Produção de EGP com Diferentes Adesivos PVAc e Sistemas de Prensagem

Iwakiri

Bonduelle

2020

MYB

Self Cite

O objetivo deste trabalho foi avaliar o potencial das madeiras de Eucalyptus benthamii, Eucalyptus dunnii, Eucalyptus grandis, Eucalyptus saligna e Eucalyptus urophylla, para produção de painéis colados lateralmente (EGP) e madeira laminada colada (MLC). As propriedades físicas e químicas das madeiras foram determinadas com base nas normas COPANT 461/459:1972 e TAPPI 204/252:2002. Foram confeccionadas juntas coladas com adesivo acetato de polivinila (PVA), com gramaturas de 150 g m-2 e 200 g m-2, e resorcina-formaldeído (RF), com 200 g m-2 e 300 g m-2. A qualidade de colagem foi avaliada por meio de ensaios de cisalhamento, com base na norma EN 13354:2008. Todas as espécies apresentaram densidade básica de média a baixa e anisotropia de contração de média a alta. O teor de extrativos totais e pH estão dentro da faixa referenciada na literatura. As avaliações dos resultados com base nos requisitos da norma EN 15353:2008 para 5º percentil inferior indicaram que as espécies E. benthamii, E. dunnii, E. grandis e E. saligna, apresentam potencial para produção de painéis EGP com adesivo PVA, para o uso interno, e externo com cobertura. Para a colagem com adesivo RF, o E. dunni apresentou melhores resultados, sendo indicativo do seu bom potencial para a produção de madeira laminada colada, visando aplicações estruturais em ambientes interno úmido e externo. Para os dois tipos de adesivos o aumento na gramatura não afetou os resultados de cisalhamento das juntas coladas.

Section: Cisalhamento Das Juntas Coladas Com Acetato De Polivinilaunclassified

Qualidade das juntas coladas de madeira de cinco espécies de Eucalyptus com adesivos acetato de polivinila e resorcina-formaldeído

Iwakiri

Bonduelle

2020

MYB

Self Cite

“…Iwakiri et al (2013) found, for wood of Eucalyptus benthamii an average shear value of 9.04 MPa. Endo et al (2017) obtained for wood Pinus taeda values between 5.12 and 5.55 MPa. Bila et al (2016) found five species of tropical wood (Eschweilera coriacea, Manilkara amazonica, Protium puncticulatum, Inga paraensis and Byrsonima crispa) containing values between 2.24 and 8.45 MPa.…”

Section: Shear Strength Of Bonded Joints -Dry Testmentioning

confidence: 91%

“…The results obtained in the humid tests for the two species of Eucalyptus and a combination of these trees were satisfactory in relation to those presented in the literature for Pinus woods and some species of tropical woods, bonded with PVA and EPI adhesives. Endo et al (2017) obtained for wood Pinus taeda bonded with PVA values between 3.36 and 5.36 MPa. Iwakiri et al (2016) found for the woods of Protium As for the percentage of failure in the wood, the values obtained after humid pre-treatment were very low, however, the standard EN-13354-2008 does not establish a minimum requirement for wood with a density higher than 0.60 g/cm³.…”

Section: Shear Strength Of Bonded Joints -Humid Testmentioning

confidence: 94%

THE USE OF Eucalyptus camaldulensis AND Eucalyptus urophylla WOOD IN THE PRODUCTION OF EDGE GLUED PANELS

Iwakiri

Stüpp

et al. 2019

Self Cite

This study aimed to evaluate the shear strength of bonded wood joints of Eucalyptus camaldulensis and Eucalyptus urophylla with vinyl polyacetate (PVA) and isocianate polymeric emulsion (EPI) adhesives with the amount of glue of 150 and 180 g/m². The specimens were submitted to shear tests in dry and wet conditions, based on the procedure described in standard EN 13354 (2008). The results of the 5th lower percentile were compared with the requirements of EN 13353 (2008). Among the studied species, Eucalyptus camaldulensis showed better glue line shear strength when compared to Eucalyptus urophylla. However, both species are potentially viable for the edge glued panel (EGP) production, since they meet the minimum requirement of 2.5 MPa, referring to the 5th lower percentile, as established by EN 13353-2008 standard. Based on the results, it is recommended the use of EPI adhesive with the amount of glue of 150 g/m² for the bonding of the wood of these species, aiming at the production of EGP.

“…The curing of PVA occurs at room temperature, which decreases production costs although its low resistance to moisture restricts it only to products for indoor uses. As pointed out by Endo et al (2017), citing the European Standard EN 204:2016 (EN 2016), the D3 class of PVA based adhesives is orientated to indoor-use products subject to frequent and fast exposure to moisture and outdoor conditions, but with no direct exposure to weather. In turn, the PVA D4 type is indicated for wood products for indoor uses but subject to frequent and long-term exposures to moisture with proper protection.…”

Section: Introductionmentioning

confidence: 99%

Production of edge-glued panels with wood from three Brazilian dry forest tree species and five types of adhesives

Souza

Pimenta

International Wood Products Journal

et al. 2020

Self Cite

This article evaluated the technical viability of producing edge-glued panels (EGPs) with wood from three Brazilian dry forest species and five adhesives. Experimental design was completely randomized, involving 3 wood species, 5 adhesives and 5 replicates, totalizing 75 observations. Test specimens were separated into groups, each one submitted to a different experimental condition or after a pretreatment: dry condition; moist condition; after 6-hour boil test; after a boil cycle test. Glueline performance indicators were the 5th lower percentile and the percentage of wood failure. The three wood species showed good potential for EGPs and two adhesives were able to withstand the 6-hour boil test and the boil cycle test. Despite a negative correlation between extractives content and 5th lower percentile was observed, when the adhesive melamine-urea-formaldehyde (MUF) was used, this detrimental effect was overcome and all the joints reached the minimum strength required by the technical standards.