3910.00.00.00 - Silicones in primary forms

This HTS category, 3910.00.00.00, specifically covers silicones when they are presented in their "primary forms." Primary forms, as defined in Chapter 39, include bulk materials such as powders, granules, flakes, and masses, as well as liquids and pastes. Therefore, this classification is for silicones in their raw or unmanufactured state, before they are processed into finished articles or even intermediate compounds intended for specific applications. Examples include silicone resins in liquid or solid form, silicone rubber in uncured states, and silicone oils not further processed.

As a leaf node within Chapter 39, this category does not have further subdivisions. Its distinction lies in its focus on the *form* of the silicone. Other categories within Chapter 39 might cover silicones that have been further processed or compounded, such as vulcanized synthetic rubbers or articles made from silicone. For instance, while this category covers uncured silicone rubber in bulk, finished silicone seals or tubing would fall under different headings related to articles of rubber. The key differentiator is whether the silicone is in a basic, unshaped state or if it has undergone manufacturing processes to impart specific properties or form.