DBL 7384-2004 Coating of plastics parts in vehicle interiors.pdf

June 2004 Mercedes-Benz Supply Specification Coating of plastics parts in vehicle interiors DBL 7384 BQF available ? Additional DaimlerChrysler Standards required: See Section 15 Supersedes edition: - Refer to Section Changes Fortsetzung Seite 2 bis 33 Issued by: DaimlerChrysler AG 70546 Stuttgart Standards (EP/QIN) Technical responsibility (name): Schatton/Faas Department: PWT/VBT Plant: 050 Telephone: +49(0)7031 90-5950 HPC: F107 Technical coordination by PWT Plant 50, Department PWT/VBT Name: Mr. Kraus Phone +49(0)7031 90 5326 Confidential! All rights reserved. Distribution or duplication in part or in whole without prior written approval of DaimlerChrysler AG is not permitted. In case of doubt, the German language original should be consulted as the authoritative text. This specification supersedes DBL 7392.20, 7392.30 1 APPLICATIONS This DBL specifies the requirements for the coating quality of coated plastic parts which are used in vehicle interiors, and describes the testing methods. The requirements of this DBL are applicable to water-borne and solvent-based coatings. 2 PRODUCT VERSIONS AND EXAMPLES Table 1 DBL product versions Paint structure Material Application examples 7384.00 single-layer, only coloured soft-effect coat or clear coat PC/ABS preferred e.g. trim, airbag caps 7384.01 two-layer, primer and soft-effect top coat PC/ABS preferred, possibly other plastics, e.g. PA6 GF, ABS e.g. fan outlets A primer may be necessary in case of inhomogeneous surfaces (e.g. in case of striation etc.) and also for adhesion in case of critical substrates 7384.02 two-layer, dyed base coat and soft-effect clear coat as PV .01 e.g. trim subject to higher mechanical stress 7384.03 laser paints one to four layers, possibly metallic, possibly with soft- effect clear coat PC, ABS, PA, PC/ABS e.g. controls, with or without soft touch and feel, depending on version 7384.04 lattice coat, single-layer as PV .01 e.g. fan outlets 7384.05 decorative paintwork one or two layers as PV .01 e.g. trim, without soft touch or feel 7384.06 lustreless matt paintwork (anti-reflection coating) as PV.00 e.g. instrument housing and frame 7384.07 high-gloss coats, matt coats one to three layers, possibly laser capability PC, PC/ABS, ABS e.g. controls, trim 7384.08 laser paint with white base coat silicone only for mulitifunctional keys 7384.09 pad printing paint on coatings see PV.00 to PV.30 and on unpainted substrates e.g. fan outlets, controls 7384.20 cubic print coatings with clear coat a) matt to high gloss b) soft clear coat as PV.00 ornamental fittings and trim 7384.30 carrier film coated with paint, see Section 3.6.2 as PV.00 ornamental fittings and trim 7384.40 coated film with printing on reverse, back-injected, see Section 3.6.2 e.g. PC e.g. controls Page 2 DBL 7384 : June 2004 Designation example for drawings: - in the block for material : e.g. PC/ABS, Bayblend T85, black, DBL 5404.00 - in the block for finish and delivery : e.g. DBL 7384.00 - in the block for surface protection : e.g. coated in accordance with DBL 7384.00, colour according to trim list The grain is defined through the design specification; direct enquiries to Deptm. DE/PKQ. Note: The selection of the product version (PV) depends on the type of coating, the substrate, the quality of the injection-moulded surface and the application. Dept. PWT/VBT Sindelfingen determines the PV in coordination with the EP/DE area and is entitled to initiate a PV change even during the current series production. Coated reference panels are available for evaluating colour and gloss. These panels shall be requested from Deptm. DE/PKQ (Design) Sindelfingen. The reference panels shall be stored in darkness and at room temperature. Any contamination and damage shall be prevented. The colour samples can be matched/checked in Deptm. DE/PKQ and replaced, if required. 3 General requirements 3.1 Blanks The blanks shall be free of manufacturing defects of any type which have a more than an insignificant impact on appearance and serviceability characteristics. The layout of the blanks, including the gating area, shall be designed so that no cracking or embrittlement of the component will subsequently occur as a result of the following coating process. No blisters, dimples, dust and dirt inclusions, silking, sinkages, roughness and/or grain fluctuations, or other surface defects visible after coating are acceptable. No substances impairing the adhesion of the coat may be present on the blank surface or exuded from it. No release agents, preservation or cleaning agents shall be used which might cause paint defects after transfer to surfaces to be coated. Exudations from the substrate after the application of the coat which would impair adhesion or result in surface changes are, for example, unacceptable. The manufacturing process shall be selected so that no delamination can occur. In the design of the components, care shall be taken to ensure that they are not capable of holding water, as the parts must be subjected to an aqueous cleaning process before painting. They shall be designed so that the parts can be retained in paint racks. Radii shall be designed so that adequate coating is possible. In the case of components with critical fit dimensions, the paint layer thickness shall be taken into account in the design of the component. The blanks to be painted shall be delivered to the paintshop in a condition ready for painting and not requiring any rework. Page 3 DBL 7384 : June 2004 3.2 Materials Preference shall be given to materials PC/ABS, e.g. Bayblend T 85 (Bayer) or Pulse A35-110 (DOW) or KU1/1446 (Bayer) or comparable materials. A dyed-through substrate shall be used for door closing handles. This substrate shall always be coated using a paint / paint structure of the same colour. The batches used, e.g. colour batches, shall not result in any impairment to adhesion or other defects and shall be indicated on the annexed sheet “Information concerning the coating of submitted samples“. The processing conditions, e.g. injection moulding conditions, shall be selected so that they do not result in any adhesion, assembly or functional impairments across the complete component. In addition, no stress impairing the coating shall be present in the component. In order to achieve a good touch and feel, a grain with a leather-type structure which is as flat as possible is required. The grain for the relevant components shall be defined in agreement between DE/PKQ and PWT/VBT plastic coating, Sindelfingen. The number of different substrates and grains shall be kept to a minimum, as the grain, in particular, strongly influences the gloss and the touch and feel. The material shall not have a tendency towards delamination and exudation even under the higher temperatures occurring in the vehicle. The application of silicone as a material for parts to be coated, see PV.08, shall be restricted to multifunctional keys, as a very intricate process sequence is required. 3.3 Paint / Paint manufacturers In principle, water-borne paints shall be used for new developments. Should the use of water-borne paints not be possible in a new development, paint systems (base paint, hardeners and thinners) with a danger class of at least A2 shall be used, and a justification shall be submitted to PWT/VBT. The paint materials shall be developed and used according to the state of the art and the statutory regulations taking into account DBL 8585, Negative substance list. The suppliers paint and process materials shall comply with all statutory regulations and decrees applicable to the relevant location until the discontinuation of the production component. In case of paint system for which new samples must be supplied, care shall be taken to ensure that all raw materials used can be procured and used unchanged 5 years. For enquiries about the paint components / paint structure, please apply to Deptm. PWT/VBT Sindelfingen. In spraying consistency, the water-borne primers and paints should have a content of organic solvents of 20 % with reference to 100% solids. The storage stability of paint components should be no less than six months. The coating shall be executed as one, two, three or four-layer paint structure in accordance with the product version or as defined by Deptm. PWT/VBT Sindelfingen. The flexibility of the paint layer / structure shall be equal to or larger than the flexibility of the plastic substrate, and it shall be coordinated to the relevant component stress. The paint material or process shall not cause any embrittlement of the parts endangering the passengers. With regard to the paint composition, DBL 7399 Section 1.2 shall apply. For requirements regarding the coating, refer to Section 4 of this DBL. If no evidence of the weathering behaviour (see Section 4.18) can be provided at the time of sampling, the supplier shall submit the test results and test specimens to Deptm. PWT/VBT as soon as possible and without further request. The paint manufacturer shall provide the paint shop with the processing guidelines for the relevant paint system. Page 4 DBL 7384 : June 2004 3.4 Coated surface The surface shall demonstrate a uniform appearance free of irregularities. The blanks shall be free of manufacturing defects of any type which have a more than an insignificant impact on appearance and serviceability characteristics. No blisters, dimples, dust and dirt inclusions, silking, runs, sinkages, roughness, drying and/or grain fluctuations, or other visible or tangible surface defects are acceptable. The products used during production shall comply with DBL8585. The finished products shall cause no damage to health. Soft-effect coats shall possess a good, soft touch and feel in line with the sample part approved by DC. In order to achieve this touch and feel with the paint systems used at present, the layer thicknesses in accordance with Section 4.3 shall be maintained. The layer thickness of the paint structure shall be within the tolerance agreed in the visible and touchable range of the parts. The touch and feel shall be identical in all accessible places. No negative influence on the areas relevant to the customer shall be caused by the non-visible and non- touchable areas. For the layer thicknesses of non-defined product versions, please consult PWT/VBT Sindelfingen. The depth of the grain after coating shall create a uniform sensual impression at all visible locations. The coated surface shall be resistant to MB cleaning and care products for vehicle interiors and against hand sweat in its as-supplied condition. Repair paintwork is not acceptable with reference to a uniform grain appearance. 3.5 Paint shops / Paint process The cleaning, pre-treatment and coating methods shall be selected so that the requirements of this DBL are fulfilled. An automated, reproducible cleaning of the components is mandatory. For the cleaning process, a multi-zone power wash plant or a chamber washer with several rinsing cycles is preferred. If a different automated cleaning process is used such as CO2 cleaning, its effectiveness shall be demonstrated in good time. The chemicals used shall be selected taking into account the choice of substrate, embrittlement, type of contamination, environmental compatibility and paint adhesion. To ensure process reliability, manual cleaning processes are not acceptable. Automated blow-cleaning using ionized air alone is not sufficient for cleaning. For production parts, status 12/2003, a period of grace is granted for the introduction of the above cleaning methods until the end of 2005, provided that no paint adhesion failures occur. For new start-ups from July 2004, one of the above cleaning concepts shall be implemented. For production parts which are presently not covered by one of the above cleaning processes and which are affected by paint adhesion problems, immediate action shall be taken to comply with the requirements of this DBL (e.g. implementation of a suitable cleaning process, relocation of painting etc.). For paint supply, two-component mixing systems shall be used. The coating process shall be automated - either using robots or automated paint sprayers forming part of appropriate systems. The paints shall be dried in continuous ovens. The drying temperature and time indicated by the paint supplier shall be maintained. The drying temperature indicated by the paint manufacturer is deemed to be the object temperature. This temperature shall be determined, checked regularly and documented. The results shall be submitted to DC on request. Only the products recommended by the paint manufacturer shall be used as hardeners, thinners and rinsing liquid. The paint shop shall confirm to DC that the painting process corresponds to the processing guidelines for the paint system. For a list of potential paint shops, apply to Deptm. PWT/VBT Sindelfingen. Page 5 DBL 7384 : June 2004 3.6 Alternative coating methods 3.6.1 Cubic print method (PV.20) A carrier film coated with paint is immersed in a water bath. The carrier film then separates in the water. The parts to be coated are placed in the water bath. The paint film then coats the part when it is removed from the water bath. The remaining paint is separated mechanically. The parts are dried and provided with a clear coat. To improve adhesion, a bonding agent or activator is often applied before the immersion process. 3.6.2 In-Mould Decoration (IMD) (PV.30) Example 1 Plastic is injected behind a temperature-resistant film placed in the mould with one or several coatings of paint. The coated side of the film must face the substrate. At the temperatures required for the injection process, the paint separates from the film. After a short cooling phase of the plastic and paint, the carrier film is pulled out of the mould, and the coated part is removed. Example 2 Plastic is injected behind a coated or uncoated film which may be preformed. The film may be printed on both sides. 4 TECHNICAL DATA Refer to Table from page 18 These characteristic values and requirements are deemed to be limit values and minimum requirements for the coatings. DaimlerChrysler AG will check the information and assumes a reliable and verifiable capability of the part manufacturer or those responsible for the part to perform this task. This includes, for example, that all indications are determined from painted parts manufactured under reproducible conditions. Additional or deviating requirements going beyond the requirements indicated may be specified if requested or required by PWT/VBT Sindelfingen or the Materials Testing/Paintwork Testing departments of the relevant receiving plant. The target values for product versions 20, 30 and 40 will be specified at a later date. Page 6 DBL 7384 : June 2004 5 TEST METHODS 5.1 Preparation of specimens The tests shall be performed in a condition where the paint is completely dried. Before tests 4.1 4.7, 4.9 - 4.13 and 4.17 4.20, the test specimens shall be stored in 60 C recirculating air for 48 h and then cooled down to room temperature. This heat storage shall not be performed before tests 4.8, 4.14, 4.15 and 4.16. The tests shall be performed in the as-supplied condition. The time of sampling for tests 4.8, 4.14 and 4.15 shall be selected so that the age of the test specimen corresponds to the shortest possible supply condition of the installed part in the DC final assembly plant. For preparation of the specimens for test 4.16, refer to VDA Recommendation 278; see Section 5.12. The tests shall be performed on the components. If a component is not suitable for performing all tests due to its dimensions, these tests may be performed on flat test panels, preferably sized DIN A 5. The test panels shall be manufactured from the same plastic materials as the production parts and coated under production conditions in the production plants. If possible, they should have the same grain as the series production parts. Test sample preparation for product version 09: The pad printing paint shall be printed onto the production paint/the unpainted plastic under production conditions. Tests 4.3, 4.8 and 4.12 shall be performed on the original print. For the other tests, the print shall be executed over the complete surface. Minimum size of the area printed: 6 cm by 3 cm. This shall be produced several times according to the number of tests. 5.2 Colour evaluation under natural daylight The visual colour comparison shall be performed from two evaluation angles under diffused light from northern direction: -Vertical top view with the test panel placed horizontally, angle 90, Light incidence from the front -Tilted towards the front, angle 70 from the horizontal, Light incidence from the front Evaluation stand front (window) back Distance of the stand from the window: 1,50 m Position of the observer: lateral, right or left Distance of the object from the eye: approx. 0,60 m Page 7 DBL 7384 : June 2004 Evaluation criteria in accordance with DIN EN ISO 4628-1, Characteristic values for the evaluation of the intensity of changes of appearance. The colour shall always be indicated as follows: e.g. 2-3 he (lighter), bl (more blue). No metamerism shall occur on the parts. For visual colour evaluation, a light booth simulating daylight is also acceptable. The evaluation angles shall be selected as described above. 5.3 Gloss assessment Assessment using measuring technology: Reflectometer measurement, measuring geometry 60 for matt coatings, 20 for high-gloss coatings. Visual assessment For evaluation angle, refer to Section 5.2 of this DBL, plus in vertical position at eye level, light incidence from behind. Evaluation in accordance with DIN EN ISO 4628-1, Characteristic values for the evaluation of the intensity of changes of appearance. Grained surfaces shall always be assessed visually. In case of metrological deviations from the target value and visual