Method for manufacturing recyclable mineral paper

Abstract

A method is provided for manufacturing recyclable mineral paper, which has a composition comprising 60-85 wt % natural inorganic mineral powders, 5-40 wt % polypropylene (PP), and 1-5 wt % assisting agents, through the following steps: feeding and mixing of the constituents of the composition; stirring and mixing the composition; pressing to cause bi-directional extension of the composition so as to form a sheet; subjecting the sheet to operation of a high density squeezing machine for further mixing and pressing the sheet; reversely turning and shaping the sheet for further extension of the sheet; and continuous compression and extension of the sheet to induce further bi-directional extension of the sheet in both lateral and longitudinal direction and to control thickness of the sheet.

1 . A method for manufacturing recyclable mineral paper, which has a composition comprising 60-85 wt % natural inorganic mineral powders, 5-40 wt % polypropylene (PP) (which comprises a mixture of polylactic acid (PLA) or PP and polyethylene (PE)),and 1-5 wt % assisting agents, wherein the composition of the mineral paper does not need to be processed for formation of raw material mother particles and is directly deposited into a compression and extension paper making device, which comprises an automatic metering machine, an automatic stirring and mixing machine, a combined sheet forming machine, a high-density squeezing machine, a five-roller compression and extension machine, and a cooling and shaping machine, the method comprising the following steps:
 step one: the automatic metering machine performs automatic feeding and mixing of the constituents of the composition according to the ratios of the constituents to be then supplied to the automatic stirring and mixing machine;   step two: the automatic stirring and mixing machine performs continuous mixture and stirring of the composition to realize uniform mixture of the compositional constituents;   step three: the well mixed composition is then directly fed to the combined sheet forming machine to be subjected to combined pressing so as to cause bi-directional extension of the compositional constituents and uniform rubbing and kneading to form a sheet of the compositional constituents in a bonded condition;   step four: the uniformly rubbed and kneaded sheet is passed through the high density squeezing machine for further mixing and pressing the sheet, so as to provide the sheet with proper hardness and proper tension;   step five: the five-roller compression and extension machine is used for reversely turning and shaping the sheet and to realize bi-directional extension of the sheet in both lateral and longitudinal directions; and   step six: the cooling and shaping machine is used to perform continuous compression and extension on the sheet to induce further bi-directional extension of the sheet in both lateral and longitudinal direction and to control thickness of the sheet.   
     
     
         2 . The method according to  claim 1 , wherein the compression and extension paper making device further comprises an automatic roll-winding machine and a trimming machine, whereby the sheet formed in step six is wound by using the automatic roll-winding machine and the trimmed to a planar piece of paper of desired size by the trimming machine. 
     
     
         3 . The method according to  claim 1 , wherein the five-roller compression and extension machine of step five is operated by employing high temperature compression and extension and the temperature employed is adjustable according to the characteristics of the composition of the mineral paper so as to effectively realize melting, mixture, and bi-directional extension of the composition of mineral paper. 
     
     
         4 . The method according to  claim 1 , wherein the cooling and shaping machine of step six is adjustable for compression time according to desired thickness and product property of the mineral paper. 
     
     
         5 . The method according to  claim 1 , wherein the sheet formed in step six is further subjected to surface coating of an oil-based coating solution. 
     
     
         6 . The method according to  claim 1 , wherein the sheet formed in step six is further subjected to surface coating of a water-based coating solution through use of a dual-side coating machine to deposit a non-coated paper sheet into an automatic leveling machine to have the sheet dragged and leveled for subsequent performance of corona treatment, whereby two surfaces of the paper sheet, after being treated with high voltage discharging, form a plurality of tiny voids, which help improving bonding force for the coating applied to the surface (the surface treatment being selectively thermal fusion coating, fluent spraying, flame spraying, plasma spraying, and electrostatic spraying); the paper sheet is conveyed to a front surface coating machine for initial coating, and then the paper sheet is conveyed to a dry type baking oven to have the surfaces thereof dried for subsequent coating on the opposite surface; a back surface coating machine uses a plurality of spraying nozzles to control the amount of coating solution sprayed and realize coating on the opposite surface; and the paper sheet is then conveyed to the dry type baking oven to dry the coated surface, whereby under the condition of being heated, the coated surface of the paper sheet is quickly dried and shows a shining face on the paper surface.