OODA Polyurethane adhesives are those glues that are made of urethane polymers with chemical based of isocyanate group, polyurethane adhesives are also known as elastic adhesives, due they have an extraordinary elasticity and elongation before the fracture occurs (up to 600%), and also like epoxy adhesives exist rigid polyurethane adhesives, due to the high fracture resistance presented by these adhesives about 25 MPa.
The elastic polyurethane adhesives are cured by polyaddition reactions, taking on a slightly reticulated structure with properties of an elastomer material; rigid polyurethane adhesives are as well as cure by polyaddition but they also acquire a high crosslink structure of thermoset material.
There are 3 different types of OODA polyurethane adhesives or glues:
- 2 component Polyurethane adhesives (Pur 2C)
- 1 component Polyurethane adhesives curing by heat (Pur 1C - heat) - Rigid polyurethane
- 1 component Polyurethane adhesives curing by moisture (Pur 1C - moisture) - Elastic polyurethane
Component polyurethane adhesives moisture curing:
Note - All information described on 1 component polyurethane adhesives moisture curing are referenced to the basic principles. For each adhesive the valid information is contained in the technical data sheet,due that the formulation of the adhesive changes its properties.
Basic Components of 1C Pur moisture curing and polyreaction
Resin / Hardener - prepolymer with isocyanate groups endings.
The polyreaction is by polyaddition, resulting in a lattice structure of elastomer polymers.
The reactions in which the polyurethane is formed by the action of moisture are the following:
- Humidity + isocyanate + CO2 = amine groups
- Amines groups + isocyanate = Polyurethane