Patent ID: 7041243
Filing Date: 2006-05-09
Classification: B29C,B29K,B32B,Y10T

Abstract:
1. A production process for producing a 5-layer co-extruded biaxial-oriented polypropylene synthetic paper with thickness between 30˜300 μm whereby a 5-layer laminated structure is produced by employing a 5-layer co-extruded biaxial-oriented production process which comprises the following steps: (a) an uppermost layer (A) of a paper sheet or resin and a bottom layer (E) of a paper sheet or resin are extruded separately by a first pair of two hopper venting type single-screw secondary extruders under a temperature between 160˜280° C. by having a mixture containing polypropylene 96˜36% by weight, polyethylene 0˜30% by weight, antiblocking agent 2˜5%, titanium dioxide master batch (30˜60%) 0˜15% by weight, calcium carbonate master batch (40˜70%) 015% by weight, ultraviolet ray absorbent 1˜2% by weight, anti-oxidation agent 1˜2% by weight, uniformly blended at first in a feeding hopper in front of the single-screw secondary extruders, and then a first well blended mixture is fed into the first pair of single-screw secondary extruders for fine blending and air venting; then the first well blended mixture, being air vented by said first pair of single-screw secondary extruders, is pressed separately into a first layer runner and a fifth layer runner of a T-die; (b) a second layer (B) of a paper sheet or resin and a fourth layer (D) of a paper sheet or resin are extruded separately by a second pair of two hopper venting type single-screw secondary extruders under temperature between 160˜280° C. by having a mixture containing polypropylene 97˜54% by weight, polyethylene 0˜15% by weight, titanium dioxide master batch (30˜60%) 0˜15% by weight, calcium carbonate master batch (40˜70%) 0˜15% by weight, antistatic agent 1˜7% by weight, ultraviolet ray absorbent 1˜2% by weight, anti-oxidation agent 1˜2% by weight uniformly blended at first in a feeding hopper in front of the second pair of single-screw secondary extruders, and then a second well blended mixture is fed into the second pair of single-screw secondary extruders for fine blending and air venting, then the second well blended mixture, which is air vented by the single-screw secondary extruders, is pressed into a second layer runner and a fourth layer runner of the T-die referred to in step (a); (c) a third layer (C) of a foamed layer is extruded by a twin-screw primary extruder equipped with venting device under temperature between 160˜280° C. by having a mixture containing polypropylene 88˜46% by weight, polyethylene 0˜15% by weight, calcium carbonate master batch (40˜70%) 5˜20% by weight, titanium dioxide master batch (30˜60%) 5˜20% by weight, ultraviolet ray absorbent 1˜2% by weight a feeding hopper in front of the twin-screw primary extruder for fine blending and air venting, and then the mixture, well blended and air vented by the twin-screw primary mixture, is pressed into a third layer runner of the T-die referred to in step (b); (d) a 5-layer laminated structure obtained from a co-extruding process by the T-die referred to in step (c) then passes a cooling and forming equipment to form a 5-layer laminated sheet under temperature range of 15˜17° C.; (e) the 5-layer laminated sheet obtained from step (d) is then introduced into a longitudinal orientation device for longitudinal drawing under temperature range of 155˜150° C. for a longitudinal enlargement of 2.5˜7 times the original length; (f) the 5-layer laminated sheet obtained from step (e) is then introduced into the lateral orientation device for lateral drawing under temperature range of 140˜200° C. for a lateral enlargement of 5˜15 times the original width; (g) then the 5-layer laminated sheet obtained from step (f) in which the longitudinal and lateral orientation of the 5-layer laminated sheet are completed is treated by corona treatment equipment; and (h) a finished product of 5-layer co-extruded biaxial-oriented polypropylene synthetic paper with a thickness between 30˜300 μm is wound into a roll by a winding machine.