Chapter 39 covers plastics and articles thereof, including polymers in primary forms, synthetic rubber, waste and scrap, and semi-finished products. This chapter divides tariff headings by polymer type, such as polyethylene, polypropylene, polyester, etc. Primary forms refer to liquids, pastes, blocks, powders, granules and other unprocessed forms, excluding finished products already made into specific shapes. This chapter is a core chapter in trade for the chemical and plastics industries, involving a wide range of commodities. Heading 3907 covers polyacetals, other polyethers and epoxide resins, polycarbonates, alkyd resins, polyallyl esters and other polyesters, in primary forms. Polyesters include polyethylene terephthalate (PET), unsaturated polyesters, alkyd resins, etc. This heading is subdivided by chemical structure, and 390799 covers other polyesters in primary forms, i.e., polyester varieties not elsewhere specified. The first 2 digits 39 represent Chapter 39, plastics and articles thereof; digits 3-4, 07, represent heading 3907, i.e., polyacetals, other polyethers, epoxide resins, polycarbonates, alkyd resins, polyallyl esters and other polyesters in primary forms; digits 5-6, 99, represent subheading 390799, i.e., other polyesters in primary forms. This subheading is a residual code covering polyesters not specified in other subheadings, such as polybutylene terephthalate (PBT), polyethylene naphthalate (PEN), etc. The goods are polyesters in primary forms but are not specifically named under particular subheadings such as PET or unsaturated polyesters, so they are classified under 390799. If they were PET, they should be classified under 390760; if unsaturated polyesters, under 390791; if alkyd resins, under 390750. Therefore, 390799 applies to other polyesters not elsewhere specified, and accurate distinction must be made according to chemical structure.

Product name: The specific name of the declared commodity, such as polybutylene terephthalate (PBT), polyethylene naphthalate (PEN), etc., which must be consistent with the chemical composition. Appearance: Describe the physical form of the primary shape, such as granules, powder, liquid, blocks, etc., and it must match the actual goods. Composition and content: List the main components and percentage content, such as polyester content ≥99%, additives, etc. Brand: The manufacturer's or trader's brand; if there is no brand, write “unbranded.” Model: The product model or grade, used to distinguish different specifications. Use: Explain the final use of the polyester in primary forms, such as for producing fibers, films, engineering plastics, etc. CAS number: Chemical substance registry number, such as 26062-94-2 for PBT, 25805-74-1 for PEN, etc. Product name: Polybutylene terephthalate (PBT); Appearance: white granules; Composition and content: PBT ≥99%, additives ≤1%; Brand: XX brand; Model: XX-100; Use: For injection molding electronic connectors; CAS number: 26062-94-2. Mistakenly classifying PET under 390799, when it should actually be classified under 390760. Failing to distinguish unsaturated polyester from saturated polyester, resulting in classification errors. Incomplete declaration elements, such as missing CAS number or composition and content.

The core basis for classification is the commodity's chemical structure, polymerization method and primary form. 390799 covers other polyesters in primary forms and applies to polyesters not specified in other subheadings of 3907. It is necessary to confirm whether it belongs to polyacetals, polyethers, epoxide resins, polycarbonates, alkyd resins, polyallyl esters, PET, unsaturated polyesters, etc. If it belongs to none of these, it is classified under 390799. At the same time, it must meet the condition of being in primary form, i.e., unprocessed or only primarily processed. 390760 Polyethylene terephthalate: 390760 specifically refers to PET, including its primary forms; while 390799 covers other polyesters, such as PBT, PEN, etc. The difference lies in whether the chemical structure is ethylene terephthalate. 390791 Unsaturated polyesters: 390791 covers unsaturated polyesters, usually used for fiberglass reinforced plastics, etc.; 390799 covers other polyesters, including saturated polyesters. The difference lies in whether unsaturated double bonds are present. 390750 Alkyd resins: 390750 covers alkyd resins, which are a type of polyester but are separately named; 390799 covers polyesters not elsewhere specified. If it is an alkyd resin, it should be classified under 390750. 390710 Polyacetals: 390710 covers polyacetals, such as POM; 390799 covers polyesters. The difference lies in the different polymer type. 390730 Epoxide resins: 390730 covers epoxide resins; 390799 covers polyesters. The difference lies in chemical structure and curing characteristics. Confirm whether the commodity is in primary form. Confirm whether the chemical structure is polyester. Confirm whether it belongs to specifically named subheadings such as PET or unsaturated polyesters. Confirm that the CAS number is consistent with the product. Confirm that the declaration elements are complete and accurate.

How can it be determined whether a polyester is classified under 390799? First confirm that the commodity is polyester in primary form, then check whether it belongs to a specifically named subheading under heading 3907, such as PET (390760), unsaturated polyesters (390791), alkyd resins (390750), etc. If it belongs to none of these, it is classified under 390799. Chemical composition, CAS number and other evidence must be provided. What are common commodities under 390799? Common commodities include polybutylene terephthalate (PBT), polyethylene naphthalate (PEN), polytrimethylene terephthalate (PTT), polyarylate, etc. These polyesters are not named in other subheadings of 3907, so they are classified under 390799. What documents are required for declaring 390799? Usually a contract, invoice, packing list, bill of lading, composition test report, CAS number explanation, certificate of origin, etc. are required. If dangerous goods are involved, an MSDS is also required. The specific requirements are subject to customs. How can the tariff rate for 390799 be checked? The latest tax rate can be obtained through the official website of the General Administration of Customs, China International Trade Single Window, or by checking the Import and Export Tariff of the People's Republic of China. Tax rates may change due to country, trade agreements, etc., and the latest official publication should be taken as authoritative. What is the main difference between 390799 and 390760? 390760 specifically refers to polyethylene terephthalate (PET), while 390799 covers other polyesters not elsewhere specified, such as PBT, PEN, etc. The key difference is whether the chemical structure is ethylene terephthalate. If the polyester is recycled material, can it still be classified under 390799? If the recycled material is in primary form and its chemical structure is polyester, it may still be classified under 390799, but attention must be paid to whether it is waste and scrap (3915). If it is waste and scrap, it should be classified under 3915. It is recommended to provide the recycling source and processing explanation. What is the export tax rebate for 390799? The export tax rebate rate must be checked according to the latest regulations of the State Taxation Administration and may be adjusted in different periods. The current rebate rate can be obtained through the electronic tax bureau or by consulting a tax advisor. What are the consequences of incorrect classification? Incorrect classification may lead to supplementary tax payments, fines, downgrading of credit rating, or even suspected smuggling. It is recommended to declare truthfully and, when necessary, consult a professional customs broker or customs advance classification.