{"id":23324,"date":"2021-08-31T12:12:23","date_gmt":"2021-08-31T06:42:23","guid":{"rendered":"https:\/\/plyinsight.com\/?p=23324"},"modified":"2021-09-22T15:39:05","modified_gmt":"2021-09-22T10:09:05","slug":"e0-plywood-boards-standards-practices-part-2","status":"publish","type":"post","link":"https:\/\/plyinsight.com\/hi\/e0-plywood-boards-standards-practices-part-2\/","title":{"rendered":"E0 Plywood & Boards – Standards & Practices (Part 2)"},"content":{"rendered":"
\n\t
\n\t\t
\n\t\t\t

“KRDF works on product development, process development, standardisation and skill development in manufacturing sectors ranging Sustainability, Biodegradable Single-use Materials, Alternate Natural Material Composites, Coir-Bamboo-Agrowaste Composites and Rural technologies.”<\/strong><\/span><\/p>\n

\n
\n

Vaidyanathan Hariharan
\n(Vaidya) is Founder Director \u2013 Kalpaka Research &
\nDevelopment Foundation (KRDF), Ernakulam, Kerala<\/p>\n

\n

In continuation with the previous article on what is E0, measurement limits and quality control test measurements & units, we shall discuss what is the basis of formaldehyde emission from composite boards made out of wood & ligno-cellulosic panels made with formaldehyde based synthetic resins.<\/p>\n

Why is Formaldehyde emitted\/released from cured panels?<\/strong><\/span>
\nFormaldehyde release from cured boards\/panels occurs due to two reasons \u2013 free formaldehyde content & formaldehyde (CH2O) released due to hydrolysis in high moisture environments and related factors.<\/p>\n

Formaldehyde Content<\/strong><\/span>
\n\u201cContent\u201d refers to the free CH2O present in composite boards. This happens due to the existence of un-reacted free CH2O present in resin used as binder. CH2O content management depends on molar ratio of resin materials, extent of cooking (temperature, pH, speed, time factors), molecular weight consistency, scavenger efficiency, free CH2O present in wood species (Wood contains, and is capable of emitting CH2O under various environmental factors. Though negligible, it adds to the emission values during testing.)<\/p>\n

Perforator test provides the measurement of CH2O \u201ccontent\u201d in the boards, and is reported per 100 grams of oven dry board. Perforator is a content extraction process apparatus.<\/p>\n

Formaldehyde Emission<\/span><\/strong>
\nEven if there is no free formaldehyde found in the manufactured resin as well as cured boards, formaldehyde keeps getting released over the operative life of product due to hydrolysis of the cured resin under various operative conditions (when the panels are used in homes & offices) such as temperature of surroundings, humidity (moisture content), air flow (ventilation), and HVAC (heating, ventilation, air conditioning) parameters in general. This is referred to as CH2O \u201cemission\u201d. Emission values are also affected significantly by the rate & extent of curing in the hot pressed boards.<\/p>\n

Desiccator, Flask, Gas Analysis, Chamber methods of testing are CH2O emission testing processes.<\/p>\n

NOTE: Contrary to Indian practice of using the Perforator test apparatus for CH2O measurements in hardwood plywood (HWPW), we must be aware that it has been removed from approved list of QC tests for HWPW by ARB (Air Resources Board, California) and EPA (Environment Protection Agency, USA). It is suggested that plywood manufacturers use the JIS A-1460 Desiccator for internal QC tests which is approved for \u201call manufacturers\u201d irrespective of the composite board product, when exporting to North American countries.<\/p>\n

FACT:<\/strong><\/span> Phenol formaldehyde resins always return E0 values in all forms of testing provided the resin manufacture is maintained at precise molar ratio, temperature of cooking & resin molecular weights (viscosity without additives). When fully cured, these resins undergo negligible hydrolysis under the regular board installation environments & are perfectly safe to use interiors.<\/p>\n

Debates continue on the efficacy of various tests. Yet, the \u201cemission\u201d tests are usually considered more realistic, considering the application\/installation surroundings of the composite boards, though there is also a concern that only a small amount of exposure is being considered\/tested during factory quality control test conditions, compared to Chamber methods of steady-state emission testing. For safe and confident supply of guaranteed emission based boards, it is always suggested to perform scheduled (say quarterly) third party chamber tests for confirmation (if the factory does not have CARB\/EPA\/BS\/JIS\/ISO CH2O emission certifications), in addition to internal QC tests.<\/p>\n

[Next issue \u2013 Part 3: E0 manufacturing parameter chart, details of JIS A 1460 desiccator QC test]<\/strong>
\nhttps:\/\/www.linkedin.com\/in\/krdf <\/strong>
\nkrdfindia@outlook.com<\/strong><\/p>\n

\n\n\t\t<\/div>\n\t<\/div>\n<\/div><\/div><\/div><\/div>
\n\t
\n\t\t
\n\t\t\t