Literature

Proceedings of the Polyurethane Foam Association Technical Program May and October, 1993

Testing Furniture Composites for Flammability Using an Oxygen Index Calorimeter, D. B. Parrish & S. A. Browning, Dow Chemical, Proceedings of the Polyurethane Foam Association, May 13, 1993.

California, Illinois and Ohio have established the full scale TB-133 flammability test for public occupancy furniture under their jurisdictions. This regulation is also under consideration by several other states. A search was initiated for a small-scale flammability test which would permit furniture manufacturers to pre-screen candidate cushion materials prior to submitting their proposed products to the expense of full-scale testing.

The Oxygen Index Calorimeter (OIC), under development at the Dow Chemical Co., as a predictive small-scale flammability test, is introduced in this paper. It is presently intended as a low cost instrument for predicting the flammability performance of upholstered cushions for use in public occupancies. A description of the instrument calibration procedures for obtaining heat release numbers, and data from a number of cushion composite burns are provided. A number of full-scale mock-ups, burned at a single TB-133 burn facility, provided a means for comparing results from an Oxygen Index Calorimeter, The Cone Calorimeter, and the Ohio State University (OSU) Heat of Release Apparatus.

Some Causes for Yellowing in Textile Materials, David M. Hall, Auburn University, Proceedings of the Polyurethane Foam Association, May 13, 1993.

The causes for yellowing in textile materials, specifically carpets and upholstery fabrics, has been under investigation for years. Several potential causes have been identified. The most common cause appears to be the inappropriate use of optical brighteners (ultraviolet absorbers) in the cleaning agent (shampoos etc.). Brighteners can give an optical illusion effect with some colors, specifically gray or charcoal shades. In any case, the color is often dulled by their use because they act to overdye the textile assembly a blue shade. Other causes for yellowing include the use of chlorine bleaching agents, the use of highly acidic or basic or anti microbial treatments, among others. One of the best analytical methods to determine the causes for discoloration in textiles is Energy Dispersive Analysis by X-Rays (EDAX). Other methods include spectroscopic analysis after reproducing the discoloration. Scanning Electron Microscopy (SEM) among others.

Models for Foam Formulating, Lee F. Lawler, Arco Chemical Co., Proceedings of the Polyurethane Foam Association, May 13, 1993.

The properties of all water blown conventional polyether polyurethane foams are controlled by formulation and processing conditions, more so than individual component properties. For good quality, high air flow cushioning grades, used for furniture bedding or carpet pad, catalyst and surfactant effects are generally small. Therefore, only the major effects of water, index, and polymer solids need be considered. The term "polymer solids" is used interchangeably with "parts of polymer polyol" even though these two items differ by a constant factor. Processing conditions include those which impact foam breathability, structure and cell count.

The critical properties of foams are density and IFD. The general rule of thumb is that as water increases (density decreases) IFD decreases. This phenomenon is dependent on the amount of polymer polyol used and the actual amount of water in the formulation, i.e. foam density. At densities corresponding to between 2.5 and 4.0 php water, IFD increases with increasing water. If more than about 30 Parts of high solids polymer polyol, like Arcol® HS-100 is used, foam firmness always decreases with increasing water.

This paper quantifies the effects associated with water, polymer polyol, and isocyanate index through linear regression analysis of data generated using designed experiments which serve to separate interactions between direct variables. Density is modeled using its physical definition, density = mass/volume. Use of such a definition as a modeling base could allow more accurate extension to density ranges beyond the actual data range. Unfortunately, such a simple mathematical definition does not exist for IFD. However, accurate predictions of IFD are obtained using linear statistical modeling techniques. It must be remembered, however, that purely empirical models can only be confidently used over the specific data range from which the model was developed. Also, since catalyst and surfactant concentrations are not considered in the work, only quality "open" foams can reasonably be predicted. Foams "artificially" hard, due to low breathability, will not correlate with the models presented.

PURRC - A Flexible Polyurethane Foam Perspective, Andy Kirk, ICI Poylurethanes, Proceedings of the Polyurethane Foam Association, May 13, 1993.

Since the late 1980's, there has been a growing concern about the environment in general, and about the efficient conservation of resources in specific. Members of the Steering Committee of the Polyurethane Division of the SPI became concerned about the industry's customers' perceptions that polyurethanes, as thermosets, were non-recyclable. Polyurethane foam customers compared polyurethanes to thermoplastics and perceived that they were not recyclable since they could not be melted and reprocessed once molded.

In 1990, the Steering Committee formed the PolyUrethanes Recycling and Recovery Council (PURRC). The goal set for the PURRC was to reduce significantly the amount of polyurethanes being disposed to landfills. Among PURRC's objectives was 1) to establish parity when compared with alternative materials for which recycling was not perceived to be a problem; 2) recycle polyurethanes to remove the perceptions that they could not be recycled; and 3) create the environmental responsibility of polyurethanes as a positive design issue.

This paper discusses several processes for recycling, recovery and reuse of polyurethane foam. Among them are opportunities for removing and recovering and reusing flexible polyurethane foam from automobile seats and mattresses, adding reground flexible foam scrap to slab foam, chemical recycling and energy recovery.

Emissions and Emission Control for Flexible Polyurethane Foam, Bert Veenendaal, RAPPA Inc., Proceedings of the Polyurethane Foam Association, May 13, 1993.

This paper provides an assessment of the emissions generated during the manufacture of flexible polyurethane foam, the current status of control technologies, and recommendations for controlling these emissions.

The True Cost of Meeting California TB-133, H. Talley, The Hugh Talley Co., Proceedings of the Polyurethane Foam Association, September 30, 1993.

The costing of furniture products is a difficult task because of the style/fashion requirements and the need to remain competitive. Costs and cost ramifications are some of the least understood subjects in all areas of upholstered furniture. Both industry people and non-industry people have tried to use a simple percentage increase number to represent the cost increase of making all furniture, which passes TB-133. When using this approach, it must be remembered that the percentages must be accompanied by a great deal more information in order to be meaningful and useful.

Examples are provided in this paper demonstrating the cost increases associated with making stacking chairs and sofas which pass the TB-133 Flammability Test. Information is presented on the effects of using different manufacturing possibilities such as types of barriers, fabrics, flame retardant foam, back coatings and other ways to meet TB-133, on the final cost of the furniture.

New Ultrasoft Low Density Foams as Alternatives to Fiber Batting, S. L. Hager and R. D. Duffy, Arco Chemical Co., Proceedings of the Polyurethane Foam Association, September 30, 1993.

Polyurethane foam and polyester batting are cushioning materials that have found widespread use in a variety of applications. In some cases they compete for the same market, in others they are used together in a complementary fashion, while in still others one or the other is dominant for performance or cost reasons. Foam has tended to be the dominant material in those applications requiring higher load bearing and/or long term durability such as cushion cores, carpet pad and mattress toppers. Fiber batting has intended to dominate lighter duty applications requiring high filling efficiency or a very soft surface such as comforters, toys, loose backs and cushion wraps.

A new foam formulating technology is introduced in this paper, Softcel™ foam, that allows the production of ultrasoft low density polyurethane foam having cushioning characteristics closer to that of fiber while maintaining the durability and other performance characteristics of foam. This new foam is a major extension of the Ultracel® slabstock technology. A variety of slabstock grades have been produced on either full scale or pilot scale machines. The full grade range possible with this technology using auxiliary blowing agents is expected to run from below 1.0 pcf to 1.8 pcf with IFDs ranging from about 5 to 20. Auxiliary blowing agent requirements to soften the foam are substantially less than for conventional foam and can be totally avoided in many grades. The limited data available at this time indicates that these foams perform well in small scale ignition and smolder resistance tests such as CAL TB117 and the UFAC Barrier Test. Comforters produced with low density soft foam grades have exhibited feel and drape comparable to fiberfil but with improved durability.

Texaco Chemical Company, Propylene Oxide Business Entry, J. Lemonds, Texaco Chemical, Proceedings of the Polyurethane Foam Association, September 30, 1993.

This paper introduces Texaco Chemical Company's entry into the propylene oxide business with a new world class facility presently being constructed at their flagship Neches Chemical Plant in Jefferson County, Texas. Propylene oxide is the building block chemical from which polyether polyols are made.

Propylene oxide design capacity is 400 million pounds per year. Coproduct MTBE is 1.3 billion pounds, or 15,000 barrels per day in motor gasoline terms. Total capitol for this project, including working capital, exceeds five hundred million dollars. Mechanical completion is expected in the third quarter of 1994.


California TB - 133 - The Nemschoff Approach, Mark Nemschoff, Nemschoff Chairs, Proceedings of the Technical Program of the Polyurethane Foam Association Meeting, Quebec City, Quebec, September 30, 1993

This presentation discusses FR compliance misconceptions dealing with issues such as how FR additives affect furniture cost, lead time for furniture production, furniture durability, and product warranties. A case is made for Calif. TB 133 compliance.

Various research strategies to determine code compliance are provided. Techniques for creating Calif. TB 113 compliant furnishings are also explained.

California Technical Bulletin 117 Revisited, S. E. Wujcik, T. M. Smiencinski, R. F. Pask, BASF Corporation, Proceedings of the Polyurethane Foam Association, September 30, 1993.

During the past 20 years, more than 30 flame tests have been developed. These range from a simple measure of the amount of oxygen needed to support combustion to full scale furniture burns under controlled conditions. The California TB 117 flame test, by far, is the most frequently run standard furniture flame test. It has been around for more than ten years.

The requirements for passing TB 117 are fairly easy to meet. The addition of a small amount of a chemical, usually a halogenated phosphate flame retardant metered in during foaming, is all that is required. Most of these chemicals have little effect on the foam process or the foam grades produced. More recent flame tests, such as BS-5852, Part II, Crib 5 or CAL TB 133 are much more involved. In order to pass these tests it is necessary to make significant changes in equipment and the chemical formulas.

This paper describes the scope of the California TB 117 flame test along with a procedure for Resilient Cellular Materials and formulations for producing flexible polyurethane foams.

Predictions of TDI Emissions from Flexible Foam Production Line, H. Metcalf, F. Sweet, Dow Chemical USA, Proceedings of the Polyurethane Foam Association, September 30, 1993.

Governmental regulation (federal, state, and local) of industrial emissions is expected to increase over the next few years. Regulations relating to the control of or tax on emissions of TDI from flexible slabstock polyurethane foam production lines, are possible. As a result, it has become increasingly attractive, if not necessary, to develop a method for predicting TDI emissions from the exhaust stacks for such facilities. Data from seven full-scale production facility emission surveys were entered into a database and analyzed per statistical method techniques.

The data included information on foam grade and formulation, component flow rates, run times, ambient conditions, and TDI emission levels. The 2,4- and 2,6- TDI emissions were measured from the pour line exhaust stacks by The Dow Chemical Company Health and Environmental Sciences personnel, utilizing EPA recognized methods.Two preliminary mathematical models have been developed to calculate the expected TDI emissions based on foam formulation, plant and ambient condition information. The resulting models allow a foam production facility to predict the total 2,4- and 2,6- TDI emissions from a given set of foam formulations using ambient condition information for the day on which the foam is produced.

The use of Unilink 4200 in Flexible Polyester-Based Polyurethane Foams, D. W. House, R. V. Scott, Jr., United Oil Products, Proceedings of the Polyurethane Foam Association, September 30, 1993.

Unilink® 4200, 4,4-bis-(secbutylamino) diphenylmethane, is a proprietary UOP additive that reacts in a urethane foam formulation to increase both the level of urea groups present and the hard segment content. As an aromatic secondary diamine, it reacts with the polyisocyanates to produce linear polymer chains. Although primary amines are known to react too rapidly for use in flexible foam formulations, the liquid Unilink 4200 has a reaction profile more similar to the polyol/isocyanate reaction.

Polyester-based urethane foams are typically chosen over polyether-based foams in applications requiring greater load-bearing, higher tensile strengths, and higher elongation. The use of Unilink 4200 in typical polyester-based formulations has led to even grater increases in these three important areas without increasing foam density. In general, the use of Unilink 4200 led to increases in load bearing of about 30% at 25% deflection and 40% at 65% deflection. Tensile strengths (both perpendicular and parallel to foam rise) increased significantly with Unilink 4200, and this increase was greater at higher densities. Elongation was only slightly improved at lower density; however, at 3.2 pcf (51kg/m(3)), the elongation was 45% greater perpendicular to foam rise and 58% greater parallel to foam rise.

Typically, efforts to increase tear strength in foams have usually been at the expense of other properties such as elongation. The use of 5 php of Unilink 4200 led to an average increase of over 40% throughout the entire density range studied, and did so without adversely affecting elongation. Though air flow was lower when Unilink 4200 was added to the formulation, there was no shrinkage of the uncrushed foam. All of these benefits have been obtained without increasing foam density above that of the control foams (without Unilink 4200).

In the present work, polyester foams representing densities ranging from 1.6 to 3.4 pcf (28 to 54 kg/m(3)) were studied as a function of density, blowing catalyst, surfactant, and Unilink 4200.

Auxiliary Blowing Agent Substitution in Slabstock Foams, C. Fiorentini, Cannon Group, T. Griffiths, TG Cellsoft Ltd., M. Taverna, Cannon Group, B. Collins, Cannon USA, Proceedings of the Polyurethane Foam Association, September 30, 1993.

As the pressure to eliminate chlorinated products such as Chlorofluorocarbons, methylene chloride, 1,1,1,-trichloroethane etc. (CFC's) from the environment increases worldwide, it is becoming necessary to eliminate them from polyurethane foam production. These additives have already been banned in some countries. The impact on the flexible foam industry would be to increase foam prices and to eliminate certain soft grades.

The use of liquid carbon dioxide (CO-2) as an auxiliary blowing agent in a polyurethane foam is a good and well accepted idea. Handling this liquid, which is a gas at room temperature, has always been one of its main problems.

Cannon has developed a new process for manufacturing flexible slabstock foams without the use of CFC's. This revolutionary new process called CarDio® (from carbon dioxide), has been able to completely eliminate the use of CFC's and other volatile Organic compounds (VOC's) from flexible foam slabstock production. This has been done without sacrificing the foam's physical mechanical properties. The CarDio process also dramatically reduces the size requirements for foaming plants, thereby allowing all the advantages derived from a reduced floor space and plant volume. Flexible slabstock foamers are able to continue producing their existing foam grades at a lower chemical cost due to the significant price differential between CFCs, ABAs, and carbon dioxide. Patents have been applied for the process

The Rapid Cure Process-Industrial Experience, Engineering and Formulation Principles, H. Stone, E. Reinink, S. Lichvar, W. Carlson, C. Sikorsky, General Foam, Proceedings of the Polyurethane Foam Association, September 30, 1993.

The concept of rapidly cooling freshly prepared flexible polyurethane foam in order to reduce space requirements and storage time in the plant has been recognized for a long time. Recently, growing concern about ozone depletion in the upper atmosphere, has led to a phase-out of chlorofluorocarbon blowing agents, and has placed new emphasis on developing alternative approaches for producing flexible slabstock foams.

The objective of the work, presented in this paper, is the development of a foaming process using only water as the source of gas for foam blowing. This approach presents two major problems. The first is the engineering problem of avoiding long exposures to the high temperatures encountered in using only water as the blowing agent, particularly for low density foams. The second is the problem of maintaining physical properties and performance for the full range of density and hardness grades of foam in industrial use.

The Rapid Cure Process basically consists of a series of cooling chambers over which the foam passes after completing its rise. At that time the hot gases as well as small amounts of volatile impurities are removed, and the foam is cooled to a safe temperature. The preferred cooling medium is air being drawn through the foam. The exhaust gases are treated in a carbon bed to remove trace impurities, including TDI, before they are discharged to the air.

One of the additional benefits of this process is a significant improvement in foam uniformity, particularly in uniformity of IFD throughout the foam block. Another is a general improvement in the plant atmosphere by elimination of trace contaminants in the air.

This paper describes equipment modifications for the full-scale foam production, and formulation developments, to optimize physical properties and processing, in the laboratory, pilot plant and on full-scale production runs.

After more than a year of commercial production experience with the Rapid Cure Process, General Foam has the ability to handle a variety of foam grades with little or no changes in physical properties from their previous standards. Engineering changes have also been introduced in the process to optimize performance.

Variable Pressure Foaming - A New Generation Foaming Technology, R. Triolo, Foamex, Proceedings of the Polyurethane Foam Association, September 30, 1993.

A new commercial process for foaming under variable pressure has been developed. The process offers numerous advantages, the first of which is that no auxiliary blowing agents are necessary to produce lower density foams. The formulation advantages now make density virtually independent of water concentration and auxiliary blowing agents. Foams can also be produced with high load bearing without the use of polymer polyols.

Commercial experience with the system has demonstrated that the foams exhibit superior physical properties. The resulting foam is more open, has better resilience, superior compression set, and better mechanical properties. There is also greater control over the density and hardness variation from run to run. The process is fully automated, offering superior control over the final product. The environmental advantages of the new system are that no auxiliary blowing agents are used, the reaction gases are treated before exhaust, and there are no isocyanate vapors in the production area.