| 摘要 |
<p>1,136,307. Moulding processes. BORDEN CHEMICAL CO. (U.K.) Ltd. 10 July, 1967 [26 July, 1966], No. 33658/66. Heading B3F. [Also in Division C3] Foundry moulds and cores are prepared by mixing and charging to a mould or core-box a moulding mixture comprising a granular refractory material and 0À5 to 5 per cent by weight of a binder comprising a liquid polyol of hydroxy value 100 to 600 mg. KOH/gm, a polyisocyanate in an amount sufficient to provide 0À8 to 1À5 isocyanate groups per OH group of the polyol and an amount of an accelerator sufficient to cause the moulding mixture to set within 5 minutes at 25‹ C. and finally allowing the moulding mixture to set while in contact with the mould or core-box. The mixture may be prepared from two separate sand sub-mixes. The mould or core-box may be warmed before the introduction of the foundry mix. In examples various foundry mixes are discharged into a cylindrical 2-inch diameter core-box and rammed three times with a 14 lb. weight dropped from a height of 2 inches before setting or alternatively the mixes may be charged to the cartridge of an air-operated core blower and blown into a mould or core-box.</p> |
