1.1 该分类涵盖了橡胶工业中使用的各种硫等级。显示了硫的典型化学和物理性质。硫主要用作不饱和橡胶的硫化剂。 1.2 本国际标准是根据世界贸易组织技术性贸易壁垒（TBT）委员会发布的《关于制定国际标准、指南和建议的原则的决定》中确立的国际公认标准化原则制定的。 ====意义和用途====== 3.1 硫是主要的橡胶硫化剂之一。 它是一种关键添加剂。当与橡胶化学结合时，硫在硫化化合物中形成基本性能，例如:抗拉强度、伸长率、模量和硬度。在软橡胶或弹性橡胶化合物中，硫是一种基本但次要的添加剂。在半硬质橡胶和硬质橡胶中，硫成为主要的复合材料，同时保留其作为硫化剂的作用。 3.2 在环境条件下，硫最稳定的分子形式是包含八个硫原子的环状结构。根据条件，这些分子定向为两种晶体结构之一。在室温下，晶体为菱形，在95°C以上，它们重新排列为单斜晶体。 小于1.5 % 硫的任何一种晶体结构在室温下都可溶于任何橡胶。 3.3 硫的第二种常见分子形式是聚合硫，由硫原子的不支链组成。在橡胶工业中通常称为不溶性硫。当这种材料通过快速加热到160°C以上并淬火到室温而形成时，硫是无定形的。如果在其他条件下形成，聚合物链可能会形成伪结晶区域。 3.4 不溶性硫是硫的一种重要形式，仅用于橡胶工业。它不溶于任何类型的橡胶碳氢化合物。 当它与橡胶混合时，它会分散，但在橡胶中不溶解。使用不溶性硫可防止在使用菱形硫时，橡胶中形成过饱和硫溶液。混合或加工后，当橡胶冷却时，未硫化橡胶件表面不会出现硫华；因此，建筑粘性得以保留。在固化温度下，不溶性硫迅速转变为可溶物质，溶解在橡胶中，并进入硫化过程。

1.1 This classification covers the variety of sulfur grades used in the rubber industry. Typical chemical and physical properties for sulfur are shown. Sulfur is principally used in unsaturated rubbers as a vulcanizing agent. 1.2 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee. ====== Significance And Use ====== 3.1 Sulfur is one of the principal rubber vulcanizing agents. It is a critical additive. When chemically combined with rubber, sulfur develops basic performance properties in the vulcanized compound such as: tensile strength, elongation, modulus, and hardness. In soft or elastic rubber compounds, sulfur is an essential but minor additive. In semi-hard rubber and ebonite, sulfur becomes a major compounding material while retaining its role as a vulcanizing agent. 3.2 The most stable molecular form of sulfur at ambient conditions is a ring structure containing eight sulfur atoms. Depending on conditions these molecules orient into one of two crystalline structures. At room temperature the crystals are rhombic and above 95°C they rearrange to monoclinic. Less than 1.5 % of either crystalline structure of sulfur is soluble in any rubber at room temperature. 3.3 The second common molecular form of sulfur is polymeric sulfur, made up of unbranched chains of sulfur atoms. It is commonly referred to in the rubber industry as insoluble sulfur. When this material is created by rapid heating to above 160°C and quenching to room temperature, the sulfur is amorphous. If formed under other conditions, the polymer chains may develop regions of pseudo crystallinity. 3.4 Insoluble sulfur is an important form of sulfur used only in the rubber industry. It is not soluble in any type of rubber hydrocarbon. When it is mixed in rubber, it disperses but remains undissolved in the rubber. The use of insoluble sulfur prevents the development of a supersaturated solution of sulfur in rubber that occurs when rhombic sulfur is used. No sulfur bloom will develop on the surface of uncured rubber pieces when the rubber cools after mixing or processing; therefore, building tack is preserved. At curing temperatures, insoluble sulfur rapidly transforms to a soluble species, dissolves in the rubber, and enters into the vulcanization process.