5.1?When
a drop of liquid rests on the surface of a solid, and a gas is in
contact with both, the forces acting at the interfaces must
balance. These forces can be represented by surface energies acting
in the direction of the surfaces and it follows that:
5.1.1?The right side of the above equation
(the difference between the surface energies of the gas - solid and
solid - liquid interfaces) is defined as the wetting tension of the
solid surface. It is not a fundamental property of the surface but
depends on interaction between the solid and a particular
environment.
5.1.2?When the gas is air saturated with
vapors of the liquid, ?GL will be the surface tension of the
liquid. If the angle of contact is 0? the liquid is said to just
wet the surface of the solid, and in this particular case (since
cos ? = 1) the wetting tension of the solid will be equal to the
surface tension of the liquid.
5.2?The
ability of polyethylene and polypropylene films to retain inks,
coatings, adhesives, etc., is primarily dependent upon the
character of their surfaces, and can be improved by one of several
surface-treating techniques. These same treating techniques have
been found to increase the wetting tension of a polyethylene or a
polypropylene film surface in contact with mixtures of formamide
and ethyl Cellosolve in the presence of air. It is therefore
possible to relate the wetting tension of a polyethylene or a
polypropylene film surface to its ability to accept and retain
inks, coatings, adhesives, etc. The measured wetting tension of a
specific film surface can only be related to acceptable ink,
coating, or adhesive retention through experience. Wetting tension
in itself is not a completely acceptable measure of ink, coating,
or adhesive adhesion.
Note 3:?A wetting tension of 35 dynes/cm or higher has been
generally found to reveal a degree of treatment normally regarded
as acceptable for tubular film made from Type 1 polyethylene and
intended for commercial flexographic printing. It is, however,
possible that some other level of wetting tension may be required
to indicate the acceptability of polyethylene films made by other
processes, or from other types of polyethylene, or intended for
other uses.
At the present date, insufficient experience
has been gained to state a generally acceptable level of wetting
tension for polypropylene films for commercial flexographic
printing.
1. Scope
1.1?This
test method covers the measurement of the wetting tension of a
polyethylene or polypropylene film surface in contact with drops of
specific test solutions in the presence of air.
1.2?The
values stated in SI units are to be regarded as standard. The
values given in parentheses are mathematical conversions to
inch-pound units that are provided for information only and are not
considered standard.
Note 1:?This test method and the specified reagents were
specifically developed for polyethylene and polypropylene films. It
is possible to utilize this test method and the specified reagents
for films composed of other polymers, but this can affect the
surface energies of the gas-liquid and solid-liquid interfaces,
which will affect the contact angle and wetting tension. The
applicability and significance for use of non-polyolefin materials
must be established by the user.
1.3?This standard does not purport to
address all of the safety concerns, if any, associated with its
use. It is the responsibility of the user of this standard to
establish appropriate safety, health, and environmental practices
and determine the applicability of regulatory limitations prior to
use. Specific hazards statements are given in Section 9.
Note 2:?This test method is equivalent to ISO 8296.
1.4?This international standard was
developed in accordance with internationally recognized principles
on standardization established in the Decision on Principles for
the Development of International Standards, Guides and
Recommendations issued by the World Trade Organization Technical
Barriers to Trade (TBT) Committee.
2. Referenced Documents
ISO 8296
Plastics--Film and
Sheeting--Determination of Wetting Tension Available from American
National Standards Institute (ANSI), 25 W. 43rd St., 4th Floor, New
York, NY 10036, http://www.ansi.org.
Potrebujeme váš súhlas na využitie jednotlivých dát, aby sa vám okrem iného mohli ukazovať informácie týkajúce sa vašich záujmov. Súhlas udelíte kliknutím na tlačidlo „OK“.
Tu máte možnosť prispôsobiť si nastavenia súborov cookies v súlade s vlastnými preferenciami.
Technické cookies
Tieto cookies sú nevyhnutné pro správne fungovanie webu a všetkých funkcií, ktoré webové stránky ponúka. Technické cookies nemôžu byť vypnuté, pretože sú zodpovedné za uchovávanie produktov v košíku, nastavenie filtrov, prevedenie nákupného procesu, zoznamu obľúbených a nastavenia súkromia.
Analytické cookies nám umožňujú meranie výkonu nášho webu a našich reklamných kampaní. Ich pomocou určujeme počet návštev a zdroje návštev našich webových stránok. Dáta získané pomocou týchto cookies spracovávame súhrnne, bez použitia identifikátorov, ktoré ukazujú na konkrétnych užívateľov nášho webu. Pokiaľ vypnete používanie analytických cookies vo vzťahu k Vašej návšteve, strácame možnosť analýzy výkonu a optimalizácie našich opatrení.
Používame taktiež súbory cookie a ďalšie technológie, aby sme prispôsobili náš obchod potrebám a záujmom našich zákazníkov a pripravili tak pre Vás výnimočné nákupné skúsenosti.
Vďaka použitiu personalizovaných súborov cookie sa môžeme vyvarovať vysvetľovaniu nežiaducich informácií, ako sú nezodpovedajúce odporúčania výrobkov alebo neužitočné mimoriadne ponuky. Navyše nám používanie personalizovaných súborov cookie umožňuje ponúkať vám dodatočné funkcie, ako napríklad odporúčania výrobkov prispôsobených vašim potrebám.
Reklamné cookies používame my alebo naši partneri, aby sme Vám mohli zobraziť vhodné obsahy alebo reklamy tak na našich stránkach, ako aj na stránkach tretích subjektov. Vďaka tomu môžeme vytvárať profily založené na Vašich záujmoch, takzvané pseudonymizované profily. Na základe týchto informácií nie je spravidla možná bezprostredná identifikácia Vašej osoby, pretože sú používané iba pseudonymizované údaje. Ak nevyjadríte súhlas, nebudete príjemcom obsahov a reklám prispôsobených vašim záujmom.
Cookies
