Rubber cement

Rubber cement is an adhesive made from elastic polymers (typically latex) mixed in a solvent such as acetone, hexane, heptane or benzene to keep them fluid enough to be used. This makes it part of the class of "drying adhesives": as the solvents quickly evaporate, the "rubber" portion remains behind, forming a strong yet flexible bond. Often a small percentage of alcohol is added to the mix.

Formula

The formula for rubber cement varies according to its targeted application. Those commonly used in office and art applications are usually non-vulcanizing and seldom differ between brands. However, they have been reformulated over time due to concerns over the toxicity of the chemicals involved, especially in regard to its use by children. Consumer-grade products generally no longer contain benzene because of its link to certain cancers. Instead, they tend to be based on less toxic solvents such as n-hexane and n-heptane.

Rubber cement based on n-heptane is very popular and ubiquitous in the United States, but is generally unknown and unavailable as a consumer product in the UK and some parts of Europe, possibly due to the severe fire hazard of that formulation. A similar solvent based product called "Cow Gum" was common in the UK, but is no longer in production. Current solvent based options include Marabu-Fixogum and Platignum "Studio Gum" which are marketed in the UK and Europe.

For tire patching, shoe repair, and other industrial applications, vulcanizing formulas are preferred. These contain chemical additives which enable them to cross-link and harden into a tougher, more resilient form.

Examples

Copydex, a common latex adhesive in the UK, uses an ammonia and water solvent and needs no special handling, making it very safe to use. Whilst, for this reason, it is often given to children, it is also used in artwork, and finds widespread use in light D.I.Y. work such as fixing carpet tiles and repairing upholstery.

Usage

Rubber cement is favored in art applications where easy and damage-free removal of adhesive is desired. For example, rubber cement is used as the marking fluid in erasable pens. The rubber cement can be removed via the eraser up to 10 hours after application.

Cement formulations based on n-heptane and n-hexane will not shrink or swell paper fibers, thereby preventing wrinkles to the adhered surfaces. This makes them safe to use on most finished paper surfaces, unlike water-based glues such as PVA glues (i.e. white or Elmer's brand glue).

Because rubber cements are designed to easily peel or rub off without damaging the paper or leaving any trace of adhesive behind, they are ideal for use in paste-up work where excess cement might need to be removed. It also does not become brittle as paste does. Rubber cement is not considered an archivally sound adhesive and will cause deterioration of photographs and papers over time, a danger associated with many other common adhesives.

Rubber cement is also used in many magic tricks due to its property of sticking only to itself when dry as opposed to other objects as well.

History

Rubber cement was invented by Paul Van Cleef in the early 1900s to be used in various applications in the Van Cleef Brothers factory in Chicago, Illinois.

Hazards

The solvents used in rubber cement present many hazards [http://www.devcon.com/techinfo/14900.PDF] , such as potential of abuse as inhalants and fire. For this reason, as with any adhesive, rubber cement should be used in an open area, and care needs be taken to avoid heat sources as n-heptane and n-hexane are highly flammable. Also if put in a person's hair, it can cause extreme pain and even damage the scalp permanently.