Effect of Modified Silane Coupling Agent on Silicone Rubber
The de-alcoholic room temperature vulcanized liquid silicone rubber (RTV silicone rubber) is characterized by its odorless, non-toxic, non-corrosive to metal substrates. It is the type of silicone structural adhesive currently used. Silicone structural adhesive is a neutral curing, designed for structural bonding assembly in building curtain walls [1]. It can be easily extruded under a wide temperature and relies on moisture in the air to form an excellent, durable high modulus, highly elastic silicone rubber. Polyfunctional alkyl siloxanes and siloxanes are cross-linking agents for the preparation of dealcoholized RTV silicone rubber. Two-component RTV silicone rubber uses ethyl orthosilicate, propyl orthosilicate and polyethyl silicate. Etc., single-component RTV silicone rubber uses methyltrimethoxysilane, and sometimes methyltriethoxysilane or vinyltrimethoxysilane. In the comparison of the hydrolysis activity of five commonly used liquid silicone rubbers, acetone type > amide type > acetic acid type > ketone oxime type > alcohol type, [2] dealcoholized type silicone rubber has low hydrolysis activity, and it is necessary to mix catalyst to promote base polymer and The condensation crosslinking reaction of the crosslinking agent, the commonly used catalysts are mainly organotin catalysts and titanates and their complex catalysts. Although the catalyst dosage is small in the formulation design, the biological toxicity of the catalyst cannot be ignored, for example. The oral lethal dose (LD50) of commonly used dibutyltin dilaurate is 175-1600 mg/kg. In order to find a way to maintain the performance of silicone rubber on the basis of reducing the amount of catalyst, this paper uses modified silane coupling agent (TH-550), modified RTV silicone rubber, compared with KH-550 as coupling agent. The mechanical properties and bonding properties of silicone rubber.
1 Experimental part
1.1 Main raw materials and equipment
α,ω-terminal hydroxyl polydimethylsiloxane (107 gel), new blue sky chemical; γ-aminopropyl triethoxysilane (KH-550), new blue sky chemical; TH-550, homemade; cross-linking Agent; organotin catalyst, silicone rubber component A, Jitai Chemical.
1.2 Preparation process
A certain amount of 107 glue is mixed with the crosslinking agent, the coupling agent and the catalyst in sequence, and after being uniformly stirred, the structural rubber component B is filled, and the structural rubber component A and the structural rubber component B are mixed at a certain ratio during use. can.

1.2 Performance test
1) Breaking time:
Mix the structural adhesives A and B, start from the mixing time, inject into the beaker, insert the wooden stick, pull up the wooden rod at intervals, and when the wooden stick glue is broken inside, it is the breaking time.
2) Physical and mechanical properties
Dumbbell test: The glue sample was injected into the mold, flattened, and cured in an environment of 25 ° C, 55% RH for 7 days. Remove the film and cut it into a standard dumbbell type. According to GB/T 528, the tensile strength was tested by an electronic universal testing machine.
Mechanical properties: standard conditions, 7d in water, 1h baking at 90°C, and mechanical properties of water UV irradiation for 300h, all tested according to GB/T 13477 method.