"The movement capability and elastic recovery of polyurethane sealants and their strong bonding power on various kinds of substrates have led to a multitude of applications in the building and metal construction sectors," says Jean-André Zembsch, managing director of Den Braven France.  "Performance properties can be tailored to meet a variety of conditions of use."

This adaptability allows the manufacture of self levelling casting materials for hard joints in industrial floors as well as thixotropic sealants for façade expansion joints, which also offer good paintability.  These products from Den Braven are sold under the trade name POLYFLEX®.

Main application
Industrial products of the TECTANE® range from Den Braven usually have lower elasticity and are used, for example, as sealants in ship building or to encapsulate windscreens.  "One main application is for gluing, jointing and anchoring of metal parts in transport engineering such as in car, coach, truck and aircraft building, container construction and other areas where structural adhesives are increasingly replacing more traditional bonding techniques," says Jean-André.

From the start, Den Braven France has used SUPRASEC® isocyanate from Huntsman Polyurethanes for the production of prepolymers.  In a discontinuous process, batches of prepolymer, fillers and various additives are stirred together in big metal containers at specific temperatures to produce homogeneous compounds of different color.

The materials are then filled automatically into tight aluminum cartridges, the standard package of one component, moisture-curing polyurethane sealants.  For professional users, larger quantities are packaged in sausage-like foil bags for use with special applicator guns.

"In the various application areas, polyurethane grades have to compete with other polymeric materials, which makes the menu of sealants on the market more comprehensive," says Jean-André.  "Our chemical kitchen, however, is particularly versatile and allows modification of formulations again and again for novel or adapted products à la carte."

Paintable glazing
In Germany and the Netherlands, for example, new environmental legislation prescribes the use of waterbased paints inside houses, while alkyd-resin paints are still permitted on the outside.  "As a consequence, the demand for a universally paintable glazing sealant has increased significantly and is now being satisfied with our new product POLYFLEX 2000 UV," he says.

Another was specifically developed for roofing work in southern France, Italy and Spain, where traditional hollow tiles are generally glued.  They are often covered with a water-repellent coating which impairs adhesion.  Den Braven's special sealant, based on a modified polyurethane, offers a strong bond on these siliconized tiles.

Yet another Den Braven specialty integrates two separate functions.  Used for laying tiles in bathrooms or on balconies and terraces, the product ensures perfect gluing and a waterproof membrane in one go.  "We also offer an elastic glue for wooden flooring, which is quickly gaining in popularity because it improves footfall sound insulation by dampening the phonic link between parquet and the sub-floor," says Jean-André.

"Flexible reaction to new or changing needs requires a fair amount of R&D," he adds.  "We appreciate our professional exchanges with a global supplier such as Huntsman, which has far-reaching expertise and is making suggestions for improvements."

Jean-André Zembsch
Den Braven France, France
Phone +33 344 916868
Fax +33 344 916891
www.denbraven.nl

JUL 2001