Hotel bathtubs need to be considerably more robust than their domestic equivalents. Constant use by a succession of hotel guests subjects them to particularly high stresses, including the use of heavy-duty detergents. The materials used to make these bathtubs therefore need to be suitably resistant and at the same time offer good sound-absorbing properties.
Bathtub manufacturer BSB (Bañera sobre Bañera) and its direct supplier Handcrafted Industrial Projects, both based in the Spanish city of Valencia, have worked closely with polyurethane systems partner BaySystems to produce extremely hard-wearing hotel bathtubs using the filler-free polyurethane system Multitec® Advanced Foam - with considerable success. BaySystems is the global umbrella brand for Bayer MaterialScience’s polyurethane systems business. It incorporates the unique know-how that the company has built up over several decades and ensures close cooperation allied to customer proximity. BaySystems can also be regarded as the pioneer in the proposal of polyurethane systems for the sanitary industry.
The shape of today’s bathtubs is created by thermoforming a polymethyl methacrylate (PMMA) or co-extruded PMMA with acrylonitrile-butadiene-styrene (ABS) thermoplastic film. To ensure that the molded part has the necessary stability, the reverse side of the thermoformed film has to be reinforced. Until now, this has been done in many cases using a time-intensive manual process that involved laminating the film with unsaturated polyesters and cut glass fibers. Two further drawbacks in addition to this time-consuming and labor-intensive hand lay-up process are the use of styrene as a solvent and co-reactant, and the need for annealing during the curing phase.
BSB has focused its activities on the entire process chain for hotel bathtubs - from design and manufacture to sales, installation and customer service. The company was looking for a technology to produce very robust bathtubs with sound-absorbing properties. Its cooperation with Handcrafted Industrial Projects and the Spanish BaySystems systems house ultimately resulted in a perfect solution in the form of the new, filler-free polyurethane dual-component spray system Multitec® Advanced Foam. This material’s excellent reactivity and easy handling ensure cost-efficient reinforcement of thermoformed films based on PMMA or ABS. "The system is applied just like a coating. No plasticizers or solvents are required and it is processed without glass fibers or fillers on high- or low-pressure equipment. There is no need for energy-intensive annealing either,"
explains Alfonso Navarro, founder and managing director of Handcrafted Industrial Projects. "The system is therefore ideal for the cost-effective and eco-friendly production of hard-wearing bathtubs. Manufacturers also benefit from the excellent design flexibility offered by the process," he concludes.