| 摘要 |
1343599 Moulding ribbed articles BP CHEMICALS Ltd 19 April 1971 [11 March 1970] 11588/70 Heading B5A An unsaturated polyester resin compound which may include a fibrous reinforcement is moulded by heat and pressure to form a panel of thickness 2t, in cms., having a fair face and an opposing face with symmetrical ribs of root width L, in cms., integrally moulded thereon, the shrinkage coefficient C of the ribs is less than 0À5 x 10<SP>-7</SP> as determined by the expression C = 2LW - W<SP>2</SP>/8Gt where G is the shear modulus of the compound expressed in grams/cms.<SP>2</SP>, in the cured state and W, in cms., is equal to the dimension IM in the figure. The figure shows a cross-section through a panel ABCD of thickness 2t with an integrally moulded rib AEB. FGH is the outline of the ribbed section of the panel reduced by half the panel thickness t in all directions and IJKM is the theoretical equivalent rectangle having the same area and height. Thus IM i.e. W is the base of the equivalent rectangle. |
