Grants and Contributions:

Grant or Award spanning more than one fiscal year (2017-2018 to 2018-2019).

Traditionally, formaldehyde based resins were used for manufacturing of engineered wood products (EWP)x000D
however the industry is shifting to the use of polymeric diphenylmethane diisocyanate (pMDI) binding resins.x000D
This shift is due to both the safety concerns with the use of formaldehyde, but also due to the significantx000D
advantages with the use of pMDI including: reduced concentration and cost; fast curing; increased panelx000D
performance through the formation of strong chemical bonds; increased strength and water resistance.x000D
However, there is a drawback limiting the use of pMDI due to its superior adhesive properties which requiresx000D
the application of effective release agents (RA). RA prevents the sticking of the produced boards to the pressx000D
plates/belts resulting in downtime, costly cleaning and production losses. Guardian has previously developed ax000D
series of Pressguard RA for pMDI bonded composite wood products which are protected by patents. Whilex000D
successful, recent industry trends such as increased press temperatures as well as competitive market pressurex000D
requires that we renew our research efforts in this field to regain lost market share and address the changingx000D
press operating conditions. Development of efficient RA requires in depth understanding of their physicalx000D
properties and wetting/adhesive interactions with the involved solid substrates, including stainless/mild steelx000D
and wood strands. The main objective of this joint project is to use microfluidic channels along with real-timex000D
high resolution microscopy to identify and measure the key physical properties that govern the adhesion/releasex000D
between hot metal plate and composite wood panels manufactured with pMDI resins. The experimental schemex000D
includes determination of dynamic surface tension, dynamic contact angles of pMDI resins, water, silicone oilx000D
and proprietary release agent (RA) blends. Microfluidic channels will be designed and fabricated in an attemptx000D
to act as micromodels to mimic the absorption of liquids in the wood porous structure. Different coating agentsx000D
will be used to change hydrophilicity/hydrophobicity of the channels to systematically study the effects ofx000D
substrate wettability on dynamic contact angle and capillary flow.