PUR Accepted as JAS CLT Adhesives
MAFF* established a new JAS standard for cross laminated timber in December 2013 and enacted it in January, 2014. The only adhesives stipulated in the standard were resorcinol resins, resorcinol phenol resins and emulsion polymer isocyanate (EPI) for service condition C. However, the standard does not stipulate One-Component Polyurethane Resin Adhesive (PUR), which is the primary adhesive used for manufacturing CLT in Canada and Europe. COFI has been involved in the lobbying activities to encourage MAFF to accept PUR adhesives that are internationally popular product to bond the CLT planks together. As reported in this blog on March 16, 2014, MAFF established an adhesive equivalency evaluation committee to assess the appropriateness to approve PUR as equivalent to the other adhesives already stipulated in the JAS standard. Dated September 9th, 2015, MAFF has accepted three types of PUR as shown in this table. PURBOND is the brand name of PUR manufactured by Henkel Company in Switzerland. It came to our attention that PURBOND used in North America has a different recipe from that for Europe. PURBOND HB E-line is used in North America, but PURBOND S-line is distributed in Europe. So far, MAFF seems to have accepted the equivalency evaluation only with the S-line.
Note: *Ministry of Agriculture, Forestry and Fisheries