Application Study Of Halogen-free Flame Retardant In Rubber

With excellent properties,such as high elasticity and electrical insulation,rubber materials were widely used in daily life.However,the flame-retardant properties of rubber was insufficient.To meet the requirements of rubber flame retardant under specific conditions,it was of great significance to study the flame-retardant modification technology of rubber.The traditional way of flame retardant was to add flame retardant to the rubber.The flame retardants can be divided into halogen-containing flame retardants and non-halogen flame retardants according to the classification.Halogen flame retardants release toxic and harmful gases due to thermal decomposition in the flame-retardant process.These gases pose a threat to the safety of people’s lives and property.In this paper,the effects of flame retardants Al（OH）₃,Mg（OH）₂ and encapsulated red phosphorus on the performance of vulcanized rubber were studied.Then,effects of expandable graphite and intumescent flame retardants（IFR）on the performance of vulcanized rubber were researched.In the study of metal hydroxide and coated red phosphorus flame retardant,the effect of silane coupling agent modified aluminum hydroxide and aluminum hydroxide with different particle sizes on the performance of vulcanized rubber were studied at first.Then the effects of compounding Al（OH）₃-Mg（OH）₂ and compounding hydroxide flame retardant with encapsulated red phosphorus on the properties of vulcanizates were studied.Finally,the effect of Al（OH）₃-Mg（OH）₂-coated red phosphorus on the properties of vulcanizates was investigated.The results show the best outcome with KH550 for modification of 2500 mesh aluminum hydroxide.The best flame retardant formula:Al（OH）₃ at 16 phr,Mg（OH）₂ at 24 phr,covered red phosphorus at 10 phr.At this time,the tensile strength of vulcanized rubber was 10MPa,the elongation at break was 347%,the ultimate oxygen index reaches 27.8%,and the vertical combustion grade reaches V-0 level.In the study of expandable graphite flame retardan,the effect of expandable graphite on the performance of vulcanized rubber was investigated firstly.Then the effect of expandable graphite and zinc borate and ammonium polyphosphate on the performance of vulcanizates rubber was investigated.The results showed that the best flame-retardant formula:zinc borate at 4 phr,ammonium polyphosphate at 6 phr,expandable graphite at 20 phr.At this time,the tensile strength of vulcanized rubber was 9.4 MPa,the elongation at break was 334%,the ultimate oxygen index reaches 28.3%.In the study of intumescent flam retardant,the synergistic effect of each component of expandable flame retardant was studied firstly.Then the phenolic resin was used as the carbon source.The effect of phenolic on the performance of vulcanized rubber was studied.The results showed that the best flame retardant formula on starch was used as a carbon source:starch at 28phr,melamine at 12 phr,ammonium polyphosphate at 18 phr.At this time,the tensile strength of vulcanized rubber was 10.3 MPa,the elongation at break was 357%,and the ultimate oxygen index reaches 28.2%;When phenolic was used as a carbon source,the best flame retardant formula:phenolic at 17 phr,melamine at 12 phr,and ammonium polyphosphate at 18 phr.At this time,the tensile strength of vulcanized rubber was 11.6 MPa,the elongation at break was 289%,and the ultimate oxygen index reaches 28.3%.