Compression induced crystallization of the crystalline polymer

摘要

The mass of amorphous crystalline polymer having a first thickness a (ft), ft: ng ratio is passed through a nip gap of counter-rotating rolls having at least 1.2 of the nip gap (ng), a polymer to produce a semi-crystalline polymer by crystallizing up at least 15% crystallinity and the crystallization method of the semi-crystalline polymer comprising to granulated. Strain crystallization of the sheet or fiber is no longer necessary due to the stretching the sheet or fiber by using a drafting process. High degree of crystallinity, even in the case of slow crystallization crystallization polyester, given almost instantaneously. This method allows extrusion of thinner crystallizable sheet, substantially retains the dimensional width of the sheet during passage through the compression rolls, moreover, substantially produce an optically clear sheets and pellets. Suitable polymers include polyethylene terephthalate or naphthalate homopolymer or copolymer.