Patent Application
20090155469
Production of painted, finished thermoplastic fascia and exterior components in limited production numbers, or for mass production, has posed difficulties for suppliers of those components. In the past, facilities adapted to produce such articles required a large volume of product to make construction of such facilities cost effective. In addition, there are environmental concerns regarding CO2 footprints, VOC's, and water contaminated with particulate materials from the paint process that required treatment and/or disposal. Because large product quantities were required to make production economically feasible, such production facilities tended to be constructed away from individual original equipment manufacturers but in geographical encatchment locations and transported significant distances to the automotive site under just in time manufacturing guidelines.
With the increasingly fractionated automotive market, smaller production runs are being made for more and difference models in an attempt by the Original Automotive Manufacturers to accommodate consumer's individual tastes. In addition increased environmental awareness and regulation have demanded a system and method to produce limited production quantities of different painted fascia etc., to accommodate such a varied production of automobiles at various sites. There is a need for a modular, waterless, low VOC and CO2 emission system and method to produce to OEM specifications thermoplastic fascia and components such as automotive body side panels, grills, and bumpers, that is waterless, of low VOC and CO2 emissions and reduces or eliminates transportation costs associated with Just in Time delivery of the painted fascia that can be expanded or contracted on site to accommodate various production requirements of many different models of automobiles.
In one aspect, the present invention relates to a waterless, low VOC and CO2 emission method for preparing a cured, painted thermoplastic substrate. The method comprises treating a thermoplastic substrate with a flame applied nitrogen agent to form functional groups on the substrate conducive to paint adhesion, applying a self curing colored base coat paint to said substrate at a dry air filtration station, applying a self curing clear coat to the painted substrate at a dry air filtration station and accelerating cure in a hybrid oven.
The nitrogen agent is preferably selected from the group consisting of nitrogen gas or dithiolamine. The method may further include passing the painted substrate through an oven having infrared and convention heat to accelerate cross linking of the paint and curing of the clear coat to facilitate drying of the painted substrate within an accelerated time. The painted substrates are preferably a polypropylene thermoplastic substrate that is formed into automotive body side panels, bumpers, grills and bumpers. Generally, the time required to dry the painted substrate is from about 5 to about 10 minutes.
The filtration station includes a permanent rigid dry filter to cause air-born particulate matter to deposit on a first surface of said filter until a pressure sensor senses a predetermined pressure drop across the filter, after which air is directed through the filter from a second side opposite the first side to deposit collected particulate paint material into a receptacle for fluidizing and re-use as pre-filter media
In another aspect, the present invention relates to a waterless, modular, low VOC and CO2 emission modular system to produce painted, cured thermoplastic resin substrates. The system is comprised of a treatment station having a flame source and a nitrogen source to apply nitrogen containing compounds to said substrate to form functional groups conducive to paint adhesion. Generally, the nitrogen source is selected from the group consisting of nitrogen gas or dithiolamine. The system further includes a paint station to apply a color base coat from a paint source to said substrate and a clear coat station to apply clear coat from a clear coat source to said base coated substrate. The system has a curing oven having infra red and convention heat sources to cure said painted substrate; said oven to apply heat to accelerate drying and curing time of said substrate. The part is generally moved from station to station by a conveyer or other mode of moving parts from one station to the next, and the curing time generally is in the range of from about 5 minutes to about 10 minutes.
The system further includes a waterless filtration system for capturing paint over-spray and particulate in close proximity to the paint station. The filtration system is generally coated with a layer of pre-filter dry particulate media to attach and hold dry or wet paint particulate matter. The rigid filtration system preferably has a Teflon coated filtration surface as the first surface on the structural element composition adapted to trap particulate matter of paint and pre-filter media. Each element cartridge in the filtration system is further equipped with a pressure sensor to detect a pressure drop across the filter such that, at a predetermined pressure drop, a pulse of air is forced through the filter from the second surface opposite the first surface to force the captured particulate matter into a receptacle for fluidizing and re-use as pre-filter media Thus, there is no need for water and chemicals to clean parts as a preparation for paint nor water and chemicals required to trap paint over-spray and particulate of the paint application process. In addition there is no requirement for an adhesion promoter to prepare for painting the parts nor is any gas consumed in heating the oven thereby, significantly reducing VOC and CO2 emissions.
The modular system thus described may be configured to accommodate any number of fascia and exterior components from limited production number to mass production of fascia. In addition, because the system is modular, it may be constructed on site or in close proximity to the automotive manufacturing site and expanded or contracted as the product need dictates. Moreover, because it is on site or in close proximity to the manufacturing site, transportation costs and the investment in racking and packaging are eliminated or minimized.
Turning now to the drawings wherein like numbers refer to like structures, and particularly to
Paint station 74 is in close proximity to clear coat station 76. Preferably, the system of the present invention is adapted to use a two component paint system, such as is available from BASF of Southfield, Mich. under the trade name 2K system. The paint station uses a base coat that may be pigmented and is applied to the nitrogen surface treated substrate as it moves on a conveyer 78 from the flame station to the paint station. Paint is applied from a paint source and a filtration system as previously described is used to ensure that particulate material is filtered from the air. The paint component of the 2K system from BASF is a self curing paint that will cross link and dry in a relatively short time. A flash station 80 may optionally be placed between the paint station and the clear coat station to permit flash of the painted substrate. The substrate is then moved to the clear coat station where the clear coat is applied. Note the filtration system as previously described in close proximity to the clear coat and the paint and the flash station to control any particulate or VOC that may occur during the painting, flashing and clear coating of the substrate. The part may them be moved to the hybrid infrared convection oven as previously described to be cured so that the resulting painted substrate product is completely cured in a minimal time of about 5 to 10 minutes.
The system as described is modular and may be sized to accommodate any number of production runs or parts. In addition, it may be increased in size or decreased in size and capacity to accommodate changes in production. Moreover, because it is a modular system it may be
The words used to describe the invention are words of description not words of limitation. Those skilled in the art recognize that many variations are possible without departing from the scope and spirit of the invention as set forth in the appended claims.
