Air pollution increases price of rubber products ^ C H I C A G O ™ s year air poilu·

v tion will add ai at least $500 million to the estimated $7.8 billion tab paid by retail pur­chasers of U.S. rubber products. In­cluded are increased manufacturers' costs on these products which add upwards of $249 million, and product life shortened to the tune of $226 million. These estimates were reached by Dr. P. B. Stickney and W. J. Muel­ler of Battelle-Columbus Laboratories, Columbus, Ohio, after extensively studying those costs that can be charged to pollution. They described their results to the Division of Water, Air, and Waste Chemistry and have presented them to the National Air Pollution Control Administration.

Ozone is the principal pollutant ex­acting this toll on rubber products. Long known for its degrading effect on rubber, the oxygen alio trope occurs naturally at background levels of 1 to 3 parts per 100 million. But it is also a component of photochemical smog and as such sometimes reaches levels of 25 to 30 parts per 100 million in certain areas. Other air pollutants such as nitrogen oxides, sulfur dioxide, and hydrocarbons have much less of an effect on rubber products.

Styrene-butadiene rubber would be used in most cases where air pollution is not a problem. Hence, the two scientists start their cost estimates at the manufacturer's level by calculat­ing the added cost of using specialty polymers as against S BR, after estimat­ing to what extent specialty uses de­pend upon ability to resist ozone.

Cost. For neoprene the estimated use for ozone resistance is 46 million pounds out of the estimated 264 mil­lion pounds used in 1969 at a cost charged to pollution of $12.6 million. Similarly, butyl rubber use because of ozone was 31 million pounds out of 202 million pounds at a cost of $1.5 million ; ethylene-propylene-diene monomer (EPDM), 36 million pounds out of 121 million pounds, $2.34 mil­lion; chlorosulfonated polyethylene, 2.5 million pounds out of 30 million pounds, $0.8 million; and polysulfide, 3 million pounds out of 22 million pounds, $3.28 million. Specialty poly­mer use due to air pollution totals $20.6 million added yearly.

Antiozonants or waxes incorporated into rubber products also increase ozone resistance. From U.S. Tariff Commission data, antiozonants use fig­ures out to $34 million annually while half, or $5 million yearly, of wax use is charged to pollution. Other

estimated costs at the manufacturer's level include those for protective coat­ings, paper wrappings (for tires, for example), and R&D costs for greater resistance to pollutants, which all total $26 million.

Manufacturer costs were also es­timated by another approach through a questionnaire sent to some 60 com­panies making a variety of rubber products, asking for estimates of yearly spending to protect against pollution and the value of the products pro­tected. Extrapolated to the national level, the cost totaled $54 million.

Replacement. Early replacement of rubber products failing prematurely

because of air pollution also adds sig­nificantly to costs. The two scientists estimate that $218 million worth of rubber products yearly, or 3% of total production, have a shortened life. Es­timating that these products lost 25 to 50% of normal service because of air pollution, the actual yearly loss is put at $81 million. The Battelle-Co­lumbus scientists were unable to ac­curately estimate other significant costs: labor to replace products, and the cost of replacing entire subassem­blies when rubber products fail.

Totaling all costs, then, by either of two methods, shows that costs at the manufacturer's level are either $161 million or $167 million. With industry estimates indicating that a reasonable markup at retail would multiply these figures by three, the total national cost is placed at at least $500 million yearly.

Air pollution adds costs at manufacturer's level

Type of cost Specialty polymers Wax Antiozonants Calculated from questionnaire Replacement of failed products Miscellaneous (protective coatings,

wrapping tires, research)

Total

From questionnaire data, million dollars

— $54.0

81.4 26.0

$161.4

From compounding costs, million dollars

$20.6 5.0

34.0

81.4 26.0

$167.0

Nonmetallic stabilizers could broaden PVC's scope ^CHICAGO First details of a se­

ries of new non-metallic stabilizers for polyvinyl chlo­ride have been released by Stauffer Chemical Co. The stabilizers are ali­phatic and aromatic thiolcarboxylic acids and anhydrides. Currently being selectively field tested, they could broaden uses for PVC, particu­larly for packaging foods.

The major properties and advan­tages of the new developmental sta­bilizers were described by Stauffer's Dr. Walter Stamm to the Division of Organic Coatings and Plastics Chem­istry during a symposium on poly­vinyl chloride stabilization. In a separate paper, the primary short­coming of the Stauffer stabilizers—color development at high processing tem­peratures—and how this problem can be overcome were discussed by Dr. Lewis B. Weisfeld of Cincinnati Mil-

acron Chemicals, Inc., New Bruns­wick, N.J., one of several firms cur­rently evaluating the compounds.

The most widely used PVC sta­bilizers today are metallic—typically dialkytin, barium, cadmium, and lead compounds. Stauffer's work has been focused on nonmetallic compounds, however, since they may cost less and are much less toxic. Lower toxicity stabilizers could pave the way to wider use of PVC for packaging foods.

Stauffer's new developmental sta­bilizers provide better protection against heat degradation of PVC than other nonmetallics, Dr. Stamm says. More important, their heat stability as determined in the Brabender plasto-graph (which measures the melt vis­cosity of the PVC resin ) is about equal to the commercially used dialkytins.

Best performance. Dr. Stamm and his coworkers Adam F. Kopacki and

SEPT. 28, 1970 C&EN 55