Chapter 39 covers plastics and articles thereof, including polymers in primary forms, waste and scrap, and semi-manufactures. This chapter is divided into two subchapters: Subchapter I (3901-3914) covers plastics in primary forms, and Subchapter II (3915-3926) covers waste, scrap, and articles. Primary forms refer to liquids, pastes, blocks, powders, granules, and similar forms, excluding products that have been shaped or further processed. Goods under this chapter are widely used in packaging, construction, electronics, automotive, and other fields. Heading 3904 covers polymers of vinyl chloride or of other halogenated olefins, in primary forms, including polyvinyl chloride (PVC), vinylidene chloride polymers, fluoropolymers, etc. Among these, vinylidene chloride polymers (390450) have excellent barrier properties and are commonly used in food packaging, coatings, and adhesives. This heading also includes other halogenated olefin polymers such as vinyl chloride-vinyl acetate copolymers. HS code 390450 is a six-digit subheading: the first two digits 39 represent Chapter 39 'Plastics and articles thereof'; digits 3-4, 04, represent the heading 'Polymers of vinyl chloride or of other halogenated olefins, in primary forms'; digits 5-6, 50, represent the subheading 'Vinylidene chloride polymers'. Specifically, the 5th digit 5 indicates the fifth subheading under heading 3904, and the 6th digit 0 is a subdivision of the subheading. The overall code refers to vinylidene chloride homopolymers or copolymers in primary forms, not mixed with other ingredients or mixed only with additives. This product is a vinylidene chloride polymer, which is a halogenated olefin polymer in primary form, and is therefore classified under 3904. If it is a copolymer of vinylidene chloride and vinyl chloride, it is still classified under 390450; if it is a copolymer of vinylidene chloride and acrylonitrile, it may be classified under other subheadings such as 390690. If it has been made into film or containers, it is classified under subsequent headings of Chapter 39 or Chapter 48, etc.

Product Name: The specific name of the declared commodity, such as 'vinylidene chloride polymer' or 'polyvinylidene chloride resin'. Appearance: Describe the physical form of the primary shape, such as powder, granules, liquid, paste, etc. Composition and Content: List the main monomer units and their content, such as vinylidene chloride content ≥90%, with the remainder being comonomers or additives. Types of Monomer Units: Specify which monomers the polymer is polymerized from, such as vinylidene chloride homopolymer or copolymer with vinyl chloride. Whether Modified: State whether it has undergone chemical modification or only physical blending, such as whether it is blended with other polymers. Use: Briefly describe the main use, such as barrier layers for food packaging, coatings, adhesives, etc. Brand: Declare the brand or manufacturer name of the commodity; if no brand, write 'None'. Model: Declare the model or specification of the commodity, such as grade, viscosity, etc. Customs declaration example: Product Name: Polyvinylidene chloride resin Appearance: White powder Composition and Content: Vinylidene chloride ≥95%, plasticizer ≤5% Types of Monomer Units: Vinylidene chloride homopolymer Whether Modified: Unmodified Use: For barrier layers in food packaging Brand: XX Brand Model: Saran-100 HS Code: 3904500000 Mistakenly classifying vinylidene chloride copolymers under 390450, when they should actually be classified under other subheadings based on the type of comonomer. Failing to distinguish between primary forms and semi-manufactures; if already made into film or containers, they should be classified under 3920 or 3923, etc. Ignoring the influence of additives; if additives change the product's properties, classification may be affected.

The core basis for classification is the Chapter 39 notes and subheading notes of the 'Import and Export Tariff'. Vinylidene chloride polymers are halogenated olefin polymers in primary forms, and are therefore classified under 3904. It is necessary to confirm whether the polymer is a homopolymer or copolymer; if it is a copolymer, it is necessary to see which monomer unit predominates. According to the subheading notes, 390450 includes only vinylidene chloride homopolymers or copolymers of vinylidene chloride with vinyl chloride. If copolymerized with other monomers, classification is based on the predominant monomer. 390410 Polyvinyl chloride, not mixed with other substances: Polyvinyl chloride is a vinyl chloride homopolymer, while vinylidene chloride polymer is a vinylidene chloride homopolymer; the monomers are different. 390430 Vinyl chloride-vinyl acetate copolymers: The comonomer is vinyl acetate, not vinylidene chloride, so it is classified under 390430. 390440 Other vinyl chloride copolymers: Refers to copolymers of vinyl chloride with monomers other than vinyl acetate; if vinylidene chloride is the main monomer, it is not classified here. 390450 Vinylidene chloride polymers: This code includes vinylidene chloride homopolymers and copolymers with vinyl chloride. 390690 Other acrylic polymers in primary forms: If vinylidene chloride is copolymerized with acrylonitrile and acrylonitrile predominates, it may be classified under 390690. Confirm the commodity is in primary form, not made into film, pipes, etc. Confirm the polymer is a vinylidene chloride homopolymer or copolymer with vinyl chloride. Confirm the proportion of monomer units and whether vinylidene chloride predominates. Confirm whether modifiers have been added and whether this affects classification. Check the tariff subheading notes to ensure no confusion with other subheadings.

How to find the HS code for vinylidene chloride polymers? You can check the customs tariff, HS code query websites, or consult a customs broker. First determine that the commodity is in primary form, then confirm the polymer type; if it is a vinylidene chloride homopolymer or copolymer with vinyl chloride, it is classified under 390450. Are all vinylidene chloride copolymers classified under 390450? No. Only copolymers of vinylidene chloride with vinyl chloride are classified under 390450. If copolymerized with other monomers, classification is based on the predominant monomer; for example, copolymerization with acrylonitrile may be classified under 390690. How should composition and content be filled in during declaration? The proportions of each monomer unit and additive should be listed in detail, such as vinylidene chloride 95% and plasticizer 5%. Avoid vaguely writing 'polymer'. If vinylidene chloride polymer has been made into film, which code should it be classified under? If made into film, it should be classified under subsequent headings of Chapter 39, such as 3920 (plastic plates, sheets, film, etc.), rather than 390450. What is the main difference between 390450 and 390410? 390410 is polyvinyl chloride (vinyl chloride homopolymer), while 390450 is vinylidene chloride polymer; the monomers are different, and their properties and applications also differ. What documents are required for importing vinylidene chloride polymers? Usually, contracts, invoices, packing lists, bills of lading, composition test reports, etc., are required, depending on customs requirements. It is advisable to consult a customs broker in advance. How to check the tariff rate for vinylidene chloride polymers? Tariff rates may change. You can obtain the latest rates through the General Administration of Customs website, tariff query tools, or by consulting a customs broker. Note that different countries of origin may be subject to different rates. What are the consequences of incorrect declaration? It may lead to customs inspection, supplementary duties, fines, or even administrative penalties. It is advisable to declare truthfully and apply for advance classification if necessary.