Utjecaj viskoznosti tiskarskih boja na kvalitetu otiska na tiskovnim podlogama s ne-drvnim vlakancima

master's thesis

• Author: Davor Zember
• Mentor: Irena Bates (mentor)
• Committee member: Ivana Plazonić (član povjerenstva)
• Committee member: Irena Bates (član povjerenstva)
• Committee member: Igor Zjakić (član povjerenstva)
• Granter: University of Zagreb; Faculty of Graphic Arts; Zagreb
• Defense date and country: 2022-7-21, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Graphic Technology

Abstract

Viskoznost je svojstvo (plinova i tekućina) da se odupru strujanju ili relativnom

gibanju susjednih slojeva. Viskoznost je vrsta unutarnjeg trenja tekućine.

Kvantitativna mjera unutarnjeg trenja je koeficijent viskoznosti tekućine.

Viskoznost ovisi o: strukturi tvari i temperaturi (značajno opada s porastom

temperature). Viskoznost je trenje koje nastaje kada molekule tekućine pomiču

svoje slojeve tijekom strujanja (deformacije) pod utjecajem odgovarajućeg

naprezanja. Očituje se samo kada se tekućina kreće. To se događa kada se

slojevi tekućine kreću različitim brzinama. Budući da tiskarske boje sadrže

suspendirane pigmentne čestice, koje su poput plastike, imaju veliki utjecaj na

mjerenje viskoznosti – relativne elastičnosti boje. To znači da se mora primijeniti

određena sila kako bi metalni cilindar viskozimetra prevladao relativnu

elastičnost boje prije nego što se cilindar aktivira. Sila potrebna da se prevlada

relativna elastičnost (krutost) prevlake naziva se granica tečenja. Granica

tečenja boje ovisi o količini pigmenta, veličini čestica i obliku pigmenta te

stupnju njegove disperzije ili flokulacije u vezivu. Viskoznost gustih tiskarskih

boja određuje se mjerenjem otpora metalne šipke kroz boju u jedinici vremena.

Za rijetke tiskarske boje koristite jednostavan ručni viskozimetar, drugačija

ispusna čašica s mlaznicom na dnu mjerne posude. Mjeri protok volumena boje

u jedinici vremena kroz otvor definiranog promjera. Viskoznost tiskarskih boja

također se može odrediti pomoću rotacijskog viskozimetra: mjerenjem otpora

koji tekućina pruža rotaciji metalne osovine/vretena.

Abstract (english)

Viscosity is the property of gases and liquids to resist flow or relative motion of

adjacent layers. Viscosity is a form of internal friction of a fluid. A quantitative

measure of internal friction is the coefficient of viscosity of a liquid. Viscosity

depends on the structure of the substance and the temperature (it decreases

significantly with increasing temperature). Viscosity is the friction that occurs

when liquid molecules move their layers during flow (deformation) under the

influence of an appropriate stress. It occurs only when the fluid is in motion.

This happens when the liquid layers move at different speeds. Since printing

inks contain suspended pigment particles, which are like plastic, they have a

great influence on the measurement of viscosity - the relative elasticity of the

ink. This means that a certain force must be applied for the metal cylinder of the

viscometer to overcome the relative elasticity of the ink before the cylinder is

activated. The force required to overcome the relative elasticity (stiffness) of the

coating is called the yield strength. The yield strength of ink depends on the

amount of pigment, the particle size and shape of the pigment, and the degree

to which it is dispersed or flocculated in the binder. The viscosity of dense

printing inks is determined by measuring the resistance of a metal bar through

the ink in a unit of time. For rare printing inks, a simple hand-held viscometer is

used, a different discharge cup with a nozzle at the bottom of the measuring

cup. It measures the flow of the ink volume in a unit of time through an orifice of

a certain diameter. The viscosity of printing inks can also be determined with a

rotational viscometer by measuring the resistance that the liquid offers to the

rotation of the metal axis/spindle.

• Keywords: boje; tehnike tiska; tiskovne podloge s ne-drvnim vlakancima; viskoznost
• Keywords (english): viscosity; inks; non-wood fiber printing substrates; printing techniques
• Language: croatian
• URN:NBN: urn:nbn:hr:216:691653
• Study programme: Title: Graphic technology; specializations in: Graphic technology, Design of graphic products; Course: Graphic technology; Study programme type: university; Study level: graduate; Academic / professional title: sveučilišni/a magistar/magistra inženjer/inženjerka grafičke tehnologije (sveučilišni/a magistar/magistra inženjer/inženjerka grafičke tehnologije)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2024-04-18 23:39:18