Since our childhood, adhesives come to our help in our most difficult times of our lives as indispensable material. We had been used different types of adhesives like repairing of broken toys, maquette homework given by teacher or photos we like to be hanged on the wall or panel etc. There were the times that we could not find adhesives in the hope of bonding for the splitted shoe during the games or the statuette that we broke mistakenly…
Even those of us who at a certain age had prepared a kind of mixture by diluting flour and starch to make paperbag by using old newspapers. In today’s world of technology from many different raw materials, different adhesives can be produced with a very specific Formula. In accordance with the needs, companies able to provide specific products.
Shoe manufacturers are working together with adhesive producers for not only supplying the adhesives, also they cooperate like production partners, they demand specially formulated products to be used in different type of materials.
The adhesive must be chosen according to the properties of the material for application. When the 2 materials coupled for bonding, the adhesive strenght ocur. Adhesives are generally developed for specific applications.
When choosing adhesives; you must be pay attention to :
The properties of the materials to be bonded,
Strength and life of the adhesive
Structure of the surface to be bonded
Application process of the adhesive
The surface and the materials to be bonded must be cleaned with an appropriate primer to make them ready for application.
The adhesive firstly must be equally applied to the surfaces that will be bonded.After the appropriate drying period, the surfaces combined and press applied.
NATURAL AND SYNTHETIC RUBBER BASED ADHESIVES
In general,these adhesives are obtained by mixing rubber with appropriate resin and solvents.
Usually preferred due to high initial adhesion strenght.
The reasons solvent based adhesives preferred are :
– Drying time can be adjusted
– Superior bonding strenght
– High resistance to humid environments
Polyurethane adhesives obtained by mixing appropriate polymers and solvents, ensures adhering the materials such as TPU, rubber etc. at the highest level.
These are environment friendly materials as there are no toxic chemicals or prohibited substances in it.
The most important advantage of polyurethane adhesives is that it is water resistant.
Polyurethane adhesives have wide range of applications.
WATER BASED ADHESIVES
It comprise water in large scale as solvent material. As the rate of evaporation of water is slower than solvents, it cause longer drying period for adhesive.
To adjust drying period, an amount of solvent or second additionnal component can be added.
As solvent material is water, this kind of adhesives are not have resistance to humid environments. After a while, bonded place can split.