Chapter 39 covers plastics and articles thereof, including polymers in primary forms, elastomers other than synthetic rubber, and semi-finished products and articles. This chapter is subdivided by polymer source and chemical structure. Primary forms refer to unprocessed forms such as liquids, pastes, blocks, powders, granules, etc. Polyisobutylene, as a synthetic polymer, falls within the scope of this chapter. Heading 3902 covers olefin polymers in primary forms, including polypropylene, polyisobutylene, polystyrene, etc. However, note that 3902 only includes chemically modified or copolymerized olefin polymers, and excludes polyethylene (3901) and polyvinyl chloride (3904). Polyisobutylene is a homopolymer of isobutylene and is classified under 3902. First 2 digits 39: represents Chapter 39, Plastics and articles thereof. Digits 3-4, 02: represents heading 3902, i.e., olefin polymers in primary forms. Digits 5-6, 20: represents subheading 390220, specifically polyisobutylene. Subheading 390220 is further divided into 39022010 (viscosity-average molecular weight ≤10000) and 39022090 (other), but the 6-digit code 390220 is already clearly identified as polyisobutylene. Polyisobutylene is a homopolymer of isobutylene, belongs to olefin polymers, and is in primary form, therefore classified under 3902. It is different from polyethylene (3901) and polypropylene (3902.10), and also different from styrene polymers (3903). If it were a copolymer, it might be classified under other subheadings, but the homopolymer is clearly classified under 390220.
Chapter
Chapter 39 covers plastics and articles thereof, including polymers in primary forms, elastomers other than synthetic rubber, and semi-finished products and articles. This chapter is subdivided by polymer source and chemical structure. Primary forms refer to unprocessed forms such as liquids, pastes, blocks, powders, granules, etc. Polyisobutylene, as a synthetic polymer, falls within the scope of this chapter.
Heading
Heading 3902 covers olefin polymers in primary forms, including polypropylene, polyisobutylene, polystyrene, etc. However, note that 3902 only includes chemically modified or copolymerized olefin polymers, and excludes polyethylene (3901) and polyvinyl chloride (3904). Polyisobutylene is a homopolymer of isobutylene and is classified under 3902.
Digit Breakdown
First 2 digits 39: represents Chapter 39, Plastics and articles thereof. Digits 3-4, 02: represents heading 3902, i.e., olefin polymers in primary forms. Digits 5-6, 20: represents subheading 390220, specifically polyisobutylene. Subheading 390220 is further divided into 39022010 (viscosity-average molecular weight ≤10000) and 39022090 (other), but the 6-digit code 390220 is already clearly identified as polyisobutylene.
Classification Basis
Polyisobutylene is a homopolymer of isobutylene, belongs to olefin polymers, and is in primary form, therefore classified under 3902. It is different from polyethylene (3901) and polypropylene (3902.10), and also different from styrene polymers (3903). If it were a copolymer, it might be classified under other subheadings, but the homopolymer is clearly classified under 390220.
📝 Declaration Elements
Product Name: Declare the commodity name, which should be stated as polyisobutylene, and distinguish whether it is modified or copolymerized. Appearance: Describe the physical form of the primary shape, such as liquid, paste, block, powder, granules, etc. Composition and Content: Indicate the content of polyisobutylene, and whether other additives, solvents, etc. are contained. Molecular Weight: Provide viscosity-average molecular weight or number-average molecular weight, especially for 39022010, it is necessary to specify whether it is ≤10000. Use: Explain the main use, such as adhesives, sealants, lubricant additives, etc. Brand: Declare the brand or manufacturer name; if no brand, fill in 'None'. Model: Declare the product model or specification to facilitate distinguishing different molecular weights or grades. Packaging Specification: Declare the packaging method and net weight, such as bagged, drummed, bulk, etc. Product Name: Polyisobutylene; Appearance: Colorless viscous liquid; Composition and Content: Polyisobutylene ≥98%, antioxidant ≤2%; Molecular Weight: Viscosity-average molecular weight 8000; Use: Used in the production of adhesives; Brand: XX; Model: PIB-8000; Packaging Specification: 200kg/drum, net weight 200kg. Failure to distinguish polyisobutylene from polybutene, the latter may be classified under other codes. Molecular weight not provided or incorrect, affecting the distinction between subheadings 39022010 and 39022090. Misreporting modified polyisobutylene as a homopolymer, leading to classification errors.
Product Name
Declare the commodity name, which should be stated as polyisobutylene, and distinguish whether it is modified or copolymerized.
⚠️ Misreporting as polypropylene or polyethylene, or vaguely writing it as plastics.
Appearance
Describe the physical form of the primary shape, such as liquid, paste, block, powder, granules, etc.
⚠️ Only writing 'solid' or 'liquid' without specifying the exact form.
Composition and Content
Indicate the content of polyisobutylene, and whether other additives, solvents, etc. are contained.
⚠️ Not indicating the content, or mistakenly including additives in the polymer content.
Molecular Weight
Provide viscosity-average molecular weight or number-average molecular weight, especially for 39022010, it is necessary to specify whether it is ≤10000.
⚠️ Not providing molecular weight, or incorrect units.
Use
Explain the main use, such as adhesives, sealants, lubricant additives, etc.
⚠️ Use description is too broad, such as 'industrial use'.
Brand
Declare the brand or manufacturer name; if no brand, fill in 'None'.
⚠️ Omitting brand information.
Model
Declare the product model or specification to facilitate distinguishing different molecular weights or grades.
⚠️ Model is incomplete or inconsistent with the actual product.
Packaging Specification
Declare the packaging method and net weight, such as bagged, drummed, bulk, etc.
⚠️ Not indicating net weight or packaging unit.
Example： Product Name: Polyisobutylene; Appearance: Colorless viscous liquid; Composition and Content: Polyisobutylene ≥98%, antioxidant ≤2%; Molecular Weight: Viscosity-average molecular weight 8000; Use: Used in the production of adhesives; Brand: XX; Model: PIB-8000; Packaging Specification: 200kg/drum, net weight 200kg.
Common Mistakes：
Failure to distinguish polyisobutylene from polybutene, the latter may be classified under other codes.
Molecular weight not provided or incorrect, affecting the distinction between subheadings 39022010 and 39022090.
Misreporting modified polyisobutylene as a homopolymer, leading to classification errors.
🎯 Classification Logic
The core basis for classification is: 1) The product is in primary form; 2) It is an olefin polymer; 3) It is a homopolymer of isobutylene. Chemically modified or copolymerized products, as well as mixtures with other polymers, must be excluded. If it is a copolymer, it may be classified under other subheadings of 3902 or 3903, etc. 39021000 Polypropylene in primary forms: Polypropylene is a homopolymer of propylene, while polyisobutylene is a homopolymer of isobutylene; the monomers are different. 39023000 Propylene copolymers in primary forms: Propylene copolymers contain other olefin monomers, while polyisobutylene is a homopolymer. 39029000 Other olefin polymers in primary forms: This subheading covers olefin polymers not elsewhere specified, such as polybutene, while polyisobutylene is separately specified. 39019090 Other ethylene polymers in primary forms: Ethylene polymers are different from isobutylene polymers, and 3901 is dedicated to polyethylene. Is it in primary form? Is it a homopolymer of isobutylene? Has it undergone chemical modification? Is the molecular weight clearly specified? Is it mixed with other polymers?
Basis
The core basis for classification is: 1) The product is in primary form; 2) It is an olefin polymer; 3) It is a homopolymer of isobutylene. Chemically modified or copolymerized products, as well as mixtures with other polymers, must be excluded. If it is a copolymer, it may be classified under other subheadings of 3902 or 3903, etc.
Confused Codes：
39021000 - Polypropylene in primary forms
Polypropylene is a homopolymer of propylene, while polyisobutylene is a homopolymer of isobutylene; the monomers are different.
39023000 - Propylene copolymers in primary forms
Propylene copolymers contain other olefin monomers, while polyisobutylene is a homopolymer.
39029000 - Other olefin polymers in primary forms
This subheading covers olefin polymers not elsewhere specified, such as polybutene, while polyisobutylene is separately specified.
39019090 - Other ethylene polymers in primary forms
Ethylene polymers are different from isobutylene polymers, and 3901 is dedicated to polyethylene.
Self-Check：
✓ Is it in primary form?
✓ Is it a homopolymer of isobutylene?
✓ Has it undergone chemical modification?
✓ Is the molecular weight clearly specified?
✓ Is it mixed with other polymers?
❓ FAQ
What is the difference in HS codes between polyisobutylene and polybutene? Polyisobutylene is a homopolymer of isobutylene, classified under 390220; while polybutene is a homopolymer of butene, usually classified under 39029000 (other olefin polymers). The monomers are different, so the classification is different. How does the molecular weight of polyisobutylene affect the subheading? 390220 is divided into two subheadings: 39022010 for viscosity-average molecular weight ≤10000, and 39022090 for other. When declaring, accurate viscosity-average molecular weight must be provided, otherwise it may be classified under the wrong subheading. Is modified polyisobutylene still classified under 390220? If polyisobutylene has undergone chemical modification, such as halogenation, grafting, etc., it is no longer a homopolymer and may be classified under 39029000 or other relevant codes. It needs to be determined based on the specific modification. What are the differences in declaration elements between polyisobutylene and polypropylene? Polypropylene is classified under 39021000, and the declaration elements are similar, but note that the monomers are different. Polyisobutylene requires the content of isobutylene, while polypropylene requires the content of propylene. The molecular weight requirements are also different. How to check the tax rate when importing polyisobutylene? Tax rates may change. It is recommended to check the latest tax rates through the official website of the General Administration of Customs, China International Trade Single Window, or consult a customs broker. Accurate HS code and country of origin must be provided. Does the packaging specification of polyisobutylene affect classification? Packaging specification does not affect classification, but it must be truthfully filled in during declaration. The definition of primary form is unrelated to packaging, but related to physical form, such as liquid, granules, etc. If polyisobutylene is used for adhesives, is additional proof required? Usually no additional proof is required, but the use must be truthfully filled in during declaration. If customs questions it, a composition statement or proof of use may be required. For cross-border e-commerce retail of polyisobutylene products, is the classification the same? If it is in primary form, it is still classified under 390220; if it is a finished product such as an adhesive, it may be classified under other chapters, such as 3506. It needs to be determined based on the actual state.
Q: What is the difference in HS codes between polyisobutylene and polybutene?
A: Polyisobutylene is a homopolymer of isobutylene, classified under 390220; while polybutene is a homopolymer of butene, usually classified under 39029000 (other olefin polymers). The monomers are different, so the classification is different.
Q: How does the molecular weight of polyisobutylene affect the subheading?
A: 390220 is divided into two subheadings: 39022010 for viscosity-average molecular weight ≤10000, and 39022090 for other. When declaring, accurate viscosity-average molecular weight must be provided, otherwise it may be classified under the wrong subheading.
Q: Is modified polyisobutylene still classified under 390220?
A: If polyisobutylene has undergone chemical modification, such as halogenation, grafting, etc., it is no longer a homopolymer and may be classified under 39029000 or other relevant codes. It needs to be determined based on the specific modification.
Q: What are the differences in declaration elements between polyisobutylene and polypropylene?
A: Polypropylene is classified under 39021000, and the declaration elements are similar, but note that the monomers are different. Polyisobutylene requires the content of isobutylene, while polypropylene requires the content of propylene. The molecular weight requirements are also different.
Q: How to check the tax rate when importing polyisobutylene?
A: Tax rates may change. It is recommended to check the latest tax rates through the official website of the General Administration of Customs, China International Trade Single Window, or consult a customs broker. Accurate HS code and country of origin must be provided.
Q: Does the packaging specification of polyisobutylene affect classification?
A: Packaging specification does not affect classification, but it must be truthfully filled in during declaration. The definition of primary form is unrelated to packaging, but related to physical form, such as liquid, granules, etc.
Q: If polyisobutylene is used for adhesives, is additional proof required?
A: Usually no additional proof is required, but the use must be truthfully filled in during declaration. If customs questions it, a composition statement or proof of use may be required.
Q: For cross-border e-commerce retail of polyisobutylene products, is the classification the same?
A: If it is in primary form, it is still classified under 390220; if it is a finished product such as an adhesive, it may be classified under other chapters, such as 3506. It needs to be determined based on the actual state.
⚠️ Disclaimer: HS code classification, declaration elements, tariff rates and regulatory conditions on this page are for reference only and do not constitute legal advice on customs classification. Tariff rates and regulations are subject to change; the latest announcements from the General Administration of Customs and on-site determinations shall prevail. Please consult professional customs brokers or customs authorities before import/export.