Loc Thien Chemicals for the Vulcanized Rubber Industry |...

Rubber Industry Chemicals — Vulcanization, Technical Additives | Loc Thien

Loc Thien provides a full range of chemicals for the rubber industry: vulcanizing agents, activators, vulcanization accelerators, and technical additives meeting TCVN 6087:2016. Serving technical rubber factories, gloves, gaskets, seals, and conveyor belts in VSIP, Nhon Trach, Amata, Long Khanh, and VSIP II Binh Duong industrial parks. Same-day delivery, with CoA/MSDS/CO/CQ for each batch. Hotline: 0979 891 929.

What is Rubber Chemical?

Chemicals for the rubber industry are a group of additives that are mixed into rubber compounds before vulcanization to create a crosslink network between polymer chains, thereby improving mechanical properties: elasticity, tensile strength, Shore A hardness, and resistance to heat and oil.

A standard rubber formulation consists of the following main chemical groups: vulcanizing agent (sulfur or peroxide), activation system (ZnO + stearic acid), vulcanization catalyst (accelerators: MBTS, CBS, TMTD), reinforcing filler (carbon black N330, N550, N660), and anti-aging additives (antioxidant, antiozonant). The mixing ratio directly affects the vulcanization rate, scorch time (onset of hardening), and the modulus of the final product.

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

Elemental sulfur (sulfur, S) is the most classical and common vulcanizing agent for natural rubber (NR), SBR, and NBR. Mechanism: sulfur reacts with the C=C double bond in the polyisoprene chain to form polysulfide crosslinks (-C-Sx-C-). This linkage can be a monosulfide (x=1), disulfide (x=2), or polysulfide (x>2) depending on the sulfur ratio and catalyst system.

ParameterTypical ValueNotes

CAS7704-34-9 Elemental sulfur
Purity≥99.51 TP3T Grade Industrial Rubber
Dosage (mg)1.5 – 3.0 phr (CV system: 0.4 – 0.8 phr) According to TCVN 6087:2016
Scorch safetyCBS accelerator is better than MBTS for scorch.
Packaged form25 kg/bag PP, powder or granular form Ho Chi Minh City – Binh Duong – Da Nang

Technical note: When the sulfur content is increased to >2.5 phr (conventional vulcanization) → polysulfide network, high elasticity but poor heat resistance. With efficient vulcanization (EV system, S <0.8 phr + accelerator cao) → monosulfide/disulfide, better heat resistance. Contact Loc Thien for suitable formulation consultation.

ZnO & Stearic Acid — Vulcanization Activator System

ZnO (zinc oxide, CAS 1314-13-2) and stearic acid (C18H36O2, CAS 57-11-4) are indispensable activator systems in sulfur vulcanization. Mechanism: stearic acid dissolves ZnO to form zinc stearate, and this complex then reacts with an accelerator to form an active zinc-accelerator complex, initiating an efficient crosslinking chain reaction.

Chemicals CAS Number Typical Content (%) Role

ZnO (zinc oxide)1314-13-23 – 5 phr Activator, accelerating crosslinking speed
Stearic acid57-11-41 – 2 phr Zinc oxide dissolution, copper catalyst, reduced friction during mixing
ZnO nano (<100 nm)1314-13-21 – 2 phrHigher activity, reduced dosage of common ZnO

Reducing ZnO to <1 phr (low-zinc or zinc-free system) is being implemented to minimize environmental impact, but this requires the use of special accelerators such as MBT or zinc complexes. Loc Thien offers both standard ZnO (grade 99.7%) and nano-ZnO for research units developing advanced formulations.

Vulcanization Accelerators: MBTS, CBS, TMTD

Accelerators (vulcanization catalysts) are a group of chemicals that determine the speed and quality of crosslinking. The choice of accelerator must balance between Scorching safety (safe time before hardening) and cure rate (Curing speed).

MBTS (2,2′-Dithiobis(benzothiazole), CAS 120-78-5): Secondary accelerator (secondary), good scorch safety, often used in combination with CBS to balance speed. Suitable for NR, SBR, NBR rubber. Typical dosage: 0.5-1.5 phr.

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

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

Standard TCVN 6087:2016 & CoA/MSDS Documents

TCVN 6087:2016 (equivalent to ISO 37:2011) specifies the method for determining the tensile properties of vulcanized rubber and thermoplastics. This is a standard for testing rubber product output and does not directly regulate the quality of input chemicals. However, to meet TCVN 6087, the input raw materials must meet their corresponding technical standards:

CoA (Certificate of Analysis)Confirm component, purity, and content of active substances — provided per batch.
MSDS/SDS (Material Safety Data Sheet)Chemical safety information according to GHS, mandatory for warehousing in industrial zones with HSE standards.
Certificate of Origin/QualityCertificate of Origin and Quality - Supports L/C payment and customs inspection.

Loc Thien provides full CoA/MSDS/CO/CQ for all rubber chemicals. The set of documents is stored by shipment lot, retrievable within 1 hour upon audit request.

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

Lộc Thiên Rubber Chemicals storage located in Ho Chi Minh City (District 12), Binh Duong, and Dong Nai — covering the entire Southern Industrial Zone area:

KCN VSIP I & II (Binh Duong)Same-day delivery before 5 PM if ordered before 10 AM
Nhon Trach I–V Industrial Park (Dong Nai)Delivery the next morning with orders ≥500 kg
KCN Amata Bien HoaSame-day delivery, truck <3.5T circulation within the area
KCN Long Khánh, Xuan Loc24-hour delivery
Binh Phuoc, Tay Ninh2 business days delivery

Flexible MOQ from 25 kg/product. Delivery support kitting — packaged according to the factory's formulation. Quick order: 0979 891 929 or leave your information to receive a quote within 30 minutes.