Dry rubber coating
The Trockengummierung is a special type of rubber coating of stamps .
Dry gum is one of the most common types of gumming on postage stamps these days. The special thing about this type of rubber coating is that it is almost invisible. If you look at the back of a postage stamp with dry gum coating, one initially believes that the stamp has remained ungummed. The dry rubber lining can only be seen on closer inspection. It looks a bit dull and rough.
During the production of the dry gum lining, it penetrates more or less strongly into the postage stamp paper . This type of gum reacts particularly well with water . Therefore, the stamps are easy on the mailing stick and it detached again.
The composition of this special type of gumming consists of a high proportion of starch or synthetic glue .