The Effects of Deinking on the Coating Compounds Used on Carbonless Business Forms

Rochester Institute of Technology RIT Scholar Works

Theses

11-1-1991

The Effects of deinking on the coating compounds used on carbonless business forms

Brooke Merrill Tinney

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Recommended Citation Tinney, Brooke Merrill, "The Effects of deinking on the coating compounds used on carbonless business forms" (1991). Thesis. Rochester Institute of Technology. Accessed from

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Certificate of Approval

Master's Thesis

This is to certify that the Master's Thesis of

Brooke Merrill Tinney

With a major in Printing Technology has been approved by the Thesis Committee as satisfactory for the thesis requirement for the Master of Science degree at the convocation of

Thesis Committee:

Joseph E. Brown Thesis Advisor

Andreas Lenger Research Advi$or

Joseph L. Noga Graduate Program Coordinator

George H. Ryan Director or Designate The Effects of Deinking on the Coating Compounds Used on Carbonless Business Forms

by Brooke Merrill Tinney

A thesis submitted in partial fulfillment of the

requirements for the degree of Master of Science in the

School of Printing Management and Sciences in the College of Graphic Arts and Photography of the Rochester Institute of Technology

November 1991

Thesis Advisor: Professor Joseph E. Brown

Research Advisor: Dr. Andreas Langner Title of Thesis: The Effects of Deinking on the Coating Compounds Used on Carbonless Business Forms

I, Brooke Merrill Tinney, hereby grant permission to the Wallace Memorial Library of R.I.T. to reproduce my thesis in whole or in part. Any reproduction will not be for commercial use or profit.

Name and Date: Acknowledgments

Special appreciation and thanks to the following people: Professor Joseph Brown for his enthusiasm and support; Thomas Oswald for his technical advise; Inna Kugel for her help with the statistical analysis; Rachel Walsh for her assistance in the chemistry lab; Sandra

Pearl for her positive energy; and Paul King for his unfaltering moral support. Most importandy, my deepest gratitude goes to Dr. Andreas Langner, for his infinite patience and scientific expertise. Without his help this thesis would not have been completed. Table of Contents

List of Tables iii

List of Figures iv

List of Symbols, Abbreviations, and Nomenclature v

Abstract vi

Chapter One: Introduction 1

Objective 1 The Deinking Process 1 Carbonless Forms 1 Recycling 2

The Relevance of This Research 3

Who Will Benefit From This Research 3

Notes 5

Chapter Two: Theoretical Basis 6

Carbonless Forms 6 The Deinking Process 6 High Performance Liquid Chromatograph 7

Notes 8

Chapter Three: Review of the Literature 9

Notes 11

Chapter Four: Statement of the Problem 12

Purpose 12 Hypotheses 12

Limitations 13

Delimitations 13

Chapter Five: Methodology 14 Equipment 16

Procedure 17

Chemical Analysis 17

Statistical Analysis 18

Chapter Six: Analysis 19

Chapter Seven: Conclusions and Recommendations for

Further Research 21

Hypotheses Restated 2 1

Conclusions 21

Recommendations For Further Research 2 3

Bibliography 25 Appendix A 27

Appendix B 32

Appendix C 36

i i List of Tables

Table 1: Concentration of Coating Compounds Per 10 Grams of Cellulose 20

Table 2: Relative Retention of Coating Compounds 20

Table 3: Student's t-statistic 21

Table 4: Relative Retention of Coating Compounds 22

Table 5: Confidence Intervals at a 90% Confidence Level 23

Table Al: HPLC Signals for Resin and Oil 28

Table A2: Weight of Handsheets 29

Table A3: Cellulose Recovery and Percent Efficiency 29

Table A4: Determining Coating Compound Weights 30

Table A5: Concentrations of Coating Compounds 31

1 1 1 List of Figures

Form 6 Figure 1: Section View of a Three-Part Carbonless

Figure 2: Chart of Samples, Control Group, and 15 Procedural Variables

.16 Figure 3: Illustration of the Deinking Process. .

.18 Figure 4: Control Group and t-test Comparisons. List of Symbols, Abbreviations, and Nomenclature

BL: Bleach and Deinking Chemicals BS: Base Stock

CB: Coated back carbonless form

CF: Coated front carbonless form

CFB: Coated front and back carbonless form CH: Deinking Chemicals Coating Compounds: CB coating compounds, dye precursor and oil, and CF resin

coating compound Deinking Chemicals: Surfactant and Caustic Soda

Furnish: Basic ingredients of pulp, can be either virgin or recycled material, fillers, and

other additives HPLC: High Performance Liquid Chromatography RP: Repulp STD: Standard Deviation

v Abstract

The purpose of this study was to determine what effects different deinking processes have on the coating compounds used on carbonless forms. Three deinking processes were studied: repulping without deinking chemicals or bleach, deinking using deinking chemicals only, and deinking using both deinking chemicals and bleach. None of the processes were successful at completely removing the oil, which is located in the microcapsules, or the resin, which is used to coat the coated-front portion (CF) of the carbonless form. Of the three deinking processes studied, simple repulping was most effective at eliminating the resin used in the coatings, while the process which included deinking chemicals plus bleach, was most effective at eliminating the oil. Chapter One

Introduction

Objective

The purpose of this study was to determine what effects the deinking process has on the coating compounds used on the printed CFB (coated front and back) portion of a

carbonless form. A chemical analysis of handsheets formed from the deinked pulp will

reveal whether the coating compounds are dispersed and washed out or remain in the handsheet.

The Deinking Process Deinking is a step in the recycling process where ink and other nonfiberous materials,

such as staples and adhesives, are removed from wastepaper. Deinked pulp can be used to

make paper products of varying grades, such as printing and writing, newsprint, and

tissue. The quality of the new products, made from secondary fibers, depends upon the

quality of the original waste paper and the effectiveness of the deinking process. In some instances a percentage of virgin pulp or other additives, such as clay, CaC03, and sizing,

are mixed with the secondary fibers to help create desired characteristics in the recycled

paper.

Carbonless Forms

A typical three-part carbonless form contains three sheets of chemically coated paper.

When the top sheet is written or typed upon the image is physically transferred to the

sheets below via a chemical reaction which forms a dark dye. (For more specific information about the coating compounds see Chapter 2: Theoretical Basis). Recycling The demand for quality recycled paper is growing due to rapidly diminishing landfill space, government legislation, increased public awareness of environmental issues, and corporate

response to this new awareness. It is estimated by waste management experts that the

landfill will 1990's.1 remaining space be filled to capacity by the early 45 percent of

public waste is paper and approximately 65 percent of office waste is paper, of which a

portion is discarded carbonless forms.2

The U.S. Environmental Protection Agency's June 1988 guidelines set forth

requirements that federal, state, and local government agencies are required by law to

purchase recycled paper whenever possible.3 Consumers have not only begun to request more environmentally friendly products, but demand that the companies they buy from adopt more conscientious business practices. John J. Buckley, Jr., President of the National Paper Trade Association stated, "Merchants are finding the biggest demand for recycled printing and writing paper right now is in big business [and] the government

contract business."4

"Producing paper from recycled fibers requires 64 percent less energy than producing fibers."5 paper from virgin Deinked pulp can save on the processing and chemicals required to extract fibers from their original sources. Recycling mills use about 75 percent

less bleach than conventional mills because wastepaper fibers require less chemical

bleaching, having already been whitened during their original processing.6 Recycling not only conserves energy but fewer trees must be harvested. "It takes 17 trees to produce one

ton of virgin paper."7

"Using deinked fiber instead of market pulp at a usage level of 200 tpd [tons per day]

would result in savings of $350/ton or $70,000/day. This $24.5-million annual savings,

with a 40% tax rate, would have a simple payout of two years on a $30-million deinking

facility."8 Despite these savings, recycled grades currently cost about 10 percent more

counterparts."9 than their virgin fiber Until the price of recycled paper becomes more competitive, individuals and businesses will continue to buy virgin paper. Research shows that businesses would be willing to pay more for recycled paper but they would not

paper used for or shareholder be willing to sacrifice quality in marketing

communications.10

An American Paper Institute (API) capacity survey revealed that in 1987, about

351,000 tons of high-grade deinking stock were used in printing/writing and related

predicted used in In grades, and 400,000 tons were to be 1990. addition about 1.014 1987.11 million tons of pulp substitutes were used in printing /writing papers in The

growing demand for quality recycled paper, especially in printing and writing grades, indicates that research into the deinkability of high quality fiber sources, such as

carbonless business forms, is important to the future success of recycling efforts.

The Relevance of This Research

forms' This research will help to either confirm or dispel the beliefs about carbonless

recyclability. At present, many people still believe that carbonless forms are not

recyclable, or not easily recycled, because the coating compounds cause problems during

the deinking process. As a result, carbonless form wastepaper is less expensive than other

waste paper even though the quality of the carbonless paper fibers is high. The ultimate

value of secondary fibers, derived from deinked business forms, will depend upon the amount of coating compounds removed by the deinking process. Note that the properties

"acceptable" desired in the final product determine what will be considered an amount of

remaining coating compounds. If, for example, the deinked pulp is to be used to make

liner board for corrugated boxes, then the presence of residual coating compounds may not

be a problem. On the other hand, if the deinked pulp is to be used to produce new

carbonless forms, it is imperative that no coating compounds remain in the pulp which might react with the new carbonless coatings being applied. The ultimate goal of

recycling is to produce a product of equal to the original. If used carbonless forms can be

recycled into new carbonless forms then the recycling process would be complete.

One of the most difficult challenges facing the recycling business is the problem of

identifying and separating waste at its source. Gordon Sisler, from Noranda Forest Recycled Papers in Canada, commented that the ability to produce consistently high

quality deinked pulp depends entirely upon the deinking facility's ability to first purchase

specific types of wastepaper and secondly, to mix the proper proportions of waste and

virgin pulp to obtain desired characteristics in the final sheet. If it can be determined that carbonless forms can be deinked then they could become an easily identifiable source of high quality secondary fiber.

Who Will Benefit From This Research?

The carbonless form industry will be most affected by the results of this research. The discoveries made by this research will assist the industry in accurately reporting the

clients. Businesses recyclability of their product to their concerned about recycling inner office waste should be attentive to the discoveries of this research. Wastepaper vendors and buyers will also be interested in the recyclability of carbonless forms. If it is found that carbonless forms can be economically deinked, then they may become a highly sought

after source of secondary fiber. Notes

1 Future," Matthew Duffey and Penny Lewis, "Don't Trash Our The New GETzette, Winter 1991.

2 Ibid.

3 Market," Charles P. Klass, "Recycling: Remaking the Coated Paper PIMA Magazine, May 1990, 33.

4 Paper," Robert B. Galin, "Demand Increasing for Recycled Printing and Writing Pulp & Paper, March 1990, 198.

5 Duffey.

6 Options," "Publishing and the Planet; A forest of Recycling Computer Publishing Magazine, December 1990, 55.

7 Duffey.

8 Lawrence A. Broeren, "New Technology, Economic Benefits Give Boost to Use," Secondary Fiber Paper & Pulp, November 1989, 69.

Paper," 9 Robert B. Galin, "Demand for Increases for Recycled Printing and Writing Pulp and Paper, March 1990, 198.

1 Klass, 32.

1 1 Robert B. Galin, "Trash Crunch Drives Demand for Recycled PrintingAVriting Papers," Paper & Pulp, March 1989, 88-89. Chapter Two

Theoretical Basis

Carbonless Forms

The following is a brief description of a typical three-part carbonless form. The underside of the CB (coated back, Part 1) top sheet is coated with spacer material, binder, and polymeric microcapsules which contain a clear dye precursor and oil in liquid form. The pressure of writing or typing ruptures the capsules, and the dye precursor is physically transferred to the CFB (coated front and back, Part 2), middle sheet. The clear dye precursor changes to a dark color when it reacts with a phenolic resin which coats the top of the CFB. The underside of the middle sheet is coated with the microcapsules and the

CF (coated front, Part 3) bottom sheet is coated with the phenolic resin, binder, and white pigments.

yfWf^B Parti CB Binder .. , , mfy m *^:,;:;;;;fi< Spacer Material T Microcapsule Containing Clear Dye Precursor and Oil ~ Part 2 CFB

and __ Phenolic Resin, Binder, White Pigment Part 3 CF

Figure 1

Section View of a Three-Part Carbonless Form

The Deinking Process

begin with a in which the "Both washing and flotation deinking repulping operation,

a reclaimed paper or paperboard is dispersed into fibrous slurry using chemical,

detach the ink from the fibers. Sodium mechanical, and thermal energy to hydroxide, sodium silicate, sodium peroxide, and detergents are commonly used to saponify the ink binders. Under shear and high temperature, the pigments of the ink are dispersed into

particles."1 small The pulp is sent through a series of washing and screening steps which remove unwanted non-fibrous materials, such as staples, adhesives, and ink particles. A

bleaching stage is added depending on the end-use requirements.

High Performance Liquid Chromatograph (HPLC)

The HPLC consists of: a high pressure-constant flow rate pump, a sample injector, a

column, a UV detector, a recorder, and an integrator. A liquid, usually containing two or more solvents, is supplied to the column by the pump. The type of column used is determined by the type of solvent being used and the nature of the sample being tested. A solution (eluant) is made by soaking the sample being tested, in a known amount of

solvent. The particular solvent used is chosen for its ability to extract the compound(s)

being tested. The resulting eluant is injected into the column where it is separated into its

components. The column packing achieves this separation by attracting (bonding) to the

various solute molecules with different strengths relative to the solvent. The eluant leaves

the column and enters the UV detector, where each compound absorbs UV light. Each

solute species has an inherent ability to absorb UV light, given by its extinction coefficient. The amount of UV absorption is recorded and quantitatively measured by the integrator. Each compound emerges from the column at a distinct time and produces a peak on the recorder. The integrator measures the area under the peak. The area is directly and linearly proportional to the quantity of compound in the original sample, the proportionality constant being the extinction coefficient. 8

Notes

1 Inks," William K. Forester, "Deinking of UV-Cured Tappi Journal, May 1987, 127. Chapter Three

Review of the Literature

A careful review of the literature revealed that there have been only a few articles published to date regarding the deinking of carbonless forms. Research that has dealt with

the recyclability of carbonless forms is proprietary and most of the published research on

deinking and recycling has concentrated on newsprint wastepaper, not printing and writing

grades. Therefore, most of the information that is relevant to this research was obtained

through personal communication with industry professionals.

The most comprehensive article on the recyclability of carbonless forms was published in the July 1979 Tappi Journal, by Lothar Pfalzer. Pfalzer found that the

coating compounds decreased the ink-fiber contact and "therefore, no chemical attack on

the binder is necessary Nor is deflaking necessary for ink separation; on the contrary it tends to be harmful, because the microcapsules that have not been decomposed are then

dyes." disintegrated, and the chemicals present would cause additional reaction of the

Pfalzer therefore, conducted some of his tests without swelling (reaction) time and without

deflaking. He found that the caustic soda "attacks part of the microcapsules, which results

reaction...." in an intensified color Pfalzer concluded that "carbonless copy paper should be

slushed at a lower mechanical load and without alkali, so as not to destroy the

microcapsules. Wood-free, white grades are completely free from ink and specks after

rebleached."1 flotation, while wood-containing and dyed grades must be

A representative from Appleton Papers Inc., commented that he was in no rush to dispel the belief that carbonless forms pose problems during recycling. At present, he purchases inexpensive carbonless form wastepaper, which his competitors believe to be of

new little use, and uses the recovered fibers to make carbonless forms. He has encountered

of carbonless form wastepaper no problems using as high as 50 percent and conjectured

percent make new forms. He added that he could probably use 100 to that in order to make new forms out of the deinked secondary fiber, the coating compounds must be entirely 10

dispersed and removed from the pulp. Otherwise, the remaining coating compounds would react with the new carbonless coatings. He also commented that Appleton changed the formulation of some of the dyes used in their carbonless coatings to make them more easily bleached during the deinking process. Recently, trade journals have begun to publish articles on Appleton Paper's carbonless paper recycling efforts. In one article Jim

Beasom, government affairs administrator, for Appleton, stated, "Recycling carbonless

paper is not vastly different from recycling any other paper that contains ink. It doesn't

recycling." require special machinery or equipment beyond that needed for other fine paper

The article also mentioned that all three sheets of a carbonless form can be recycled

together.2 Gordon Sisler, of Noranda Forest Recycled Papers, commented that his furnish

sometimes contains a small percentage of carbonless forms, and reported having no

problems with his pulp related to the coating compounds. Although these are qualitative

observations, they do provide the researcher with some idea as to what can be expected

from this research. 1 1

Notes

1 Papers," Lothar Pfalzer, "Deinking of Xerographic and Carbonless Copy Tappi Journal, July 1979, 27-30.

2 Loop' Paper," Dennis Hulgren, "Appleton Papers 'Closes the On carbonless Paper Age Recycling Annual 1990, 47. Chapter Four

Statement of the Problem

Purpose

The purpose of this study was to determine what effects the deinking process has on the coating compounds used on the printed CFB (coated front and back) portion of a carbonless form. A chemical analysis, using HPLC, of handsheets formed from deinked pulp revealed whether the coating compounds were dispersed and washed out or remained in the handsheet. As a control, the various deinking procedures were not only run on the

CFB portion of the form, but on unprinted, uncoated, base stock, as well. The base stock control was used to test whether the various deinking procedures introduced materials

which might have been read by the HPLC as indistinguishable from the coating compounds.

Hypotheses

1. Without the addition of deinking chemicals and bleach, there will be no significant

amount of coating compounds remaining in the handsheet formed by repulping the

printed CFB portion of a carbonless form.

2. Without bleach, there will be no significant amount of coating compounds remaining

in the handsheet formed by deinking the printed CFB portion of a carbonless form. 3. With deinking chemicals and bleach, there will be no significant amount of coating

compounds remaining in the handsheet formed by deinking the printed CFB portion of

a carbonless form.

Limitations

Limited time and resources restricted the number of replicates for each sample, and

one lot of paper from one deinking procedure, to five. Additionally, only manufacture, and

of ink was studied. one printing process and brand

12 13

Delimitations

and CB Only the CFB portion of the form was studied because it contains both the CF

realistic coating compounds. A printed form was studied because it represents the most type of wastepaper which would be found in a recycling facility. This project was

made restricted to white, carbonless form paper and did not include the study of forms from tinted stocks. Chapter Five

Methodology

The methodology of this research project was designed to emulate industry procedures, as best possible, while maintaining the amount of control over the process, that was essential to obtaining reliable results. The deinking procedure that was followed was derived from a laboratory procedure provided by David K. Frondorf, of Miami Paper in

West Carrollton, Ohio. In an attempt to isolate different variables in the process, three variations of the deinking procedure were run. First, the wastepaper was repulped without deinking chemicals or bleach. Second, the waste paper was deinked using deinking chemicals, without bleach, and third, the waste paper was deinked with deinking chemicals and bleach.

For comparison purposes, mean coating compound weights and variances for the original CFB sample were determined. As a control, the various deinking procedures were not only run on the CFB portion of the form, but on unprinted, uncoated, base stock, as well. The base stock control was used to test whether the various deinking procedures introduced materials which might be read by the HPLC as indistinguishable from the

of materials were subtracted from the coating compounds. The weights these coating compound weights of the printed CFB sample before it was compared to the original CFB sample.

14 15

Deinking Procedure Repulping Deinking Deinking 2. No Chemicals Chemicals a. E Chemicals No Bleach & Bleach a ^ U f Base O O 1 weights i OOl weights of OOl weights f u added added added

remaining OO > remaining OO V rcmaining CFB OOl coating OO f coating OO 1 coating 1 pi piJ compounds pi. pi J compounds pi piJ compounds

Figure 2

Chart of Samples, Control Group and Procedural Variables 16

Equipment:

1 . Heating mantle with temperature control 2. Variable speed T-Line Stirrer

blades- 3. Marine Impeller 3 or 4 no sharp edges 4. Standard Tappi 6 1/4" diameter British Sheet Mold.

5. Chemicals: surfactant (Drewsperse 190), caustic soda (Sodium Hydroxide),

and concentrated bleach (Hydrogen Peroxide 30 wt% in water).

6. Wastepaper Furnish: uncoated-unprinted base stock and printed CFB.

7. 400 ml beaker 8. Thermometer

9. 100 mesh sieve

10. 2 gallon bucket

1 1 . Triple Beam or Digital Balance 12. Felts

13. Hand roller 14. Hot plate drying unit and blotting paper

Waste Paper Handsheets Base Stock 2 for each replicate CFB

10g G

1 Deinking Procedure

surfactant

-caustic

bleach

Figure 3

Illustration of the Deinking Process 17

Procedure:

1. Heat 250 ml of tap water in a 400 ml beaker.

2. At add 100F, 1 drop (.03 ml) of surfactant (Drewsperse 190) and . lg of Soduim

Hydroxide (caustic soda) to achieve a pH of 1 1 Allow to mix for a few minutes at a

low speed (500 rpm). Note: this step will be used as a variable for tests without deinking chemicals (surfactant and caustic).

l"xl" 3. Slowly add lOg of furnish, torn into pieces. After 5 minutes stop the mixer and clean off any paper wound around the Impeller blade. Increase temperature

slightly.

4. Resume mixing and increase the speed to 1300 rpm. Make certain that all of the slurry is moving at the same speed.

5. Add (.15ml) of concentrated bleach (Hydrogen Peroxide 30 wt.% in water) to the

slurry. Note: this step will be used as a variable for tests without the bleach step.

6. After the temperature reaches 140F, let the slurry mix for 25 minutes . Maintain a constant temperature throughout the cooking step and do not let the temperature

exceed 150F.

7. Immediately wash the fibers on the 100 mesh screen for approximately one minute until a one gallon level has been reached in the washing bucket.

8 Weigh the fibers and divide them into two equal portions . Make a handsheet from

5" each by filling the British Sheet Mold with of water and letting it drain. 9. Couch the handsheet onto a felt, press out excess water, and dry between blotting

paper on a hot plate. Do not scorch the handsheet in the dryer. NOTE: be certain to

keep track of the felt and wire side of the sheet throughout this step. 11. Make 5 replicates for each variation in the deinking process and for each sample.

12. Before measuring the dried handsheets. stack them between blotter paper, under

pressure, for at least twenty-four hours. This will equalize the moisture content, and

make final weights more accurate.

Chemical Analysis

A known weight of the handsheet was immersed in an organic solvent, which extracted

compounds. A calibrated High Performance Liquid Chromatograph any remaining coating amount of compounds. The solvent (HPLC) was used to measure the remaining coating

precursor used in the CB and resin used was able to extract the oil and dye coating, the

solvent not extract the binders or the pigments used in the CF coating. The did used in the

were compared to standard coatings. The resulting measurements coating compound 18

weights for the same weight of original CFB and means for each sample group were calculated.

Statistical Analysis

T-tests were used to compare the mean weights of the residual coating compounds in the

handsheets, formed from the printed CFB, with those of the original CFB. Before the

Printed CFB was compared to the original CFB, the results of the base stock control were

subtracted from the printed CFB figures to eliminate any effects the deinking procedures

might have had on the HPLC results.

PRINTED CFB BASE STOCK

OO. xbI ai Originalool ^ 1 OO I 4mcan USING T-TEST COMPARE OOlwc!eh" for weights for > uul",uCFB. No No O O OO I residual coating.__ OOl anV detectable Processing oo^ cnii,ounds Processing go-* n*u"ia1'

2 2 ,00^ xw Repulpingoodo! 4 mean RepulpingooljOO I ft*.4 mean Xc-h2 1 weights foifor No oo \ weights for No O O > a ool residual coating OOl any dctoct* Chemicals oo compounds Chemicals oor\ r\J materials ORIGINAL 66 75&. CFB 3 Deinking oo 3 Deinking oo 4 mean xc-b3 oo weights for Xa-bl Chemicals Chemicals detectable gg oo any 4 mean No Bleach oo No Bleach oo} materials coating "S3 compound 4 4 Deinking oo Deinking xc-b4 weights Chemicals weights for Chemicals residual coating & Bleach oo;} compounds & Bleach

Figure 4

Control Group and t-test Comparisons Chapter Six

Analysis

In an effort to extract any remaining coating compounds, one CFB handsheet, from each of the three deinking procedures, and five grams of unprocessed CFB were immersed in an organic solvent. These solutions were sonicated for one hour and the resulting liquid was withdrawn. The handsheets from the base stock control group, and five grams of unprocessed base stock were also made into solutions and sonicated for one hour. Five grams of base stock contains more cellulose than five grams of CFB because a portion of the CFB weight is coating weight. Therefore, a larger amount of solvent was used to account for the difference in weight. The solvent employed was tetrahydrofurane (THF).

This solvent was able to extract the oil and dye precursor used in the CB coating, and the resin used in the CF coating. It was observed that the solvent did not extract the binders or the pigments used in the coatings. It must also be noted, that the assumption has been made that the solvent was able to extract all the remaining coating compounds.

The prepared solutions were analyzed using the HPLC. The coating compounds absorb a certain amount of UV light, depending upon the amount of coating compound present, and the HPLC's recorder draws a peak reflecting the strength of the signal. The numbers generated by the HPLC's integrator are a measurement of the areas under these peaks. As a

stock samples were subtracted from the control, the signals generated by the base signals

samples. numbers are recorded in Table Al (Appendix generated by the CFB The resulting observed of the A). It should be noted that there were no signals dye precursor. This

precursor present in the samples or means that there was either no dye deinked that the

undetectable the HPLC. amount present was so small as to be by

Since these numbers generated by the HPLC are not easily understood, a series of

signals units calculations were made to convert the HPLC into familiar (concentration of

grams of cellulose). Tables A2-A5 (Appendix contain coating compounds per 10 A)

make the from signals additional information necessary to conversion, HPLC to

19 20

concentration, and illustrate the process by which this conversion was made. Table 1, below, is a copy of the final step in the conversion process (Step 8). The numbers in this chart were used in the statistical analysis.

RESIN: Concentration per of lOg Cellulose OIL: Concentration per 10 g of Cellulose Sample Concentration STD Sample Concentrat ion STD CFB 1.630 0.269 CFB 0.986 0.360 RP 0.021 0.004 RP 0.015 0.003 CH 0.045 0.007 CH 0.019 0.004 BL 0.032 0.004 BL 0.011 0.002

Table 1

Concentration of Coating Compounds per lOgrams of Cellulose

Table 2 is, a copy of Step 9 of Table A5, and is a further simplification of the data. It

shows the relative retention of the coating compounds using percentages of remaining

coating compounds as compared to the amount of coating compounds present in the

unprocessed CFB form.

RESIN: Relative Retention of Coating OIL: Relative Retention of Coating CFB 100% CFB 100% CFBRP 1.3% CFBRP 1.5% CFB CH 2.7% CFBCH 1.9% CFBBL 1.9% CFBBL 1.1%

Table 2

Relative Retention of Coating Compounds Chapter Seven

Conclusions and Recommendations for Further Research

Hypotheses Restated

1. Without the addition of deinking chemicals and bleach, there will be no significant amount of coating compounds remaining in the handsheet formed by repulping the

printed CFB portion of a carbonless form.

2. Without bleach, there will be no significant amount of coating compounds remaining in the handsheet formed by deinking the printed CFB portion of a carbonless form. 3. With deinking chemicals and bleach, there will be no significant amount of coating compounds remaining in the handsheet formed by deinking the printed CFB portion

of a carbonless form.

Conclusions

Statistical analysis revealed that, at a 99 percent confidence level, the amount of resin and oil remaining in the handsheets, after each of the deinking procedures, compared to zero, was significant. Therefore, the results do not support the hypotheses.

RESIN: t-statistic at 99% confidence OIL: t-statistic at 99% confidence CFB RP if 10.50 > 5.841 reject Hx CFBRP if 10.00 > 5.841 reject Hj CFB CH if 12.86 > 5.841 reject H2 CFBCH if 9.50 > 5.841 reject H2 CFB BL if 16.00 > 5.841 reject H3 CFBBL if 11.00 > 5.841 reject H3

Table3

Student's t-statistic

(See Appendix B for statistical procedures and calculations) According to the Relative Retention percentages (Table 4, below), the repulping

successful at the while the process (RP) was the most removing resin, process which

21 22

used only the deinking chemicals was the least successful. The process which included both the chemicals and bleach (BL) was the most successful at removing the oil, while the process which included just the deinking chemicals (CH) was least successful.

In Appendix B are the derivations of the confidence intervals, at a 90% confidence level, for both the resin and the oil. Table 5, below, is a summary of this information. For the resin, the calculations show that the confidence intervals, for all three processes, do not overlap, and are distinctly different from each other. The confidence interval results, support the conclusion that the repulping process was the most successful at removing the resin and the chemical-only process was least successful. For the oil, the confidence intervals for the chemicals-only and the chemicals-plus-bleach processes do

chemicals-plus- not overlap . These processes are distinctly different, with the deinking bleach process being the most successful and the chemical-only process the least successful at removing the oil. Conversely, the confidence interval for the repulping procedure overlaps with the other two procedures. Therefore, one cannot state whether

the repulping process was more or less effective than the other processes. These findings are in keeping with the 1979 study by Lothar Pfalzer, which found that deinking procedures were more effective when the alkali (sodium hydroxide; one of the deinking chemicals) was removed from the process. The addition of bleach somewhat counteracts the negative effects of the deinking chemicals, especially in the removal of the oil. This may be due to the bleach attacking the microcapsule, which are

still intact after repulping, causing more oil to be released then washed away.

RESIN: Relative Retention of Coating OIL: Relative Retention of Coating CFB 100% CFB 100% CFBRP 1.3% CFBRP 1.5% CFB CH 2.7% CFBCH 1.9% CFBBL 1.9% CFBBL 1.1%

Table 4

Relative Retention of Coating Compounds

RESIN

RP 0.0163 < ^i < 0.0257

CH 0.0368 < |i < 0.0532

BL 0.0273 < u. < 0.0367 23

OIL

RP 0.0115

CH 0.014 <|i< 0.0237

BL 0.0086

Table 5

Confidence Intervals at a 90% Confidence Level

Recommendations For Further Research

The beaker level experiment, used in this study, is limited in its ability to replicate the deinking process of a full-scale facility. For example, the beaker level experiment is unable to simulate the effects various washing techniques might have on the removal of the coating compounds. Grams of furnish do not respond in the same manner as tons of furnish. It is therefore necessary to do additional research using bench-scale and semi- pilot-scale equipment, which more closely emulate the process of deinking in a full-scale facility. In addition, the number of replicates must be increased to insure more reliable results.

End use requirements are important in recycling. If the deinked pulp is to be used to make cardboard boxes then the presence of some remaining coating compounds is not crucial. But, if the deinked pulp is to be used to make new carbonless forms, then the presence of coating compounds may cause problems if they react with pew coatings being applied. Although the t-statistic indicated that the deinking processes were not compounds that will cause when entirely successful, the percentage of coating problems, trying to make new carbonless forms from deinked forms, is still to be determined. Carbonless forms from various manufactures should be studied, since each manufacture has their own coating formulas. If carbonless forms are not to be source

of waste then the separated, but included with other types paper, coating formulas may

compatible with the require modifications to make them more deinking processes.,

process for an single source of wastepaper. To discover more rather than modifying the

and bleach react with the individual about how the deinking chemicals coating

portions of the should be studied independently. If compounds, the CB and CF form,

are and their inert or microcapsules are washed out intact, they contents, do they pose

waste water treated and of? problem later in the cycle when is disposed Forms which 24

are made from tinted stocks must also be studied. If additional bleach is need to remove the color from the tinted stocks, then how will this impact the removal of the coating compounds? Bibliography

25 26

Bibliography

Broeren, Lawrence A. "New Technology, Economic Benefits Give Boost to Secondary Use." Fiber Paper & Pulp, November 1989, 69.

Computer Publishing Magazine, December 1990. "Publishing and the Planet; A forest of

Options." Recycling

Future." Duffey, Matthew, and Penny Lewis. "Don't trash Our The New GETzette, Winter 1991.

Inks." Forester, William K. "Deinking of UV-Cured Tappi Journal, May 1987, 127.

Paper." Galin, Robert B. "Demand for Increases for Recycled Printing and Writing Pulp and Paper, March 1990, 198.

Paper." Galin, Robert B. "Demand Increasing for Recycled Printing and Writing Pulp & Paper, March 1990, 198.

Papers." Galin, Robert B. "Trash Crunch Drives Demand for Recycled Printing/Writing Paper & Pulp, March 1989, 88-89.

Loop' Paper." Hulgren, Dennis. "Appleton Papers 'Closes the On carbonless Paper Age Recycling Annual 1990, 47.

Market." Klass, Charles P. "Recycling: Remaking the Coated Paper PIMA Magazine, May 1990, 33.

Papers." Pfalzer, Lothar. "Deinking of Xerographic and Carbonless Copy Tappi Journal, July 1979, 27-30. Appendix A

27 28

Appendix A

HPLC Signals Translated Into Concentrations

RESIN: CFB Signals (HPLC) minus Base Stock Signals (HPLC) Sample 1 Average STD CFB 2.877E+05 2.952E+05 3.458E+05 3.365E+05 3.540E+05 3.238E+05 2.714E+04 RP * 4.552E+04 3.902E+04 2.433E+04 2.942E+04 3.457E+04 8.230E+03 CH * 7.009E+04 8.675E+04 6.044E+04 7.609E+04 7.334E+04 9.543E+03 BL * 5.880E+04 4.985E+04 5.438E+04 4.596E+04 5.225E+04 4.816E+03

OIL: CFB Signals (HPLC) minus Base Stock Signals (HPLC) Sample 1 Average STD CFB 1.510E+06 1.378E+06 1.469E+06 1.459E+06 1.515E+06 1.466E+06 4.959E+04 RP * 1.419E+05 2.239E+05 1.749E+05 2.126E+05 1.883E+05 3.237E+04 CH * 2.772E+05 2.261E+05 2.274E+05 2.008E+05 2.329E+05 2.772E+04 BL * 1.445E+05 1.193E+05 1.467E+05 1.113E+05 1.305E+05 1.543E+04

signals obtained for these samples were inaccurate and * Due to improper cleaning of the HPLC injector port, therefore, were not used in statistical analysis

Table Al

HPLC Signals for Resin and Oil 29

Weight of Handsheets in Grams (each Handsheet was made from half of original lOgm Furnish) BSRP BSCH BSBL CFBRP CFBCH CFBBL 4.320 4.290 4.500 3.400 3.460 3.510 4.360 4.440 4.500 3.560 3.490 3.400 3.990 4.360 4.240 3.380 3.610 3.430 4.670 4.370 4.470 3.410 3.390 3.410 4.590 4.360 4.270 3.540 3.510 3.480 4.180 4.330 4.380 3.460 3.440 3.370 4.370 4.230 4.300 3.420 3.510 3.360 4.360 4.480 4.420 3.530 3.410 3.550 4.270 4.360 4.240 3.470 3.310 3.380 4.440 4.280 4.430 3.510 3.680 3.570 AVG 4.355 4.350 4.375 3.468 3.481 3.446 STD 0.183 0.070 0.099 0.061 0.101 0.073

Table A2

Weight of Handsheets

Cellulose Recovery per 10 grams of Furnish BSRP BSCH BSBL CFBRP CFBCH CFBBL 8.710 8.700 8.750 6.698 6.545 6.614

Percent Efficiency of Cellulose Recovery [Furnish - (Resin and on)+ too] BSRP BSCH BSBL CFBRP CFBCH CFBBL 0.871 0.870 0.875 0.845 0.826 0.834

Table A3

Cellulose Recovery and Percent Efficiency 30

STEP1 STEP 2

Weight of Forms Used in Furnish By doing doing the following calculations Base Stock CFB CF the weight of the Coating Compounds 2.652 3.402 3.118 can be determined: 2.608 3.405 3.073

2.609 3.361 3.059 CFB - CF = OIL 2.639 3.309 3.132 3.344 - 3.082 = 0.261 (2SIG 0.095) 2.619 3.281 3.077

2.675 3.384 - 3.116 CF BASE = RESIN 2.663 3.300 3.089 3.082-2.651 = 0.432 (2SIG 0.071) 2.674 3.307 3.072

2.691 3.323 3.072 CFB - BASE = RESIN and Oil

2.664 3.299 3.051 3.344 - 2.65 1 = 0.693 (2SIG 0.099) 2.660 3.369 3.069 3.342 3.068 Manufacture's Coating Compound Weights 3.332 3.076 Base Weight = 12.2 3.402 CF Coating Weight = 1.5 (this is the Resin) AVG 2.651 3.344 3.082 CB Coating Weight = 0.85 (this is the Oil) STD 0.027 0.041 0.024

STEP 3 Comparison of Our Calculated Coating Compound Weights Used in Furnish to Those Supplied by the Manufacturer

Ratios (Resin + Oil) -s- Base Resin *- Oil Oil + (Resin + Oil) Resin + (Resin + Oil) Manuf. 0.193 0.567 0.362 0.638 Calc. 0.262 0.605 0.377 0.623

Table A4 Determining Coating Compound Weights 31

STEP 4 STEP 5 STEP 6

Mass Per Sheet Concentration Extinction Coefficient 8.5" 11" (grams per x sheet) (grams /ml Solvent) (UV Absorbance/gram/ml) Value STD Base 2.651 7.926E-02 Resin 0.432 1.292E-02 2.507E+07 3.120E+06 Oil 0.261 7.819E-03 1.875E+08 3.736E+07

STEP 7

RESIN: Concentration (grams/ml THF) OIL: Concentration per (grams/mlTHF) Sample Concentration STD Sample Concentration STD RP 1.379E-03 2.500E-04 RP 1.004E-03 1.864E-04 CH 2.926E-03 3.724E-04 CH 1.242E-03 1.976E-04 BL 2.084E-03 2.257E-04 BL 6.957E-04 1.105E-04

STEP 8

RESIN: Concentration per lOg ofCellulose OIL: Concentration per 10 g of Cellulose Sample Concentration STD Sample Concentration STD CFB 1.630 0.269 CFB 0.986 0.360 RP 0.021 0.004 RP 0.015 0.003 CH 0.045 0.007 CH 0.019 0.004 BL 0.032 0.004 BL 0.011 0.002

STEP 9

RESIN: Relative Retention of Coating OIL: Relative Retention of Coating CFB 100% CFB 100% CFBRP 1.3% CFBRP 1.5% CFBCH 2.7% CFBCH 1.9% CFBBL 1.9% CFBBL 1.1%

Table A5

Concentrations of Coating Compounds Appendix B

32 33

Appendix B

Statistical Procedures

STUDENT'S T-DISTRIBUTION

Since the population variance is not known, the random variable tn-l=X-u. Sx/Vn follows a Student's t-distribution with (n-1) degrees of freedom

Hj: p: = |i0 -> 0.021 = 0 is rejected against the alternative Hq: 0.021 > 0

Reject H0 if x-u.0

Sx/Vn >tn.i,a/2

CFB RP Resin

0.021-0