ASTM D6105-04(2012)
(Practice)Standard Practice for Application of Electrical Discharge Surface Treatment (Activation) of Plastics for Adhesive Bonding
Standard Practice for Application of Electrical Discharge Surface Treatment (Activation) of Plastics for Adhesive Bonding
SIGNIFICANCE AND USE
Bonding of many polymeric substrates presents a problem due to the low wettability of their surfaces and their chemical inertness. Adhesive bond formation begins with the establishment of interfacial molecular contact by wetting. Wettability of a substrate surface depends on its surface energy. The surface activation with electrical discharges improves wettability of polymers and subsequent adhesive bonding. The surface activation with electrical discharges results in addition of polar functional groups on the polymer surface. The higher the concentration of polar functional groups on the surface the more actively the surface reacts with the different polar interfaces.
To achieve a proper adhesive bond the polyolefin substrate's polar component should be raised from near zero to 15 to 20 mJ/m2.
The pre-treated surfaces are ready for application of the adhesive immediately after the treatment.
SCOPE
1.1 This practice covers various electrical discharge treatments to be used to enhance the ability of polymeric substrates to be adhesively bonded. This practice does not include additional information on the preparation of test specimens or testing conditions as they are covered in the various ASTM test methods or specifications for specific materials.
1.2 The types of discharge phenomena that are used for surface modification of polymers fit into the general category of nonequilibrium or non-thermal discharges in which electron temperature (mean energy) greatly exceeds the gas temperature.
1.3 The technologies included in this practice are:
TechnologySection Gas plasma at reduced pressure8 Electrical discharges at atmospheric pressure9 AC dielectric barrier discharge9.1 High Frequency Apparatus9.1.1 Suppressed Spark Apparatus9.1.2 Arc Plasma Apparatus9.2 Glow Discharge Apparatus9.3
Note 1—The term “corona treatment” has been applied sometimes in the literature to the different electrical discharge treatment technologies described in Section 9. This practice defines each electrical discharge treatment technology at atmospheric pressure presented in Section 9 and draws the necessary distinctions between them and corona discharge. See Test Method D1868 for “corona discharge.”
1.4 The values stated in SI units are to be regarded as the standard.
1.5 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. Specific hazard statements appear in Section 6.
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Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation: D6105 − 04 (Reapproved 2012)
Standard Practice for
Application of Electrical Discharge Surface Treatment
(Activation) of Plastics for Adhesive Bonding
This standard is issued under the fixed designation D6105; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 2. Referenced Documents
2.1 ASTM Standards:
1.1 This practice covers various electrical discharge treat-
D724Test Method for Surface Wettability of Paper (Angle-
ments to be used to enhance the ability of polymeric substrates
of-Contact Method) (Withdrawn 2009)
to be adhesively bonded. This practice does not include
D907Terminology of Adhesives
additional information on the preparation of test specimens or
D1868Test Method for Detection and Measurement of
testingconditionsastheyarecoveredinthevariousASTMtest
Partial Discharge (Corona) Pulses in Evaluation of Insu-
methods or specifications for specific materials.
lation Systems
1.2 The types of discharge phenomena that are used for D2578TestMethodforWettingTensionofPolyethyleneand
Polypropylene Films
surface modification of polymers fit into the general category
D2651GuideforPreparationofMetalSurfacesforAdhesive
of nonequilibrium or non-thermal discharges in which electron
Bonding
temperature (mean energy) greatly exceeds the gas tempera-
D5946Test Method for Corona-Treated Polymer Films Us-
ture.
ing Water Contact Angle Measurements
1.3 The technologies included in this practice are:
Technology Section 3. Terminology
Gas plasma at reduced pressure 8
3.1 Definitions—Many terms are defined in Terminology
Electrical discharges at atmospheric pressure 9
AC dielectric barrier discharge 9.1
D907.
High Frequency Apparatus 9.1.1
Suppressed Spark Apparatus 9.1.2 3.2 Definitions of Terms Specific to This Standard:
Arc Plasma Apparatus 9.2
3.2.1 AC dielectric barrier discharge, n—a self-sustaining
Glow Discharge Apparatus 9.3
AC discharge in relatively short gaps with a solid dielectric
NOTE 1—The term “corona treatment” has been applied sometimes in layer, where the discharge bridges the entire air gap.
the literature to the different electrical discharge treatment technologies
3.2.2 contact angle, n—the angle in degrees between the
described in Section 9. This practice defines each electrical discharge
substrate surface and the tangent line drawn to the droplet
treatment technology at atmospheric pressure presented in Section 9 and
surface from the three-phase point.
draws the necessary distinctions between them and corona discharge. See
Test Method D1868 for “corona discharge.”
3.2.3 corona, n—visible partial discharges in gases adjacent
to a conductor.
1.4 The values stated in SI units are to be regarded as the
standard. 3.2.4 corona treatment, n—see Note 1.
3.2.5 electrical discharge, n—any of several types of elec-
1.5 This standard does not purport to address all of the
trical breakdown of gases, primarily air.
safety concerns, if any, associated with its use. It is the
3.2.5.1 Discussion—The type of discharge depends upon
responsibility of the user of this standard to establish appro-
several controllable factors, such as electrode geometry, gas
priate safety and health practices and determine the applica-
pressure, power supply impedance, etc. When, at atmospheric
bility of regulatory limitations prior to use. Specific hazard
pressure,thevoltagereachesacertaincriticalvalue,thecurrent
statements appear in Section 6.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
This practice is under the jurisdiction ofASTM Committee D14 on Adhesives contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
and is the direct responsibility of Subcommittee D14.40 on Adhesives for Plastics. Standards volume information, refer to the standard’s Document Summary page on
Current edition approved May 1, 2012. Published May 2012. Originally the ASTM website.
approved in 1997. Last previous edition approved in 2004 as D6105–97(2004). The last approved version of this historical standard is referenced on
DOI: 10.1520/D6105-04R12. www.astm.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D6105 − 04 (2012)
increases very rapidly and a spark results in the establishment the concentration of polar functional groups on the surface the
of one of the self-sustaining discharges, such as corona, arc, more actively the surface reacts with the different polar
glow and dielectric barrier discharge. In many electrical interfaces.
discharges, ionized regions called plasma exist.
5.2 To achieve a proper adhesive bond the polyolefin
3.2.6 electrical discharge treatment, n—activation of a
substrate’spolarcomponentshouldberaisedfromnearzeroto
polymer surface using electrical discharges to increase surface
15 to 20 mJ/m .
energy and create polar functional groups on the polymer
5.3 The pre-treated surfaces are ready for application of the
surface; nonequilibrium discharges are used primarily for
adhesive immediately after the treatment.
surface treatment.
6. Hazards
3.2.7 electric arc, n—a self-sustaining discharge in the gap
between two electrodes having a low voltage drop and capable
6.1 Ozone—Ozone is a by-product of the electrical dis-
of supporting large currents.
chargeinatmospheric-pressureair.Theozoneproducedduring
the treatment can be vented into external atmosphere where
3.2.8 gas plasma, n—extremely reactive, partially ionized
gas consisting of free electrons, positive ions, free radicals, dilution and subsequent breakdown will occur. If the ozone
cannot be vented out, the station should be equipped with an
metastables and other species; plasmas exist over a wide range
of temperature and pressure and are capable of inducing exhaust hood and activated carbon filter or manganese dioxide
catalyst.
chemical modifications on polymer surfaces.
3.2.8.1 Discussion—Thepositiveions,theelectrons,andthe
6.2 Electrical Hazard: Warning—The users of these prac-
neutral gas atoms of a plasma may or may not be in thermal
tices must be aware that there are inherent dangers associated
equilibrium. Since plasma is usually established by an electric
with the use of electrical instrumentation and that these
field,thetemperatureofthepositiveionsisusuallygreaterthan
practices cannot and will not substitute for a practical knowl-
the gas temperature, and the electron temperature may be very
edgeoftheinstrumentusedforaparticularsurfacepreparation.
high.
6.3 Radio Frequency: Warning—Persons with pacemakers
3.2.9 glow, n—in electrical discharges, a self-sustaining
may be affected by the radio frequency.
discharge in the air gap, where the gas near the sharply curved
6.4 Electrical discharge treatments produce no volatile or-
electrode surfaces breaks down at a voltage less than the spark
ganic compound (VOC) emissions.
breakdown voltage for that gap length.
3.2.10 partial discharge, n—electric discharge that only
7. Procedure - General
partially bridges the insulation between conductors.
7.1 Surface Cleanliness—Thesurfacemustbecleanpriorto
3.2.11 polarity, n—in surface chemistry, value that quanti-
submitting the specimen to any of the treatment processes.
fies concentration of polar functional groups on the polymer
Potential surface contaminants include the following:
surface and is measured as a polar component of surface
additives, handling residue (fingerprints), mold release, ma-
energy divided by a sum of polar and non-polar components.
chine oil, and grease.
3.2.12 spark breakdown, n—a sudden transition from the 7.1.1 Techniques for Cleaning Surface—Useatechniquefor
“dark” discharge to one of the several forms of self-sustaining cleaning the surface appropriate for the substrate. If no other
discharge; this transition consists of a sudden change in the cleaningmethodisspecified,useasolventwipewithisopropyl
current. alcohol and clean, low lint cloth or wipes.
3.2.13 surface energy, n—for a given solid, defines molecu-
7.2 Selection of Appropriate Electrical Discharge
lar forces of its interaction with other interfaces, J/m .
Treatment—When making a choice the following factors must
be considered:
4. Summary of Practice 7.2.1 Necessary treatment level,
7.2.2 Treatment speed,
4.1 This practice identifies and defines several electrical
7.2.3 Treated parts shape and size,
discharge treatment technologies for surface modification of
7.2.4 Process type – continuous, batch, etc, and
polymers. The practice outlines essential technical aspects of
7.2.5 Economics.
each technology.
Consult the attribute chart in Appendix X1 for comparison.
5. Significance and Use 7.3 Procedure for Polymer Surface Treatment—Surface
treatment with electrical discharges involves, in general, ap-
5.1 Bonding of many polymeric substrates presents a prob-
plying the discharge, and the plasma generated in the
lem due to the low wettability of their surfaces and their
discharge, to the surface to be treated.
chemical inertness. Adhesive bond formation begins with the
establishment of interfacial molecular contact by wetting. 7.4 Procedure for Determining Effıcacy of Treatment:
Wettabilityofasubstratesurfacedependsonitssurfaceenergy. 7.4.1 Water Break Test, Guide D2651, Section 5.5.4. A
The surface activation with electrical discharges improves water-break test is a common method used to analyze surface
wettability of polymers and subsequent adhesive bonding.The cleanliness. This test depends on the observation that a clean
surface activation with electrical discharges results in addition surface (one that is chemically active or polar) will hold a
of polar functional groups on the polymer surface. The higher continuous film of water, rather than a series of isolated
D6105 − 04 (2012)
droplets. This is known as a water-break-free cond
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