Question

What are the roles of these parameters in the pultrusion process of fibreglass? ( the three temperatures in hearing die, ambient temperature and relative humidity , line speed, weight percent of resin, weight percent of low profile additive, weight percent of the initiator, roving count )

Answer 1

Pultrusion is a process where raw material ( glass fibre reinforcements and resins) are drawn into a profile die by mechanical pulling force.

- the pulturation die consists of three parts an injection chamber, a heating zone, and a cooling zone. The glass fibre was preheated and arranged prior to entering the pultrusion die to avoid inhibition of polymerization by moisture on the cold fibres. The fibres were heated by the hot air at 150 degree C. And heat conduction from the metal tention rollers. Two heating techniques work together to ensure the removal of moisture from the surface of glass fibre. -Humidity has a large influence on gel coat resin and the curing effect, ideal humidity range from 40 to 60, if the manufacture of die relative humidity over 65, it should wait till the appropriate conditions for production and construction. It should always keep the ambient temperature same in the whole process that is 21-28 C. - the main problem with using thermoplastic matrices for composites is the difficulty in impreganeting fibrous reinforcements with high viscosity resins. With more powerful processing equipment even higher line speed could be achieved than that of 10m/Min. - pultrusion pulled the material through die the use of the die closely control resin: fibre ratio and pulturation has the ability to manufacture composite with high fibre ratio. Die contains the resin bath. The composite is cured in a die and composite have higher volume of fibre hence the weight percent of resin is low. - the low profile additive composition is disclosed which comprises ethylene glycol, at least one nonpolar diol, adipic acid and trimellitic anhydride. The low profile additive when included in an unsaturated polyester resin system, for use in making sheet molding compositions. - initiator are not used effeciently in free radical polymerization. A significant proportion of the primary radicals and that are generated are not captured by monomers. - fibre roving are drawn from the rear of the machine, the are guided into position, passed through a resin bath and then trough a die.