Literature

Abstracts

Proceedings of the Polyurethane Foam Association Technical Program, Newport, RI, October 12, 2000

New No Emission Catalysts For Flexible Slabstock Polyurethane Foam, J. G. Kniss, L. A. Mercando, M. L. Listemann, Air Products and Chemicals, Inc., Proceedings of the Polyurethane Foam Association, October 12, 2000.

Increasing environmental concerns over the emission of volatile organic compounds (VOCs) during and following the production of polyurethane foam products has placed increased pressure on foam additive suppliers to reduce and/or control the ways in which these emissions occur. One of the more pressing market needs is for lower and ultimately no-emissions of polyurethane foam additives into the environment. These emissions can cause a variety of quality problems such as odor, vinyl staining and window fogging in the final application of the foam. While the currently available amine catalysts perform in an acceptable manner, they do not address the emerging need of more environmentally friendly, lower odor and lower fogging catalyst systems.

This paper describes recent work aimed at producing no emission gelling and blowing catalysts for flexible polyurethane foams. It was found that using a newly developed no-emission gelling catalyst (Dabco NE500) in combination with a newly developed no-emission intermediate blowing catalyst (Dabco NE600) resulted in equal or improved performance compared to standard amine catalyst combinations in a variety of flexible slabstock formulations. It was also found that either newly developed catalyst could be used in combination with traditional fugitive tertiary amine catalysts to obtain improved performance. In all cases, these catalyst combinations can partially replace the use of Dabco 33LV, Dabco BL11, or Dabco BLV and dramatically reduce or eliminate amine emissions from the flexible slabstock foam product. Key physical properties are maintained or improved.

Two newly developed catalysts have been developed which chemically bind into the polyurethane foam matrix rendering them incapable of migrating back out of the foam once the reaction is complete. These catalysts meet the industry challenge of optimized foaming and provide no amine emissions.

New Alternatives for Flame Retarding Flexible Polyurethane Foam, P. Jacobs, F. Liu, P. Orizondo, M. Philips, R. Rose, Great Lakes Chemical Corp., Proceedings of The Polyurethane Foam Association, October 12, 2000.

Pentabromodiphenyl oxide based flame retardants are used extensively in North America to flame retard flexible polyurethane slabstock foams which meet the California Bulletin 117 furniture flammability standard. Two issues are currently beginning to have an impact on the use of this type of flame retardant. The first is concern about the human toxicity of pentabromodiphenyl oxide, and the second is concern about the use of halogenated compounds in general.

Although Great Lakes Chemical Corporation continues to believe that halogenated flame retardants and pentabromodiphenyl oxide offer a safe and effective means to protect people from the hazards of fire, they also feel an obligation to inform industry of events which may have an impact, and to offer alternative products. This paper describes work on a European risk assessment program, and the development of an alternative to pentabromodiphenyl oxide.

Work on a European risk assessment of pentabromodiphenyl oxide is essentially complete. Risk to human health is no longer an issue. The concern now is the potential for accumulation in the environment. It appears that this concern will lead to a ban on the use of pentabromodiphenyl oxide in Europe. A ban would restrict export to Europe of products, such as furniture, containing pentabromodiphenyl oxide.

The impact of a European ban on the US EPA's behavior toward pentabromodiphenyl oxide is unknown. Unilateral action by global corporations may limit its use.

Concern about the use of halogens appears strongest in Germany and Sweden. Great Lakes Chemical Corp. is aware of small amounts of halogen free, flame retardant foam being supplied to the automotive market in Europe. Reofos 95 is a halogen- free flame retardant currently being used in Europe to meet MVSS-302 flammability test criteria for automotive applications. These non-halogen flame retardants are considerably less effective and considerably higher in cost than commercially used halogenated flame retardants. The relative lack of concern about halogenated additives, combined with the significant cost penalty, makes non-halogenated use in North America unlikely. Barring a major shift in laws or attitudes in North America, the need for alternatives to halogenated flame retardants seems unlikely.

Great Lakes Chemical's developmental product, CN-2635, was created as an alternative to pentabromodiphenyl oxide. It has stable aromatically bound bromine to prevent scorch. The viscosity (177 cps.@ 20C) is lower than the viscosity of pentabromodiphenyl oxide blends used commercially.

The performance of CN-2635 was compared to that of a commercial pentabromodiphenyl oxide blend, DE-60F Special, in a California Bulletin 117 flexible slabstock foam formulation. Conventional foams were prepared at 1.2 and 1.8 pcf. density, and tested for physical properties, and flammability. The data indicate that the flame properties of foams having a density of 1.2 pcf. were marginally lower, requiring 21 php of CN-2635 vs.20 php. of DE-60F Special. Physical properties were similar. The overall efficiency of CN-2635 in foams, having a density of 1.8 pcf., was found to be identical to that of DE-60F Special. Cal 117 results were comparable at equivalent load levels and physical properties were essentially identical. No difference in smolder properties was observed between foams containing either the CN-2635 or DE-60F Special. There was no observable difference in processing or foam catalysis.

Based on these results, it was concluded that a viable alternative to pentabromodiphenyl oxide exists for California Bulletin 117 flexible polyurethane furniture foam. Although there is no mandate for change outside Europe, a solution is provided which satisfies industry desire for an alternative.

Automation in the Fabrication of FPF, Gail Vosburg, Ferry Industries, Proceedings of the Polyurethane Foam Association, October 12, 2000.

Ferry Industries is the world's largest manufacturer of Rotational Molding equipment. Ferry also manufacturers the FEMCO line of flexible polyurethane foam fabrication equipment and has the exclusive sales and manufacturing rights for the Wintech line of programmable foam cutters in the United States and Canada. Wintech is located in Western Australia and markets their equipment worldwide. This paper provides a description of manual foam fabricating practices compared with the use of automatic programmable foam cutting machines.

In the past, automation in foam fabrication was relegated to the large fabricators. A new line of cutting machines from Wintech International now makes programmable cutting machines affordable to the small foam fabricator. The typical advantages of automation in Flexible foam fabrication are:

  1. Substantial labor and overtime savings.
  2. Less training since fewer skills are required.
  3. Improved safety because the operators never get close to the oscillating blade and the cutting area can be effectively guarded.
  4. No patterns are required, therefore, the related problems of storage, changes and repairs are eliminated.
  5. More accurate costing computed by the programmable cutter.
  6. Fewer machines required. In a small shop or satelite operation one programmable cutter is all that is needed. It will do the work of a vertical saw, slitter, and contour cutter.
  7. Time savings through automatic cutting rather than a continual operator attendance required for a manual machine.
  8. Material savings with less waste as a result of optimized nesting of parts and common line cutting. Scrap reduction comes from precise and repeatable computer controlled cutting.

Automated cutting capability also allows you to provide more services to existing customers, service new customers which you previously couldn't, and frees up time to pursue new higher added value business.

A brief description of six programmable cutting machines made by Femco and Wintech is provided in the paper.

Activated Carbon Systems For TDI Emissions Abatement, W. J. Aldridge, Calgon Carbon Corporation, Proceedings of the Polyurethane Foam Association, October 12, 2000.

Activated carbon is widely used for various applications, and is highly effective for treating Toluene diisocyanate (TDI) emissions. It can be described as a hybrid mixture of a wide variety of graphite platelets that are interconnected by non-graphitic carbon bonding, organized in a random or amorphous fashion, with only slight localized ordering at the molecular scale. This paper discusses Calgon Carbon Corporation's work relating to the development and use of activated carbon systems for the treatment of TDI emissions associated with the polyurethane foam industry.

The overall adsorption process can be broken down into several steps that help illustrate how an activated carbon system works to adsorb contaminants, like TDI, from an air stream.

  1. First the TDI contaminant has to be transported through the air space to come into contact with the bed of activated carbon.
  2. Second the contaminant has to move across a very thin boundary layer at the surface of the carbon granule or pellet.
  3. Third the targeted contaminant moves into the carbon structure through an elaborate series of pores of decreasing size.
  4. Finally the targeted contaminant, such as TDI, makes its way to an adsorption site where it is adsorbed on the surface of the carbon.

All these steps are taken into consideration during the design of a properly engineered activated carbon system. Contact time between the air stream and the carbon bed must be adequate for all the steps above to occur. An improperly sized system where the air flow is too high or too low will result in lower than expected removal efficiencies and incomplete use of the carbon bed.

This document reviews a basic model of activated carbon and how Calgon Carbon Corporation has demonstrated its effectiveness in treating TDI emissions. The current approach to treating TDI emissions involves a properly engineered deep bed of activated carbon. This technology has been proven to remove in excess of 95% of TDI emissions where it has been applied.

End of Life Value-A New Approach to Recycling, Ivan Vanherpe, Salyp ELV Center, Proceedings of the Polyurethane Foam Association, October 12, 2000.

Salyp ELV (End of Life Value)is a recycling company based in Belgium. They are newcomers to the recycling industry, having started in 1997. Their company is rooted in automotive businesses, and their objective is to encourage breakthroughs in recycling based on technology and market intelligence, and take initiatives to implement sustainable solutions for post-consumer goods.

Salyp ELV has launched technology for the continuous scanning of input waste for contamination by PCB, Pb, Hg, using electronic sniffing sensors (e-noses). They have also pioneered the separation of complex bulk mixtures, revaluing open celled foams by separation and cleaning, and revaluing plastics by thermoplastic-sorting (tps) and rubber separation.

The total metals value of a mid-size end of life vehicle has been estimated at $ 64.35 and the total plastics and PU-foam at $ 73.99. The caloric value of the plastics from an end of life vehicle is estimated at $ 6.50 based on the prediction that the caloric value of mixed organics from Auto Shredder Residue (ASR) could be transformed, and could achieve the same price as natural gas.

Plastics and PU-foam in post consumer goods and ASR can be regarded not as a threat, but as a business opportunity for auto parts dismantlers, Shredder operators, plastic converters, and auto manufacturers. The End-of-Life-Value of plastics is the driving force to open up new markets.

CarDio™ AIRLESS—Quality plus Production Flexibility, Tony Griffiths, Cannon Viking Ltd. Proceedings of the Polyurethane Foam Association, October 12, 2000.

The gatebar principle, for mixing and metering of chemicals has proven to be very successful in the production of carbon dioxide frothed flexible polyurethane slabstock foams. The gatebar slot provides the controlled pressure drop to atmospheric pressure required when the carbon dioxide comes out of solution, forming a froth. The full width froth laydown provided by the gatebar ensures good block shape. The relatively large dimensions of the slot (used for pressure let down) allow processing of materials which are difficult to handle. These include powders, polymer polyols, and other particulate materials.

CarDio Airless is a further extension of the gatebar principle. The outlet of the laydown device is machined to create turbulence in the high velocity stream of chemicals as it exits. The chemical stream contains dissolved carbon dioxide, which is in a state of super-saturation. The turbulence causes small amounts of the dissolved carbon dioxide to be extracted in the form of minute bubbles, finely dispersed in the chemical stream, forming nucleation sites. The introduction of turbulent nucleation by CarDio Airless has enabled nucleating gas levels to be drastically reduced.

CarDio Airless has been in full production at NIR, Italy for more than six months. It has recently been introduced into regular production at another Italian foamer.

This paper describes the production flexibility of the gatebar principle using several examples of production runs which include melamine powder, calcium carbonate, ground PU scrap, MDI prepolymers, and polymer polyols.

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