The first UTECH Automotive Congress was held in Amsterdam in mid-October 2017. The first day’s proceedings concentrated on the size of the prize, and featured a range of presentations about polyurethane additives that were designed to reduce emissions inside the vehicle. Simon Robinson chaired the meeting
The interior air quality of passenger cars is one of the hottest topics in the polyurethane industry right now, and many companies are devoting considerable time and resources to find ways of removing the new car smell.
It is a complex battle that is being waged on several fronts by OEMs, standards bodies and raw materials suppliers.
OEMs understand the issues that affect their customers not only in terms of the smell of new cars, but also the potential health risks attached to that smell and different consumer preferences around the world.
Standards bodies are working to produce a coherent set of global standards that will account for what is possible, what is desirable, and what is achievable.
Raw material suppliers, from large polyol producers through to integrated and speciality businesses, are working hard to produce formulations and additives that will help Tier 1 and Tier 2 suppliers produce products that fit with the standards, and the demands of both OEMs and demands for lower volatile materials in the future.
Many of these topics were addressed on the first day of the Congress, but the meeting opened with a presentation from Justin Cox of LMC Automotive, who set the scene by giving data on the size of the automotive industry in a number of key regions.
The size of the prize
Cox opened by warning, ‘2016 was the eighth year of global light vehicle sales growth, but, we can’t get too light-hearted. This is a recovery from a very deep recession, and we are looking at about 2% growth in light vehicle demand, which is relatively modest.’
In a business as complex as automotive and on a stage as big as the world, performance is a patchwork of highlights and slow growth. ‘In Latin and South America, light vehicle sales could grow by 11% this year,’ Cox said. Growth here is because South America and its dominant economy, Brazil, is coming out of a very nasty recession. ‘The first two quarters of this year have shown very small signs of economic growth and this has started to feed through into sales,’ he said.
Central and Eastern Europe are also bright spots, Cox believes, and this region is dominated by the Russian market. ‘This, like South America, was ravaged by economic difficulties and turmoil. This is starting to bottom out, and we are seeing positive growth. We expect sales to increase by 6% on average,’ he predicted.
He believes there is more good news in Asia-Pacific, excluding China, with 5% growth this year. ‘This is underpinned by a robust Indian market,’ he said. ‘Despite tax changes, the economic activity in the region has been enough to propel forward a rise of almost 10% this year. In Japan has not seen growth as fast as India but economic performance has supported activity in that part of the world.’
Turning to the key markets of China and North America, Cox said that in North America things are starting to cool down. ‘We expect to see a decline of 2% this year,’ he said. ‘In China, there is a big growth transformation from 13% last year to around 1% this year.’
China is a region that has exhibited phenomenal growth, he claimed. ‘In 1999, the Chinese market was not much bigger than the Italian market today, and in 20 years it has grown to 30m units, which represents a third of the global total of light vehicle sales,’ Cox said.
Cox said that, from the end of 2015 going into 2016, there were signs of a wobble, and the economy was starting to slow. However, the Chinese authorities gave incentives that supported the market.
‘This played through from 2016 to 2017 to such a degree that there has been a payback from the start of 2017, which is likely to extend into 2018.’ The authorities are not likely to introduce more incentives into China unless the market stalls again.
The US market is much more mature and stable, with production now around 17m to 17.5m units. ‘Going forward, we expect growth to remain,’ he said.
‘Europe has not had the V-shaped recovery that was seen in the US, but there have been bumper years. Growth in 2015 was 9%, and 2016 had 6% growth. That momentum had pushed through into the first part of 2017. But it’s beginning to fall off slightly, to around 3%.’
The European light vehicle market is a mixed bag,’ Cox said. ‘Italy is growing at 9% this year, and Spain 2%, both markets which are playing catch-up from the recession. More mature markets such Germany and France, which are growing a little faster than expected, but not as dramatically Italy and Spain.’
Economic troubles in Turkey and cyclical slowdown and the Brexit effect in the UK are adding drag to the market, he said.
Cox said that demand in the Russian market has been a rollercoaster ride. ‘Two to three years ago, it was producing 2m or 3m units/year,’ he said. ‘This had fallen by more than one-third in 2015, and has bumped along the bottom since then.’ There are signs of an up-turn, he added. ‘We expect to see 10% growth in Russia, but from a very low base.’
This is a result of a Russian devaluation, which has helped local companies, including Lada, as imports have fallen.
Move towards the Exit
‘Brexit is an issue in the UK market, the devaluation itself is squeezing incomes and causing prices to rise,’ Cox said. This has had a marked effect on automotive demand.
‘The UK imports 90% of its cars, and 80% of those are built in Europe,’ he explained. ‘Brexit has a big impact. Our base case, with no shock no cliff edge, has production down by about a million units/year. If a harder Brexit is pursued, that could be down by more than 2m units/year.’
Reducing Emissions
The next section of the meeting featured a collection of papers looking at the latest developments in additives designed to help reduce the level of emissions in automotive interiors.
Anti-scorch or anti-oxidant packages play an important role in protecting polyurethane foam from the effects of heat that is generated during the exothermic polymerisation reaction. They are designed to protect against a number of free radicals, those unstable and highly reactive chemical species that are generated by heat or chemical reactions. This can damage foams, and lead to the emission of other low molecular weight products that are formed during the polyurethane polymerisation process. The protection can also help retain the colour of polyethylene foams.
Cinzia Tartarini, Application Specialist in BASF’s global competence centre for automotive, focused on the company’s Irgastab PUR 70 anti-scorch package for polyols and PU foams, which is used in automotive interiors.
Flexible polyethylene foams represent a large proportion of automotive interiors, and contribute to emissions. ‘With a state-of-the-art polyurethane anti-scorch system used in polyol and polyurethane foams, the emissions are quite high,’ she said.
| European Air Quality test complexity |
|---|
| OEM |
Test |
Method |
Limit |
Unit |
| Daimler |
Themodesorption |
DBL 5430 |
VOC ≤ 400 |
µg/g |
|
|
VDA 278 |
FOG ≤ 600 |
µg/g |
|
|
VDA 276 |
Odour ≤ 3 |
|
|
| Renault |
Termodesorption |
D42 3109 |
| µg/g (1) |
|
|
D49 3001 |
Odour ≤ 2.5 |
|
|
| BMW |
1m3 chanmber |
GS97014-3 |
TVOC
| µg/m3 |
|
|
VDA270 |
Odour ≤ 2.5 |
TA/kg |
|
| PSA |
|
D10 5495 |
Total VOC (n-C20)
| µg (1) |
|
|
|
total amine
| µg |
|
|
|
TEDA
| µg |
|
|
D10 5517 |
BTXES |
|
|
|
|
Odour ≤ 3.5 |
|
|
| Audi |
chamber test |
PV 3942 |
| ppm |
|
|
|
| ppm |
|
|
PV 3900 |
Odour ≤ 3 |
|
| Notes:
(1) equivalent toluene/g
(2) front seat cushion, rear seat back,
(3) rear seat cushion |
| Source: Dow Automotive |
Tartarini said that while an anti-scorch system may produce under 25 ppm of VOC emissions, which she described as ‘quite low’, levels of FOG may be much higher. FOG emissions are those produced by substances containing a range of carbon chain lengths from C14 or C16 to C32, depending on the definition in the test standard.
In her presentation, she showed how by changing from BASF’s earlier anti-scorch product Irgastab PUR 68 which, according to VDA 278 2011, produced foams which emitted approximately 650 ppm FOG to the firm’s new Irgastab PUR 70 product, this could fall to approximately 10 ppm or lower. Foams emitting more than 100 ppm VOC and 250 ppm FOG will fail the VDA 278 test.
She added that the Irgastab PUR70 grade increases resistance to discoloration to a greater degree than the previous PUR 68 grade. It also improves the heat resistance of polyols before they start to oxidise.
Fading away
Gas fading – discoloration as a result of the interaction between polyurethane foam and nitrous oxides (NOx) – can also be considerably reduced using anti-scorch packages, she added. Again, the Irgastab PUR 70 grade gives significantly better performance than Irgastab PUR 68.
In moulded foams, the heat build-up is generally less than within slabstock because smaller moulded parts have a higher surface area-to-volume ratio than larger blocks. Because the heat stress is much lower in moulded foams, a single antioxidant can often be added at 0.2% to give acceptable results, she said. The PUR 70 grade will give equivalent results at 0.1% addition levels, she added. Similarly, adding at half the level of an antioxidant the new PUR 70 grade gives greater thermal stability in polyols.
BASF developed the new scorch system in response to increasingly tough automotive standards, she said. The new additive will improve the durability and quality of foams used for seating, and will also help companies comply with emission requirements and enhance the air quality drivers and passengers experience inside the cockpit.
Sven de Vis, Technical Service and Development Engineer at Milliken, outlined the use of the company’s Milliguard AOX-1 reactive antioxidant.
Like several other of their product offerings, it contains an active moiety, in this case an antioxidant, grafted onto a polymeric tail. This increases the compatibility with the host polymer, De Vis said. ‘For the polyurethane industry, the hydroxyl group at the of the end of the polymeric tail will react with isocyanates, and Milliken’s additive becomes incorporated into the PU matrix. There is no migration, and no contribution to emissions.’
| Asian standards for indoor air quality |
|---|
| Substance |
Test Method |
|
OLD China
GB/T27630 25 C for 16 hrs |
New China (1)
GB/T27630 25 C for 16 hrs |
Korea
25 C for 2 Hrs |
Japan (JAMA)
(2) 23/40 C for 4.5 hrs |
| Formaldehyde |
100 |
100 |
210 |
100 |
| Benzene |
110 |
60 |
30 |
-- |
| Toluene |
1,100 |
1,000 |
1,000 |
260 |
| Ethyl Benzene |
1,500 |
1,000 |
10000 |
3,800 |
| Xylene |
1,500 |
1,000 |
870 |
870 |
| Styrene |
260 |
260 |
220 |
220 |
| Acetaldehyde |
50 |
200 |
-- |
48 |
| Acrolein |
50 |
50 |
50 |
-- |
| Phenol |
|
|
|
|
| Glycol Esters/ethers |
|
|
|
|
| Total VOC |
|
|
|
400 |
| Notes:
(1) New China in force from 1 Jan 18
(2) Exposure limits suggested by Ministry of Health, Labour and Welfare |
| Source: Milliken |
Milliken developed its antioxidants after studying the effects on aged polyether polyol, and examining the radical families that were generated. This showed that almost 20% of the radicals were carbon-centred. ‘This encouraged us to think that lactone-based antioxidants would be useful,’ he said.
Microwave scorch tests were used to evaluate the anti-scorch performance with different levels of antioxidant, followed by larger scale tests where Milliken evaluated the antioxidant performance on 1m
3 foam blocks to reflect real-life conditions. The temperature in the centre the block was measured by probes. After foaming, the samples, were stored outside for safety reasons, de Vis added.
He continued that the box foam trials helped determine the optimal AO level in the polyol. This was confirmed by trials at industrial customer sites.
Stability
Milliguard technology also has a positive effect in the stability of PU foam to UV light and to gas fading. This was proved via trials in which foams are exposed to NOx fumes, and the discoloration evaluated after different periods of exposure time.
He explained that, compared with standard antioxidants, Milliguard AOX-1 technology has a minimum contribution to VOC and FOG based on trials performed under the VDA278 protocol in a flame-retarded lab foam at 40kg/m³ density. Looking at FOG values, conventional antioxidants fail the 250ppm limit. The Milliguard product gives almost no contribution, he said.
De Vis also outlined a new aldehyde scavenging technology which, he said, could reduce levels of formaldehyde, acetaldehyde and acrolein found in automotive seat foams.
According to results carried out in a 1m³ environmental test chamber following the VW PV3942-2000 test, Milliken’s scavenger technology could reduce the levels of formaldehyde, acetaldehyde and acrolein.
These impurities in foam come from degradation products formed during foaming, and from raw materials such as polyols. They can be reduced with proper stabilisation and scavenger technology.
De Vis said, ‘We are still working on further versions, but this technology could be the first step in reducing aldehyde emissions.’
Stefano Grassini of Dow Automotive spoke about the complexity involved reducing emissions in car interior,s and the OEMs’ different requirements in this matter.
‘Not only do OEMs have their own individual specifications and requirements for emissions, odour and related testing standards, the countries in which the cars are used also have their own concentration limits for the specific substances of concern,’ he told the meeting. ‘Polyurethanes are not the only materials used in car interiors, and other materials can also significantly contribute to VOC, FOG and odour.’
He continued, ‘Often, variations within the method being used and between labs have been observed, as well as variations because of possible external interference and potential cross contamination in test samples.’ The mixture of products found in the cab is complex, and components come from a number of different sources, he said.
‘Aldehydes found in car interiors can come from a variety of raw materials used to make polyurethane,’ he said, adding that the level and type of aldehydes found also depends on the way that the raw materials are manufactured and purified. Other detected compounds such as amines can come from amine catalysts and siloxanes from surfactants.
‘This means that a primary strategy is to have a portfolio of clean raw materials in terms of polyols and a portfolio of clean additives,’ he said. ‘This represents a very powerful toolbox when combined with formulation know-how and foaming process control, allowing emissions to be limited.’
Dow’s approach has been to look at improving polyols, for example minimising residual aldehydes and glycol ethers which can form as by-products during manufacture.
The company has produced a range of ultra-purified polyols. ‘This means they have significantly lower levels of aldehydes and glycol ethers,’ Grassini said. Dow’s internal analysis has shown these new grades have one-tenth of the acetaldehyde and half of the propionaldehyde of earlier grades, he claimed.
These polyols have also more precise functionality, he added, which gives advantages including faster network formation as well as improved ageing and comfort characteristics of foams. ‘These polyols include a 6,000 molecular weight grade and a high functionality grade. There is no change in processability, compared to earlier grades’, he said. ‘All properties are retained in formulations containing the new polyols.’
The second approach was to create new building blocks, Grassini said, which are available under the Specflex Activ brand This is a new additive polyol family with high and specifically balanced catalytic activity that allow the reduction, or even complete elimination, of amine catalysts.
Combining the two technologies will give formulators a more powerful toolbox to work with without altering production processes for the foam, he said.
Looking at a range of tough formulations, Clement Barriere, Principal Chemist at Addivant, told delegates about his company’s low VOC, low FOG anit-scorch antioxidants for polyurethane foams.
Barriere said, these are drop-in solutions for the slabstock market and require no investment by customers to change antioxidant packages. ‘Polyol producers prefer liquid antioxidants with good miscibility and low viscosity. This makes it easy to produce blends, with good stability for transportation and storage enabling the polyol blend to retain its initial colour and protect against degradation during subsequent processing.’
Antioxidants also help to prevent the combustion or heat-triggered discoloration of the foam during production. They should also protect against gas fading caused by interactions with NOx found in foam storage areas and generated by the exhaust gases of vehicles such as fork-lift trucks, he added.
Addivant has carried out trials of its additive on foam with densities between 20 and 25 kg/m³. ‘Foams of this density typically have a very high risk of scorch,’ he explained. In addition, work was done on 40 kg/m³ foams which are more representative of automotive applications. These are less prone to scorch, he said, but because there is more foam per cubic meter, they tend to emit more than the 20 and 25 kg/m³ foams. Consequently, it is harder for these foams to meet emission standards.
Barriere introduced Addivant’s low viscosity Naugard Foamplus LE Series of antioxidants as new formulations for the slabstock market, and showed results of lab-scale tests. The laboratory tests were verified by an independent laboratory, he said.
Barriere said that using the Naugard Foamplus LE Series antioxidants it is possible to reduce FOG emissions by 95% compared to earlier types of antioxidant, he said. This enables compliance with the VDA 278 standard and the same time there is ‘excellent scorch protection in foams with the density of 20 kg/m³.’
‘We also looked at the how antioxidants can help reduce the formation of aldehydes during foaming by interrupting the reactions that cause them, he said. Using Naugard Foamplus LE series antioxidants can lead to a significant reduction in emissions according to VDA 275 and NES M0402 protocols,’ he said.
‘Several polyol producers and foamers have tested Naugard Foamplus LE Series antioxidants under industrial conditions and have achieved good results,’ he said.
