Klucel™ G — Hydroxypropylcellulose for Conservation (Kremer)

Klucel™ G is a hydroxypropyl cellulose (non-ionic cellulose ether) soluble in cold water and in most polar organic solvents. It is manufactured by Ashland (formerly Hercules) and distributed by Kremer Pigmente under reference 63706. The manufacturer's data sheet belongs to the pharmaceutical industry and does not mention conservation-restoration: what supports its use on artworks is the published literature of the field.

Why choose Klucel G?

• Soluble in water and in alcohol: it allows sizing and consolidation where introducing water is not an option. Kremer puts it concretely — in ethyl alcohol it glues without leaving water tidelines.
• It is the grade the field uses: in the Getty Conservation Institute survey of 155 conservators from the Book and Paper Group of the American Institute for Conservation, grade G was almost the only hydroxypropyl cellulose in use.
• It dries matte and saturates colour very little, which is why it is used on dark, underbound colours.
• Flexible film without plasticizers, and it redissolves in its own solvent.

Uses and applications

• Sizing and repair of works on paper without introducing water, in alcoholic solution.
• Consolidation of leather degraded by red rot — the decay of vegetable-tanned leather that turns it into a reddish powder — in alcoholic solution.
• Consolidation of paint and pastel, in a thin layer and at low concentration.

The limits, stated

• Its ageing is not predictable, and recent literature recommends avoiding it. A 2022 paper from the Hochschule der Künste Bern documents batches that aged very differently and advises considering hydroxypropyl methylcellulose where alcohol is required as the solvent. Other sources — the Getty Conservation Institute and the Spanish Conservation Group — do recommend it for consolidating matte paint. Both positions are published and we give you both.
• Low glass transition temperature, between −4.5 and 15 °C: above that temperature the film is in flow.
• Insoluble in water above 45 °C. Between 40 and 45 °C it precipitates rather than gelling, so heating the water to speed up dissolution achieves the opposite. The precipitation is completely reversible: cooling below 40 °C with stirring redissolves it and restores the original viscosity.
• Medium adhesive strength. It sizes paper and consolidates; it does not solve a joint that has to bear a mechanical load.

Data declared by the manufacturer

• Off-white, odourless and tasteless powder. CAS No. 9004-64-2 — the international registry number that identifies each chemical substance.
• Molecular weight 370,000 · viscosity 150-400 mPa·s (2 % in water, Brookfield LVF at 25 °C) and 75-400 mPa·s (2 % in anhydrous alcohol).
• Softening temperature 100-150 °C · bulk density 0.5 g/ml · refractive index 1.337 in 2 % solution.
• Hygroscopic: keep the container tightly closed.
• Kremer states that it does not pack under food-quality conditions, so it is not suitable as a food additive.

Klucel™ is a trademark of Ashland (formerly Hercules). Kremer Pigmente distributes it under reference 63706. If you are looking for the 500 g size in stock with immediate delivery, it has its own page: Klucel® G (500 g).

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