| 摘要 |
<p>A mould for forming glass articles comprises a metal shell having a porous lining of glass or ceramic with a m.pt. >400 degrees C and thermal conductivity is not >0.005 J/cm. degrees K at room temperature, thickness 40-3000 mu and porosity 30-70%. Pref. materials are enamel or hollow glass spheres having a particle size is not >200 mu. In a modification the mould is lined with a thermal insulation layer of the above thickness and thermal conductivity, over which is laminated a porous layer of metal, glass or ceramic having a m.pt. >400 degrees C, th ickness 40-1000 mu and porosity 30-70%. Pref. the second layer is of sintered powder having particle size is not >200 u. The mould is used particularly for rotational blow moulding. The thermal insulation ensures a good surface finish on the moulded articles, while the outer layer provides abrasion resistance and long life. The controlled porosity of the surface ensures retention of the correct amt. of water.</p> |
