Air Products launches new non–emission catalysts

PU processors worldwide are requiring innovative additives that are capable of producing high quality foams with reduced environmental emissions. Designed for use in automotive foams and flexible slabstock, the company has continued to extend the Dabco range with the development of low-emission catalysts.

“When developing low emission catalysts, the biggest challenge has been to fulfil he physical property standards of flexible foams used in automotive seating, in particular to meet the properties after humid ageing of the foam” explained Steve Hulme, Global Marketing Manager, PU Chemicals, Air Products. “These new Dabco products, NE1090 and BA305, have been designed specifically to produce non-emissive TDI foams that can meet the humid ageing specifications of seating foams required by the automotive industry.” According to the company, the technology will close a gap that foam manufacturers have been looking to fill for many years.

The demand for non-emission catalyst technology has developed globally during the past decade and is expected to continue further. Initially, interest in these products came from the European automotive industry, but this has since spread to flexible slabstock and rigid foam products. “We are also experiencing increased demand for this advanced foam technology from furniture and bedding manufacturers in Asia, who are supplying markets in Europe and the US,” Hulme stated.

The automotive industry has been looking for non-emissive additives for a long time. Legislation regarding VOC emissions and cabin air quality has become increasingly important from a health and safety perspective, as has the need to reduce the exposure of manufacturing staff to VOC emissions during foam manufacturing processes. Alongside these important environmental benefits is that additional advantage that non-emissive catalysts reduce the problems of PVC staining caused by volatile amine emissions from the foam. It has taken ten years to develop an additive that can replace conventional catalysts such as TEDA, and will meet the various OEM specifications. “The main driver has not been EU legislation but self-regulation among the automotive OEMs to meet customer’s odour perception especially in a new vehicle, and so the profile of interior emission has been raised,” explained Mathias Lohe, Marketing Manager Europe, PU Additives, Air Products.

VOC emission is only one of many performance properties required of polyurethane foams used in automotive applications, others include tensile strength and compression set performances as well as the physical property of the foam over the lifetime of the vehicle. Humid ageing is the main property used to determine the long term stability and durability of foams for the automotive industry. Premium manufacturers of seat foams have driven the industry towards the most stringent tests.

Historically, TDI-based foams manufactured with non-emissive catalysts have been unable to meet humid ageing specifications. During the past ten years TDI-based foams supplied into the European OEMs has only just managed to reach these standards. An important target for product development has been to allow foamers to produce TDI foams with non-emissive catalysts that meet all the physical properties required by the automotive OEMs.

New catalysts increase opportunities for TDI foams

The use of TDI-based foams is dominant amongst US automotive OEMs and is typically used by US transplants in Europe. Attitudes to low emission standards in the US will be specific to TDI-based foams where Dabco RE catalysts (reduced emissions) can be used. In China, VW transplants are also driving the demand for lower emissions and there is now a government directive concerning cabin air quality.

TDI automotive seat foams typically have a lower density and therefore lower weight in comparison to MDI foams, and are therefore attractive in terms of weight reduction of the vehicle. Standard front seat foams based on 100 % MDI are 50 – 60 kg/m³ density, while TDI-based foams are typically 45 – 50 kg/m³ density. Therefore, the use of TDI/MDI-based foams can save up to 3 kg in the overall weight of a typically European four door family car.

The new Dabco non-emissive catalysts are suitable for use with 80/20 TDI/MDI and 100 % TDI systems. MDI-based systems currently use non-emissive catalysts such as Dabco NE1070 gel catalyst and Dabco NE300 blow catalyst to meet specifications.

Limiting emissions from silicone-based surfactants is another important requirement to meet the most stringent standards for automotive moulded foam. Air Products has launched Dabco SI 1101, a second generation ultra low emission silicone surfactant for use in moulded MDI-based systems. Up to a 60 % VOC reduction is achievable when using the new surfactant, reducing typical VOC emissions from 25 ppm to 8 ppm.

Non-automotive opportunities

Beyond the automotive market there are other applications for non-emissive catalysts where reduction or elimination of emissions is required. Flexible slabstock applications such as HR or viscoelastic foams are of increasing focus to meet industry specifications. Specific Dabco NE products are suitable for use in conventional polyether and polyester flexible slabstock to achieve low or zero emissions.