Molded pulp article and method for producing molded pulp article

Abstract

A molded pulp article that has a small thickness and high strength and is excellent in release properties at the time of production, comprising a percentage of fibers having a fiber length of 1 mm or less to pulp is in the range of 35% to 50%, the pulp has an average fiber length in the range of 1.2 mm to 1.5 mm, the molded pulp article has a density is in the range of 0.65 g/cm3 to 1.3 g/cm3, and the molded pulp article has a nitrogen content is in the range of 400 μg/g to 2000 μg/g.

What is claimed is: 
     
         1 . A molded pulp article, comprising:
 a percentage of fibers having a fiber length of 1 mm or less in pulp is in the range of 35% to 50%,   the pulp has an average fiber length in the range of 1.2 mm to 1.5 mm,   the molded pulp article has a density in the range of 0.65 g/cm 3  to 1.3 g/cm 3 , and   the molded pulp article has a nitrogen content in the range of 400 μg/g to 2,000 μ/g.   
     
     
         2 . The molded pulp article of  claim 1 , wherein
 the molded pulp article has a thickness in the range of 0.5 mm to 1 mm.   
     
     
         3 . The molded pulp article of  claim 1 , wherein
 the molded pulp article has a density in the range of 0.65 g/cm 3  to 0.80 g/cm 3 , and   the molded pulp article has a nitrogen content in the range of 500 μg/g to 1,000 μ/g.   
     
     
         4 . The molded pulp article of  claim 1 , wherein
 the molded pulp article has a tensile strength in the range of 30 kN/m to 55 kN/m.   
     
     
         5 . The molded pulp article of  claim 1 , wherein
 the molded pulp article has a peeling strength in the range of 0.3 N/mm 2  to 0.9 N/mm 2 .   
     
     
         6 . The molded pulp article of  claim 1 , wherein
 the molded pulp article has a standard deviation of basis weight in the range of 2 g/m 2  to 30 g/m 2 .   
     
     
         7 . The molded pulp article of  claim 1 , wherein
 the molded pulp article is a container.   
     
     
         8 . A method for producing a molded pulp article, the method comprising the steps of:
 preparing a slurry that contains pulp and water in which a percentage of fibers having a fiber length of 1 mm or less in pulp is in the range of 35% to 50%;   depositing the pulp on a paper-making mold having a three-dimensional shape to form a pulp layer;   dehydrating the pulp layer to obtain an intermediate molded article; and   holding the undried intermediate molded article between male and female molds, and heating the intermediate molded article to a temperature in the range of 150° C. to 220° C. while applying pressure in the range of 0.4 MPa to 4.5 MPa.   
     
     
         9 . The method for producing a molded pulp article of  claim 8 , wherein
 depositing the pulp on a paper-making mold comprises:   preparing a cover body as a hollow body having an opening;   fixing the paper-making mold to the opening;   immersing the paper-making mold fixed to the opening in the slurry; and   depressurizing a space surrounded by the cover body and the paper-making mold immersed in the slurry.   
     
     
         10 . The method for producing a molded pulp article of  claim 9 , wherein
 the paper-making mold is immersed in the slurry such that the paper-making mold is positioned above the cover body.   
     
     
         11 . The method for producing a molded pulp article of  claim 8 , wherein
 the pressurization and heating of the undried intermediate molded article held between the male and female molds is performed under a pressure in the range of 0.4 MPa to 2.0 MPa and at a temperature in the range of 150° C. to 200° C., respectively.