Scavengers for achieving zero formaldehyde emission of wood-based panels

Costa, Nuno; Pereira, João; Ferra, João; Cruz, Paulo; Martins, Jorge; Magalhães, Fernão D.; Mendes, Adélio; Carvalho, Luísa

doi:10.1007/s00226-013-0573-4

Cited by 91 publications

(55 citation statements)

References 17 publications

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“…Formaldehyde emissions can be lowered by several methods, such as reducing the formaldehyde ratio during composition and the addition of more formaldehyde scavengers to the resin (Dongbin and An 2006;Hematabadi and Behrooz 2012;Costa et al 2013). …”

Section: Introductionmentioning

confidence: 99%

Influence of Urea-formaldehyde Adhesive Modification with Beech Bark on Chosen Properties of Plywood

Ružiak¹,

Igaz²,

Krišťák³

et al. 2017

BioResources

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The influence of beech bark concentrations as filler in urea-formaldehyde (UF) adhesives was investigated relative to the composite forming process and selected properties of final 5-layer beech plywood. Beech bark was used as filler to lower the wood processing waste production and decrease formaldehyde emissions. A combination of UF adhesives filled with different beech bark concentrations as the adhesive was used. Three different concentrations of beech bark, 15 wt.%, 20 wt.%, and 25 wt.% were used in the experiment. Urea-formaldehyde adhesive filled with 20 wt.% technical flour was used as a reference sample. The effect of the filler was studied via its temperature profile during pressing, mechanical properties in bending, water absorption, thickness swelling, and formaldehyde emissions after pressing. The time needed to reach the temperature between the beech veneers, at least 105 °C, which was equal to the final temperature filler-adhesive-wood matrix cross-linking, was also investigated during the pressing process. The measurements of the free formaldehyde emissions showed that for samples with non-zero bark concentrations there was a decrease of formaldehyde emissions by at least 46%.

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Section: Introductionmentioning

confidence: 99%

Influence of Urea-formaldehyde Adhesive Modification with Beech Bark on Chosen Properties of Plywood

Ružiak¹,

Igaz²,

Krišťák³

et al. 2017

BioResources

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“…As discussed in previous works, UF resins actually may act as formaldehyde scavengers due to the presence of excess unreacted urea (Paiva et al 2012). However, this is not an efficient approach, because the amount of urea needed to reduce this formaldehyde content dramatically reduces the resin reactivity, and the thickness swelling is considerably increased (Costa et al 2013c). The performance of acids in solid form (oxalic and citric acid) as catalysts was evaluated and the results compared with a latent catalyst (ammonium sulphate).…”

Section: Hexamine As Formaldehyde Release Agentmentioning

confidence: 99%

“…Wood based panels (WBPs), namely fibre and particleboards can incorporate between 50 to 100% of recycled wood in their composition (Costa et al 2012a). …”

Section: Introductionmentioning

confidence: 99%

Formaldehyde emission in wood based panels: effect of curing reactions

Costa

Pereira

Ferra³

et al. 2014

International Wood Products Journal

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The influence of hexamine formed as byproduct during the UF cure was ignored in the past. However, with the increasing interest on low formaldehyde emission boards, this issue has become more pertinent. Formaldehyde release from hexamine degradation is extensive and could limit the success of the development of low formaldehyde emission adhesives if the conventional latent catalysts remain in use.In this study, formaldehyde released from recycled wood, hexamine and cured UF resin was assessed. Citric and oxalic acid, in solid form, were used as catalysts for UF resin in the production of particleboard. Mats with solid acids are less susceptible to resin pre-cure than with a latent catalyst. However, they can have higher formaldehyde emissions than latent catalyst. When both catalysts were used, combined with an ultra-low formaldehyde to urea molar ratio resin the internal bond was improved and formaldehyde content was below 4 mg per 100 g of oven dry board.

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“…Reduced formaldehyde emitting particleboards include urea-formaldehyde (UF) formulations with low molar ratios (Roffael 1976, Marutzky et al 1979, alternative gluing systems (Ernst 1985), or additions of copolymerizing substances such as lignosulfonates (Roffael and Dix 1991). Further methods refer to scavenger additions such as the inclusion of protein-containing paper sludges (Migneault et al 2011), or posttreatments of boards using wax emulsions with incorporated urea as a scavenger, ammonia gas and salts or surface treatments with paints, lacquers, veneers, and papers (Roffael 1982, 2006, Eom et al 2006, Costa et al 2013, Johnsson et al 2014.…”

Section: Introductionmentioning

confidence: 98%

Diatomaceous earth as an inorganic additive to reduce formaldehyde emissions from particleboards

Funk

Wimmer²,

Αδαμόπουλος

2015

Wood Material Science & Engineering

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The presented research is about the use of a new type of a functional inorganic additive in particleboards, for the purpose of reducing free formaldehyde releases. One-layered particleboards were prepared in the laboratory by mixing industrial wood particles and urea-formaldehyde resin. Natural, abundantly and cheaply available nano-mesoporous diatomaceous earth (DE) was used, without and in combination with urea as a scavenger. Silica quartz sand was also added as a nonporous analogy. Particleboards were pressed at two press factors (9 and 15 s/mm). Formaldehyde release was determined using the rapid 3-hour-flask method (DIN EN 717-3). As a result, DE additions insignificantly reduced bending properties of particleboards. Internal bonding was in part significantly lowered. The particleboard produced with 3% urea loaded on 5% DE prior to application almost halved (-45%) the formaldehyde release. Formaldehyde release was on the average 17% lower when pressed at 15 s/mm instead of 9 s/mm. By loading urea onto the nano-mesoporous structure of DE, an improved scavenging function of urea could be shown.

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Scavengers for achieving zero formaldehyde emission of wood-based panels

Cited by 91 publications

References 17 publications

Influence of Urea-formaldehyde Adhesive Modification with Beech Bark on Chosen Properties of Plywood

Influence of Urea-formaldehyde Adhesive Modification with Beech Bark on Chosen Properties of Plywood

Formaldehyde emission in wood based panels: effect of curing reactions

Diatomaceous earth as an inorganic additive to reduce formaldehyde emissions from particleboards

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