The Influence of Soap on Starch-Pigment Coated Paper

A literature survey is presented concerning the effects of soap on the rheological properties of coatings, and upon the physical properties of the coated paper. The influence of sodium, ammonium, and calcium stearates is investigated, and it is found that soaps produce desirable effects upon both the flow properties of coating colors and the physical properties of the coated paper. The experimental results indicate that sodium stearate is superior to either ammonium or calcium stearate, in that all of the properties tested for are either enhanced or remain about the same when sodium soap is added to the coating, whereas the ammonium and calcium soaps produce both desirable and deleterious effects

Laboratory investigation of the effect of the dampening solution on the loss of surface strength of coated paper

Wet pick is thought to be caused by the presence of water used in lithography. The quantity of the wetting fluid, surface tension of the wetting fluid and the time interval between wetting and printing were tested to see if they affect the paper surface strength. Two rolls of web paper are pre-sampled from the RIT press room. One was found to exhibit the problem of wet pick while the other did not exhibit this defect. These papers were tested on the IGT Printability Tester in a manner similar to that predicted on press when a moisture film of 0.2 micrometer is applied with no delay between application of ink and water. This method can be used to predict the defect referred to as wet pick. Adding to the moisture film thickness results in an increased wet pick in both good and bad paper with a delay between dampening and inking of 0.3 and 0 . 6 seconds . This researcher hypothesized that for a wetting fluid, the factors that contribute to picking are the quantity, the evaporation rate, and the wetting characteristic

A Study of the Relative Effectivness of Four Insolubilizing Agents in Starch-Latex and Protein-Latex Coatings

The process of offset lithography requires several unique characteristics in paper. One of these is an ability in the sheet surface to accept water without deteriorating. Offset coatings commonly use starch and protein in their binder systems. These adhesives are inherently water sensitive. The characteristic of water resistance in coated grades can be obtained through the use of crosslinking agents. Among the more commonly used are unreaformaldehyde, melamine-formaldehyde, and glyoxal. A more recent development involves the use of ammonium zirconium carbonate. Through the years many studies have examined the effects of various insolubilizing agents in starch coatings. Most of these have analyzed only one agent and have all but excluded protein coatings. A need seemed to exist for a comparative analysis of the commonly used insolubilizing agents in both starch and protein coatings. The lack of literature concerning ammonium zirconium carbonate suggested that its analysis should be included. A series of starch and protein based coatings were prepared using 16 parts adhesive and 100 parts clay. Styrene-butadiene latex was included in both coatings. Urea-formaldehyde, melamine-formaldehyde, and glyoxal were added at levels of 5, 7, 9, 11, and 13 percent based on dry starch or protein. Ammonium zirconium carbonate, due to its purported superior insolubilizing efficiency was added at levels of 1, 3, 5, 7, and 9 percent. A four pound coat weight was applied by a hand-held blade drawdown technique to a 45 pound base sheet. Testing of water resistance was carried out via an on-press technique. The samples were allowed to cure two months before testing. The samples were allowed to cure two months before testing. Results showed that urea-formaldehyde produced the highest degree of water resistance. Ammonium zirconium carbonate was competitive with UF and MF resins when added at levels greater than 5%, even when those agents were added at higher levels. Glyoxal harmed starch-latex coating water resistance. Analysis of the protein-latex coatings proved inconclusive

A Laboratory study of ink splitting forces at different film thicknesses and an investigation of the stefan equation

Ink tack is a term used by printers to describe the force required to split an ink film. Such film splitting is influenced by rheological and adhesive properties as well as the internal cohesion of ink. Furthermore, the concept of ink tack in printing is associated with the forces or energy developed in the splitting of ink film at the exit of a printing nip. Stefan studied the forces required to split a thin film. He found that the force required to split a thin film is inversely proportional to the cube of the thickness of that film. This association between the film thickness and film splitting force has been questioned in the literature and by this study. In printing, the practical condition related to ink film splitting forces might be revealed by measurement on the Inkometer ( Inkometer response), paper picking, and ink trapping. This study used these responses. The purpose of this study was to investigate the relationship (not mathematical) between ink film thickness (0.6 to 5.4 pm) that should include the film thicknesses found on presses. Experiment one was accomplished on the Inkometer with the two black vegetable-oil-based inks to obtain the Inkometer response under the proposed three way factorial experimental design ( inks, ink film thicknesses, and time.) Experiment two made use of the IGT Printability Tester with the same inks, the IGT oil, and one of the paper samples to find the critical picking velocity under the proposed two way factorial experimental design ( fluids, ink film thicknesses.) Experiment three was accomplished with the IGT Printability Tester, the same inks, and two substrates including a second paper sample and a plastic film. The response is gravimetric trapping under the proposed three way factorial experimental design ( inks, substrates, and ink film thicknesses.) Inkometer response, picking velocity, and gravimetric trapping are not direct measurements of film splitting force. They are related to film splitting force. The greater the Inkometer response, the more tacky the ink. The higher the picking velocity the lower the splitting force. With increased gravimetric trapping of the second-down inks, the more tacky the first-down inks. The data was analyzed by ANOVA at a level of significance equal to 0.05 ( two-sided ) to test the null hypotheses. The null hypotheses are the following: Hq^: There is no significant effect due to vegetable-oil-based ink film thickness on ink tack as measured by an Inkometer. Hq2: There is no significant effect due to film thickness of vegetable-oilbased fluid on picking velocity under the proposed experimental design on the IGT Printability Tester. H.Q3: There is no significant effect due to the first down vegetable-oil-based ink film thickness on ink trapping capability under the proposed experimental design on the IGT Printability Tester. An overview of the results show that the ink film thickness could affect the Inkometer response and gravimetric trapping, and the oil-based fluids\u27 film thicknesses could affect the picking velocity within the film thicknesses range of 0.6 to 5.4 pm. The graph of data, regression analysis, and R2 are prepared for predicting and evaluating the specific tendency of the measurements ( Inkometer response, picking velocity, and gravimetric trapping ) when ink film thicknesses change. They also show the tendency of change of the splitting forces at the different film thicknesses. The other general results on the basis of the graphs, regression analysis, and Rz show that the Inkometer response increases when ink film thicknesses increased from 0.6 to 5.4 pm with both of the inks and at each time interval. Picking velocity decreased when the ink film thicknesses increased up to about 3.0 pm and then increases with increased ink film thickness from around 3.0 pm to 5.4 pm at each the ink level. The gravimetric trapping on both the paper and plastic substrates and with both inks decrease with the ink film thickness increased from 0.6 to 5.4 pm. There is no consistent agreement with the equation proposed by Stefan

The Effects of Styrene-Butadiene Latex Binder on the Properties of a Coated Sheet

The objective of this thesis proposal is to determine the effect of a varying latex binder on the physical and optical characteristics of a coated sheet with different binder addition levels. A total of nine separate coating formulations were made up of three different styrene to butadiene ratios and three different binder addition levels. The optical properties that were tested include opacity, brightness, paper gloss, and K&N ink absorption. The adhesive properties were evaluated by testing the physical properties of pick strength, abrasion resistance, and wet rub. The porosity and roughness characteristics were also tested. One liter of each coating formulation was made and ran on the CLC laboratory coater. A fifty pound basis weight base sheet was used. The parameters such as coat weight, percent solids, low shear viscosity, pH, pigment, and drying conditions were held constant at values to ensure good runnability on the CLC and resembling those most commonly used within the industry. The focus of this thesis topic being the binder variable, more specifically styrene-butadiene latex. The latex was obtained from the Dow chemical company at three different styrene to butadiene ratios within each latex. One formulation contained Dow 617 latex (hard} with a styrene/butadiene ratio of 1.9 and a glass transitional temperature (Tg) of 18 C. The second formulation contained Dow 620 latex (typical) with a styrene/butadiene ratio of 1.7 and a Tg of 12 C. The final formulation contained Dow 679 latex (soft) with a styrene/butadiene ratio of 1.3 and a Tg of -10 C. The amount of latex binder based on dry pigment became another variable. One coating formulation contained the typical 12% binder, one was lower approximately containing 8% binder, and the other was above the typical at 18% binder based on dry pigment. By altering the latex binder, the properties of the coating formulation itself alters. Certain properties such as film formation, glass transitional temperature, coalescence, and pigment to binder interactions all vary by changing the amount and type of latex. It can be concluded that the hard latex at a lower binder level is desired to achieve optimum optical characteristics while soft latex at a high binder level is desired for optimum binding strength characteristics. A compromise between the two must be achieved while making the proper coating formulation

A Study of Bentonite as an Additive for Starch Size Press Treatment

The size press has been examined in the past for its application for coating or pre-coating. Bentonite has been found to be a rheology modifier and also has been found to form a film on paper. Bentonite has been found to improve holdout and printing properties as well. In this study, bentonite was applied in small quantities on a pilot machine size press and the paper thus produced was examined for any improvements in coating, physical, and optical properties. Testing showed that bentonite had the greatest effect on porosity and pick strength, in that porosity decreased with increasing bentonite and pick increased with small amounts of bentonite but then fell off with higher levels of bentonite. Generally, it was found that addition of bentonite could be beneficial to some properties at one level of addition while being beneficial to other properties at other levels of addition

Use of the Vandercook Proof Press to Predict Rotogravure Print Quality

The object of this thesis is to investigate a new idea in predicting printability for rotogravure printing. Present proof presses in the gravure industry are clumsy, expensive, and in most cases, impractical for regular use. In order to understand the relationship between ink, paper, and plate, it is necessary to consider many variables such as smoothness, ink receptivity, porosity, moisture content, formation, surface strength, and opacity. The laboratory work performed and presented in this paper shows that a Vandercook proof press may be used to predict printability in the gravure process

Monikerroskartongin lujuuskemia

The consumption of multiply packaging boards has vastly increased. To save environment and materials, the consumption of recycled fibers has grown at the same time. However, recycled fibers are poor in quality. Especially Z-directional tensile between plies is difficult to improve and lower quality fibers address more challenges. The aim of the thesis was to establish reliable way to make multiply sheets in laboratory environment, using the latest z-directional strength improving techniques. Both folding boxboard (FBB) and testliner sheets were formed with dynamic sheet former (DSF). At the same time, the best performing plybond chemistry was under study. A nonionic spray starch was introduced between top/middle and middle /bottom plies of FBB. Anionic, amphoteric and cationic strength chemicals were tested in the spray starch. Z-strength was tested, and the retention of starch granules was observed microscopically. The study showed, that multiply sheets including special layers were possible to form, but the time-consuming forming of several layers needs some alteration. Results revealed, that the spray starch alone promotes strength. The strength of FBB was improved by 23 % with combination of spray starch, low amount of cationic starch and amphoteric polymer carrying relatively low anionic charge. Starch granules were detected between layers. Also, anionic chemical was found to improve strength when sufficient amount of cationic starch was added into the pulp. An aqualayer consisting of refined pulp, cationic starch and cationic, anionic or amphoteric strength chemical was introduced between testliner plies. Testliner was tested for burst, short span compression SCT and Z-strength. It was seen that refined pulp had strength improving tendency. Anionic strength chemistry was found to improve the z-strength of testliner even further. The burst strength and SCT of test liner were also improved. In this study charge of the strength chemical was not dictating property.Pakkauskartonkien kulutus on kasvanut merkittävästi ja samaten kiertokuidun ja matala tiheyksisen kemi-hierteen (CTMP) käyttö pakkausmateriaalina, tarkoituksenä säästää ymäristöä ja tehostaa materiaalien käyttöä. Riittävä kerrostenvälinen z-suuntainen lujuus on vaikea toteuttaa ja kiertokuidun heikentyvä laatu sekä kemi-hierteen entistäkin alhaisempi tiheys vaikeuttaa lujuuden saavuttamista entisestään. Työn tavoitteena oli luoda luotettava laboratoriomittakaavainen monikerroskartonkien valmistustapa käyttäen uusimpia, kerrosten välistä lujuutta parantavia tekniikoita. Sekä taivekartongin että lainerin valmistusta testattiin dynaamisella arkkimuotilla. Samanaikaisesti testattiin erilaisia lujuuspolymeereja etsien parasta kerrostenvälistä lujuutta parantavaa yhdistelmää. Taivekartongin kerrosten väliin ruiskutettiin veteen sekoitettua keittämätöntä natiivia maissitärkkelystä, johon oli sekoitettu joko anionista, kationista tai amfoteerista lujuuspolymeeriä. Arkkien lujutta testattiin mittaamalla z-lujuus ja arkkien poikkileikkeet kuvannettiin, jotta saatiin todistettua tärkin asettuminen kerrosten rajapintaan. Tulokset osoittivat, että monikerroskartonkia oli mahdollista valmistaa uudella menetelmällä, mutta arkintekoon kuluva aika saattoi olla liian pitkä. Tulokset osoittivat, että spray-tärkki itsessään parantaa jonkin verran lujuutta. Amfoteerisen polymeerin, spray-tärkin ja kationisen massatärkin yhdistelmällä lujuus parani jopa 23 % referenssiin verrattuna. Kuvantamalla saatiin todistettua tärkkipartikkeleiden sijoittuminen kerrosten rajapintaan. Myös anioninen lujuuskemikaali paransi merkittävästi lujuutta kun tärkin määrä kaksinkertaistettiin. Kiertokuidusta valmistetun lainerin pintakerrosten väliin ruiskutettiin vesikerros, joka koostui jauhetusta massasta, kationisesta tärkistä sekä anionisesta, kationisesta tai amfoteerisesta lujuuspolymeeristä. Lujuus testaattin mittaamalla z-lujuus, puhkaisulujuus sekä puristuslujuus (SCT). Tulokset osoittivat, että jauhettu massa yksinään parantaa huomattavasti Z-suuntaista lujuutta, anionisen kemikaalin lisätessä tätä vaikutusta. Z-lujuuden parantuminen ei tapahtunut muiden lujuusominaisuusien kustannuksella. Myös puhkaisu- ja puristuslujuus paranivat jonkin verran. Tässä tutkimuksessa tärkkimäärän nosto näkyi anionisen polymeerin tehoa nostavana tekijänä, vaikka lujuuspolymeerien varauksien suuruudella ei havaittu olevan johdonmukaista merkitystä

The Effect of Sizing and Wet-Strength Agents on the Ease of Ink Removal in Reclaiming of Ink Printed Waste Paper

Introduction The new call for conservation of resources inherent in ecological movement has put a spotlight on the recycling of materials. Not the least of these materials are paper and paperboard on which some 58 million tons were used in the United States in the year 1969. About 40 million tons of this was discarded which resulted in a severe trash removal problem. Paper accounts for 35% of the total solid waste collected and disposed of in most municipalities

A Study of how coated paper\u27s roughness, gloss and absorptivity affect on side and print gloss

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