Properties of adhesives based on
Baypren® ALX

 

Baypren ALX

Good resistance to environmental influences, excellent solubility in many organic solvents, as well as a high rate of crystallization make Baypren® ALX ideal for the production of solvent based contact adhesives. Contact bonding requires the application of the adhesive on both substrates. After brief surface drying the substrates are joined with pressure within the open time (contact bonding time) of the adhesive. One of the most prominent features of adhesives based on Baypren® ALX is the high initial strength that is established instantly with joining. The bonded substrates can be handled immediately, fixation of the substrates until the cure is finalized is not needed.
Following momentary strength, crystallization of the polychloroprene further increases cohesion, resulting in a final bond strength, that is markedly exceeding adhesion strength achievable with contact adhesives based on natural or nitrile rubber. Apart from their simple, economical processing, contact adhesives based on Baypren® ALX are distinguished by their excellent adhesion to a wide range of materials. Additionally they allow formation of soft bond lines for the joining of flexible substrates like rubber, foams or leather.

The Baypren® ALX portfolio is consisting of two grade lines, distinguished by their rate of crystallization. The 300 grades are crystallizing more readily and are reaching a higher final degree of crystallization than the 200 grades. Within both grade lines products with varied viscosities (chain lengths) are available, to allow the choice of the best suiting raw material for the distinct application.


Fast crystallizing 300 grades

The fast crystallizing 300 grades are giving contact adhesives with high initial strength, high final strength and rapid bond formation. These adhesives are specially useful in industries with fast production cycles like the shoe industry. Due to the high initial strength, production processes following the bonding step can be done at once. The joined substrates can be handled immediately, without waiting for the final cure of the adhesive.
Baypren® ALX can be dissolved directly, without a previous milling step. Most of the grades are delivered in approx. 2 mm chip thickness allowing a quick solvation of the polymer. Polymers with long chain length generally need more time for solvation. To offset the longer solvation times, due to the long chain length, the high viscosity grades B340-2 to B350-2 are produced in 1 mm chip thickness.
If the final application is challenging regarding flow properties of the adhesive, milling of the chips is helpful to reduce viscosity and normal stress of the adhesive formulation. Within the Baypren® ALX portfolio, the thiuram modified grades 321 and 331 are specially suitable for milling and the preparation of smooth, easy-to-apply adhesives. Under unfavorable conditions, e.g. in the presence of certain leather greases or on contact with iron, the use of thiuram modified grades holds the danger of producing a yellowish discoloration. When bonding sensitive, light-colored materials, it is advisable to use the thiuram-free Baypren® ALX grades.


Medium fast crystallizing 200 grades

In cases where high initial bond strength is not needed (e.g. flooring or roofing), use can be made of the medium fast crystallizing Baypren® ALX grades of the 200 range. They prolong the open time of the adhesives, enhancing processing reliability and are giving a softer, more flexible bond line.
The medium crystallizing Baypren® ALX grades can be used both on their own or in combination with fast crystallizing Baypren® ALX grades. Additionally blending of grades of different viscosities is no problem, allowing the formulation of an adhesive with well-fitting viscosity and crystallization for the distinct application.


Main application industries

The demand for contact adhesives based on Baypren® ALX is particularly high in the shoe industry, in fabrication of mattresses, in furniture production, in the construction and automotive industries and in the do-it-yourself sector.