ASTM D5946-09
(Test Method)Standard Test Method for Corona-Treated Polymer Films Using Water Contact Angle Measurements
Standard Test Method for Corona-Treated Polymer Films Using Water Contact Angle Measurements
SIGNIFICANCE AND USE
The ability of polymer films to retain inks, coatings, adhesives, etc. is primarily dependent on the character of their surfaces and can be improved by one of several surface-treating techniques. The electrical discharge treatment, such as corona treatment, has been found to increase the wetting tension of a polymer film. The stronger the treatment, the more actively the surface reacts with different polar interfaces. It is therefore possible to relate the contact angle of a polymer film surface to its ability to accept and retain inks, coatings, adhesives, etc., if the ink, coating, or adhesive contains the polar functionalities. Contact angle in itself is not a completely acceptable measure of ink, coating, or adhesive adhesion.
The wetting tension of a polymer film belongs to a group of physical parameters for which no standard of accuracy exists. The wetting tension of a polymer cannot be measured directly because solids do not change shape measurably in reaction to surface energy. Many indirect methods have been proposed. Different test methods tend to produce different results on identical samples. Practical determination of a solid's surface energy uses this interaction of the solid with test liquids.
Although the level of surface treatment of polymer films has been traditionally defined in the industry in terms of dynes/cm (mN/m), these values are derived from a subjective interpretation of the observed test liquid behavior.
The following ranges of water contact angle values can be used as a guide for defining the level of surface treatment of polyolefins and many other polymer films with initial low surface energies:
Marginal or no treatment>90° Low treatment85 to 90° Medium treatment78 to 84° High treatment71 to 77° Very high treatment71°
The suitability of the test for specification acceptance, manufacturing control, and end use of polymer films will have to be established through capability studies for each particular film and treatment.
A...
SCOPE
1.1 This test method covers measurement of the contact angle of water droplets on corona-treated polymer film surfaces.
Note 1—This test method is identical to ISO 15989.
1.2 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.
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 and health practices and determine the applicability of regulatory limitations prior to use.
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Designation: D5946 − 09
Standard Test Method for
Corona-Treated Polymer Films Using Water Contact Angle
1
Measurements
This standard is issued under the fixed designation D5946; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope* 3.1.1 static contact angle, θ (degrees), n—theanglebetween
the substrate surface and the tangent line drawn to the droplet
1.1 This test method covers measurement of the contact
surface at the three-phase point, when a liquid drop is resting
angle of water droplets on corona-treated polymer film sur-
on a plane solid surface.
faces.
3.1.1.1 Discussion—Contact angle values can be deter-
NOTE 1—This test method is identical to ISO 15989.
mined as follows: (1) by analyzing an image of a droplet using
1.2 The values stated in SI units are to be regarded as the
various projection or reflective devices and measuring the
standard. The values given in parentheses are for information
contact angle directly with a protractor by using tangential
only.
alignment of a cursor line or the use of reference alignment
procedures (Test Method D724); or (2) by analyzing an image
1.3 This standard does not purport to address all of the
of a droplet using various projection or reflective devices and
safety concerns, if any, associated with its use. It is the
measuring the height and width on the substrate surface to
responsibility of the user of this standard to establish appro-
calculate the contact angle as follows:
priate safety and health practices and determine the applica-
bility of regulatory limitations prior to use.
θ 5 2·arctan~H/R! (1)
where:
2. Referenced Documents
θ = contact angle,
2
2.1 ASTM Standards:
H = height of a droplet’s image, and
D618 Practice for Conditioning Plastics for Testing
R = half its width.
D724 Test Method for Surface Wettability of Paper (Angle-
3
of-Contact Method) (Withdrawn 2009)
E691 Practice for Conducting an Interlaboratory Study to
Determine the Precision of a Test Method
4
2.2 ISO Standard:
ISO 15989 Plastics—Film and Sheeting—Measurement of
Water-Contact Angle of Corona-Treated Films
3. Terminology
3.1 Definitions of Terms Specific to This Standard:
1
This test method is under the jurisdiction ofASTM Committee D20 on Plastics
and is the direct responsibility of Subcommittee D20.19 on Film, Sheeting, and
Molded Products.
3.1.1.2 Discussion—Instrumentation is also available that
Current edition approved April 1, 2009. Published April 2009. Originally
utilizes an image and directly determines the contact angle
approved in 1996. Last previous edition approved in 2004 as D5946 - 04. DOI:
10.1520/D5946-09.
based on the calculation shown for Method (2) of U.S. Patent
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
No. 5,268,733.
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
3.1.1.3 Discussion—Method (1) may be biased due to the
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website.
subjective nature of visually finding a tangent to the droplet
3
The last approved version of this historical standard is referenced on
image at the three-phase point; if Method (1) is to be used, the
www.astm.org.
4
bias of each operator’s measurements shall be determined.
Available fromAmerican National Standards Institute (ANSI), 25 W. 43rd St.,
4th Floor, New York, NY 10036, http://www.ansi.org. Because Method (2) utilizes measured dimensions of the
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
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D5946 − 09
droplet, it would be expected to have less bias. Comparative Therefore, multiple measurements are necessary to reflect
analyses using these various procedures have not been con- variation in treatment and surface roughness.
ducted. Therefore, caution is recommended when comparing
data obtained from these different methods. 6. Interferences
3.1.1.4 Discussion—Method (2) may not be applicable in
6.1 The wetting tension of a polymer film in contact with a
special cases in which the contact angle is greater than 90°
drop of liquid in the presence of air is a function of the surface
energies of both the air-film and film-liquid interfaces; any
4. Summary of Test Method
trace of surface-active impurities in the test liquid or on the
4.1 In this test method, drops of water are placed on the
film may affect the results. It is therefore important that the
surface of a film sample, and the contact angle
...
This document is not anASTM standard and is intended only to provide the user of anASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation:D5946–04 Designation:D5946–09
Standard Test Method for
Corona-Treated Polymer Films Using Water Contact Angle
1
Measurements
This standard is issued under the fixed designation D 5946; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope*
1.1This1.1 Thistestmethodcoversmeasurementofthecontactangleofwaterdropletsoncorona-treatedpolymerfilmsurfaces.
NOTE1—There is no similar or equivalent ISO standard. 1—This test method is identical to ISO 15989.
1.2 The values stated in SI units are to be regarded as the standard.The values given in bracketsparentheses are for information
only.
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 and health practices and determine the applicability of regulatory
limitations prior to use.
2. Referenced Documents
2
2.1 ASTM Standards:
D 618 Practice for Conditioning Plastics for Testing
D 724 Test Method for Surface Wettability of Paper (Angle-of-Contact Method)
E 691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
3
2.2 ISO Standard:
ISO 15989 Plastics—Film and Sheeting—Measurement of Water-Contact Angle of Corona-Treated Films
3. Terminology
3.1 Definitions of Terms Specific to This Standard:
3.1.1 static contact angle, u (degrees), n—the angle between the substrate surface and the tangent line drawn to the droplet
surface at the three-phase point, when a liquid drop is resting on a plane solid surface.
3.1.1.1 Discussion—Contact angle values can be determined as follows: (1) by analyzing an image of a droplet using various
projection or reflective devices and measuring the contact angle directly with a protractor by using tangential alignment of a cursor
line or the use of reference alignment procedures (Test Method D 724); or ( 2) by analyzing an image of a droplet using various
projection or reflective devices and measuring the height and width on the substrate surface to calculate the contact angle as
follows:
u5 2 · arc tan ~H/R! (1)
where:
u = contact angle,
H = height of a droplet’s image, and
R = half its width.
1
This test method is under the jurisdiction ofASTM Committee D20 on Plastics and is the direct responsibility of Subcommittee D20.19 on Film and Sheeting . Current
edition approved February 1, 2004. Published March 2004. Originally published as D5946–96. Last previous edition D5946–01.on Film and Sheeting .
Current edition approved April 1, 2009. Published April 2009. Originally approved in 1996. Last previous edition approved in 2004 as D 5946 - 04.
2
For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
3
Wu, S., Polymer Interface and Adhesion, Marcel Dekker, Inc., New York, NY, 1982.
3
Available from American National Standards Institute (ANSI), 25 W. 43rd St., 4th Floor, New York, NY 10036, http://www.ansi.org.
*A Summary of Changes section appears at the end of this standard.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
1
---------------------- Page: 1 ----------------------
D5946–09
3.1.1.2 Discussion—Instrumentation is also available that utilizes an image and directly determines the contact angle based on
the calculation shown for Method (2) of U.S. Patent No. 5,268,733.
3.1.1.3 Discussion—Method (1) may be biased due to the subjective nature of visually finding a tangent to the droplet image
atthethree-phasepoint;ifMethod(1)istobeused,thebiasofeachoperator’smeasurementsshallbedetermined.BecauseMethod
(2) utilizes measured dimensions of the droplet, it would be expected to have less bias. Comparative analyses using these various
procedures have not been conducted. Therefore, caution is recommended when comparing data obtained from these different
methods.
3.1.1.4 Discussion—Method (2) may not be applicable in special cases in which the contact angle is greater than 90°
4. Summary of Test Method
4.1 In this test method, drops of water are placed on the surface of a film sample, and the contact angle values are measured
an
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