CONTEXT

Phenolic resins are well known and are generally prepared from phenols and formaldehyde. The use of formaldehyde introduces environmental and toxicological problems in the preparation , fabrication and even in the long term use of such materials.
Formaldehyde –a « VOC » or volatile organic compound-  is a widely used chemical in glues and adhesives and is a preservative used in paints and finishes. .The World Health Organisation’s International Agency for Cancer Research (IARC) in 2004 recommended classification of formaldehyde from group 2A -« probably carcinogenic to human » to group 1 – « carcinogenic to humans ». Under European Union standards, formaldehyde is currently classified as a category 3 chemical – « weak level carcinogenic hazard -« 
This invention could provide new solutions to obtain phenolic resins without free formaldehyde.  

TECHNICAL DESCRIPTION

The present invention relates to a method for preparing a formaldehyde-free phenolic plastic resin, including a step of preparing a hardener by means of careful oxidation of a polyol and a step of reacting said hardener with phenolic compounds.

A polymer containing aldehyde fonctions is used as hardener for phenol resins instead of using formaldehyde for phenolic compounds reticulation. It can be obtained either by polymerization of acroleine or by oxidation of a polyol.

BENEFITS

These hardeners could be mixed in particular with natural aromatic and polyaromatic compounds resulting from the biomass and more particularly extracted from plants, trees, vine, grape or algae.

The hardener could be also sourced from biomass either in the case of the polymerization of acroleine as acroleine could be obtained by a catalysed reduction of glycerol, by-product of biodiesel process or in the case of biobased primary polyols.

INDUSTRIAL APPLICATIONS

Phenolic resins are used in wood products and moulding powders applications. They also have a wide range of applications on the electrical, mechanical and decorative markets, in the automotive industry in building and construction (glass-reinforced composites) or but not last in thermal insulation products (foams and fibre binders).

DEVELOPMENT STAGE

Formaldehyde free resins were formulated and tested. Mechanical and thermal properties could be adapted owing to starting polyol and regarding the expected properties.

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