Métodos de Extracção de Taninos e de Preparação de Adesivos para Derivados de Madeira: Uma Revisão

 

Fernando Caldeira Jorge¹*, Paulo Brito**, Lina Pepino***, António Portugal****, Helena Gil**** e Rui Pereira da Costa*****

 

*Investigador WOODTECH – Consultadoria e Intermediação Tecnológica para as Indústrias dos Produtos Florestais, Lda. Rua da República, 198 – Alagoas – 3810 159 AVEIRO

** Estudante de Doutoramento, ***Bolseira e

****Professor Associado Departamento de Engenharia Química. Universidade de Coimbra, Polo II, Pinhal de Marrocos, 3030-290 COIMBRA

*****Director-Geral Bresfor. Indústria do Formol, Apartado 13, 3834-908 GAFANHA DA NAZARÉ

 

 

Sumário. Com o objectivo de contribuir para a utilização e valorização do resíduo abundante que é a casca de pinheiro bravo em Portugal, são revistos vários métodos de extracção de casca ou de cerne de algumas espécies florestais para a obtenção de extractos taninosos, com especial destaque para a casca de pinheiro. Discute-se a utilização desses extractos na preparação de adesivos para madeira ou derivados de madeira, nas vertentes de resinas só com extracto, com extracto e resina sintética, resinas de cura a frio e como captadores de formaldeído.

Palavras-chave: taninos; extracção; adesivos; revisão

 

Abstract. With the objective of increasing the use and value of maritime pine bark in Portugal, which is an abundant residue, this paper reviews several methods for the extraction of tannin-rich extracts from the bark or heartwood of some forest species, with an emphasis on pine bark. The utilisations of such extracts are discussed as applied to the preparation of adhesives for wood and wood-derivatives, including resins based solely on these extracts, with extract and synthetic resin, with cold set resins and as formaldehyde scavengers.

Key words: tannins; extraction; adhesives; review

 

Résumé. Pour contribuer à l'utilisation et à la valorisation d'un résidu abondant au Portugal qu'est l'écorce de pin maritime, on revoit dans ce texte quelques méthodes d'extraction de l'écorce ou du cerne de quelques espèces forestières pour obtenir des extraits riches en tannins, en insistant sur l'écorce du pin. On discute l'utilisation de ces extraits dans la préparation des adhésifs pour le bois ou dérivés du bois, dans le cas des résines préparées seulement avec extrait, avec extrait et résine synthétique, résines de cure à froid ou comme captateur de formaldéhyde.

Mots clés: tannins; extraction; adhésifs; révisio

 

 

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Submetido para publicação em Janeiro de 2001

Aceite para publicação em Outubro de 2001

 

¹ 1º Autor E-mail: mail@woodtech.pt