Process for facilitating the use of high lignin containing waste paper in the manufacture of paper products

Abstract

This invention relates to a rapid process for determining groundwood pulp derived from waste paper. The process comprises (a) preparing a pulp from recycle furnish to form secondary papermaking fiber; and (b) preparing an absorbent sheet from said secondary papermaking fiber, characterizing the initial color of the absorbent sheet and staining the absorbent sheet with a phloroglucinol stain, characterizing the color of the absorbent sheet and comparing the color of the stained sheet with the initial color and selecting a target paper product based on the comparison. The process also comprises determining CIE, L*, a*, b* and brightness values. The delta L*, a*, b* and brightness values are used to produce products having commercially acceptable properties.

What is claimed is:  
     
         1 . A process for the manufacture of absorbent paper sheets from pulp derived from waste paper said process comprising: 
 (a) preparing a pulp from recycle furnish to form secondary papermaking fiber;    (b) preparing an absorbent sheet from said secondary papermaking fiber;    (c) characterizing the initial color of said absorbent sheet;    (d) staining said absorbent sheet with a phloroglucinol stain;    (e) characterizing the color of said absorbent sheet; and    (f) comparing the color of said stained sheet with initial color and selecting a target paper product based on the comparison    
     
     
         2 . The process of  claim 1 , wherein the characterization comprising a parameter selected consisting of a lightness parameter, a red green parameter and yellow blue parameter.  
     
     
         3 . The process of  claim 1 , wherein the groundwood percent range is preselected.  
     
     
         4 . The process of  claim 1 , said process comprising conducting a spectrophotometric analysis of absorbent sheets made from waste paper feedstock before and after treatment of the sheets with phloroglucinol, the spectral analysis including CIE a* color measurements and determining delta a* values between the untreated and treated sheets and using the delta a* value to select deinking and bleaching processes.  
     
     
         5 . The process of  claim 1 , said process comprising conducting a spectrophotometric analysis of absorbent sheets made from waste paper feedstock before and after treatment of the sheets with phloroglucinol, the spectral analysis including CIE L* color measurements and determining delta L* values between the untreated and treated sheets and using the delta L* value to select deinking and bleaching processes.  
     
     
         6 . The process of  claim 1 , said process comprising conducting a spectrophotometric analysis of absorbent sheets made from waste paper feedstock before and after treatment of the sheets with phloroglucinol, the spectral analysis including CIE b* color measurements and determining delta b* values between the untreated and treated sheets and using the delta b* value to select deinking and bleaching processes.  
     
     
         7 . The process of  claim 1 , said process comprising conducting a spectrophotmetric analysis of absorbent sheets made from waste paper feedstock before and after treatment of the sheets with phloroglucinol, the spectral analysis including CIE brightness measurements determining the delta brightness values to select deinking and bleaching processes.  
     
     
         8 . The process of  claim 4 , wherein the delta a* values are about 0 to 20.  
     
     
         9 . The process of  claim 5 , wherein the delta L* values are about 0 to 28.  
     
     
         10 . The process of  claim 6 , wherein the delta b* values are about −2 to 17.  
     
     
         11 . The process of  claim 7 , wherein the delta brightness values are about 5 to 21.  
     
     
         12 . A method of making absorbent sheet from recycle furnish comprising: 
 (a) pulping waste paper to form papermaking fiber;    (b) preparing an absorbent sheet from said secondary papermaking fiber;    (c) characterizing said absorbent sheet by way of analytical technique comprising applying a phloroglucinol thereto and determining the color thereof; and    (d) based upon the characterization of step (c) selecting a target product for said secondary papermaking fiber.    
     
     
         13 . A process for increasing the amount of inexpensive high lignin containing waste paper used as feedstock in the manufacture of paper products exhibiting GE brightness value of about 60 to 85, said process comprising conducting a spectrophotometric analysis of handsheets made from waste paper feedstock before and after treatment of the handsheets with phloroglucinol, the spectral analysis including CIE a* color measurement and determining delta a* values between the untreated and treated handsheets and using the delta a* values to select deinking and bleaching processes and controlling the amount of high lignin fiber feedstock which is to be utilized to produce absorbent paper products exhibiting GE brightness of about 60 to 85.  
     
     
         14 . The process of  claim 13 , wherein the delta a* values between untreated and treated handsheets are determined in less than 10 minutes.  
     
     
         15 . The process of  claim 13 , wherein the delta a* is less than 20.  
     
     
         16 . The process of  claim 15 , wherein the delta a* is between 10 and 20.  
     
     
         17 . The process of  claim 15 , wherein the delta a* is less than 10.  
     
     
         18 . The process of  claim 13 , wherein the GE brightness value is about 60 to 85.  
     
     
         19 . A process for tailor blending high lignin waste paper pulp with other waste paper pulp to produce paper products having predetermined commercially acceptable brightness properties comprising conducting a spectrophotometric analysis of handsheets from pulps derived from various waste paper sources before and after treatment with phloroglucinol, the spectral analysis including CIE a* color measurements and determining the delta a* values of the untreated and treated handsheets and using the delta a* values in blending the combination of waste paper pulp for appropriate deinking and bleaching treatment and to produce paper having the desired brightness while including the maximum amount of the low cost high lignin containing groundwood fiber.  
     
     
         20 . The process of  claim 19 , wherein the groundwood fiber comprises substantial amounts of bleached chemithermochemical pulp (BCTMP) fiber.  
     
     
         21 . The process of  claim 13  or  claim 19  wherein the delta a* values obtained determine the bleaching and deinking process used.  
     
     
         22 . The process of  claim 21 , when delta a* values exceed 20, the pulp is deinked but unbleached or semibleached.  
     
     
         23 . The process of  claim 21 , when the delta a* values are in the range of about 10 to 20, a peroxide, hydrosulfide or a combination of both processes are used to deink and bleach the pulp to produce feedstock for the manufacture of paper products which exhibit a GE brightness of at least 60.  
     
     
         24 . The process of  claim 23 , wherein the paper products exhibit a GE brightness of about 65-80.  
     
     
         25 . The process of  claim 21 , when the delta a* values are 10 or below, a hypo deinking bleaching process is used to produce feedstock for the manufacture of paper products exhibiting a GE brightness of at least 60.  
     
     
         26 . The process of  claim 25 , wherein the paper products exhibiting a GE brightness of about 65 to 80.  
     
     
         27 . An economical high speed process for increasing the amount of inexpensive and readily available high lignin containing waste paper used in the manufacture of paper products exhibiting commercially acceptable brightness, said process comprising conducting in less than ten minutes a spectrophotometric analysis of handsheets from waste paper pulp before and after treatment of the handsheets with phloroglucinol, the spectrophotometric analysis including CIE a* color measurement and determining the delta a* values between the untreated and treated handsheets and using the delta a* values to select the deinking and bleaching process and controlling the amount of high lignin fiber feedstock which can be utilized to produce paper products having predetermined commercially acceptable brightness properties.  
     
     
         28 . The process of  claim 27 , wherein the delta a* values obtained determine the bleaching and deinking process.  
     
     
         29 . The process of  claim 28 , when delta a* values are in the range of about 10 to 20, a peroxide, hydrosulfide or a combination of both processes are used to deink and bleach the pulp to produce feedstock for the manufacture of paper products having acceptable brightness.  
     
     
         30 . The process of  claim 29 , when the delta a* values are 10 or below a hypo deinking bleaching process is used to produce feedstock for the manufacture of paper products having commercially acceptable brightness.  
     
     
         31 . The process of  claim 27 , wherein the delta a* values are obtained within 7 minutes.  
     
     
         32 . A rapid process for determining groundwood in pulp derived from waste paper, said process comprising conducting a spectrophotometric analysis of handsheets made from said pulp before and after treatment of the handsheets with phloroglucinol, the spectral analysis including CIE a* color measurements and determining delta a* values between the untreated and treated handsheets.  
     
     
         33 . The process of  claim 32 , wherein delta a* values below 10 indicate that the pulp is of very high quality.  
     
     
         34 . The process of  claim 32 , wherein the delta a* values of 10-20 indicate that the pulp is suitable for production of paper products exhibiting a GE brightness value of at least 76.  
     
     
         35 . The process of  claim 32 , wherein the delta a* values in excess of 20 indicate that the paper products produced should be unbleached stock, known as brown stock, or semi-bleached stock.  
     
     
         36 . The process of  claim 32 , wherein bleached chemithermal mechanical pulp (BCTMP) fibers are not analyzed as untreated groundwood and included in delta a* values.  
     
     
         37 . The process of  claim 32 , wherein the delta a* values are determined within 10 minutes.  
     
     
         38 . The process of  claim 37 , wherein the delta a* values are determined in about 5 to 7 minutes.  
     
     
         39 . An economical high speed process for increasing the amount of inexpensive and high lignin containing waste paper used in the manufacture of paper products exhibiting commercially acceptable brightness, said process comprising conducting in less than ten minutes a spectrophotometric analysis of handsheets from waste paper pulp before and after treatment of the handsheets with phloroglucinol, the spectrophotometric analysis including CIE L* color measurements and determining the delta L* values between the untreated and treated handsheets and using the delta L* values to select the deinking and bleaching process and controlling the amount of high lignin fiber feedstock which can be utilized to produce paper products having predetermined commercially acceptable brightness properties.  
     
     
         40 . An economical high speed process for increasing the amount of inexpensive and high lignin containing waste paper used in the manufacture of paper products exhibiting commercially acceptable brightness, said process comprising conducting in less than ten minutes a spectrophotometric analysis of handsheets from waste paper pulp before and after treatment of the handsheets with phloroglucinol, the spectrophotometric analysis including CIE b* color measurements and determining the delta b* values between the untreated and treated handsheets and using the delta b* values to select the deinking and bleaching process and controlling the amount of high lignin fiber feedstock which can be utilized to produce paper products having predetermined commercially acceptable brightness properties.  
     
     
         41 . The process of  claim 39 , wherein the delta L* values are about 0 to 28.  
     
     
         42 . The process of  claim 40 , wherein the delta b* values are about −2 to 17.  
     
     
         43 . An economical high speed process for increasing the amount of inexpensive high lignin containing waste paper used in the manufacture of paper products exhibiting commercially acceptable brightness, said process comprising conducing in less than ten minutes a spectrophotometric analysis of handsheets from waste paper pulp before and after treatment of the handsheets with phloroglucinol the spectrophotometric analysis including CIE brightness measurements and determining the delta brightness values between the untreated and treated handsheets and using the delta brightness values to select the deinking and bleaching process and controlling the amount of high lignin fiber feedstock which can be utilizing to produce paper products having predetermined commercially acceptable brightness properties.  
     
     
         44 . The process of  claim 43 , wherein the delta brightness values are about 5 to 21.  
     
     
         45 . The process of  claim 2 , wherein the groundwood percent range is preselected.  
     
     
         46 . The process of  claim 2 , said process comprising conducting a spectrophotometric analysis of absorbent sheets made from waste paper feedstock before and after treatment of the sheets with phloroglucinol, the spectral analysis including CIE a* color measurements and determining delta a* values between the untreated and treated sheets and using the delta a* value to select deinking and bleaching processes.  
     
     
         47 . The process of  claim 2 , said process comprising conducting a spectrophotometric analysis of absorbent sheets made from waste paper feedstock before and after treatment of the sheets with phloroglucinol, the spectral analysis including CIE L* color measurements and determining delta L* values between the untreated and treated sheets and using the delta L* value to select deinking and bleaching processes.  
     
     
         48 . The process of  claim 2 , said process comprising conducting a spectrophotometric analysis of absorbent sheets made from waste paper feedstock before and after treatment of the sheets with phloroglucinol, the spectral analysis including CIE b* color measurements and determining delta b* values between the untreated and treated sheets and using the delta b* value to select deinking and bleaching processes.  
     
     
         49 . The process of  claim 2 , said process comprising conducting a spectrophotometric analysis of absorbent sheets made from waste paper feedstock before and after treatment of the sheets with phloroglucinol, the spectral analysis including CIE brightness measurements determining the delta brightness values to select deinking and bleaching processes.  
     
     
         50 . The process of  claim 46 , wherein the delta a* values are about 0 to 20.  
     
     
         51 . The process of  claim 47 , wherein the delta L* values are about 0 to 28.  
     
     
         52 . The process of  claim 48 , wherein the delta b* values are about −2 to 17.  
     
     
         53 . The process of  claim 49 , wherein the delta brightness values are about 5 to 21.