Chapter 39 covers plastics and articles thereof, including polymers in primary forms, synthetic rubber, cellulose and its chemical derivatives, etc. This chapter divides tariff headings by polymer source and chemical structure, such as 3901 to 3914 for plastics in primary forms, and 3915 to 3926 for waste, scrap and articles. Primary forms refer to liquids, pastes, blocks, powders and other unprocessed forms, including aqueous dispersions. The chapter notes strictly define the scope, for example, the distinctions from Chapter 28, Chapter 29 and Chapter 40. Heading 3905 covers polymers of vinyl acetate or of other vinyl esters in primary forms and other vinyl polymers in primary forms, including aqueous dispersions. Specifically, it includes poly(vinyl acetate), vinyl acetate copolymers, poly(vinyl alcohol), poly(vinyl acetals), etc. Aqueous dispersions refer to polymers dispersed in the form of fine particles in an aqueous medium, usually obtained by emulsion polymerization. Under this heading, subheadings are further divided by polymer type and form. The first 2 digits '39' represent Chapter 39, plastics and articles thereof. The 3rd-4th digits '05' represent heading 3905, namely polymers of vinyl acetate or of other vinyl esters in primary forms and other vinyl polymers in primary forms. The 5th-6th digits '21' represent subheading 3905.21, specifically aqueous dispersions of vinyl acetate copolymers. The 5th digit '2' indicates vinyl acetate copolymers, and the 6th digit '1' indicates the aqueous dispersion form. Therefore, 390521 specifically refers to aqueous dispersions of vinyl acetate copolymers in primary forms, distinct from other forms or other vinyl polymers. The goods are vinyl acetate copolymers and exist in the form of an aqueous dispersion, meeting the subheading description of 'vinyl acetate copolymers' under heading 3905, and the form is an aqueous dispersion, so they are classified under 390521. If they were poly(vinyl acetate) homopolymers, they would be classified under 390512; if in solid form, under 390529; if other vinyl ester copolymers, under 390599. Therefore, the copolymer nature and aqueous dispersion form are the key factors for classification under this code.

Product name: The specific name of the declared goods, such as 'vinyl acetate-ethylene copolymer aqueous dispersion' or 'VAE emulsion', which must be consistent with the code description. Composition and content: Indicate the types and proportions of comonomers, such as vinyl acetate content, ethylene content, other monomer content, as well as the content of water, emulsifiers and other additives. Appearance: Describe the physical state of the product, such as milky white liquid, uniform without lumps, free of impurities, etc., to confirm the aqueous dispersion form. Source: Explain the production process, such as emulsion polymerization, monomer source, etc., to prove it is a copolymer in primary form. Use: Briefly describe the main application fields, such as adhesives, coatings, paper treatment, textile auxiliaries, etc., to assist in classification determination. Packaging specifications: Indicate the packaging form and net weight, such as '200kg plastic drum', 'bulk in tanker truck', which affects measurement and supervision. Brand type: Fill in 'no brand', 'domestic independent brand', 'foreign brand (OEM)', etc., for statistics and intellectual property verification. Model: Fill in the product model or grade, such as 'BJ-707', 'Vinnapas 5010N', to facilitate identification of the specific product. Product name: Vinyl acetate-ethylene copolymer aqueous dispersion (VAE emulsion); Composition and content: vinyl acetate 75%, ethylene 20%, water and additives 5%; Appearance: milky white uniform liquid; Source: produced by emulsion polymerization of vinyl acetate and ethylene; Use: used to prepare water-based adhesives; Packaging specifications: 200kg/plastic drum; Brand type: no brand; Model: BJ-707. Misreporting an aqueous dispersion as a solid polymer, resulting in classification under 390529 instead of 390521. The composition and content do not list the comonomer proportions, making it impossible to distinguish homopolymers from copolymers. The use description is too general and does not reflect the specific application, affecting classification determination.

The core basis for classification is: the goods are vinyl acetate copolymers in primary forms and exist in the form of an aqueous dispersion. According to Chapter 39 notes and subheading provisions of the Import and Export Tariff, 3905.21 explicitly covers aqueous dispersions of vinyl acetate copolymers. It is necessary to confirm that the polymer is a copolymer (not a homopolymer), the form is an aqueous dispersion (not solid or organic solvent dispersion), and it has not undergone further processing. If other substances are added that change the essential character, classification may be affected. 390512 Poly(vinyl acetate) aqueous dispersion: 390512 is an aqueous dispersion of vinyl acetate homopolymer, while 390521 is a copolymer. The difference lies in whether the polymer chain contains other comonomers, such as ethylene, acrylates, etc. 390529 Other vinyl acetate copolymers: 390529 covers other forms besides aqueous dispersions, such as solids, powders, organic solvent dispersions, etc. If the product is an aqueous dispersion, it should be classified under 390521. 390599 Other vinyl polymers: 390599 covers other vinyl polymers not elsewhere specified, such as poly(vinyl butyral), polyvinylpyrrolidone, etc. If it is an aqueous dispersion of vinyl acetate copolymers, it should preferentially be classified under 390521. 350691 Adhesives based on polymers: 350691 is a finished adhesive, usually with added solvents, fillers, etc., while 390521 is a polymer in primary form, which requires further formulation to become an adhesive. If the product already has adhesive characteristics, it may be classified under 3506. 320910 Paints and varnishes based on acrylic or vinyl polymers: 320910 is a finished coating, containing pigments, solvents, etc., while 390521 is a polymer in primary form, used to manufacture coatings. If the product is a water-based coating, it should be classified under 3209. Confirm that the polymer is a vinyl acetate copolymer, not a homopolymer. Confirm that the form is an aqueous dispersion, not a solid or organic solvent dispersion. Confirm that no other substances have been added that change the essential character. Confirm that it has not been further processed into articles. Check that the composition and content are consistent with the declaration to avoid classification disputes.

How to determine whether a vinyl acetate copolymer aqueous dispersion should be classified under 390521 or 390512? The key is whether the polymer is a copolymer or a homopolymer. 390512 applies only to poly(vinyl acetate) homopolymer aqueous dispersions; if the polymer chain contains other comonomers (such as ethylene, acrylates, etc.), it is classified under 390521. This can be confirmed through composition analysis or production formula. What is the difference between an aqueous dispersion and an emulsion? Are they equivalent in classification? In HS classification, an aqueous dispersion generally refers to a system in which polymer particles are dispersed in water, including emulsions. There is no difference between the two under 390521; both are classified as aqueous dispersions. However, note that if the product is an organic solvent dispersion, it cannot be classified under 390521. If preservatives are added to VAE emulsion, does it affect classification? If the added preservative is only to prevent microbial growth and does not change the essential character of the polymer, it usually does not affect classification and it remains under 390521. However, if the amount added is large or it gives the product a new function, it may need to be classified as a mixture. It is recommended to truthfully indicate the type and content of additives when declaring. Does a product under 390521 require an MSDS when exported? Yes, aqueous dispersions are usually chemical products, and an MSDS (Material Safety Data Sheet) is required for export to explain composition, hazards, etc. The specific format and content must meet the requirements of the importing country. In addition, a non-hazardous guarantee letter or hazardous goods identification report may also be required. How to check the import tariff rate for 390521? You can log in to the website of the General Administration of Customs of China or use the 'Customs Import and Export Tariff' to check, and determine the applicable rate (MFN, agreement rate, etc.) according to the country of origin. You can also consult a customs broker or use a professional tariff query tool. Note that rates change, and the latest announcement shall prevail. How should 390521 products be declared in cross-border e-commerce? Cross-border e-commerce declaration requires complete declaration elements, including product name, composition, appearance, packaging, etc. If it is a small parcel, it can be simplified but must be truthfully declared. Note that the supervision methods for personal items and commercial express shipments are different; it is recommended to consult the logistics provider or customs broker. If the product is an aqueous dispersion of vinyl acetate copolymer but used for coatings, should it be classified under 390521 or 320910? If the product is a polymer in primary form and is only used to formulate coatings, it is classified under 390521; if it has been formulated into a finished coating (containing pigments, additives, etc.), it is classified under 320910. The difference lies in whether it has been further processed into a coating. How to distinguish between 390521 and 390529 when declaring? 390521 is limited to the aqueous dispersion form, while 390529 covers other forms (such as solids, powders, organic solvent dispersions). When declaring, the product form must be clarified; if it is an aqueous dispersion, it is classified under 390521; otherwise, under 390529.