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PV 3.3.3 Group Standard

Issue 2007-09

Class. No.:

57650

Descriptors:

paint, varnish, scratch resistance, automatic car wash, Amtec-Kistler method, car wash lab apparatus

Paints and Varnishes Scratch Resistance Testing of Clear Coats

Previous issues PV 3.3.3: 2001-09, 2006-07 Changes The following changes have been made as compared to Test Specification PV 3.3.3: 2006-07: ─ ─

1

Evaluation methods added Referenced documents updated Scope

This standard contains additional specifications to be applied when testing scratch resistance according to DIN EN ISO 20566. 2

Description

Scratch resistance according to PV 3.3.3 Test method

The test is carried out acc. to DIN EN ISO 20566 using the car wash lab apparatus made by Amtec-Kistler GmbH. The operating manual of the device and the applicable work instructions must be observed. It is essential to recognize that this method cannot be used to determine reliable absolute values as the age of the brush has a considerable influence on the scratching results. The results can only be compared to reference material tested at the same time. Check standard for current issue prior to usage. The English translation is believed to be accurate. In case of discrepancies the German version shall govern. Numerical

Page 1 of 3

notation acc. to ISO practice. This electronically generated standard is authentic and valid without signature.

Technical Responsibility

Standards

P1O Reinhard Alberts P1O/D Eckhard Bricke P1O/D Katharina Gallenkemper

Phone: +49-5361-9-72122

EKTC/4 Jürgen Wiesner Phone: +49-5361-9-29064

EKTC Manfred Terlinden

Vertraulich. Alle Rechte vorbehalten. No part of this document may be transmitted or reproduced without the prior permission of a Standards department within the Volkswagen Group. Contract partners shall obtain the standard only through the B2B supplier platform www.vwgroupsupply.com.

© VOLKSWAGEN AG

vwnorm-2007-07

QUELLE: NOLIS

3

Page 2 Issue PV 3.3.3: 2007-09

In addition, the following deviations from the standard must be considered: ─

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Washing suspension (Section 4.1 of DIN EN ISO 20566: 2007-01) The washing suspension consists of 1,5 g of quartz powder (Dorsilit® 10000 made by Dorfner, Hirschau, telephone: +49 (0) 9622-82-0) with an average grain size d50 of 19 µm per liter of deionized water (DI water). The water temperature must be between 18 °C and 28 °C. A constant temperature level of 25 °C, for example, allows for an improved repeatability. NOTE: Tap water can also be used instead of DI water as long as no inter-instrumental comparison is carried out. Test plates (Section 6 of DIN EN ISO 20566: 2007-01) Unless otherwise agreed upon, the test plates and reference plates are made from sheet steel with original paint structure, size (290 x 120 x 0,8) mm (body panel sheet steel). Solid black paint is to be preferably used as a base coat. Testing in the car wash lab apparatus is to be carried out only after conditioning of the plates once the coating samples are applied. To this end, the plates are conditioned for 1 day at 60 °C and then for another day at standard climate acc. to DIN EN 23270. Test procedure and evaluation (Sections 7 and 8 of DIN EN ISO 20566: 2007-01) Prior to testing, the initial gloss values at 20° acc. to DIN EN ISO 2813 are to be documented. The applicable value is the mean value calculated from nine values measured transverse to the expected scratching direction. (Note: haze is not applicable as a measuring quantity.) A test run consisting of 10 double strokes is carried out without test plates. Then the test plates are subjected to 10 double strokes each. After loading, the test plates are rinsed with cold DI water in order to remove quartz powder residues. Then the plates are carefully dried using a non-scratching paper towel and cleaned with a microfiber cloth soaked in petroleum spirit in order to remove the abraded bristle material without residues. Within 2 hours after drying, the residual gloss is then measured at 20° acc. to DIN EN ISO 2813, transverse to the scratching direction. In the homogeneous area of the test plate, the mean value is determined from nine individual measurements. At least 2 test plates per sample are to be measured. The specimens are aged for 2 hours at 60 °C in order to evaluate the reflow behavior. After cooling to room temperature, the residual gloss is determined again. Test report (Section 10 of DIN EN ISO 20566: 2007-01) In order to consider the degree of wear of the brushes, the test report must also contain actual and initial measured values of the reference panels in addition to the values of gloss and residual gloss after loading and reflow. Cross-check of car wash lab apparatus (Section A.1 of DIN EN ISO 20566: 2007-01) With each test, a reference plate must also be loaded in parallel which always remains in the same position on the washing table, in order to check the washing brushes. The brush must be exchanged after about 50 h of load. Note: It is recommended to prepare a sufficient number of reference plates for the test duration from standard production material. If new reference plates are required, their characteristics must come as close as possible to those of the existent panels. Deviations must be considered and documented.

As far as this is required by the particular task, deviations from this standard are possible subject to documentation of the changes made. 4

Evaluation

The evaluation as compared to the reference values is done by calculating differences or quotients, depending on the agreement with the entity granting the release.

Page 3 Issue PV 3.3.3: 2007-09

4.1

Evaluation based on calculation of differences

The following values must be given: ─ ─ ─ ─ ─ ─

Initial gloss of sample GA Residual gloss after load GE Residual gloss after reflow GR Gloss difference of sample GD sample = GA sample – GE sample Gloss difference of reference GD reference = GA reference – GE reference Gloss loss compared to reference GV reference = GD reference – GD sample

Interpretation: ─

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4.2

Comparative values for loss of gloss compared to reference GV reference = 0 Sample and reference plate are equal regarding their resistance to automatic car wash treatment. Comparative values for loss of gloss compared to reference GV reference > 0 The sample has a higher resistance to automatic car wash treatment than the reference. Comparative values for loss of gloss compared to reference GV reference < 0 The sample has a lower resistance to automatic car wash treatment than the reference. Evaluation based on calculation of quotients

The following values must be given: ─ ─ ─ ─ ─ ─ ─

Initial gloss of sample GA Residual gloss after load GE Residual gloss after reflow GR Percentage of residual gloss after load GE [%] = (GE *100)/ GA Percentage of reflow after load GR [%] = (GR *100)/ GA Corresponding values for the reference plate GE reference and GR reference Comparative values for scratch resistance VE= GE [%]/GE reference [%] and VR= GR [%]/GR reference [%]

Interpretation: ─

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5

Comparative values for scratch resistance VE = 1 Sample and reference plate are equal regarding their resistance to automatic car wash treatment. Comparative values for scratch resistance VE < 1 The sample has a lower resistance to automatic car wash treatment than the reference. Comparative values for scratch resistance VE > 1 The sample has a higher resistance to automatic car wash treatment than the reference. Referenced standards

The following documents cited in this standard are necessary for its application. In this Section, terminological inconsistencies may occur as the original titles are used. DIN EN 23270

Paints, Varnishes and their Raw Materials; Temperatures and Humidities for Conditioning and Testing

DIN EN ISO 2813

Coating Materials; Determining the Reflectometer Value of Coatings (Excluding Metallic Coatings) below 20°, 60° and 85°

DIN EN ISO 20566 Paints and varnishes – Determination of the Scratch Resistance of a Coating System Using a Laboratory Car-Wash