3-Mercaptopropyltriethoxysilane CAS 14814-09-6

Introduction

3-Mercaptopropyltriethoxysilane, model KT9582, is a mercaptosilane. Its molecular structure contains a mercapto functional group and three hydrolyzable ethoxy functional groups. As a sulfur-containing functional group, mercapto can participate in the vulcanization process of sulfur-vulcanized rubber. At the same time, there is an active hydrogen on the mercapto group, so it can also be used for end-capping modification of isocyanate. Its dual reactivity allows it to improve the bonding, adhesion, and compatibility between inorganic materials (glass, metal, filler) and organic polymers (thermosetting resins, plastics, elastomers) through a two-way chemical reaction, thereby improving the mechanical properties of resin-based composite materials or improving the bonding strength and water resistance of resin coatings. In different applications, it can be used as a coupling agent, adhesion promoter, cross-linking agent, surface modifier of pigments and fillers, end-capping modification monomer of polyurethane, etc.

Application 

1. This product is particularly suitable for all kinds of rubbers with yellowing vulcanization and metal oxide vulcanization systems. It can significantly improve the mechanical strength of the rubber (especially 300% tensile stress and tear strength) with inorganic fillers (white carbon black, kaolin, aluminum hydroxide, magnesium hydroxide, talcum powder, etc.); significantly reduce fatigue heat generation, permanent deformation, and wear; and improve its processing rheology. It is particularly effective in light-colored rubber products. This product can be used to pretreat mineral fillers, or it can be added during rubber mixing.
2. This type of product can replace polysulfide silane in the formulation of green, environmentally friendly, and energy-saving tires with low positive rolling force; rubber shoe soles; rubber rollers; light-colored rubber conveyor belts; and rubber cables, and only a small amount is needed to achieve the same performance. When making this substitution, the amount of accelerator in the formula should be appropriately reduced, and the amount of sulfur donor should be increased.
3. This product can be used as an adhesion promoter in the formulation of polyurethane and polysulfide sealants. It can also be used for end-capping modification of isocyanates to give polyurethane sealants moisture-curing properties and excellent adhesion and weather resistance.

Reaction characteristics:

In the presence of water, the alkoxy group of KT9582 will hydrolyze to generate active silanol groups, while releasing a hydrolysis reaction byproduct—ethanol. This silanol group will undergo a condensation reaction with the hydroxyl groups on the surface of various inorganic materials (substrates or pigments and fillers) to form a chemical bond; and its hydrophobic group can be chemically cross-linked or physically adsorbed by suitable resins and elastomers. Through the above-mentioned two-way reaction, this product realizes the coupling and connection between inorganic fillers (or substrates) and organic polymer materials or realizes the silanization end-capping modification or cross-linking of resins.
The hydrolysis of KT9582 requires the use of organic acids (such as formic acid, acetic acid, etc.) as catalysts. Specifically, the pH value of water is adjusted to about 3.5~4.5, and then silane is added and stirred for a period of time (at least 30 minutes or more) until the silane is completely dissolved and the solution is clear and transparent. Its hydrolyzate is unstable, and it is recommended to be used up within 24 hours. The fogging of the solution indicates that the silane has partially self-polymerized to form a polymer of silane (sulphonone) and has failed.
When treating mineral fillers, minerals can be blended with silane under high-speed shear without adding any solvent. After silane treatment, the treated substrate or mineral surface should be dried briefly at ~104~121℃ to complete the polycondensation of silanol and remove the small amount of methanol or ethanol formed when methoxysilane is hydrolyzed.
Inorganic materials suitable for this product include glass, glass fiber, glass wool, mineral wool, mica, quartz, and other siliceous materials; aluminum hydroxide, magnesium hydroxide, kaolin, talcum powder, steel, zinc, aluminum, and other metals and their oxides; but it has little effect on fillers such as calcium carbonate, graphite, carbon black, barium sulfate, etc. that do not contain hydroxyl groups on the surface.
Suitable polymers for this product include (but are not limited to) polysulfide rubber and sulfonated or metal oxide-cured rubber (such as natural rubber, styrene-butadiene rubber, butadiene rubber, chloroprene rubber, etc.). This product can also modify some polymers (such as polyurethane, PVC, etc.) by addition or grafting methods to give the polymer some superior physical and chemical properties of moisture curing and silane cross-linking.

Specification

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