What is methyl cellulose? Its use in paper restoration and how to prepare it

Methyl cellulose is a water-soluble cellulose ether derived from plant cellulose. In paper and book restoration it is used as a reversible adhesive, as a consolidant for weak papers and as a surface sizing agent. When dry it leaves a colourless, flexible film, and it can be redissolved with moisture when needed.

Why is methyl cellulose preferred?

• Reversible: because it dissolves in water, a repair can be removed later without causing damage; this is a core principle of conservation ethics.
• Transparent and flexible: when dry it does not change the colour of the document or form a brittle layer.
• Resistant to biodeterioration: unlike starch paste it has no nutritional value, so it is more resistant to mould and insects.
• Adjustable consistency: by changing the ratio you can obtain anything from a fluid solution to a thick gel.

Where is methyl cellulose used?

• Tear repair: as the adhesive together with strips of Japanese tissue paper.
• Consolidation and sizing: as a thin solution on the surface of papers whose size has weakened after washing.
• Mixed with starch paste: to extend the working time of wheat starch paste and slow its drying.
• Residue removal: as a gel or poultice to soften old adhesive and tape residues.

How is methyl cellulose prepared?

Restoration work generally uses solutions of roughly 1% to 4% by weight; a lower ratio is chosen for thin sizing and a higher one for adhering. When preparing it:

1. Use pure (purified or deionised) water.
2. Sprinkle the powder slowly into the water while stirring; do not pour it in all at once, or it will form lumps. Some grades dissolve faster if first dispersed in hot water and then topped up with cold water.
3. Leave the solution to swell for a few hours, preferably overnight; once it is clear and smooth, it is ready to use.
4. Store it in a closed container in a cool place, and discard it if it turns cloudy or develops an odour.

Each product has its own dissolving temperature and recommended ratios; follow the values on the technical data sheet and test on a trial sheet before applying it to an original document.

What is the difference between methyl cellulose, Tylose and CMC?

All three are cellulose ethers, but their chemical structures and behaviour differ. Methyl cellulose (MC) dissolves in cold water and gels when heated. Tylose MH 300 is a methyl hydroxyethyl cellulose (MHEC); it is used for similar purposes, especially adhering and sizing. Carboxymethyl cellulose (CMC) is ionic and shows a different consistency and adhesion behaviour. The choice depends on the type of repair and the conservator's preference.

Starch paste or methyl cellulose?

Wheat starch paste bonds more strongly and is the traditional choice for tear repair with Japanese tissue paper. Methyl cellulose dries more slowly, is more flexible and stands out for sizing and residue removal. Many workshops use the two side by side or as a mixture. We explain the repair technique with Japanese tissue paper in our Japanese tissue paper guide.

Where can I buy methyl cellulose?

Our shop stocks methyl cellulose, Tylose MH 300 P2 and Aytex-P wheat starch. For other conservation materials, see our restoration materials page, and for repair services, our conservation and restoration page.