products indicated that no unreacted TBTO was present. A film of each 

 organotin resin was cast on an Irtran 4 plate, and the spectrum of each 

 was recorded on a Beckman IR-7 Spectrophotometer. Each spectrum was 

 quite similar to that of the unreacted resin from which it., came except 

 that a new absorption peak occurred for each near 1650 cm . Cummins 

 and Dunn [11] report that liquid organotin carboxylates have an infrared 

 absorption peak near 1640! cm". A comparison of spectra of the two 

 original alkyd resins with those of the phthalic acids used, as well as 

 those published for phthalic acids [12], was used to identify each alkyd 

 resin as to the type of phthalic acid present. 



Table 1 . Organotin Products Synthesized 





Type of 



Original 



Percent 



No. 



Product 



Acid 



Tin in 





Reacted 



Number 



Product 



1 



ortho-phthalic alkyd 



54.7 



9.2 



2 



isophthalic alkyd 



25.7 



4.8 



3 



ortho-phthalic alkyd 



6.6 



1.4 



4 



isophthalic alkyd 



5.7 



1.2 



5 



fish oil isophthalic alkyd 



4.8 



0.9 



6 



linseed oil acids 



198.0 



21.0 



LABORATORY TESTS ON RESISTANCE TO FUNGAL GROWTH 



It has long been recognized [13] that limitations exist on laboratory 

 testing of paint films for resistance to fungal growth, but at least 

 two standard tests [14,15] are currently finding use. Their findings 

 cannot be translated into effectiveness in the field, but they can still 

 provide valuable basic information on resistance of materials to fungal 

 growth. 



The laboratory test used in this study was a modification of Federal 

 Test Method 6271.1 [14]. All three species of fungi listed in the 

 Federal Test Method, Aureobasidium pullulans, aspevgillas nigev, and 

 aspevg-Vttus ovyzae, were used. The resins tested were both the original 

 and the modified resins of Table 1. They were run with metal driers 

 alone and with metal driers plus pigmentation. 



The paint tested was applied to a sheet of mylar (polyethylene 

 terephthalate) plastic at a wet film thickness of 0.003 inch (0.008 cm). 

 After the paint had dried hard, the sheet was cut into several 4 cm 

 squares. These squares were then placed on sterile culture plates 

 containing a mildew test medium (Table 2) . Inoculation was achieved 



