Particleboard Formaldehyde Emissions and Decay Under Elevated Temperature and Humidity Conditions

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1 Particleboard Formaldehyde Emissions and Decay Under Elevated Temperature and Humidity Conditions 2013 International Conference on Wood Adhesives October 11, 2013 Darren Riedlinger

2 Background CARB Composite Wood Products ATCM (2009) Federal rule being implemented by EPA which is supposed to mirror CARB rule However, EPA had concerns regarding a lack of available information on the performance of low emitting amino chemistries under elevated environmental conditions We believed it would be beneficial to re-examine panel formaldehyde emissions and decay characteristics: Using modern amino, phenolic and formaldehyde-free chemistries At extreme temperatures and relative humidities Using industry-standard, steady-state (dynamic) emissions test methods. 2

3 Experimental Resin Chemistries: UF: Formulation similar to commercial amino resins and would meet PII emission requirements MUF: containing melamine, urea, and formaldehyde and would meet PII emission requirements PF: CARB-certified, commercial ULEF resin pmdi: No-added formaldehyde, similar to commercial resins Panel Making: Four panels per chemistry All furnish from a CH 2 O-free mill 50% Face, 50% Core Increased MC for pmdi Adhesive type Press temp. ( 0 F) Press time at position (sec) Density (lbs./ft. 3 ) Thickness (in.) PF UF MUF pmdi Increased press time for PF 3

4 Experimental Two Environmental Conditions (two different Arclin facilities): A. 77 o F, 50% RH: using the ASTM D-6007 with standard conditions as specified in ASTM E-1333 B. 85 o F, 75% RH, corresponding to daily average summer temp in SE US. Both laboratories correlated their respective 6007 chambers to an E1333 large chamber 77 F, 50% RH All emissions are reported as E1333 correlated values Panel emissions monitored for 50 days At the conclusion of the study, laboratory B chambers adjusted to 77 o F, 50% RH and used to re-test the panels from laboratory A (verifying that each laboratory provided equivalent values). 4

5 Experimental ASTM D 1036 B 5

6 Control Results: 77 o F, 50%RH 6

7 Elevated Results: 85 o F, 75%RH 7

8 Emissions Decay in Elevated and Control Environments 8

9 Results--Summary Day: Resin control elevated ratio control elevated ratio control elevated ratio MUF UF PF pmdi

10 Panel re-conditioning after 50 days i ii iii iv Lab A Lab B Lab A Panel Lab B Panel Resin Control Elevated Re-tested at Lab B Re-conditioned Final Final 77 F/50% RH 77 F/50% RH PF pmdi UF MUF

11 Panel re-conditioning after 50 days i ii iii iv Lab A Lab B Lab A Panel Lab B Panel Resin Control Elevated Re-tested at Lab B Re-conditioned Final Final 77 F/50% RH 77 F/50% RH PF pmdi UF MUF Agreement between Lab A and Lab B 11

12 Panel re-conditioning after 50 days i ii iii iv Lab A Lab B Lab A Panel Lab B Panel Resin Control Elevated Re-tested at Lab B Re-conditioned Final Final 77 F/50% RH 77 F/50% RH PF pmdi UF MUF Prolonged exposure to the elevated environment did not permanently impact emissions 12

13 Panel Quality Internal Bond Properties 11-15% loss in IB following exposure to the elevated environment PF best retention, MUF poorest retention; however, all within variance of test Surface Quality All panels conditioned at extreme environmental conditions-- regardless of adhesive type--showed excessive raised grain which would be unacceptable for further processing such as laminating. 13

14 Conclusions All panel resin chemistries exhibited emissions which significantly decreased throughout the monitoring period, regardless of the environmental condition. While subjected to the elevated, 85 F, 75% RH environment, emissions for all panels regardless of chemistry--were generally 2-3x greater than in the control environment. Exposure to the elevated environment had a significant impact on panel surface quality and internal bond strength. However, the elevated conditioning environment did not appear to permanently impact the emissions once the panels were re-equilibrated in a control environment 14

15 Acknowledgements Chase Kayes Simon McAllister Pierre Martin Tom Holloway 15