News Details
Effect of flame retardant on PVC plastics
2017-11-6 11:43:03
Effect of flame retardant on PVC plastics
The addition of flame retardant in a certain proportion of PVC plastics can increase the oxygen index, and the flame retardant effect is obvious. Of course, the oxygen index of flame retardant materials but said combustible and flame retardant, flame retardant effect of PVC plastics should also adopt a series of parameters, such as heat, heat spontaneous combustion critical parameters of ignition energy, thermal self ignition temperature.
Generally speaking, when flame retardant plastics are used in the combustion process, the flame retardants act in various reaction areas (gas phase and condensed phase). For different materials, the role of flame retardants may also be different.
The mechanism of flame retardants is complex. But its purpose is to cut off the combustion cycle in both physical and chemical ways. The effects of flame retardants on PVC plastics are as follows:
(1) in the condensed phase flame retardant endothermic decomposition, so that the condensed relative temperature rise within the slow phase, in order to delay the thermal decomposition temperature of plastics, flame retardant heat generated by the decomposition of incombustible gas to reduce the temperature of heat of vaporization.
(2) flame retardant thermal decomposition, releasing trapped in the combustion reaction? OH (Qiang Ji) flame retardant free radicals, the combustion process is carried out according to the free radical chain reaction termination of chain reaction.
(3) under the action of heat, the flame retardant exhibits endothermic phase transition, which prevents the increase of the temperature in the condensed phase and slows down the combustion reaction until it stops.
(4) thermal decomposition of catalytic condensed phase produces solid phase product (coking layer) or foam layer, which hinders heat transfer. This leads to a lower level of condensed phase temperature, leading to a decrease in the formation rate of the gaseous reactants (decomposition products of flammable gases).
In a word, the effect of flame retardant can slow down the reaction rate of combustion, or make the reaction (thermal self ignition) become difficult, so as to restrain and reduce the harm of fire.
The physical effects of flame retardants on the performance of PVC plastic, when plastic is burned, delaying the temperature solid reaction zones with elevated speed, or the gas flame zone to the heat transfer area of solid phase reaction becomes difficult, the total effect of this physical process, the result is that the reaction zone temperature maintained at a low level the relative cooling.
It is very important to study the role of flame retardants from chemical reaction kinetics. The flame retardant can slow down the thermal decomposition in the condensed phase and reduce the rate of flame reaction. The former makes the thermal self ignition parameters (such as critical temperature and critical size) of condensed phase become larger, which makes combustion difficult. The latter decreases the exothermic rate of the flame reaction and inhibits the expansion and propagation of the reaction.
Tris(2-chloroisopropyl)Phosphate(TCPP)
The production process of flame retardant TCPP with the following steps:
(1) to three phosphorus oxychloride and epichlorohydrin by phosphoric acid, three in catalysis of AlCl3 (2, 3- two Lv Bingji) ester mixture.
(2) added to the mixed solutions of alkali, alkali washing to neutral, static stratified, removing water; reservoir water again after the static stratified, removing water, reservoir after distillation liquid phosphoric acid three (2, 3- two Lv Bingji) ester, and the nitrogen gas purification. This process has the advantages of simple preparation process, to produce phosphoric acid three (2, 3- two Lv Bingji) ester as compared with the existing production process of high purity, its quality detection results were better than the existing technology in the production process to produce phosphoric acid three (2, 3- two chloropropyl) ester.
Process the above description of the product, such as the flame retardant TCPP production technology to further understand please contact us.
The product is used for the soft / hard polyurethane foam, with thermal and hydrolytic stability good, especially suitable for ASTME84 (Level 11) foam, with low viscosity unsaturated polyester resin in low temperature application and phenolic plastics at. This product is also used to grab the foam sealant and sheet production. For polyvinyl chloride, polystyrene, phenolic resin, acrylic resin and rubber, coating, flame retardant, also used for soft and hard polyurethane foam, epoxy resin, polystyrene, cellulose acetate, ethyl cellulose tree and phenolic plastics, polyvinyl acetate and gun type foam sealant production. Particularly recommended for rigid polyurethane foam has excellent thermal and hydrolytic stability is particularly suitable for ASTM84 (II), compound for polyurethane foam and unsaturated resin and phenolic plastics.
Most of the phosphorus containing flame retardants are phosphorus containing organic or inorganic compounds, and the flame retardant effect is better than that of bromide. It is found that the phosphorus containing flame retardant can make the flame retardant material produce more coke, and reduce the amount of combustible volatile matter, and the weight loss of flame retardant material will be greatly reduced when burning.
At present, most of the flame retardants used in plastic foams are additive flame retardants, while reactive flame retardants are mainly used in thermosetting resins such as epoxy resins and polyurethane resins. Few flame retardants are used in actual flame retardant technology. Usually, several kinds of flame retardants are used to increase the flame retardant efficiency by using their synergistic effect.
In the test conditions specified, plastic materials can just keep the minimum oxygen concentration required for combustion state in oxygen and nitrogen mixed gas flow, the oxygen percentage (OI%). The oxygen index is high, maintaining the oxygen concentration required for combustion state is higher, more difficult to burn material.
At the same filling amount, the difference between the different ratio of the aluminum hydroxide, magnesium hydroxide flame retardant effect is not obvious, but the two kinds of composite is better than that when using, because all the dehydration reaction, but there are differences in decomposition temperature and heat absorption. Magnesium hydroxide needs to be dehydrated at higher temperatures and has a carbonation effect at the same time. Magnesium hydroxide absorbs less heat than aluminum hydroxide because of its inhibition of temperature rise, and the combination of them can supplement each other, and its flame retardant performance is better than that of single use. However, Mg (OH) 2 has the disadvantages of poor acid resistance, poor dispersibility and poor compatibility, so it is necessary to develop new varieties with good compatibility.
Flame retardant magnesium hydroxide (mghz-df) with hexagonal sheet microstructure, fine grain size (7000-7500 mesh), uniform particle size distribution, a special surface full modification has good lipophilic hydrophobicity, can good compatibility and high polymer material, dispersion and uniformity of high polymer materials in the.
Magnesium hydroxide flame retardant must be in accordance with the proportion of polymer materials and fully mixed evenly. For example, using magnesium hydroxide as flame retardant in preparation of flame retardant PP for Mg (OH) 2 in PP uniformly dispersed, the available high speed mixer, or buss kneader (busskenader), or German double screw extruder, reciprocating single screw or mixed mixing extruding machine, and the use of reasonable mixed feeding mixed mode. For example, all PP and toughening agents and the required amount of Mg (OH) 2 should be first added to the mixing mixer for several minutes, then mixed for 60% minutes, and then the remaining Mg (OH) 2 will be added second times.
Copyright: Zhang Jia Gang YaRui Chemical co.,Ltd
http://www.yaruichem.com
The addition of flame retardant in a certain proportion of PVC plastics can increase the oxygen index, and the flame retardant effect is obvious. Of course, the oxygen index of flame retardant materials but said combustible and flame retardant, flame retardant effect of PVC plastics should also adopt a series of parameters, such as heat, heat spontaneous combustion critical parameters of ignition energy, thermal self ignition temperature.
Generally speaking, when flame retardant plastics are used in the combustion process, the flame retardants act in various reaction areas (gas phase and condensed phase). For different materials, the role of flame retardants may also be different.
The mechanism of flame retardants is complex. But its purpose is to cut off the combustion cycle in both physical and chemical ways. The effects of flame retardants on PVC plastics are as follows:
(1) in the condensed phase flame retardant endothermic decomposition, so that the condensed relative temperature rise within the slow phase, in order to delay the thermal decomposition temperature of plastics, flame retardant heat generated by the decomposition of incombustible gas to reduce the temperature of heat of vaporization.
(2) flame retardant thermal decomposition, releasing trapped in the combustion reaction? OH (Qiang Ji) flame retardant free radicals, the combustion process is carried out according to the free radical chain reaction termination of chain reaction.
(3) under the action of heat, the flame retardant exhibits endothermic phase transition, which prevents the increase of the temperature in the condensed phase and slows down the combustion reaction until it stops.
(4) thermal decomposition of catalytic condensed phase produces solid phase product (coking layer) or foam layer, which hinders heat transfer. This leads to a lower level of condensed phase temperature, leading to a decrease in the formation rate of the gaseous reactants (decomposition products of flammable gases).
In a word, the effect of flame retardant can slow down the reaction rate of combustion, or make the reaction (thermal self ignition) become difficult, so as to restrain and reduce the harm of fire.
The physical effects of flame retardants on the performance of PVC plastic, when plastic is burned, delaying the temperature solid reaction zones with elevated speed, or the gas flame zone to the heat transfer area of solid phase reaction becomes difficult, the total effect of this physical process, the result is that the reaction zone temperature maintained at a low level the relative cooling.
It is very important to study the role of flame retardants from chemical reaction kinetics. The flame retardant can slow down the thermal decomposition in the condensed phase and reduce the rate of flame reaction. The former makes the thermal self ignition parameters (such as critical temperature and critical size) of condensed phase become larger, which makes combustion difficult. The latter decreases the exothermic rate of the flame reaction and inhibits the expansion and propagation of the reaction.
Tris(2-chloroisopropyl)Phosphate(TCPP)
The production process of flame retardant TCPP with the following steps:
(1) to three phosphorus oxychloride and epichlorohydrin by phosphoric acid, three in catalysis of AlCl3 (2, 3- two Lv Bingji) ester mixture.
(2) added to the mixed solutions of alkali, alkali washing to neutral, static stratified, removing water; reservoir water again after the static stratified, removing water, reservoir after distillation liquid phosphoric acid three (2, 3- two Lv Bingji) ester, and the nitrogen gas purification. This process has the advantages of simple preparation process, to produce phosphoric acid three (2, 3- two Lv Bingji) ester as compared with the existing production process of high purity, its quality detection results were better than the existing technology in the production process to produce phosphoric acid three (2, 3- two chloropropyl) ester.
Process the above description of the product, such as the flame retardant TCPP production technology to further understand please contact us.
The product is used for the soft / hard polyurethane foam, with thermal and hydrolytic stability good, especially suitable for ASTME84 (Level 11) foam, with low viscosity unsaturated polyester resin in low temperature application and phenolic plastics at. This product is also used to grab the foam sealant and sheet production. For polyvinyl chloride, polystyrene, phenolic resin, acrylic resin and rubber, coating, flame retardant, also used for soft and hard polyurethane foam, epoxy resin, polystyrene, cellulose acetate, ethyl cellulose tree and phenolic plastics, polyvinyl acetate and gun type foam sealant production. Particularly recommended for rigid polyurethane foam has excellent thermal and hydrolytic stability is particularly suitable for ASTM84 (II), compound for polyurethane foam and unsaturated resin and phenolic plastics.
Most of the phosphorus containing flame retardants are phosphorus containing organic or inorganic compounds, and the flame retardant effect is better than that of bromide. It is found that the phosphorus containing flame retardant can make the flame retardant material produce more coke, and reduce the amount of combustible volatile matter, and the weight loss of flame retardant material will be greatly reduced when burning.
At present, most of the flame retardants used in plastic foams are additive flame retardants, while reactive flame retardants are mainly used in thermosetting resins such as epoxy resins and polyurethane resins. Few flame retardants are used in actual flame retardant technology. Usually, several kinds of flame retardants are used to increase the flame retardant efficiency by using their synergistic effect.
In the test conditions specified, plastic materials can just keep the minimum oxygen concentration required for combustion state in oxygen and nitrogen mixed gas flow, the oxygen percentage (OI%). The oxygen index is high, maintaining the oxygen concentration required for combustion state is higher, more difficult to burn material.
At the same filling amount, the difference between the different ratio of the aluminum hydroxide, magnesium hydroxide flame retardant effect is not obvious, but the two kinds of composite is better than that when using, because all the dehydration reaction, but there are differences in decomposition temperature and heat absorption. Magnesium hydroxide needs to be dehydrated at higher temperatures and has a carbonation effect at the same time. Magnesium hydroxide absorbs less heat than aluminum hydroxide because of its inhibition of temperature rise, and the combination of them can supplement each other, and its flame retardant performance is better than that of single use. However, Mg (OH) 2 has the disadvantages of poor acid resistance, poor dispersibility and poor compatibility, so it is necessary to develop new varieties with good compatibility.
Flame retardant magnesium hydroxide (mghz-df) with hexagonal sheet microstructure, fine grain size (7000-7500 mesh), uniform particle size distribution, a special surface full modification has good lipophilic hydrophobicity, can good compatibility and high polymer material, dispersion and uniformity of high polymer materials in the.
Magnesium hydroxide flame retardant must be in accordance with the proportion of polymer materials and fully mixed evenly. For example, using magnesium hydroxide as flame retardant in preparation of flame retardant PP for Mg (OH) 2 in PP uniformly dispersed, the available high speed mixer, or buss kneader (busskenader), or German double screw extruder, reciprocating single screw or mixed mixing extruding machine, and the use of reasonable mixed feeding mixed mode. For example, all PP and toughening agents and the required amount of Mg (OH) 2 should be first added to the mixing mixer for several minutes, then mixed for 60% minutes, and then the remaining Mg (OH) 2 will be added second times.
Copyright: Zhang Jia Gang YaRui Chemical co.,Ltd
http://www.yaruichem.com
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