Ordinary two-component solvent-free polyurethane glue

Formulation of two-component solvent-free polyurethane adhesive There are also many kinds, such as:

① More terminal NCO prepolymers are used as component A, and component B is polyol or polyol/polyamine compound, similar to the cast polyurethane elastomer system;

②More A mixture of oligomer polyols such as polyether polyols and additives constitute component A, and component B uses low molecular weight polyisocyanate such as PAPI;

③Polyether polyol and additives (including fillers, etc.) constitute component A, containing NCO's polyether polyurethane prepolymer is used as component B. These two-component solvent-free polyurethane adhesives can be used to bond solvent-sensitive substrates such as polystyrene, plexiglass, etc., can be used as potting glue for electronic components, and can be used as bonding sealant, etc. Here are some recipe examples.

【Example1]

Composed of phthalic anhydride, adipic acid, ethylene glycol, 1,2-propanediol , branched polyester prepared from trimethylolpropane is used as component A, with a viscosity of about 3.1 Pa·s. Use PAPI as component B.

A. Mix component B according to the calculated proportion, stir vigorously and mix well , vacuum to remove bubbles, and leave it at room temperature for a week to stabilize the performance, and obtain a polyurethane cured product with a hardness above Shore A90 and a tensile strength of about 10MPa.

【Example2]

Polyester diol is prepared from phthalic anhydride, adipic acid, ethylene glycol, diethylene glycol and catalyst. Add a small amount of small molecule diol and coupling agent to the polyester diol and mix evenly to obtain component A. A castor oil polyurethane prepolymer with an NCO content of about 3.3% is prepared from castor oil and excessTDI (or MDI).

Component A/Component B is prepared at a mass ratio of 1/(1~2). The tensile strength of the cured product can reach 10.7mPa, and the elongation can reach 450 %, good temperature resistance. The pot life of the formulated adhesive is approximately 5 hours. The glue can be used in industries such as composite films, cement bags and shoemaking industries.

【Example3]

Prepolymer is synthesized from dehydrated polyether polyol and polyisocyanate, NCO at 9% ~13%, as component A. The dehydrated and dried polyol, various fillers and catalysts are ground evenly to form a uniform and stable paste as component B. The two components are mixed according to a certain ratio and cured at room temperature for 5 hours to achieve higher strength.

There are also polyester polyol as a component and polyether polyol-MDI prepolymer as a component, which are used for composite film adhesives and other purposes.