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Rubber Industry Chemicals — Vulcanization, Technical Additives | Loc Thien

Loc Thien provides a complete range of rubber industry chemicals: vulcanizing agents, activation systems, vulcanization accelerators, and technical additives compliant with TCVN 6087:2016. Serving technical rubber, gloves, gaskets, seals, and conveyor belt factories in VSIP, Nhon Trach, Amata, Long Khanh, VSIP II Binh Duong Industrial Zones. Same-day delivery with CoA/MSDS/CO/CQ per batch. Hotline: 0979 891 929.

What Are Rubber Chemicals?

Rubber industry chemicals are a group of additives blended into rubber compounds before vulcanization to create crosslinks between polymer chains, thereby improving mechanical properties: elasticity, tensile strength, Shore A hardness, heat resistance, and oil resistance.

A standard rubber formulation includes key chemical groups: vulcanizing agents (sulfur or peroxide), activation systems (ZnO + stearic acid), vulcanization accelerators (accelerator: MBTS, CBS, TMTD), reinforcing fillers (carbon black N330, N550, N660), and anti-aging additives (antioxidant, antiozonant). The blending ratio directly affects vulcanization speed, scorch time (initial hardening time), and final product modulus.

Sulfur — Primary Vulcanizing Agent (CAS 7704-34-9)

Elemental sulfur (sulfur, S) is the most classic and widely used vulcanizing agent for natural rubber (NR), SBR, NBR. Mechanism: sulfur reacts with C=C double bonds in polyisoprene chains to form polysulfide crosslinks (-C-Sx-C-). These bonds can be monosulfide (x=1), disulfide (x=2), or polysulfide (x>2) depending on sulfur ratio and accelerator system.

ParameterTypical ValueNotes

CAS7704-34-9Elemental sulfur
Purity≥99.5%Industrial rubber grade
Usage (phr)1.5 – 3.0 phr (CV system: 0.4 – 0.8 phr)According to TCVN 6087:2016
Scorch safetyDepends on acceleratorCBS provides better scorch safety than MBTS
Packaging25 kg/PP bag, powder or granular formWarehouses in HCM–BD–DN

Technical Note: Increasing sulfur ratio >2.5 phr (conventional vulcanization) → polysulfide network, high elasticity but poor heat resistance. With efficient vulcanization (EV system, S <0.8 phr + high accelerator) → monosulfide/disulfide, better heat resistance. Contact Loc Thien for suitable formulation advice.

ZnO & Stearic Acid — Vulcanization Activation System

ZnO (zinc oxide, CAS 1314-13-2) and stearic acid (C18H36O2, CAS 57-11-4) are an essential activator pair in sulfur vulcanization. Mechanism: stearic acid dissolves ZnO to form zinc stearate, which then reacts with the accelerator to create an active zinc-accelerator complex, initiating efficient crosslink reactions.

ChemicalCASTypical Usage (phr)Role

ZnO (zinc oxide)1314-13-23 – 5 phrActivates accelerator, increases crosslink speed
Stearic acid57-11-41 – 2 phrDissolves ZnO, co-catalyst, reduces mixing friction
Nano ZnO (<100 nm)1314-13-21 – 2 phrHigher activity, reduces ZnO dosage

Reducing ZnO to <1 phr (low-zinc or zinc-free system) is being applied to minimize environmental impact but requires compensation with special accelerators like MBT or zinc complex. Loc Thien offers both standard ZnO (99.7% grade) and nano ZnO for advanced formulation research.

Vulcanization Accelerators: MBTS, CBS, TMTD

Accelerators (vulcanization catalysts) are chemicals that determine crosslink speed and quality. Accelerator selection must balance scorch safety (safe time before hardening) and cure rate (vulcanization speed).

MBTS (2,2'-Dithiobis(benzothiazole), CAS 120-78-5): Secondary accelerator, good scorch safety, often combined with CBS to balance speed. Suitable for NR, SBR, NBR. Typical dosage: 0.5 – 1.5 phr.

CBS (N-cyclohexyl-2-benzothiazolesulfenamide, CAS 95-33-0): Sulfenamide accelerator, best scorch safety in benzothiazole group, delayed-action — ideal for technical products requiring long pressing cycles (tires, conveyor belts). Typical dosage: 0.5 – 1.5 phr.

TMTD (Tetramethylthiuram disulfide, CAS 137-26-8): Ultra-accelerator, extremely fast, typically used at very low doses (0.1 – 0.5 phr) as a secondary accelerator in EV systems. Requires strict control to avoid overcure.

TCVN 6087:2016 Standard & CoA/MSDS Certificates

TCVN 6087:2016 (equivalent to ISO 37:2011) specifies methods for determining tensile properties of vulcanized and thermoplastic rubber. This is a product testing standard, not directly regulating input chemical quality. However, to meet TCVN 6087, input materials must meet corresponding technical standards:

CoA (Certificate of Analysis): Confirms composition, purity, active content — issued per batch.
MSDS/SDS (Material Safety Data Sheet): Chemical safety information per GHS, mandatory for HSE-compliant industrial zones.
CO/CQ (Certificate of Origin/Quality): Certifies origin and quality — supports L/C payments and customs checks.

Loc Thien provides full CoA/MSDS/CO/CQ for all rubber chemicals. Documents are stored per batch and retrievable within 1 hour upon audit request.

Same-Day Delivery to VSIP, Nhon Trach, Amata Industrial Zones

Loc Thien's rubber chemical warehouses are located in Ho Chi Minh City (District 12), Binh Duong, and Dong Nai — covering Southern Vietnam's industrial zones:

VSIP I & II (Binh Duong): Same-day delivery before 5 PM if ordered by 10 AM
Nhon Trach I–V (Dong Nai): Next morning delivery for orders ≥500 kg
Amata Bien Hoa: Same-day delivery, trucks <3.5T allowed within the zone
Long Khanh, Xuan Loc: 24-hour delivery
Binh Phuoc, Tay Ninh: 2 business days delivery

Flexible MOQ from 25 kg/product. Supports kitting delivery — packaging according to factory formulations. Fast order: 0979 891 929 or leave your information for a quote within 30 minutes.