During the vulcanization process, rubber tensile strength, elongation at break, elasticity and other properties change with the extension of vulcanization time. Usually, the curve of a certain property of rubber with the vulcanization time is used to characterize the vulcanization history and the change law of rubber properties. This is the vulcanization history (Figure), as shown in Figure 1-3. The first half of the figure is the Mooney scorch curve, and the second half is the tensile strength curve. The two parts of the curve constitute a complete vulcanization history. The vulcanization process of rubber can be divided into four stages: scorching stage, hot vulcanization stage, flat vulcanization stage and over-vulcanization stage.