Utjecaj razvijača na promjenu karakteristika slobodnih površina kod CtP ofsetnih ploča

master's thesis

• Author: Martina Jelenić
• Mentor: Miroslav Gojo (mentor)
• Committee member: Miroslav Gojo (član povjerenstva)
• Granter: University of Zagreb; Faculty of Graphic Arts; Zagreb
• Defense date and country: 2006-00-00, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Graphic Technology

Abstract

Zavisno o koncentraciji otopine za vlaženje određivala su se njena fizikalno-kemijska svojstva kao što su električna provodnost, pH vrijednost i napetost površine, dok je na slobodnim površina-ma CtP tiskovnih formi za ofsetni tisak mjeren kontaktni kut. Kontaktni kut je mjeren na uzorci-ma razvijanim u različitim koncentracijama razvijača i različitim vremenima razvijanja.

Dobiveni rezultati ukazuju da električna provodnost raste u cijelom području ispitivanih ko-ncentracija otopine za vlaženje, pri nižim kocentacijama brže, a pri višim koncentracijama sporije, što se objašnjava pokretljivošću iona i njihovoj difuziji u otopini.

Povećanjem koncentracije otopine za vlaženje naglo se smanjuje površinska napetost, što je posljedica povećanja koncentracije dodanih površinski aktivnih tvari. Iz toga proizlazi da, o doda-noj PAT zavisi i sama vrijednost površinske napetosti.

pH vrijednost ispitivanog uzorka otopine za vlaženje naglo se smanjuje, a djelovanje pufera zamjetno je već kod koncentracije od oko 10 vol % otopine za vlaženje.

Kontaktni kut zavisi o koncentraciji otopine za vlaženje, vremenu razvijanja, koncentraciji razvijača i temperaturi razvijača. Povećanjem temperature razvijača kontaktni kut je linearno za-visan o vremenu razvijanja, dok za razrličite temperature pokazuje logaritamsku zavisost o konce-ntraciji otopine za vlaženje.

Dobiveni rezultati ukazuju da vrijeme razvijanja ne bi trebalo biti manje od 75 sekundi za niže temperature i koncentarcije razvijača, dok za više to vrijeme iznosi oko 60 sekundi.

Abstract (english)

Depending on the concentrations of the fountain solution, its physical/chemical properties, such as electrical conductivity, pH value and surface tension were determined, while, on non-image areas of CtP offset printing forms, the contact angle was measured. Contact angle was measured on samples developed in different concentration of developer and during different development time.

The results show that electrical conductivity increases in entire area of examined concentrations of fountain solution more quickly at lower concentrations and slowly at higher concentrations. That can be explained by ions’ mobility and their diffusion in solution.

With increasing concentration of the fountain solution, its surface tension decreases sharply, which is a result of increased concentration of added surface active substances. That indicates that surface tension value depends on added surface active substances.

pH value of examined samples of the fountain solution decreases sharply, and buffers activity can be noticed at the concentration of 10% of the fountain solution.

Contact angle depends on the concentration of the fountain solution, development time and developer’s temperature. By increasing developer’s temperature, contact angle is linearly dependent on development time, while different temperatures are logarithmically dependent on the concentration of the fountain solution.

The results show that the development time should not be shorter then 75 seconds for lower temperatures and concentrations of developer. On the other hand, at higher temperatures and concentrations development time is approximately 60 seconds.

• Keywords: Kontaktni kut; CTP tiskovne forme; proces razvijanja; Električna provodnost; otopina za vlaženje; pH vrijednost; napetost površine
• Keywords (english): Contact angle; CTP printing forms; development process; electrical conductivity; fountain solution; pH value; surface tension
• Language: croatian
• URN:NBN: urn:nbn:hr:216:188203
• 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: Closed access
• Created on: 2024-04-18 14:16:26