Introduction

The invention relates to a new adhesive system for relining paintings on canvas, in order to reduce the wetting power of aqueous dispersions, effectively preventing their penetration into the canvas.

Technical features

The novel system is able to overcome the limit of traditional products in water dispersion such as glues in the process of lining paintings on canvas. In fact, by modifying their viscosity through a rapid gas dispersion process (foaming), it is possible to achieve a better control of their wetting power, limiting the amount of material used, and ultimately preventing their penetration into the fabric. In addition, the use a smaller amount of emulsion, compared to traditional use in the liquid phase, leads to significant economic savings (up to 90%), making thus the process more sustainable.

This system has been tested during the relining of some paintings on canvas. There are available commercial adhesive products, based on aqueous dispersion, for the relining of paintings on canvas: such products are characterized by low viscosity (and volatility), due to the use of water as solvent, which promote the phenomenon of vertical diffusion, detrimental for the painting system, especially in highly porous materials. Water can penetrate along the stratigraphic structure of the painting, which in most cases is composed of different hydrophilic materials, and cause irreversible damages in terms of chemical interactions and structural resistance. Other available commercial products make use of organic solvents, potentially hazardous for the restoring operators or require adhesive activation by either high temperature or pressure, thus limiting the use of these products to controlled environments.

Possible Applications

• The main field of application is cultural heritage, focused on the restoration of paintings on canvas.

Advantages

• Reduced use of adhesive compared to traditional aqueous dispersion: a reduction of up to about 90% is obtained, whereas it maintains an optimal mechanical resistance value.
• Limitation of product penetration into the substrate, without compromising the possibility to spread it on the canvas.
• Reduction of drying times, with no need of thermal activation.
• Low environmental impact, due to the absence of organic solvents, and no hazardous substances needed by the restoring operators.
• Easy to use and to apply on canvas.
• Possibility of in situ application.