Chapter 39 covers plastics and articles thereof, including polymers in primary forms, synthetic resins, chemical fibers, etc. This chapter is divided into two subchapters: Subchapter I (3901-3914) covers plastics in primary forms, and Subchapter II (3915-3926) covers waste, parings and scrap, and articles. Heading 3914 belongs to Subchapter I and is the last heading for plastics in primary forms, specifically addressing ion exchangers as a functional polymer material. Heading 3914 covers ion exchangers in primary forms, including ion exchange resins based on polymers (such as styrene-divinylbenzene copolymers), as well as ion exchangers based on other materials (such as cellulose, cross-linked dextran). These products are typically in the form of beads, granules, powder, or paste, not further worked or only surface-treated, and are used for ion exchange, adsorption, catalysis, and other purposes. Code 391400 is a six-digit subheading: the first two digits 39 represent Chapter 39 (Plastics and articles thereof); the third and fourth digits 14 represent heading 3914, i.e., ion exchangers in primary forms; the fifth and sixth digits 00 indicate that there is no further subdivision under this heading, and all ion exchangers in primary forms are classified under this subheading. Therefore, 391400 is a complete six-digit subheading with no further subdivision in the HS classification. The goods are ion exchangers in primary forms, meeting the description of heading 3914. They differ from ordinary plastics of headings 3901-3913 because they have an ion exchange function; they also differ from waste and scrap of heading 3915 or other articles of heading 3926 because they are in primary forms and are ion exchangers. Therefore, they are classified under 391400.

Product Name: Fill in the standard name of the product, such as ion exchange resin, ion exchanger, etc., which must be consistent with the commercial invoice. Appearance: Describe the shape (such as beads, granules, powder), color, transparency, and other physical states. Composition: Indicate the main chemical components, such as styrene-divinylbenzene copolymer, sulfonic acid groups, etc., as well as the type of functional groups. Use: Explain the specific use, such as water treatment, pharmaceuticals, food processing, catalysis, etc., and specify the industry or process. Ion Exchange Type: Indicate whether it is a cation exchanger, anion exchanger, or amphoteric exchanger, and the specific functional groups (such as sulfonic acid groups, quaternary ammonium groups). Brand: Fill in the brand name of the manufacturer or supplier, such as Dow, Purolite, etc. If there is no brand, write 'None'. Model: Fill in the product model or grade, such as Amberlite IR120, Dowex 50W, etc., to distinguish specific products. Packaging Specifications: Specify the packaging form and net weight, such as 25 kg bags, 1000 L drums, etc. Product Name: Ion Exchange Resin; Appearance: Amber transparent beads; Composition: Styrene-divinylbenzene copolymer containing sulfonic acid groups; Use: For water softening treatment; Ion Exchange Type: Strongly acidic cation exchange resin; Brand: Purolite; Model: C100E; Packaging Specifications: 25 kg/bag. Failing to distinguish ion exchangers from ordinary adsorbent resins, leading to incorrect classification. Composition description is too general and does not indicate functional groups, affecting classification. Use is not specific, such as writing only 'industrial use', which may raise customs doubts.

The core criteria for classification are: 1) whether the product is in primary form (such as beads, granules, powder, etc.); 2) whether it has an ion exchange function, i.e., separation or purification through ion exchange mechanism; 3) whether it has not been further worked or only surface-treated. Reference should also be made to the description of 3914 in the Explanatory Notes to confirm that it is an ion exchanger rather than ordinary plastic. 3901 Polymers of ethylene in primary forms: 3901 covers ordinary ethylene polymers without ion exchange function; 3914 covers ion exchangers with specific functional groups. 3903 Polymers of styrene in primary forms: 3903 covers ordinary polystyrene without functionalization; 3914 covers styrene-based ion exchange resins containing functional groups. 3915 Waste, parings and scrap of plastics: 3915 covers waste and scrap, while 3914 covers ion exchangers in primary forms, not waste. 3926 Other articles of plastics: 3926 covers finished or semi-finished products, while 3914 covers ion exchangers in primary forms. Is it in primary form (beads, granules, etc.)? Does it have an ion exchange function? Does it contain functional groups (such as sulfonic acid groups, quaternary ammonium groups)? Has it not been further worked? Is it not waste, scrap, or articles?

How to determine whether an ion exchange resin is classified under 391400? First confirm that the product is in primary form (such as beads, granules), then confirm that it has an ion exchange function, i.e., contains exchangeable ionic groups (such as sulfonic acid groups, carboxyl groups, quaternary ammonium groups, etc.), and has not been further worked. If so, it is classified under 391400. What is the difference in classification between ion exchange membranes and ion exchange resins? Ion exchange membranes are generally classified under 3921 (other plates, sheets, film, etc. of plastics), because they have been processed into membrane form; while ion exchange resins are in primary forms and are classified under 3914. How should the composition column be filled in during declaration? The main polymer matrix (such as styrene-divinylbenzene copolymer) and the type of functional groups (such as sulfonic acid groups) should be indicated, along with the degree of cross-linking (such as 8% DVB), to distinguish different products. If the ion exchanger is used in the food industry, are there special declaration requirements? Food-grade certification or a statement of compliance with relevant regulations is required, and 'for food processing' should be clearly stated in the use column. If necessary, provide the manufacturer's quality certificate. Are imports of ion exchangers subject to anti-dumping or tariff quotas? Check the latest announcements from the General Administration of Customs. Some ion exchange resins may be subject to anti-dumping measures. It is recommended to check by tariff code or consult a professional customs broker. How to distinguish between cation and anion exchangers? Cation exchangers contain acidic groups (such as sulfonic acid groups, carboxyl groups) and can exchange cations; anion exchangers contain basic groups (such as quaternary ammonium groups) and can exchange anions. The type must be clearly stated during declaration. What is the classification difference between ion exchangers and adsorbent resins? Adsorbent resins (such as macroporous adsorbent resins) are generally classified under 3901-3913 because they mainly rely on physical adsorption rather than ion exchange; if they also have an ion exchange function, they may be classified under 3914. Must the model and brand be filled in during declaration? Brand and model are important declaration elements that help customs confirm the product attributes. If the brand cannot be provided, 'None' may be filled in, but the model should be filled in as much as possible to facilitate classification.