| 摘要 |
Polypropylene resin expanded particles comprising: a polypropylene resin as a base material resin, the propylene resin having at least two melting peaks on a DSC curve for a second temperature rise measured at a heating rate of 10 g/min with use of a heat flux differential scanning calorimeter (DSC), the at least two melting peaks including (i) a lowest temperature melting peak of not lower than 100� C. and not higher than 130� C. and (ii) a highest temperature melting peak of not lower than 140� C. and not higher than 160� C., the propylene resin having a resin DSC ratio change rate of 0.5%/� C. to 3.0%/� C., the expanded particles having two melting peaks in a DSC measurement made at a first temperature rise at the heating rate of 10 g/min, the two melting peaks including, (i) on a lower temperature side, a melting peak temperature of not lower than 100� C. and not higher than 130� C. and, (ii) on a higher temperature side, a melting peak temperature of not lower than 140� C. and not higher than 160� C. allow an in-mold foaming molded product to be produced of expanded particles that (i) have only a small change in expanded particle DSC ratio, the change corresponding to a change in foaming temperature, (ii) allow production of an in-mold foaming molded product at a very low mold heating steam pressure, (iii) exhibit low distortion, low shrinkage, and a wide range of heating conditions for molding, even if the mold heating steam pressure is increased, (iv) indicate a satisfactory moldability even in a case where the expanded particles are molded with use of, for example, a mold having a complicated shape, a large mold, and (v) keep its properties such as compressive strength, without being impaired largely, in a case where the polypropylene resin expanded particles are used to prepare an in-mold foaming molded product. |
