What is the formula for foam glue?

Polyurethane foam sealant is called foam glue, which is an energy-saving material and is relatively environmentally friendly to use. Many people worry whether this glue will be harmful to the human body. In fact, it is harmless to the human body and can be used with confidence. The main ingredient is polyurethane prepolymer. Polyurethane foam glue has a relatively high activity. This glue is relatively strong and has good toughness. It is suitable for gluing rubber. Many people wonder what the formula of foam glue is. Let's take a look.

1. Foam

The synthesis process of polyester diol is to accurately add dibasic acid and diol into a stainless steel reactor, heat and protect with N2 gas. When the temperature reaches 140℃, water begins to flow out. The water flow rate and the temperature of the top of the reflux tower are controlled. The top temperature is preferably between 100 and 102℃ under normal pressure. Then the temperature in the reactor is slowly raised to 160-80℃ and kept warm for 2-3h, mainly to adjust the molecular weight distribution of the polyester polyol. Then slowly raise the temperature to 220-230℃, until the theoretical water output is basically completed, keep warm for 2h, take samples to measure the acid value, hydroxyl value and moisture, etc. Then start vacuuming and gradually increase the vacuum degree. It takes about 4 hours to reach the maximum vacuum degree. During the vacuum period, samples are taken at regular intervals to measure the acid value, hydroxyl value and moisture content until they are qualified. The product appearance is a white waxy solid or viscous liquid.

2. Foaming glue formula

Polyether (YB-3082-75) 30, methyl hexahydrophthalic anhydride 130, 2-ethyl-4-methylimidazole 1, silicon powder 250, 80℃/2h+160℃/6h curing, used for more demanding potting such as ships, ⑤E-51 epoxy resin 100, resorcinol diglycidyl ether 50, JLY-121 polysulfide rubber 15

35% m-phenylenediamine, 200% HG-600 active silica powder, 10% titanium dioxide, 2% KH-550, a small amount of chromium trioxide, cured at 25℃/3h+80℃/3h, used for potting of power converter assemblies of aerospace products.

3. Performance and Usage

This product has strong bonding performance and medium resistance, good toughness, and is suitable for rubber bonding.

Apply the prepared glue on both surfaces of the adherend preheated to 60°C, bake in an oven at 80°C for 30 minutes; then apply a pressure of 0.49MPa, place in an oven to heat and cure, and cure at 105°C for 1h.

Preparation method: Weigh the formula amount, mix the epoxy resin, liquid nitrile rubber-40, and 2-ethyl-4-methylimidazole evenly, then add human phenylenediamine, mix and stir evenly.