IL33992A - Fire-retardant polyester resins - Google Patents

Description

polyester DEAD SEA WORKS LIMITED The inventors Theodor Stanley Scherf This invention relates to polyester resins containing In accordance with accepted polyester resins so protected against quick burning will be referred to hereafter as retardant for Encyclopedia of Polymer Science and page It is known that can be imparted to polyester resins by the admixture of organic chlorine or bromine Bromine compounds are known to be more effective than chlorine but their use has the back that organic bromine compounds undergo photochemical decomposition more readily than do organic chlorine whereby bromine compounds are produced which are apt to be lost from the resin by diffusion and evaporation washing This invention has the object to provide retardant polyester resins in which the effect of bromine compound additives is enhanced and the danger of their photochemical decomposition is It has surprisingly been found that both these aims are achieved if the polyester resins contain both retardant organic bromine compounds and finely distributed carbo It is presumed that the carbon has a synergistic action on the bromine for it has been found that the same proportion of added bromine compound has a stronger effect on the polyester resin in the presence of the carbon than in its effect is all the more surprising as the addition of carbon by in the absence of a Increases the flammability of polyester the present invention enables the addition of finely distributed carbon as a filler of polyester resins without increasing the of the Though such addition of carbon is desirable from several points of for making the resin more opaque and giving it a better esthetic it could not be resorted to up to now because of the increased flammability imparted to the resin by the The esthetic ment is highly desirable in especially where the polyester resin is with glass since the latter tend to show in the final product and to make the product unless the resin is made Although various kinds of finel distributed carbon can be used for the purposes of this carbon it is found that activated charcoal has an increased synergistic action on the effect of the bromine The difference in effect of various kinds of carbon is not yet fully understood though certain available experimental data tend to warrant the assumption that the carbon is the more effective as a increasing synergist for organic bromine the better it acts as an adsorbent towards these bromine The conventional kinds of polyester resin that can be rendered by the combined addition of bromine compounds and carbon in accordance with the include linear and additives are preferably admixed to the liquid commercial resin though the addition may even be effected to the It is even possible to use the bromine compounds in the form of substances that take part themselves in the ization and become part of the structure of the All organie bromine compounds known to have properties can be used for the purposes of this Inorganic bromine such as ammonium could als be used in principle but they do not mix well with the The amount of carbon which can be added is usually limited by the fact that carbon interferes with the hardening of the polyester admissible upper limit will have to be ascertained empirically for any given kind of polyester a proportion of up to of carbon has no adverse effect on the Bromine compounds may be for at Br levels of preferably depending on the degree of The aforesaid proportions of carbon and bromine are calculated on the weight of the mixture of carbon and bromine The appropriate proportion of Br also depends on proportion of carbon the higher the proportion of the more bromine is The sequence of mixing the the carbon and the bromine compound has no effect on the properties of the final The invention is illustrated by the following Examples to which it is not EXAMPLE 1 The used a product by Makhteshim Chemical The consisted of weight of a condensate of phthalic anhydride and propylene glycol in the molar ratios of and of st A was prepared g of g of activated charcoal g of polyester g The bromine content of the mixture was by 100 g of the mixture was admixed with ml of a solution of cobalt naphthenate in benaene and 2 ml of ketone in order to bring about the final polymerization and hardening of the The product was a virtually inflexible Its was tested by the US standard D Por this slabs 146 ram ma wide and mm thick were In this which is a measure of the rate of flame sample is held with the longitudinal axis horizontal and the transverse axis inclined by to the One edge of the sample is e posed to the flame of a burner for 30 and if the sample proves to be it is again exposed for 45 seconds to the Bunsen burner The results are g uped in four extinguishing I in which case the sample is quickly exposure to the flame for both the 30 and 45 second and II in which case a large portion of the sample had upon extinguishment of the flame from either the first 50 second period of exposure to the flame or the aubsequent 45 second With the particular mixture of additives of this of bromine and of the test slabs proved to be Comparative tests were raade as the same bromine compound of no carbon of no bromine Comparative test shows that in the absence of a proportion of bromine higher by than in test gives a definitely inferior as against The resin containing carbon but no bromine burned freely 2 The composition of Example 1 was varied in that the was replaced by of the proportion of bromine in the mixture was by The results of the fire tests with the bromine compound and carbon with the same bromine compound of no carbon with of no bromine The samples prepared as described in Example except that the bromine compounds Example g of content of mixture by g of content of mixture Example g of content of mixture In all three cases the Br content of the samples for tost was by the amounts of the bromine compound were and per lOOg of the The result of the tests made with these samples are tabulated in the Table Example 3 Example Example 5 Test Test Test B B B in all these the presence of the carbon considerably enhanced the effect of the bromine compound in the absence of the had either virtually no such effect even at a bromine level tha was by higher than in the sample for test and or a much weaker effect insufficientOCRQuality

Claims (1)

1. polyester containing a retarding organic bromine compound finely proportion therei a proportion of carbon up to the herein polyester resins according Claim wherein the content of organic compound corresponds to a bromine level of 1 preferably 5 to by weight polyester resins according to Claim 1 wherein the carbon an activated o activated polyester resins according to Claims 2 or wherein the proportion of carbon is up to by weight of the an one o polyester according 1 to wherein organic bromine compound one of the polyester resins containing a retarding organic bromine compound and finely distributed aa described herein with reference to method for the preparation of polyester wherein the organic compound and carbon are admixed to the liquid and the mixture is finally polymerized with the aid of conventional polymerization catalysts insufficientOCRQuality