Patent ID: 8815994
Filing Date: 2014-08-26
Classification: B29C,B29K,C08J

Abstract:
1. A heat-shrinkable polyester-based single-layer film, comprising a polyester-based resin matrix including a repeating unit of 2,2-dimethyl(-1,3-propylene)terephthalate and particles dispersed in the resin matrix, wherein the film has a haze of 80 95%, a haze deviation of within ±5% of an average haze over an entire width of a film roll, a shrinkage of 40 80% in a maximum shrinking direction upon treatment with warm water at 90° C. for 10 sec, and a shrinkage deviation of within ±5% of an average shrinkage in the maximum shrinking direction, wherein the heat-shrinkable polyester-based single-layer film is manufactured by a method of extruding and stretching a polyester-based resin, comprising: compounding particles having an average particle size of 0.1-5 μm and a 2,2-dimethyl(-1,3-propane)diol copolyester resin having an intrinsic viscosity of at least 0.6 dl/g to give a polyester-based resin master batch containing the particles, wherein the particles are included in an amount of 10-70 wt % based on a total weight of the master batch; mixing and extruding the polyester-based resin master batch containing the particles and additional 2,2-dimethyl(-1,3-propane)diol copolyester resin to produce an unstretched polyester-based sheet, wherein the particles are included in an amount of 2-10 wt % based on a total weight of the sheet; preheating the extruded polyester-based sheet; and stretching the sheet in a transverse direction at 65-100° C., and wherein the manufacturing the master batch comprises: providing a mixture of the 2,2-dimethyl(-1,3-propane)diol copolyester and the particles; placing the mixture in a twin-screw extruder or a kneader so that the mixture is melted and mixed to give polyester-based master batch chips containing the particles; rubbing the master batch chips with each other to form minute roughness on at least a portion of a surface thereof; and drying the master batch chips having minute roughness on at least the portion of the surface thereof.