Top Tack Info

Protein adhesives


Protein adhesives are made of gelatine, a product made out of the lower skin layers of hide, a leftover from the leather processing industry. Because of its high polymer structure, the protein adhesive forms a physical bond, and thus develops fast and high tack. 

High initial and final tack
Protein adhesives are the sole adhesives with the capability to jellify. Applied at a temperature of approx. 60°C the jellification point will be reached when cooling. Then the adhesive jellifies and passes from the liquid to the solid state. During this transition, the protein adhesive develops extremely high tack, and this leads to fast adhesion with high initial tack, called top tack.

When the water proportion enters the material to be glued (the substrate), the adhesive concentrates and enhances its tack. The water evaporates. Additional physical bonds are formed, providing a final tack which is even higher than the initial tack. Thanks to this feature, the laminated material can be processed very soon after application.

Improved evenness
Protein adhesives offer obvious benefits in the evenness of laminates: when compared to PVAc- dispersions, approx. 40 percent less water has to be applied into the laminating materials during the adhesion process.

In the graphics industry, the recyclability of the applied products is a market-winning benefit. Protein adhesives are a great contribution: they are not poisonous, they are recyclable and they are biodegradable. Thanks to the water solubility of protein adhesives, there is no risk of stickies in paper recycling as is the case with most hotmelts.  Processing machines can be cleaned easily with hot water.

Protein based adhesives are proof against ethereal oils and almost all solvents, and they are heatproof up to approx. 200°C. This not only makes them the most widely used adhesives for bookcover production, it also makes them suitable for ever more applications as packaging adhesives.


Gelatine is the heart of every jelly formula and is responsible for the tack of the jelly.  Jellies are processed at approx. 60°C in liquid state. When passing into the solid state, the jelly develops its immediate, enormous tack. This is strong enough to retain even cover binding materials of high restoring force. This tack makes jelly unique under all adhesive systems.

Jellies with strong tack tend to make clean processing difficult. Fritz Häcker developed the PLAKAL-product range and succeeded in realizing a compromise between ease of processing and tack of the jelly. This made the company one of the world’s leading manufacturers of protein adhesives.


also known as hot adhesives, hot glue, or melts, will be applied to the surface to be glued while hot. They produce the bond when cooling down. At room temperature, these adhesives are solid.

Heterogeneous mix of at least two substances which will not or hardly dissolve into each other or will not enter a chemical bond with each other.

Laminating is used to apply a protective or decorative layer onto another material and /or to add several favourable material characteristics.


Residues of adhesives, which can be a problem for paper recycling, and which are mainly caused by hotmelts.

Open time
Time between application and conversion of the material to be glued: the time in which the adhesive has to work.

Restoring force
physical force which works into the direction of the resting position of a mass moved out of this resting position.

  » Contact
Fritz Häcker GmbH + Co. KG
Im Holzgarten 18
D-71665 Vaihingen

Phone: +49 (0) 70 42 / 94 62-0
Fax: +49 (0) 70 42 / 94 62-66

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