GB2280864A

GB2280864A - Vacuum coating elongate aluminium sections with UV curable acrylic lacquer

Info

Publication number: GB2280864A
Application number: GB9414662A
Authority: GB
Inventors: Philip Duckworth
Original assignee: KOMFORT SYSTEMS Ltd
Current assignee: KOMFORT SYSTEMS Ltd
Priority date: 1993-08-13
Filing date: 1994-07-20
Publication date: 1995-02-15
Anticipated expiration: 2014-07-20
Also published as: GB9414662D0; GB2280864B

Abstract

A method of coating elongate mill-finished profiled sections of aluminium (for use with partitions, room dividers) with a pigmented UV curable acrylic lacquer or paint comprises the sequential steps of continuously passing the aluminium sections 2 through a vacuum deposition chamber 6 to coat predetermined surfaces of the sections with a UV curable acrylic lacquer or paint and through a UV dryer or oven 10 positioned immediately downstream of the vacuum deposition chamber to cure the lacquer or paint coated sections. A peening cabinet 4 may be arranged upstream of the vacuum chamber 6 so as to blast the sections with aluminium oxide particles. <IMAGE>

Description

Method of Coating Elongate Aluminium Sections This invention relates to a method of coating an elongate profiled section of aluminium with an ultra-violet ( W ) curable fluid such as an W curable acrylic lacquer.

Ultra violet curing ovens for curing W curable acrylic lacquers applied to elongate sections or sheets of wood, chipboard, MDF and plywood are known. It is also known to apply W curable acrylic lacquers to such sections and sheets by passing the sections or sheets through a housing within which lacquer particles are drawn under vacuum.

Profiled sections used to support partitions employed to divide office space and the like are conventionally produced from aluminium, the mill finished profiled sections generally being subjected to an expensive anodising stage before delivery to a customer. For coloured sections, the aluminium lengths are conventionally primed, rubbed down and then hand sprayed with one or more coats of paint, each coat being dried using a conventional oven.

As will be appreciated, the painting process is unpleasant and can, if not properly controlled, be harmful to those operating the spray guns. Also, during the drying/curing process, undesirable pollutants in gas and particulate form enter the atmosphere.

In making the present invention, the Applicants appreciated that elongate aluminium mill-finished profiled sections to be used for partitions, room dividers and the like can surprisingly be treated by sequentially and continuously applying to predetermined sides of such sections a coating of a pigmented ultra-violet curable acrylic lacquer or paint by vacuum deposition and by immediately curing the lacquer or paint coating by passing the coated aluminium section through an ultra violet dryer positioned immediately downstream of the vacuum applicator.

The advantages of so doing are numerous and include a substantial reduction or elimination of contaminants normally released to the atmosphere during oven drying and curing by conventional routes, substantial increases in the rates at which coloured sections can be produced with substantial savings in production costs, and an ability to use mill-finished sections instead of conventional and more costly anodised sections.

According to the present invention in one aspect, there is provided a method of coating elongate millfinished profiled sections of aluminium for use with partitions, room dividers and the like, with a pigmented W curable acrylic lacquer or paint, the method comprising the sequential steps of continuously passing the elongate aluminium sections through a vacuum deposition chamber to coat predetermined surfaces of the sections with a UV curable acrylic lacquer or paint and through a W dryer or oven positioned immediately downstream of the vacuum deposition chamber to cure the lacquer or paint coated sections.

Preferably, the elongate mill-finished aluminium sections are subjected to a peening operation before they are passed to and through the vacuum deposition chamber.

The aluminium sections typically include re-entrant and partially enclosed features which are difficult to coat and which1 if desired, can simply be marked by tape or the like.

The peening operation is preferably achieved by passing the elongate aluminium sections through a cabinet in which particles of aluminium oxide are blasted onto the surfaces of the sections. The blast material may be introduced through one or more venturi nozzles, the particles being conveyed in streams of compressed air.

Guide rolls are preferably positioned at entry to the vacuum disposition chamber and/or exit from the W dryer or oven to assist feed of the sections through the apparatus.

The sections may be conveyed to and from the apparatus on a continuous moving belt.

In another aspect, the invention provides elongate profiled sections of aluminium produced by the method described in the preceding five paragraphs.

The invention will now be described by way of example only with reference to the accompanying diagrammatic drawing in which: Figure 1 is a perspective view of a typical aluminium section to be coated by the method of the present invention, and Figure 2 is a plan view from above of apparatus for carrying out the method of the present invention.

As will be seen from Figure 1, aluminium sections employed as supports for partitions, room dividers and the like are typically of complicated sections and include various re-entrant and partially enclosed sections. Such sections are notoriously difficult to coat by conventional processes. These sections can vary in length, typically lengths being of the order of 7' to 9'.

As mentioned previously, aluminium sections for use with partitions are conventionally coloured by applying several coats of primer and paint to the sections by hand.

The painted sections are then dried in ovens for periods of time normally in excess of 20 minutes. In place of painted sections, recourse has been made to relatively expensive anodised aluminium sections.

The apparatus illustrated in Figure 2 of the drawings comprises a conveyor 1 in the form of a continuous belt moving in the direction of arrow A for transporting elongate mill-finished profiled sections of aluminum 2 for use in the assembly of partitions, room dividers and the like to guide rollers 3 of a peening cabinet 4 within which aluminium oxide in particulate form is directed onto the surfaces of sections 2 via one or more venturi nozzles supplied with compressed air. The shot peened sections are then passed by guide rollers 5 to a vacuum applicator 6.

The applicator 6 comprises a chamber 7 including entry and exit ports 8 shaped to conform at least approximately to the configuration of the profiled sections 2. The chamber 7 is maintained at a pressure below atmospheric by a vacuum pump 9. W curable acrylic lacquer or paint is drawn continuously into the chamber 7 from a source (not shown).

The sub-atmospheric pressure extant in the chamber draws air into and through the chamber via the ports 8 to cause particles of lacquer or paint to be deposited onto unmasked surfaces of the sections. The thickness of the coating applied is determined inter alia by the speed of travel of the sections through the chamber, the viscosity of the lacquer or paint and the flow rate of air drawn into and through the chamber.

As the coated sections leave the chamber 7 they immediately enter and pass through a dryer or oven 10 including an array of ultra violet lighting tubes 11 rapidly to cure the lacquer or paint applied to the sections. Exit guide rollers to are provided to assist movement of the sections 2 through the vacuum applicator 6 and dryer 10.

Sides or portions of the aluminium sections 2 not required to be lacquered are simply masked with tape or the like before the sections are placed on the conveyor 1.

Typically, mill finished aluminium sections pass through the apparatus illustrated at speeds approaching 4050 metres per minute.

It will be appreciated that the forgoing is merely exemplary of methods in accordance with the invention and that modifications can readily be made thereto without departing from the true scope of the invention.

Claims

1. A method of coating elongate mill-finished profiled sections of aluminium for use with partitions, room dividers and the like, with a pigmented 1w curable acrylic lacquer or paint, the method comprising the sequential steps of continuously passing the elongate aluminium sections through a vacuum deposition chamber to coat predetermined surfaces of the sections with a 1w curable acrylic lacquer or paint and through a W dryer or oven positioned immediately downstream of the vacuum deposition chamber to cure the lacquer or paint coated sections.

2. A method as claimed in claim 1 wherein the aluminium sect ions include re-entrant and partially enclosed features.

3. A method as claimed in claim 1 or claim 2 wherein the peening operation is achieved by passing the elongate aluminium sections through a cabinet in which particles of aluminium oxide are blasted onto the surfaces of the sections.

4. A method as claimed in claim 3 wherein the blast material is introduced through one or more venturi nozzles, the particles being conveyed in streams of compressed air.

5. A method as claimed in any one of the preceding claims wherein guide rolls are positioned at entry to the vacuum disposition chamber.

6. A method as claimed in any one of claims 1 to 5 wherein guide rolls are positioned at exit from the W dryer.

7. A method as claimed in any one of the preceding claims wherein the sections are conveyed to and from the apparatus on a continuous moving belt.

8. A method of coating elongate mill-finished profiled sections of mill-finished profiled sections of aluminium substantially as herein described and as described with reference to Figures 1 and 2 of the accompanying drawings.

9. A coated elongate mill-finished profiled section of aluminium produced by a method as claimed in any one of the preceding claims.