperature and time in the compressed state, and on the temperature and time when the height is restored. At high temperatures, chemical changes are the main cause of compression permanent deformation of rubber. The compression permanent deformation is measured after removing the compression force applied to the specimen and recovering the height at a standard temperature. In tests at low temperatures, changes caused by glass-hardening and crystallization effects are predominant, and these effects disappear when the temperature returns, so that the height of the specimen must be measured at the test temperature.