Deinking of Inkjet Printed Paper. PTS Deinking Symposium April 27-29, 2010

Transcription

1 Deinking of Inkjet Printed Paper PTS Deinking Symposium April 27-29, 2010

2 Overview for Today o Who is the DPDA o Dye Based Ink Investigation and Results o Comment on Lab Methods vs Commercial Conditions o Continued Investigations and Next steps

3 The Digital Print Deinking Alliance

4 Objectives and Purpose of DPDA o Consolidate OEM resources for production inkjet printing and investigate deinking concerns related to inkjet technology o Understand and define the specific issues and concerns of inkjet printing. Determine seriousness, urgency and resources required for problem solving o Identify system based solutions including inks, papers, and deinking technologies that will be cost effective and practical o Collaborate with deinking industry associations, related businesses and research organization for long term solutions o Facilitate the sharing of information and best practices

5 Definition of Problem o A concern has been raised, based upon Method 11 lab testing, regarding flotation deinking performance of inkjet printed papers o Yet, commercial deinking mills typically have not reported lower brightness due to inkjet prints. o Despite 40 years of production inkjet printing, currently inkjet s share of total print is < 1%. Now high growth in some market applications. o We need to investigate what issues aqueous inkjet inks may pose to current recycling mills and plan for solutions in 5-10 year horizon.

6 Dye Based Ink Investigation o What was tested o Experimental protocol o Black dye inkjet results o Cyan dye inkjet results o Magenta dye inkjet results o Yellow dye inkjet results o Summary

7 Test Objectives o Determine if one dye set can be established for future deinking testing Speed and Economy of testing Determine if dye type or OEM source matters o Investigate parameters of various lab scale flotation deinking methods Test conditions: Method 11, CTP Additional variables commonly used in commercial mill systems

8 Test Parameters o Three OEM supplied aqueous dye based inks o Four colors (CMYK) o High and Low density print o Uncoated woodfree paper (office type) o Three bleaching chemistries Peroxide Hydrosulphite Ozone

9 Experimental Protocol o Samples were printed with INGEDE test form o CTP Pulping conditions: 15% pulp consistency, 128 mg Ca 2+ /l hardness, 45 o C, 0.6% NaOH, 1.8% silicate 0.8% Serfac MT90 soap in a NCM10 Hobart pulper with1 min agitation (speed 2), then 0.7% peroxide is added and agitated for another 20 min.

10 Experimental Protocol For Bleaching o Peroxide o 80 o C o 10% consistency o 1% NaOH o 1% H 2 O 2 o 2.5% silicate o 0.15% DTPA o Mixed and held for 90 min o Hydrosulphite o Ozone o 55 o C o 3% consistency o 1% hydrosulphite o gentle agitation and held for 15 min o 2.5% consistency o 2% ozone

11 Black Dye Results Brightness Luminosity Ink A Ink B Ink C Ink A Ink B Ink C Pulper Peroxide Hydro Ozone Brightness of unprinted paper = 88 Luminosity threshold = 47

12 Black Dye Results Ink A Ink B Ink C Ink A Ink B Ink C Pulper Peroxide HydroS Ozone Target Brightness Luminosity

13 Cyan Results a* Target: -0.5 b* Target 3.5 Ink A Ink B Ink C Ink A Ink B Ink C Pulper Peroxide Hydro Ozone Deinkability of cyan inkjet printed uncoated, bleached wood free paper

14 Magenta Dye Results a* Target: -0.5 b* Target 3.5 Ink A Ink B Ink C Ink A Ink B Ink C Pulper Peroxide Hydro Ozone Deinkability of magenta inkjet printed uncoated, bleached wood free paper

15 Yellow Dye Results a* Target: -0.5 b* Target 3.5 Ink A Ink B Ink C Ink A Ink B Ink C Pulper Peroxide Hydro Ozone Deinkability of yellow inkjet printed uncoated, bleached wood free paper

16 Summary of Test Results o Noticeable differences were observed between dyes, Between OEM s and also within colors. Premature to select a representative ink system o Hydrosulfite bleaching performed the best and increased pulp brightness and luminosity for all dye inks tested. Better than Ozone bleaching Peroxide had little to no improvement o Dye based inks on office paper (UWF) are unlikely to pass Method 11. Modifying test conditions has significant impact. o Some dyes are easily deinked using existing commercial mill conditions

17 Next Steps o Repeat study using aqueous pigment based inks o Begin to test impact of paper types on deinkability Mechanical and Chemical Coated, treated and uncoated Paper componentry Mixed furnish impact o Investigate additional commercial deinking process variables and degree of impact compared to lab tests

18 Questions?