Application US20200115110

(1) spinning PLA, wherein spinning-grade PLA slices are used as raw materials to prepare PLA fibers,

including melt spinning using a screw-type spinning machine, wherein the melting point of PLA is 175° C., and the spinning box is using a heating medium with a low boiling point so that it is suitable for PLA,

comprising following detailed steps: drying the raw materials until that a water content is less than 30 ppm, setting a screw pre-melting temperature to be 195˜210° C., setting a screw outlet temperature to be 200˜215° C., setting a spinning head temperature to be 200˜210° C., cooling, winding, cutting into sections, and then obtaining PLA short fibers;

(2) manufacturing thin non-woven fabrics, wherein PLA short fibers are used as raw materials, and a hot-rolled non-woven fabric equipment is used,

including following steps: carding PLA fibers, feeding fibers pneumatically, spreading fibers using a vibrating screen, hot rolling with a couple of roller, and then forming non-woven fabric;

(3) coating non-woven fabric, wherein the outer surface of some thin non-woven fabric is coated, and PBAT material is used for the coating,

including placing pure PBAT slices into a hopper of a coating machine, into a extruding screw and then forward to a coating die according to designated levels of temperatures, wherein the temperatures of the screw and the die are controlled by a PLC controller of the coating machine, so that temperature control, die extrusion volume and non-woven fabric speed match with one another, wherein the thickness of the coating is effectively controlled to be 20˜60 g/meter square, and then cooling by a cooling drum;

(4) printing, including printing on the coated layer of the non-woven fabrics;

(5) forming a bag, so that a bag body with a filling hole on its side is formed;

(6) filling fibers, wherein PLA fibers are used as heat-insulating fibers and are filled into the sandwich layer of the bag body,

including making PLA fibers fluffy, automatically suctioning the fibers into a filling machine, aligning the filling hole of the bag body with a filling outlet of the filling machine, quantitatively filling the fibers, sealing the filling holes, and obtaining a finished product of a heat-insulating bag.