Melt dripping

This phosphinic anhydride [15171 -48-9] C H O P, is then reacted with glycol and other precursors of poly(ethylene terephthalate), to produce a flame-retardant polyester [82690-14-0] having phosphinate units of the stmcture —0P(0)(CH2)CH2CH2C00—. Trevira 271 is useflil for children s sleepwear, work clothing, and home flirnishings. A phosphoms content as low as 0.6% is reported to be sufficient for draperies and upholstery tests if melt-drip is not retarded by print pigments or the presence of nonthermoplastic fibers (28). 

Thermoplastic Fibers. The thermoplastic fibers, eg, polyester and nylon, are considered less flammable than natural fibers. They possess a relatively low melting point furthermore, the melt drips rather than remaining to propagate the flame when the source of ignition is removed. Most common synthetic fibers have low melting points. Reported values for polyester and nylon are 255—290°C and 210—260°C, respectively. 

Regulatory Legislation. In Febmary 1978, the Consumer Products Safety Commission approved changes in the FF-3 and FF-5 standards for children s sleepwear. It eliminated the melt—drip time limit and coverage for sizes below 1 and revised the method of testing the trim. This permits the use of untreated 100% nylon and 100% polyester for children s sleepwear (157—162). 

The details of the development of the EBRD process have been described by Pietsch et al.[187] There are two alternative operation modes in addition to the above continuous non-contact mode. The first one may be referred to as continuous contact atomization. In this mode, liquid metal contacts the bottom surface of the container instead of melt dripping, and then flows continuously from the center to the rim of the container. The second one may be termed discontinuous non-contact atomization. In this mode, the container is first filled by dripping melt while it is rotating at a very low speed of about 3 x 10-3 radians/s. The rotating speed of the container is then enhanced to about 14 radians/s while the metal or alloy is remelted and atomized. More than one focused electron beam may be used to provide energy for melting metal. 

Polymers form the basis for fire-resistant textiles. For instance, many of the firefighters and race car drivers wear clothing made from aromatic nylons because these materials resist melting, dripping, supporting combustion in air, or burning. 

The melt-dripping behavior of various ethylene-acrylate formulations with chalk and silicone have also been addressed by exposing these formulations to a Bunsen burner. It has been demonstrated that viscosity plays a crucial role in this process by affecting the transport of volatile gases, eventual dripping, and the formation of the intumescent structure.32... 

Fire testing was performed according to 14 CFR Part 25 for heat release rate (HRR), smoke density, and flame resistance [22], HRR was measured using retaining wires on the sample holder in an attempt to prevent melt dripping. At least two samples were tested and averaged to obtain reported values. 

As nitro compounds of toluene the low-melting drip oils from TNT manufacture containing di- and trinitrotoluenes may be used. 

Polyester fabrics when burned exhibit a melt-drip behaviour. Since the fabric melts away from the flame, some polyester fabric constructions can actually pass vertical flame tests without any flame-retardant treatment. The waiving of melt-drip specifications for children s sleepwear has allowed untreated polyester garments to be sold into that market. 

Three things must be pointed out at this time At first there is an additional component of heat transfer due to diffusion from the air stream through the porous frost which must be added to the derived conductivity expression this component appears to be proportional to the rate mjAy but disappears when the frost becomes sufficiently dense (indicated by the increased conductivity shown in Fig. 8). At about the same time, the expression for density (10) also breaks dowm and the net mass transfer becomes much smaller due to melting, dripping, etc. Some of the runs checked seemed to go through this transition at a density of about 35 Ib/ft. Exact expressions for frost properties will be difficult to obtain because we have observed two kinds of frost on the test section where the boundary line was at the separation point on the cylinder. In fact, Pingry, et al. p] reports three kinds of frost formation and the data tend to indicate that the properties differ somewhat for the different kinds of frost. 

Cellulose acetate Yellow-green, sparks Acetic acid, burnt paper Melts, drips, bums rapidly, chars, acidic fumes... 

Any break through, melting, dripping, charring, embrittlement, shrinkage, or other ignition phenomena are also recorded. 

Melting, dripping, and ignition of materials in close proximity to the sample by the hot burning molten droplets... 

Char/melt Melts Melts Melts, drips Melts, drips Melts Chars Chars... 

Melamine and its derivatives are effective fire retardants for pure nylons because they provoke melt dripping and extinction of the flame without combustible drops, whereas the melamines are ineffective in the reinforced nylon-6 [143]. In the framework of a systematic mechanistic study of halogen-free fire retardant nylon-6, combustion performance and thermal decomposition behavior of non-reinforced nylon-6 with added melamine, melamine cyanurate, melamine oxalate, melamine phthalate, melamine pyrophosphate or dimelamine phosphate were studied [144],... 

B8.1 The appropriate current (type and magnitude) should be selected for the electrode size to be used. Too great a current will cause excessive melting, dripping, or volatilization of the electrode. A welding current which is too low to properly heat the electrode tip may cause instability of the welding arc or inability to maintain a welding arc. 

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