Aquazol® — Water-Soluble Resin for Conservation (Kremer)

Aquazol® (poly(2-ethyl-2-oxazoline), CAS No. 25805-17-8 — the international registry number that identifies each chemical substance) is a thermoplastic resin soluble in water and in polar organic solvents. It is manufactured by Polymer Chemistry Innovations (Tucson, Arizona) as a technical polymer for industrial use, and its documentation does not mention conservation-restoration among the product's uses: what supports its use on artworks is the published literature of the field, starting with the Getty Conservation Institute study of 1994. It is distributed by Kremer Pigmente. The manufacturer specifies it as a light-yellow solid, and the shade varies from batch to batch within that specification.

Why choose Aquazol?

• Applied in one solvent and removed with another. Soluble in water, methanol, ethanol, acetone, methylene chloride and methyl ethyl ketone; not in toluene or aliphatic hydrocarbons.
• It ages by depolymerising, not by cross-linking. In the Getty study, after a dose equivalent to some 24 years of museum exposure the films were still completely resoluble. The condition goes with the figure: that study measured grades 50 and 500, not 200.
• Colour behaviour: without ultraviolet it holds up very well; under unfiltered ultraviolet it does not. Pigmented and in an opaque film it is among the most stable tested.
• pH of the aqueous solution: neutral, according to the manufacturer.
• Versatile: consolidant, adhesive and retouching medium depending on grade and concentration.

Grades available

• Aquazol 50: target molecular weight 50,000 and kinematic viscosity 5-7 cSt — penetration and consolidation of powdery, sensitive surfaces.
• Aquazol 200: target molecular weight 200,000 and 18-24 cSt — the compromise grade, general use and adhesion.
• Aquazol 500: target molecular weight 500,000 and 60-80 cSt — greater adhesive strength and film formation.

The manufacturer titles these molecular weights as target values, not as measured ones.

Uses and applications

• Consolidation of polychromy, water gilding and gesso ground — documented in the conservation literature, which notes that some water in the solution improves the bond with the gesso.
• Setting down and fixing colour on works on paper, wood or canvas.
• Adhesive for securing layers where moderate adhesive forces are enough.
• Binding medium for pigmented, opaque chromatic reintegration.

Where it must not be used

• Neither outdoors, nor where relative humidity is likely to rise above 85 %. Beyond that it gels and loses adhesive and consolidating capacity. This is an express prohibition by the distributor C.T.S. in its technical data sheet, not a recommendation.
• And the published literature is stricter still: the granulate starts to become tacky from 65 % relative humidity and the film from 70 %, with a recommendation not to exceed 65-70 % in uncontrolled environments (Muros, Cotsen Institute, University of California, Los Angeles, 2012). For a church, a crypt or an unconditioned space, ask us first.
• Not for structural bonding, where the joint must bear shear or tensile load from weight. It is a weak adhesive.
• Unpigmented or as a transparent glaze there are better options for reintegration: the very source that measured it advises against this.
• It is hygroscopic: store airtight and dry.

Aquazol® is a registered trademark of Polymer Chemistry Innovations, Inc. (Tucson, Arizona, USA). Kremer Pigmente distributes it. If you are looking for grade 200 in a 1 kg container in stock with immediate delivery, it has its own page: Aquazol® 200 (1 kg).

Product on request — estimated delivery 1-2 weeks. Questions about the grade or the concentration for your treatment? Write to us: WhatsApp · innovart.art · info@innovart.art