Light fastness of printing inks: a review

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The interaction between inks and substrates is critical during printing. Adhesion of the ink film is determined by the reciprocal interactions of polar and nonpolar (dispersive) components between polymer films and inks. The greater the similarity between the polar and dispersive components of inks, coating and substrates, the better the wetting and adhesion on the surface of printing substrate. Various liquid materials in printing such as inks, varnishes, lacquers, and adhesives contain high ratios of water. The highly polar nature of water makes the interaction of these materials unsuitable with predominantly disperse polymer surfaces. Some films with polyolefin structure, especially polypropylene, and polyethylene, are nonpolar and cannot form strong bonds with ink, varnish, or lacquer coatings due to their chemical structure. Increasing surface energy components overcomes the poor wetting and adhesion on polymer surfaces. In this review, the topics of water contact angle measurement and determination of surface energy, surface tension, and using sessile drop method for the wettability and ink adhesion of polymer films are surveyed. Information on structural and chemical processes was given that assists in obtaining wettable film surfaces. Recommendations were made for good adhesion and printability based on surface treatment methods and ink modification.

Section: Discussionmentioning

confidence: 99%

Surface analysis of polymer films for wettability and ink adhesion

Aydemir

Altay

Akyol

2020

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“…Light fastness is the resistance of colors to fading or darkening under the influence of light. 29 Pigment selection is one of the key critical factors affecting the light fastness of ink. However, other components in ink are also thought to affect light fastness resistance.…”

Section: Color Change Following Light Fastnessmentioning

confidence: 99%

The use of natural (Pinus pinaster) resin in the production of printing ink and the printability effect

Karademir

Aydemir

Yenidoğan

et al. 2020

Self Cite

Alkyd resins are generally used in the production of printing inks. All industries look for alternative raw materials in the production of ink with the growing inclination toward using natural products. Resins forming the vehicle of the ink to be obtained from natural resources will provide benefits for the environment, nature, and living creatures. The aim of the study was to promote the use of natural resin in the ink system. Natural Pinus pinaster resin was added into vegetable and mineral oil-based solvents in pure form with alkyd resin in different amounts and ink varnishes of different combinations were prepared. Then, printing inks were produced from these varnishes in pure and hybrid form. Following the assessment of the rheological properties of the inks prepared, printing tests were conducted to assess the printing quality parameters. Ideal mixing ratios of the natural resins in the ink were determined for printability. The environmental importance and advantages of the use of natural resins were discussed. Recommendations were given in line with the results to encourage widespread use of natural resins in near future.

“…[21][22][23] Nishimura et al 24 have discussed about the significant role of temperature and humidity on the yellowing rates of digital prints in cultural heritage collections. Aydemir and Yenidogan 25 have applied a standard blue wool scale to characterize the light fastness properties of printed ink where the pigment selection is considered as an important factor on the lightfastness of printed material. The color degradation has been explained by applying the first-order kinetic model by Medley, 26 Ahmed et al, 27 and Mandal et al 1 The photofading mechanism of colored materials are detailed by Haillant 28 who has reported the photochemical behavior of organic or mineral colorant molecules and resin due to exposure of real or artificial light conditions.…”

Section: Related Workmentioning

confidence: 99%

Artificial neural network approach to predict the lightfastness of gravure prints on the plastic film

Mandal

Bandyopadhyay

2020

The lightfastness of prints is an important property for assessing their print stability. The objective of this study is to determine the lightfastness rate of printed films due to long‐time exposure by applying artificial neural network (ANN). Package printing is gradually becoming extremely important because its color and quality increase the marketability of the product. Sometimes it has been observed that the initial print quality is bright and attractive. However, with time, it degrades the exposure of light, water, or other external parameters. Thus, it reduces the marketability if its color degrades before its expiration. Therefore, the lightfastness of prints may be considered for the authenticity or validity of the product. The plastic film substrate is chosen because it has extensive usage in food and other packaging industries. The samples printed in the gravure process are exposed in artificial lightfastness tester BGD 865/A Bench Xenon Test Chamber (B‐SUN) for assessing the lightfastness of prints. The ocean optics spectroradiometer (DH2000BAL) is used to measure the spectrophotometric properties of prints before and after exposure. The obtained reflectance spectra are modeled by applying an ANN technique that is proposed to predict the fading rate of the printed film. The optimal model gives excellent prediction with the minimum mean square error for each color and a correlation coefficient of 0.80 to 0.99. ANN model and a Regression model (assuming first‐order kinetic equation) are compared for predicting the lightfastness properties of prints. The results show that the ANN has better prediction capability than the regression model.