ASTM D6105-04(2019)

Standard Practice for Application of Electrical Discharge Surface Treatment (Activation) of Plastics for Adhesive Bonding

SIGNIFICANCE AND USE
5.1 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.  
5.2 To achieve a proper adhesive bond the polyolefin substrate's polar component should be raised from near zero to 15 to 20 mJ/m2.  
5.3 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:    
Technology  
Section  
Gas plasma at reduced pressure  
8  
Electrical discharges at atmospheric pressure  
9  
AC dielectric barrier discharge  
9.1  
High Frequency Apparatus  
9.1.1  
Suppressed Spark Apparatus  
9.1.2  
Arc Plasma Apparatus  
9.2  
Glow Discharge Apparatus  
9.3
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, health, and environmental practices and determine the applicability of regulatory limitations prior to use. Specific hazard statements appear in Section 6.  
1.6 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.

General Information

• Status: Published
• Publication Date: 31-May-2019
• ICS: 83.140.01 - Rubber and plastics products in general
• Technical Committee: D14 - Adhesives
• Drafting Committee: D14.40 - Adhesives for Plastics

Relations

• Replaces: ASTM D6105-04(2012) - Standard Practice for Application of Electrical Discharge Surface Treatment (Activation) of Plastics for Adhesive Bonding
• Effective Date: 01-Jun-2019
• Refers: ASTM D1868-20 - Standard Test Method for Detection and Measurement of Partial Discharge (Corona) Pulses in Evaluation of Insulation Systems
• Effective Date: 01-Mar-2020
• Refers: ASTM D5946-17 - Standard Test Method for Corona-Treated Polymer Films Using Water Contact Angle Measurements
• Effective Date: 01-May-2017
• Refers: ASTM D2651-01(2016) - Standard Guide for Preparation of Metal Surfaces for Adhesive Bonding
• Effective Date: 01-May-2016
• Refers: ASTM D1868-13 - Standard Test Method for Detection and Measurement of Partial Discharge (Corona) Pulses in Evaluation of Insulation Systems
• Effective Date: 01-Nov-2013
• Refers: ASTM D907-12a - Standard Terminology of Adhesives
• Effective Date: 01-Jul-2012
• Refers: ASTM D907-12 - Standard Terminology of Adhesives
• Effective Date: 01-May-2012
• Refers: ASTM D907-11a - Standard Terminology of Adhesives
• Effective Date: 01-Dec-2011
• Refers: ASTM D907-11 - Standard Terminology of Adhesives
• Effective Date: 01-Jan-2011
• Refers: ASTM D2578-09 - Standard Test Method for Wetting Tension of Polyethylene and Polypropylene Films
• Effective Date: 01-Sep-2009
• Refers: ASTM D5946-09 - Standard Test Method for Corona-Treated Polymer Films Using Water Contact Angle Measurements
• Effective Date: 01-Apr-2009
• Refers: ASTM D2578-08 - Standard Test Method for Wetting Tension of Polyethylene and Polypropylene Films
• Effective Date: 01-Nov-2008
• Refers: ASTM D907-08b - Standard Terminology of Adhesives
• Effective Date: 01-Oct-2008
• Refers: ASTM D907-08a - Standard Terminology of Adhesives
• Effective Date: 15-Aug-2008
• Refers: ASTM D2651-01(2008) - Standard Guide for Preparation of Metal Surfaces for Adhesive Bonding
• Effective Date: 01-Apr-2008

Overview

ASTM D6105-04(2019) is a widely recognized standard that provides a practice for applying electrical discharge surface treatment-also known as activation-of plastics to enhance adhesive bonding. Developed by ASTM International, this standard addresses the challenges of bonding polymeric substrates, which often have low surface energy and poor wettability, making adhesive bonding difficult. By using various electrical discharge methods, the surface energy and polarity of plastics are significantly increased, enabling better molecular contact and stronger adhesive bonds.

Electrical discharge surface treatments introduce polar functional groups to the plastic surface, greatly enhancing its reactivity with adhesives. This activation process is immediately effective, allowing for rapid application of adhesives following treatment.

Key Topics

• Purpose of Electrical Discharge Treatments: Overcomes the low wettability and chemical inertness of many plastics, especially polyolefins.
• Principles of Surface Activation: Electrical discharges increase surface energy by adding polar functional groups, which allows better interaction with adhesives.
• Types of Electrical Discharge Technologies:
  • Gas plasma at reduced pressure
  • Atmospheric pressure electrical discharges
  • AC dielectric barrier discharge (including high frequency and suppressed spark apparatus)
  • Arc plasma apparatus
  • Glow discharge apparatus
• Selection Considerations: Treatment level, speed, part size and geometry, process type (continuous, batch), and economic factors.
• Testing for Efficacy: Methods include water break tests, contact angle measurement, and dyne solution tests for confirming increased surface wettability.

Applications

Electrical discharge surface treatment is widely used in industries that require reliable adhesive bonding to plastics, such as:

• Automotive manufacturing: Enabling adhesives to bond to polyolefin body panels, interior trims, and bumpers.
• Consumer goods: Improving adhesion of coatings, graphics, and labels on plastic packaging.
• Medical devices: Enhancing bonding strength of plastic parts and assemblies.
• Electronics: Preparing housing materials for bonding or coating processes.
• Aerospace: Facilitating structural adhesive applications to composite and plastic aerospace components.

By increasing the polar component of a plastic substrate’s surface energy to optimal levels (from near zero to 15–20 mJ/m² for polyolefins), immediate and robust adhesion is achieved, streamlining manufacturing or assembly operations.

Related Standards

• ASTM D907: Terminology of adhesives, essential for understanding concepts and definitions related to adhesive technology.
• ASTM D1868: Test method for detection and measurement of partial discharge (corona) pulses in insulation evaluation.
• ASTM D2578: Test method for wetting tension of polyethylene and polypropylene films.
• ASTM D2651: Guide for preparation of metal surfaces for adhesive bonding; relevant when bonding plastics to metals.
• ASTM D5946: Test method for water contact angle measurement on corona-treated polymer films.

Practical Value

Adopting ASTM D6105-04(2019) for electrical discharge surface treatment ensures repeatable, reliable improvement of plastic adhesion, vital to product durability and process consistency. It guides users in selecting appropriate technology, establishing effective process parameters, and verifying treatment quality-all key for optimizing industrial adhesive bonding to plastics.

Keywords: electrical discharge surface treatment, polymer activation, adhesive bonding, plastic surface preparation, ASTM D6105, plasma treatment, corona treatment, surface energy enhancement.

Standards Content (Sample)

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.
Designation: D6105 − 04 (Reapproved 2019)
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 Development of International Standards, Guides and Recom-
mendations issued by the World Trade Organization Technical
1.1 This practice covers various electrical discharge treat-
Barriers to Trade (TBT) Committee.
ments to be used to enhance the ability of polymeric substrates
to be adhesively bonded. This practice does not include
2. Referenced Documents
additional information on the preparation of test specimens or
testingconditionsastheyarecoveredinthevariousASTMtest 2.1 ASTM Standards:
D724Test Method for Surface Wettability of Paper (Angle-
methods or specifications for specific materials.
of-Contact Method) (Withdrawn 2009)
1.2 The types of discharge phenomena that are used for
D907Terminology of Adhesives
surface modification of polymers fit into the general category
D1868Test Method for Detection and Measurement of
of nonequilibrium or non-thermal discharges in which electron
Partial Discharge (Corona) Pulses in Evaluation of Insu-
temperature (mean energy) greatly exceeds the gas tempera-
lation Systems
ture.
D2578TestMethodforWettingTensionofPolyethyleneand
1.3 The technologies included in this practice are:
Polypropylene Films
Technology Section
D2651GuideforPreparationofMetalSurfacesforAdhesive
Gas plasma at reduced pressure 8
Bonding
Electrical discharges at atmospheric pressure 9
D5946Test Method for Corona-Treated Polymer Films Us-
AC dielectric barrier discharge 9.1
High Frequency Apparatus 9.1.1
ing Water Contact Angle Measurements
Suppressed Spark Apparatus 9.1.2
Arc Plasma Apparatus 9.2
3. Terminology
Glow Discharge Apparatus 9.3
3.1 Definitions—Many terms are defined in Terminology
NOTE 1—The term “corona treatment” has been applied sometimes in
the literature to the different electrical discharge treatment technologies D907.
described in Section 9. This practice defines each electrical discharge
3.2 Definitions of Terms Specific to This Standard:
treatment technology at atmospheric pressure presented in Section 9 and
3.2.1 AC dielectric barrier discharge, n—a self-sustaining
draws the necessary distinctions between them and corona discharge. See
Test Method D1868 for “corona discharge.”
AC discharge in relatively short gaps with a solid dielectric
layer, where the discharge bridges the entire air gap.
1.4 The values stated in SI units are to be regarded as the
standard.
3.2.2 contact angle, n—the angle in degrees between the
substrate surface and the tangent line drawn to the droplet
1.5 This standard does not purport to address all of the
surface from the three-phase point.
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro- 3.2.3 corona, n—visible partial discharges in gases adjacent
priate safety, health, and environmental practices and deter-
to a conductor.
mine the applicability of regulatory limitations prior to use.
3.2.4 corona treatment, n—see Note 1.
Specific hazard statements appear in Section 6.
3.2.5 electrical discharge, n—any of several types of elec-
1.6 This international standard was developed in accor-
trical breakdown of gases, primarily air.
dance with internationally recognized principles on standard-
ization established in the Decision on Principles for the
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 [e-mail]. 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 June 1, 2019. Published June 2019. Originally the ASTM website.
approved in 1997. Last previous edition approved in 2012 as D6105–04(2012). The last approved version of this historical standard is referenced on
DOI: 10.1520/D6105-04R19. www.astm.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D6105 − 04 (2019)
3.2.5.1 Discussion—The type of discharge depends upon The surface activation with electrical discharges improves
several controllable factors, such as electrode geometry, gas wettability of polymers and subsequent adhesive bonding.The
pressure, power supply impedance, etc. When, at atmospheric surface activation with electrical discharges results in addition
pressure,thevoltagereachesacertaincriticalvalue,thecurrent of polar functional groups on the polymer surface. The higher
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.
3.2.7 electric arc, n—a self-sustaining discharge in the gap
6. Hazards
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
3.2.8 gas plasma, n—extremely reactive, partially ionized
the treatment can be vented into external atmosphere where
gas consisting of free electrons, positive ions, free radicals,
dilution and subsequent breakdown will occur. If the ozone
metastables and other species; plasmas exist over a wide range
cannot be vented out, the station should be equipped with an
of temperature and pressure and are capable of inducing
exhaust hood and activated carbon filter or manganese dioxide
chemical modifications on polymer surfaces.
catalyst.
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
electrode surfaces breaks down at a voltage less than the spark
6.4 Electrical discharge treatments produce no volatile or-
breakdown voltage for that gap length.
ganic compound (VOC) emissions.
3.2.10 partial discharge, n—electric discharge that only
partially bridges the insulation between conductors. 7. Procedure - General
3.2.11 polarity, n—in surface chemistry, value that quanti-
7.1 Surface Cleanliness—Thesurfacemustbecleanpriorto
fies concentration of polar functional groups on the polymer
submitting the specimen to any of the treatment processes.
surface and is measured as a polar component of surface
Potential surface contaminants include the following:
energy divided by a sum of polar and non-polar components.
additives, handling residue (fingerprints), mold release, ma-
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,
4.1 This practice identifies and defines several electrical
7.2.2 Treatment speed,
discharge treatment technologies for surface modification of
7.2.3 Treated parts shape and size,
polymers. The practice outlines essential technical aspects of
7.2.4 Process type – continuous, batch, etc, and
each technology.
7.2.5 Economics.
Consult the attribute chart in Appendix X1 for comparison.
5. Significance and Use
7.3 Procedure for Polymer Surface Treatment—Surface
5.1 Bonding of many polymeric substrates presents a prob-
treatment with electrical discharges involves, in general, ap-
lem due to the low wettability of their surfaces and their
plying the discharge, and the plasma generated in the
chemical inertness. Adhesive bond formation begins with the
discharge, to the surface to be treated.
establishment of interfacial molecular contact by wetting.
Wettabilityofasubstratesurfacedependsonitssurfaceenergy. 7.4 Procedure for Determining Effıcacy of Treatment:
D6105 − 04 (2019)
7.4.1 Water Break Test, Guide D2651, Section 5.5.4. A transformer(s). Each generator/transformer(s) set is capable of
water-break t
...