Method for adjusting fibrous properties of pulp

Abstract

The invention relates to a method for adjusting the fibrous properties of chemical pulp, mechanical pulp or chemi-mechanical pulp, for adjusting the smoothness of the properties and for decreasing any variation in quality. According to the method, in the manufacture of pulp, a wood material is used, which is selected according to the number of the tree's annual rings. The wood material is classified according to the number of annual rings into categories that represent a certain fibre dimension property, such as the fibre length or the fibre coarseness. The wood material is classified by log or group of logs at any stage in connection with the felling of the wood or in the plant or at some stage of the chain between the stub and pulping and grinding or a refiner.

1 . A method for adjusting the fibrous properties of pulp to a preselected level, characterized in that in the manufacture of the pulp, a wood material is used, which is classified by log or group of logs according to the number of annual rings into categories that represent a certain fibre dimension property.  
     
     
         2 . A method according to  claim 1 , characterized in that the wood material is classified in connection with felling the wood or in a plant or at some stage of the chain between the stub and pulping, the stub and grinding or a (C) TMP refiner.  
     
     
         3 . A method according to  claim 1 , characterized in that the wood material is classified mechanically.  
     
     
         4 . A method according to  claim 1 , characterized in that the wood material originates in a tree that has a periodic growth habit.  
     
     
         5 . A method according to  claim 1 , characterized in that the wood material is softwood.  
     
     
         6 . A method according to  claim 1 , characterized in that the wood material is hardwood.  
     
     
         7 . A method according to  claim 1 , characterized in that the fibre dimension property refers to the fibre length or the fibre coarseness.  
     
     
         8 . A method according to  claim 1 , characterized in that the wood material is classified according to the number of annual rings into different categories, the number of which is 2 to 60, preferably 2 to 6.  
     
     
         9 . A method according to  claim 1 , characterized in that the wood material is classified by log or group of logs according to the number of annual rings, for example, into the following categories: less than 20 annual rings, 21 to 30 annual rings, 31 to 40 annual rings, over 40 annual rings.  
     
     
         10 . A method according to  claim 1 , characterized in that the wood material is classified by log or group of logs according to the number of annual rings, for example, into the following categories: less than 10 annual rings, less than 20 annual rings, less than 30 annual rings, less than 40 annual rings, less than 50 annual rings and over 50 annual rings.  
     
     
         11 . A method according to  claim 1 , characterized in that the wood material is classified by log or group of logs according to the number of annual rings into various categories, and the desired fibre dimension property, such as the fibre length, is obtained by selecting the wood material separately from a certain category or by fully or partly combining wood materials obtained from various categories.  
     
     
         12 . A method according to  claim 1 , characterized in that the method can be used to manufacture mechanical, chemical or chemi-mechanical pulp.  
     
     
         13 . A method according to  claim 1 , characterized in that in case of softwood, to obtain a fibre length (the mean value weighted by the length) of less than 2.0 mm, a wood material is selected, wherein the number of the log's annual rings at the butt of the log is less than 20 annual rings.  
     
     
         14 . A method according to  claim 1 , characterized in that in case of softwood, to obtain a fibre length (the mean value weighted by the length) of 2.0 . . . 2.3, a wood material is selected, wherein the number of the log's annual rings at the butt of the log is 21 to 30 annual rings.  
     
     
         15 . A method according to  claim 1 , characterized in that in case of softwood, to obtain a fibre length (the mean value weighted by the length) of 2.3 . . . 2.5, a wood material is selected, wherein the number of the log's annual rings at the butt of the log is 31 to 40 annual rings.  
     
     
         16 . A method according to  claim 1 , characterized in that in case of softwood, to obtain a fibre length (the mean value weighted by the length) of 2.5 . . . 3.5, a wood material is selected, wherein the number of the log's annual rings at the butt of the log is over 40 annual rings.  
     
     
         17 . A method for manufacturing pulp that has preselected fibre dimension properties, characterized in that 
 wood with a periodic growth habit is used as wood material,    the wood material is classified by log or group of logs according to the number of annual rings into categories, which represent a certain fibre dimension, such as the fibre length and/or the coarseness,    the raw material is selected separately from a certain category or by combining the raw materials of the various categories partly or fully so that the preselected fibre dimension properties are achieved, and    mechanical, chemical or chemi-mechanical pulp is manufactured of the wood material.    
     
     
         18 . A method for manufacturing a fibrous product that has preselected fibre dimension properties, characterized in that 
 annual ring categories of the wood material are determined by logs or groups of logs according to the number of annual rings, representing a certain fibre dimension,    the wood material is selected from a category of annual rings that provides the preselected fibre dimension properties,    mechanical, chemical or chemi-mechanical pulp is manufactured from the wood material, and    the fibre product is made of the pulp.