Primary Form Silicone Rubber
CN β USAI Analysis
π§ͺ Primary Form Silicone Rubber (Silicone Rubber Raw Material / Compound)
π HS Code Reference & Customs Clearance Guide | 2026 Latest Tariff Analysis | Professional Clearance Strategy
π I. Product Definition & Classification: Do You Really Understand "Primary Form Silicone Rubber"?
Primary Form Silicone Rubber, often referred to in trade as Silicone Rubber Compound, Raw Silicone Rubber, or Liquid Silicone Rubber (LSR) Base, is the unvulcanized, raw material used to manufacture silicone products. It is not yet a finished good (like a baby bottle or medical seal) but rather the foundational polymer ready for processing (molding, extruding, etc.).
In international trade, it is critically distinguished from: 1. Finished Silicone Articles: (e.g., gaskets, tubing, sheets) β These have a specific shape/function. 2. Silicone Oil/Fluids: These are liquids with low viscosity, not rubbery compounds. 3. Vulcanized Silicone: Once cured, the HS Code often changes depending on the final use.
β οΈ Key Distinction Point:
- If it is a liquid, putty, or paste that is not yet cured/vulcanized and is in bulk form (drums, bags, cartridges) β It is classified under Chapter 39 (Plastics in Primary Forms).
- If it is already cured/vulcanized into sheets, cords, or profiles β It may fall under Chapter 40 (Rubber) or Chapter 39 depending on composition and form.
- CRITICAL: Most "Primary Form" silicone rubber imported for manufacturing is unvulcanized and thus falls under 3910.
π¦ II. HS Code Classification Details (2026 Latest Tariff Authorityε―Ήη §)
| HS Code | Product Description | Application Scenario | State of Matter |
|---|---|---|---|
| 3910.00.40.00 | Silicone rubber in primary forms, other than in sheets, film, or similar basic forms | Unvulcanized liquid silicone rubber (LSR), putty, paste, bulk compound | β Unvulcanized |
| 3910.00.10.00 | Silicone rubber in sheets, film, or similar basic forms | Unvulcanized sheets or films ready for further processing | β Unvulcanized |
| 4002.99.60.00 | Synthetic rubber (including silicone) in primary forms, not compounded with carbon black | Rare for pure silicone; usually for other synthetic rubbers | β Unvulcanized |
| 4016.93.00.00 | Other articles of vulcanized rubber other than hard rubber | Vulcanized silicone gaskets, seals, mats | β Cured |
| 3926.90.97.90 | Other articles of plastics | Finished silicone products (e.g., kitchenware, toys) | β Cured/Finished |
π Focus Reminder:
- The term "Primary Form" strongly implies Chapter 39.
- 3910.00.40.00 is the most common code for liquid or paste silicone rubber compounds in bulk drums.
- 3910.00.10.00 is used if the silicone is already formed into sheets but not yet vulcanized.
- Do NOT use 4016 or 3926 for raw, unvulcanized material. Misclassification leads to severe penalties.
π° III. 2026 Latest Tariff Rate Breakdown (Including Surtaxes & Policy Surcharges)
β Applicable Country: United States (US)
β Country of Origin: China (CN)
β Effective Date: From November 10, 2025 (including subsequent imports)
π― 1. 3910.00.40.00 ββ Silicone Rubber in Primary Forms (Bulk/Paste/LSR)
| Item | Details |
|---|---|
| Base Tariff Rate | 0% (ad valorem) |
| USITC Surtax | +25% (Under USITC Footnote 9903.88.01) |
| IEEPA Surtax | +10% (For China/HK origin, effective from Nov 10, 2025) |
| Total Tariff Rate | 35% |
| Tax Calculation | CIF Value Γ 35% |
| De Minimis Eligibility | β Not Eligible (deny_de_minimis) |
| Legal Basis Path | IEEPA:9903.01.25 β IEEPA:9903.01.24 β USITC:3910.00.40.00 β FOOTNOTE:9903.88.01 |
π Explanation:
- The 25% USITC surtax is part of the Section 301 tariffs on Chinese goods.
- The 10% IEEPA surtax is a new additional tariff on Chinese imports effective late 2025.
- Total 35% is a high tariff for raw materials. Must be anticipated in cost modeling!
π― 2. 3910.00.10.00 ββ Silicone Rubber in Sheets/Film (Unvulcanized)
| Item | Details |
|---|---|
| Base Tariff Rate | 0% |
| USITC Surtax | +25% |
| IEEPA Surtax | +10% |
| Total Tariff Rate | 35% |
| Tax Calculation | CIF Γ 35% |
| De Minimis Eligibility | β Not Eligible |
| Legal Basis Path | IEEPA:9901.25 β IEEPA:9903.01.24 β USITC:3910.00.10.00 β FOOTNOTE:9903.88.01 |
π Note:
- Same rate as bulk paste; form factor (sheet vs. drum) does not reduce tariff.
- If the sheet is vulcanized, it moves to 4016 or 3926, which may have different rates (see below).
π οΈ IV. Customs Clearance Practical Advice (Real-World Pitfall Guide)
β 1. Required Document Checklist (Essential)
| Document | Mandatory | Description |
|---|---|---|
| β Technical Data Sheet (TDS) | βοΈ | Must state: Unvulcanized, Silicone Polymer, Composition, Viscosity/State |
| β Certificate of Analysis (COA) | βοΈ | Confirms chemical composition (no carbon black, no fillers if claiming pure silicone) |
| β Product Photos (Bulk/Packaging) | βοΈ | Show drums, bags, or cartridges; label must match HS code description |
| β Commercial Invoice | βοΈ | Describe as "Unvulcanized Silicone Rubber Compound" or "Liquid Silicone Rubber Base" |
| β Material Safety Data Sheet (MSDS/SDS) | βοΈ | Required for chemical import compliance |
| β Certificate of Origin (CO) | βοΈ | If non-China origin, may qualify for exemptions |
β 2. Declaration Tips (Key Mnemonic)
π₯ "Unvulcanized = 3910, Cured = 4016/3926, Sheets vs. Paste Matter, But Tax Is Same!"
| Scenario | Correct Declaration | Wrong Practice |
|---|---|---|
| Liquid/Paste Silicone (Bulk) | 3910.00.40.00 |
Misdeclare as "Silicone Sealant" β 35% + Penalties |
| Unvulcanized Sheets | 3910.00.10.00 |
Misdeclare as "Finished Rubber Sheet" β 89.5% |
| Cured Silicone Gasket | 4016.93.00.00 or 3926.90.97.90 |
Misdeclare as raw material β Audit Risk |
| Silicone Oil (Low Viscosity) | 3824.99.92.00 or 3911.90.00.00 |
Misdeclare as rubber β 45% vs 0%+10% |
β 3. Special Handling
| Scenario | Handling Advice |
|---|---|
| LSR (Liquid Silicone Rubber) for Medical Use | Ensure FDA compliance documents are attached; declare as "Unvulcanized" |
| Silicone with Fillers (e.g., Silica) | Still 3910.00.40.00 if unvulcanized; disclose filler content in COA |
| Mixed with Other Polymers | If >50% silicone by weight, classify under 3910; otherwise, consider primary polymer |
| Samples for Testing | If < $800, may qualify for de minimis IF classified correctly; but silicone rubber from China is deny_de_minimis |
π V. Global Major Market Clearance Comparison (2026 Latest)
| Country/Region | Recommended HS Code | Tariff | Certification Requirement | Notes |
|---|---|---|---|---|
| πΊπΈ USA | 3910.00.40.00 |
35% (China) | FDA (if food/medical), SDS | High tariff due to Section 301 |
| π¨π³ China | 3910.00.40.00 |
5% | None | Standard import duty |
| πͺπΊ EU | 3910.00.00 |
0% (if REACH compliant) | REACH Registration | Low duty if compliant |
| π¦πΊ Australia | 3910.00.00.00 |
5% | AICIS | Standard duty |
| π―π΅ Japan | 3910.00.00 |
0% | PSE (if applicable) | No additional surtax |
π Conclusion:
- USA is the only major market with high additional tariffs (35%) for Chinese-origin silicone rubber.
- EU, Japan, Australia have much lower or zero duties, making them attractive alternative markets for Chinese silicone manufacturers.
- REACH (EU) compliance is critical for silicone imports into Europe.
π VI. Common Mistakes & Pitfall Guide (Blood & Tears Lessons)
β Mistake 1: Declaring "Silicone Sealant" instead of "Unvulcanized Silicone Rubber"
π Consequence: Sealants may be classified under 3913.90 or 4008, which could have different tariffs. Misdeclaration leads to delay + penalties.
β Mistake 2: Using "Silicone Oil" HS Code for High-Viscosity Rubber
π Consequence: Silicone oil is a different chemical class. If misclassified, customs may assess higher tariffs or reject the entry.
β Mistake 3: Not providing MSDS/SDS
π Consequence: Holds at customs for chemical safety review. Delays shipment by 2-4 weeks.
β Mistake 4: Declaring "Primary Form" for Cured/Finished Products
π Consequence: If the product is already vulcanized, it should be under 4016 or 3926. Misclassification leads to audits.
β Correct Practice:
"Unvulcanized Liquid Silicone Rubber (LSR) Compound, Food Grade, 20kg Drum, Viscosity: XXXX cP, Material Safety Data Sheet Attached"
π― VII. Conclusion: Professional Declaration, Time-Saving, Cost-Efficient!
π― Remember the Mnemonic:
πΉ "Unvulcanized = 3910, Cured = 4016/3926, Bulk/Paste = .40, Sheets = .10, Tax = 35% for US-China!"
πΉ "HS Code Defines Life, Tax Difference Is Critical, Declaration One Step Wrong, Penalty Is Huge!"
π Tip:
If your silicone rubber is originated from Vietnam, Mexico, Thailand, Malaysia, you may apply for IEEPA Exemption, reducing the tariff to 0%~5%.
Recommend Advance Ruling (Pre-Classification) with CBP to avoid clearance risks.
π£ Immediate Action:
π Contact Professional Broker + Provide TDS/MSDS + Apply for HS Code Advance Ruling
π Let your Silicone Rubber, Clear Customs Smoothly, Efficiently Export, Profit Double!
β¨ Professional Clearance Starts with Accurate Classification!
πΌ Every Cent of Your Cost Deserves Precise Calculation!
Customer Reviews
About HS Code Classification
The Harmonized System (HS) is an internationally standardized nomenclature developed by the World Customs Organization (WCO) to classify traded products. Over 200 countries use the HS system as the basis for customs tariffs, trade statistics, and import/export regulations.
Each HS code follows a hierarchical structure:
- Chapter (2 digits) β Broad category of goods (e.g., Chapter 84: Machinery and Mechanical Appliances)
- Heading (4 digits) β More specific grouping within the chapter
- Subheading (6 digits) β Internationally standardized breakdown, used by all WCO member countries
- National subdivisions (8-10 digits) β Country-specific extensions for further classification, such as US HTSUS 10-digit codes
Correct HS code classification is essential for smooth customs clearance, accurate duty payment, and compliance with trade regulations. Misclassification can lead to customs delays, overpayment of duties, or penalties.
When importing from CN to US, the applicable tariff rates may include:
- Most-Favored-Nation (MFN) rate β The standard duty rate applied to WTO members
- General rate β Applied to countries without trade agreements
- Trade remedy duties β Additional tariffs such as Section 301 (anti-dumping), Section 232 (national security), or countervailing duties
The information provided on this page is for reference purposes only. For official classification, please consult with your local customs authority or a licensed customs broker.