Sulfur-Silane Coupling Agent, liquid HP-669/SI-69, CAS No. 40372-72-3, Bis-[3-(triethoxysilyl)-propyl]-tetrasulfide

Short Description:

Product Detail

Product Tags

Chemical Name


Structural Formula


CAS Number


Equivalent Product Name

SI-69 (Degussa),Z-6940 (Dowcorning),A-1289 (Crompton),
KBE-846 (Shin-Etsu),KH-845-4 (China)

Physical Properties

It’s a pale yellow clear liquid with light odor of alcohol and soluble easily in alcohol, acetone, benzene, toluene etc. It’s insoluble in water. It can hydrolyze when contact with water or moisture. specific gravity is 1.08g/ml.



Light yellow clear liquid

Alcohol Content

£ 0.5%

γ2 Contentα

£ 3.0%

Other Impurities Contentβ

£ 1.0%

Viscosity 25℃ (cps)

£ 19.0

Sulfur Content

22 ± 1%

α γ2: γ-chloropropyltriethoxy silane. β: mainly contains some silane impurities.

Application Range

HP-669 is used successfully in the rubber industry as a dual functional organic poly sulfur silane coupling agent.
HP-669 can be used in the vulcanized rubber system with fillers such as silica, fiberglass, talc powder, mica powder and clay as reinforcing agent. It can improve the reinforcing properties of fillers and rubber abrasive resistance properties.
It is suitable to be used as rubber additive—vulcanizing agent and activator in polymers such as NR, IR, SBR, BR, NBR and EPDM.
In the process of vulcanization, the crosslinking rate of poly-sulfur alkyl is the same as deoxidizing rate of sulfur, so it act to resist deoxidization of vulcanization, and then improve dynamic bending properties such as heat build up and cracks expansion .The four sulfur atoms can act as activator for vulcanization.
In dynamic and static conditions, It is used for producing these rubber products: tire, hose, rubber roll, belting, cable, footwear and mechanical founding products. It can improve abrasive resistance, cutting resistance and pressure resistance, reduce hysteresis loss and hygroscopicity, improve mechanical and adhesive properties, and increase thermal ageing performance, modulus and flex life.
Add sulfur-silane coupling agent in the industry of rubber tire, it’s not only debase the risk of puncture as temperature too high running on the high speed road or long time, but also reduce roll resistance of tire, then reduce the consume of gasoline, the emissions quantity of CO2 as to accord the environmental protection of carbon reduction.


Recommend dosage:1.0-4.0 PHR.

Package and storage

1. Package: 25kg or 200 kg or 1000kg in plastic drum.
2. Sealed storing:Keep in the cool, dry and well-ventilated places.
3. Storage life:Longer than two years in normal storage conditions.

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