The PX-100 series of adhesives has been modified by the unconventional technology of creating interpenetrating networks, allowing for extensive control of adhesive properties without sacrificing thermal stability.
Conventional epoxy adhesives consist of chemicals containing epoxy groups. During the curing process, these substances can crosslink with the aid of a curing agent and create a stable, three-dimensional network. This network formation is one of the reasons for the typically high strength and good adhesion properties of epoxy adhesives on many substrates.
The products of our PX-100 series of adhesives are also based on resins containig epoxy groups. Additionally, they contain further monomers that can create a network of their own using a different chemical mechanism, without reacting with the epoxy monomers. During the curing of these adhesives two independent networks are created, penetrating each other but not being covalently bonded. Such a mixture of networks is called an interpenetrating network (IPN). Therefore, the PX-100 adhesives practically consist of two adhesives in a single system.
Crosslinked epoxy adhesives belong to a group of chemicals known as polymers having the characteristic property that in general they cannot be mixed with other polymers. If one tries to mix polymers anyway, the mixture will tend to separate into phases soon after stopping agitation.
However, if one succeeds in mixing the monomers (from which the polymers are formed) and then conduct the polymerization in a way that phase separation of the created polymers is prevented, then the resulting polymer mixture can exhibit interesting synergy effects. This concept has been applied to the adhesives of the PX-100 series.
For properties such as adhesive strength or impact resistance much higher values can be measured for the IPN than for the stand-alone single networks (e.g pure epoxy networks). At the same time adhesive strength is improved at elevated temperatures as well.
Our IPN modified adhesives have shown great resistance to acids, bases and many solvents. They exhibit high glass transition temperatures and thermal resistance.
Combining two independent networks opens a wide range of variations in the formulation of adhesives and enables to customize the properties to specific needs of many applications.
The effect of IPN modification is therefore best described as using synergy effects that only become visible in the combination of two networks but not in the single networks on their own. Often the synergy effects result in a maximization of useful properties and a possible minimization of unwanted properties.
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