Natural rubber is one of those commodities that quietly underpins entire industries without most people noticing. Every tire on every vehicle on every road in the world depends on it. Every surgical glove, every industrial conveyor belt, every aircraft landing gear component — natural rubber is irreplaceable in applications where synthetic alternatives simply cannot match its combination of elasticity, tensile strength, and heat resistance.
Indonesia is the world's second-largest producer of natural rubber, and the country's benchmark export grade — SIR20 (Standard Indonesian Rubber grade 20) — is the raw material of choice for tire manufacturers, latex goods producers, and industrial rubber product factories across Asia, Europe, and North America. If your factory consumes natural rubber in any significant volume, there is a strong probability that Indonesian SIR20 is already somewhere in your supply chain.
This guide provides the complete technical and logistical picture for buyers who are evaluating Indonesia as a natural rubber source, placing a first container order, or looking to understand the specification differences that affect their production quality.
What is SIR20? The Technical Specifications Explained
SIR stands for Standard Indonesian Rubber, and the number 20 refers to the maximum allowable dirt content — 0.20% by weight. This is the defining specification that separates SIR20 from higher grades like SIR10 (max 0.10% dirt) or SIR5 (max 0.05% dirt). The grade designation follows the same logic as Thailand's TSR20 and Malaysia's SMR20 — all three are essentially equivalent grades produced under similar technical specifications, which is why they are traded interchangeably on the global rubber market.
SIR20 is produced from field coagulum — rubber collected from plantation trees and processed through a standard crumb rubber manufacturing process. The result is a dense, dark brown bale with consistent physical and chemical properties that tire manufacturers can feed directly into their mixing lines.
| Technical Parameter | SIR20 Specification | SIR10 | SIR5 |
|---|---|---|---|
| Dirt Content (max) | 0.20% | 0.10% | 0.05% |
| Ash Content (max) | 0.75% | 0.60% | 0.50% |
| Nitrogen Content (max) | 0.60% | 0.60% | 0.60% |
| Volatile Matter (max) | 0.80% | 0.80% | 0.80% |
| DRC (min) | 99% | 99% | 99% |
| Mooney Viscosity (ML 1+4, 100°C) | Max 79 | Max 79 | Max 79 |
| Initial Plasticity (Po) | Min 30 | Min 30 | Min 30 |
For the majority of tire manufacturers and general rubber goods producers, SIR20 is perfectly adequate — the difference in dirt content between SIR20 and SIR5 has no meaningful impact on end-product quality for most applications. SIR5 and SIR10 are typically required only for specific technical applications such as medical-grade rubber products or precision industrial components where purity margins are extremely tight.
Bale Configuration and Container Loading
SIR20 is packaged in 33.3 kg bales — this is the SICOM (Singapore Commodity Exchange) standard bale weight, which has been adopted globally by rubber producers and traders. Each bale is wrapped in a thin polyethylene film to prevent sticking and contamination, and bales are typically palletized for container loading to facilitate mechanical unloading at the destination factory.
A standard 20-foot container of SIR20 holds approximately 20 to 22 metric tons net weight, which equates to roughly 600 to 660 bales. The palletized configuration means containers can be unloaded efficiently with forklifts, which is important for buyers receiving large volumes at factory warehouses.
| Container Size | Bale Weight | Net Weight | Bale Count | Loading Method |
|---|---|---|---|---|
| 20ft Standard | 33.3 kg each | 20–22 MT | 600–660 bales | Palletized, forklift-ready |
| 40ft Standard | 33.3 kg each | 22–25 MT | 660–750 bales | Palletized, forklift-ready |
| 40ft High Cube | 33.3 kg each | 24–26 MT | 720–780 bales | Palletized, forklift-ready |
One practical point for buyers receiving large volumes: SIR20 bales in polyethylene wrapping can stick together in very hot weather. This is not a quality defect — it is a natural property of unvulcanized rubber — and the bales will separate normally during processing. However, buyers storing rubber in warm climates should ensure adequate airflow in storage facilities.
Indonesian Rubber Plantation Origins: Sumatra vs Kalimantan
Natural rubber in Indonesia is produced primarily in two regions: Sumatra (particularly South Sumatra / Sumatera Selatan) and Kalimantan (Indonesian Borneo). Each region has plantation characteristics that result in slightly different raw material properties, though both produce rubber that meets or exceeds the SIR20 standard.
South Sumatra is the dominant rubber-producing region in Indonesia, accounting for approximately 60–65% of national output. The region's well-established plantation infrastructure, processing factories (crumb rubber factories), and proximity to the port of Palembang make it the most efficient sourcing origin for large-volume buyers. SIR20 from South Sumatra is considered the benchmark for Indonesian rubber quality.
Kalimantan rubber, while produced in somewhat smaller volumes, is sourced primarily from smallholder plantations and tends to have slightly higher variability in raw material quality — though reputable crumb rubber factories in Kalimantan apply rigorous quality control processes to ensure final SIR20 product meets all specification requirements.
SIR20 vs TSR20 vs RSS3: Which Grade for Your Factory?
Buyers new to natural rubber procurement often encounter multiple grade designations across different origins and are uncertain which is appropriate for their application. The three most commonly traded grades on the global market are Indonesian SIR20, Thai TSR20, and Ribbed Smoked Sheet (RSS3) — also produced primarily in Thailand.
| Grade | Origin | Processing Method | Dirt (max) | Primary Application | Typical Market |
|---|---|---|---|---|---|
| SIR20 | Indonesia | Crumb rubber (field coagulum) | 0.20% | Tires, industrial goods | China, EU, USA |
| TSR20 | Thailand | Crumb rubber (field coagulum) | 0.20% | Tires, industrial goods | China, EU, USA |
| SMR20 | Malaysia | Crumb rubber (field coagulum) | 0.20% | Tires, industrial goods | China, EU |
| RSS3 | Thailand / Indonesia | Ribbed smoked sheet | Visual grade | Latex products, specialty | Specialty applications |
For most tire manufacturers and general industrial rubber goods producers, SIR20, TSR20, and SMR20 are completely interchangeable. The choice between them is typically made on the basis of price, delivery lead time, and supplier relationship — not quality differences. Indonesian SIR20 is often preferred by Chinese buyers due to shorter shipping distance and competitive FOB pricing, while European automotive suppliers may blend Indonesian and Thai material depending on market conditions.
Natural Rubber vs Synthetic Rubber: Why Manufacturers Continue to Choose SIR20
The question of natural versus synthetic rubber comes up regularly in procurement discussions, particularly given the significant volatility in natural rubber prices. Synthetic rubber — primarily SBR (styrene-butadiene rubber) and BR (butadiene rubber) — can substitute for natural rubber in many applications and has the advantage of more stable, predictable pricing tied to petrochemical feedstocks.
However, there are specific performance characteristics of natural rubber that synthetic alternatives cannot fully replicate, which is why global tire manufacturers and industrial rubber producers continue to consume millions of tons of natural rubber annually despite decades of synthetic rubber development.
Natural rubber's superior tensile strength, tear resistance, and thermal properties under dynamic stress conditions make it essentially irreplaceable in truck tires, aircraft tires, and heavy equipment tires. A fully synthetic truck tire would generate excessive heat during use — a safety issue that natural rubber's molecular structure is uniquely suited to prevent. This is why the global natural rubber market continues to grow even as synthetic alternatives improve.
Lead Time and Shipping from Indonesia to Key Markets
Lead time for SIR20 from Indonesian rubber factories is typically 14 to 25 days from order confirmation to port departure. Ocean transit times from Indonesian ports (primarily Palembang, Surabaya, or Jakarta) to major rubber-consuming markets are as follows:
| Destination | Key Port | Transit Time | Notes |
|---|---|---|---|
| China | Shanghai / Guangzhou / Qingdao | 7–10 days | Largest single market for Indonesian rubber |
| Japan | Tokyo / Yokohama / Osaka | 10–14 days | High-specification automotive supply chain |
| South Korea | Busan / Incheon | 8–12 days | Tire manufacturing hub |
| Europe | Rotterdam / Hamburg / Antwerp | 22–28 days | Via Suez Canal; automotive industry supply |
| USA | Los Angeles / Houston | 18–22 days | Via Pacific; industrial rubber goods |
Actual transit times may vary based on weather conditions, port congestion, and vessel routing. Indonesia's geographic position gives it a natural shipping advantage over Thailand and Malaysia for China-bound rubber, as Indonesian ports are closer to major Chinese manufacturing centers.
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Request a Free Quote →Frequently Asked Questions
What is the MOQ for natural rubber SIR20 from Indonesia?
Our minimum order quantity is 1 x 20ft container, which holds approximately 20–22 metric tons of SIR20 in 33.3kg bales (600–660 bales per container), palletized for efficient unloading at your factory.
How can I get the current FOB price for SIR20 from Indonesia?
Natural rubber prices are traded on the SICOM exchange in Singapore and fluctuate daily. Our FOB prices are derived from SICOM benchmark pricing plus a processing and logistics premium. Please contact us with your required volume and destination port for a current price quotation.
How long does shipping take from Indonesia to China?
Estimated ocean transit from Indonesian rubber ports (Palembang, Surabaya, or Jakarta) to Shanghai is 7–10 days, to Guangzhou 7–9 days, and to Qingdao 9–12 days. Actual transit time may vary based on weather conditions and port congestion.
What is the difference between SIR20 and TSR20?
SIR20 (Standard Indonesian Rubber 20) and TSR20 (Thai Standard Rubber 20) are equivalent grades produced in different countries under the same technical specification — maximum 0.20% dirt content, minimum 99% DRC. For most applications including tire manufacturing, both grades are fully interchangeable. The choice between them is typically based on price, availability, and shipping logistics from your sourcing location.
Can I request a pre-shipment sample of SIR20?
Yes. A production sample (approximately 1–2 kg) from the specific production batch intended for your order can be provided for laboratory testing. Standard test certificates covering DRC, dirt content, ash content, Mooney viscosity, and volatile matter are provided with every shipment.
What is the HS Code for natural rubber SIR20 from Indonesia?
The HS Code for Technically Specified Natural Rubber (TSNR) including SIR20 is 4001.22. This applies to all standard crumb rubber grades exported from Indonesia.
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