What is it?
Seen all over the place in foams (both solid or with flexible characteristics, furniture, white goods such as fridges or even used behind wall paper too, they all play their part and act as good insulation materials.
When formulated as an adhesive, including some woodworking glues, polyurethanes have the inbuilt advantage of offering a measure of water resistance. Technology has developed it and now has properties that allow it to coagulate evenly particularly at room temperatures. This single factor lends itself beautifully to act as a bonding agent uniformally and as a result, structural glues, adhesives and sealants with their measure of polyurethanes enable prominency in the market place.
Polyurethane (also termed as the acronym PUR) has specific advantages in moisture and temperature resistance from below −35°C to around 100°C. It can be a thermoset type (where additional heat is added) but still remains flexible. Also it serves as an excellent protection tape particularly against impact from debris and foreign objects - but hold on; that's a different story...
We list below the various adhesive groups which are based on PUR.
3M EPX range
The EPX system is one of the simplest methods currently available for dispensing two-component adhesives. Acting as a quality structural adhesive, it has enough cohesive strength and creep resistance to stick permanently high-strength materials with the potential to replace mechanical / fusion fastening in many applications.
Materials benefitting for PUR type adhesives are plastics and some woods.
3M Scotch-Weld Reactive range
This system offers a performance similar to the two part adhesives but benefits from little requirement to jig or clamp substrates together for long periods: simple alignment by hand is all that's required.
Using the hand-held Adhesive Applicator the moisture-curing urethane adhesives enable powerful production capabilities in assembly operations. Once cured (and some polyurethanes do have fast setting times) any overspill can easily be cut away leaving neat and smooth edges.
3M Scotch-Weld 2-Part adhesives
Mixed normally by hand and measured out by weight, these two-part structural strength polyurethane adhesives are able to cure at room temperature. In addition by adding heat, they provide a tough, impact-resistant bond with high peel strength.
Formulations include rapid-curing adhesive for flexible bonds of many plastics, wood and rubber.
3M™ Polyurethane Adhesive Sealants
This latest exciting innovation has come in the form of Sealants for use with either a caulking gun or by kneading from sausage packs directly onto the joint or seam.
These one component formulations form robust, permanent and flexible bonds offering resistance to:
- foaming, bubbling and expansion
- bleeding, staining and shrinkage
- These polyurethanes are flexible and especially great for bonding dissimilar materials. They are also thick having paste like consistency and therefore have excellent gap-fill formulations from sealing through to bonding.
Click here to see the full technical 3M Sealant range
Polyurethane Multi Purpose Adhesive is similar in packaging to Sealants but has high performance qualites that can stick many substrates together from plastics to concrete.
Wood in particular is ideal and does not matter if the timber has a hign moisture content. Excellent for dovetail joints, mitres, flooring tongues & grooves. A word of caution, any exoctic timbers you are considering working upon, then do check it out as the surfaces may have high oil contents and will need to be treated beforehand.
Please contact us for further information.