Chapter 40 covers rubber and articles thereof, including natural rubber, synthetic rubber, reclaimed rubber, unvulcanized rubber, vulcanized rubber, and various rubber products. This chapter covers everything from raw materials (such as raw rubber and latex) to semi-finished products (such as unvulcanized compounded rubber) to finished products (such as tires and rubber hoses). The core characteristic is that the material is based on rubber, and this chapter has strict distinctions regarding the definition, form, and processing stage of rubber. Heading 4005 covers unvulcanized rubber in primary forms or in plates, sheets, or strips, including unvulcanized rubber mixed with carbon black or other compounding agents. Specifically, it includes: unvulcanized rubber mixed with carbon black (4005.10), unvulcanized rubber mixed with silica (4005.20), and other unvulcanized rubber mixtures (4005.91, 4005.99). Goods under this heading are typically compounded rubber, which is the upstream raw material for manufacturing rubber products. First 2 digits 40: represents Chapter 40 'Rubber and articles thereof', determining the broad category. Digits 3-4, 05: represents heading 4005 'Unvulcanized rubber mixtures', distinguished from raw materials such as 4001 (natural rubber) and 4002 (synthetic rubber), and also distinguished from 4006 (other forms of unvulcanized rubber) and 4007 (vulcanized rubber thread and cord). Digits 5-6, 10: represents subheading 4005.10, specifically 'unvulcanized rubber mixed with carbon black', i.e., compounded rubber with carbon black as the primary reinforcing agent. This subheading emphasizes the specific combination with carbon black as a compounding agent; other compounding agents (such as precipitated silica) fall under 4005.20 or 4005.91. This product is a mixture of unvulcanized rubber and carbon black, belonging to compounded rubber, not subjected to vulcanization crosslinking, and carbon black is the primary compounding agent. Therefore, it is classified under 4005.10, rather than 4005.20 (mixed with silica) or 4005.91 (other unvulcanized rubber mixtures). At the same time, it does not belong to the primary raw materials of 4001 or 4002, because it has already been mixed with carbon black; nor does it belong to 4006, because it is typically in block or sheet form rather than a specific shape.

Product Name: The Chinese and English names of the declared goods should accurately reflect the substance of 'unvulcanized rubber mixed with carbon black', such as 'unvulcanized compounded rubber' or 'carbon black compounded rubber'. Composition and Content: List the rubber type (such as natural rubber, styrene-butadiene rubber) and the mass percentages of carbon black, oil, and other additives. The carbon black content usually needs to be specified. Appearance: Describe the color, shape (such as block, sheet, strip), and whether preliminary sheeting has been performed. Unvulcanized state is usually tacky. Source: State whether the rubber is natural or synthetic, such as 'natural rubber compounded with carbon black' or 'styrene-butadiene rubber compounded with carbon black'. Brand and Model: Fill in the manufacturer's brand and model to facilitate identification of specific use and formulation. If no brand, write 'no brand'. Packaging Specifications: Indicate the packaging method (such as pallet, box) and unit weight (such as 25kg/block), affecting the dutiable value and inspection. Use: Briefly describe the final use, such as 'for manufacturing tire treads', 'for producing rubber hoses', to assist in determining classification. Product Name: Unvulcanized rubber mixed with carbon black (carbon black compounded rubber); Composition and Content: Natural rubber 55%, carbon black 30%, processing oil 10%, zinc oxide 2%, stearic acid 1%, antioxidant 2%; Appearance: Black block, slightly tacky; Source: Natural rubber compounded with carbon black; Brand and Model: XX brand, model CB-100; Packaging Specifications: 25kg/block, pallet packaging; Use: For manufacturing tire treads. Incorrectly declaring unvulcanized compounded rubber as vulcanized rubber, leading to classification under 4007 or 4016. Incomplete declaration of composition and content, failing to specify the carbon black proportion, making it impossible to prove classification under 4005.10. Describing the appearance as 'sheet' when it is actually block, which may affect the distinction between 4005 and 4006.

Core basis for classification: First, confirm the goods are in an unvulcanized state, excluding 4007 and the latter part of Chapter 40; second, confirm it is a mixture of rubber and carbon black, with carbon black as the primary reinforcing agent, conforming to the subheading description of 4005.10; finally, confirm the form is primary form or plates, sheets, strips. If it is a specific shape (such as rods, bars), it may be classified under 4006. Also refer to the Explanatory Notes to the Harmonized System for heading 4005, which states that carbon black mixtures are typically used for tire manufacturing. 4005.20 Unvulcanized rubber mixed with silica: The compounding agent is silica (precipitated silica) rather than carbon black, classified under 4005.20. If both carbon black and silica are present, determine based on the primary reinforcing agent, or classify under 4005.91. 4005.91 Other unvulcanized rubber mixtures: Refers to unvulcanized rubber not mixed with carbon black or silica, or mixed with other compounding agents, such as mixed only with oil or resin. Carbon black mixtures are not classified here. 4006.10 Plates, sheets, strips of unvulcanized rubber: 4006 covers plates, sheets, strips of unvulcanized rubber, but not mixed with carbon black, or although mixed, already cut into specific shapes. 4005.10 is typically in block form or unshaped. 4002.11 Styrene-butadiene rubber latex: 4002 is synthetic rubber raw material, not mixed with carbon black. If styrene-butadiene rubber is mixed with carbon black, it is classified under 4005.10. 3812.10 Prepared rubber accelerators: 3812 is rubber compounding agents, not the rubber body. 4005.10 has rubber as the matrix and carbon black as the compounding agent. Is it confirmed to be unvulcanized? Is carbon black the primary reinforcing agent? Is it mixed with silica? Is the appearance block or sheet? Is the composition and content specified?

How to determine whether unvulcanized rubber mixed with carbon black is classified under 4005.10? The key is three points: first, the rubber is unvulcanized, without crosslinking; second, carbon black is added as the primary reinforcing agent, not merely for coloring; third, the form is primary form (block, sheet, strip). If these are met, it is classified under 4005.10. If carbon black and silica are used together, determine based on the primary reinforcing agent, or classify under 4005.91. What is the difference between 4005.10 and 4005.20? 4005.10 specifically refers to unvulcanized rubber mixed with carbon black; 4005.20 specifically refers to unvulcanized rubber mixed with silica (precipitated silica). The difference lies in the type of reinforcing agent. If both are present, it is usually classified based on the primary reinforcing agent, or under 4005.91. How to fill in the composition and content in the declaration elements for unvulcanized compounded rubber? List the rubber type and percentage, carbon black percentage, processing oil, other additives, etc. For example: Natural rubber 55%, carbon black 30%, processing oil 10%, zinc oxide 2%, stearic acid 1%, antioxidant 2%. The carbon black content must be specified to prove classification under 4005.10. If the compounded rubber has been pressed into sheet form, is it still classified under 4005.10? If it is only pressed into sheet form but not cut into specific shapes, it is still classified under 4005.10. If it has been cut into shapes other than rectangular or further processed, it may be classified under 4006. Judgment should be based on the Tariff and Explanatory Notes. How to check the import tariff rate for 4005.10? Tariff rates change. It is recommended to check the latest 'Import and Export Tariff of the People's Republic of China' or through the General Administration of Customs website or single window. Typically, the MFN rate, general rate, VAT rate, etc. should be based on the actual declaration. What should be noted when declaring compounded rubber for cross-border e-commerce sales? Accurately declare the product name, composition, and use to avoid misdeclaration as finished products. Compounded rubber is usually an industrial raw material, and cross-border e-commerce retail imports may be restricted. General trade declaration is recommended. Also pay attention to elements such as origin, brand, and model. If the compounded rubber contains a small amount of vulcanizing agent, does it affect classification? If it contains only a small amount of vulcanizing agent but is not vulcanized, it is still classified under 4005.10. However, if it has been partially vulcanized or prevulcanized, it may be classified under 4007 or 4016. The key is whether crosslinking reaction has occurred. How to distinguish 4005.10 from 4006.10 in practice? 4005.10 is unvulcanized rubber mixed with carbon black, typically in block form or unshaped; 4006.10 is plates, sheets, strips of unvulcanized rubber, but not mixed with carbon black, or although mixed, already cut into specific shapes. If compounded rubber is pressed into sheets and not cut, it is still classified under 4005.10.