Abstract:
A semi-finished wood simulating product and method is disclosed. The product is manufactured by providing a substrate having at least one surface to be finished. A liquid basecoat is applied on the substrate and dried. A wood grain pattern is deposited, in liquid form, on the basecoat. Some of the pattern is transferred from the originally deposited position on the basecoat to a subsequent position. The pattern is then cured. A polymerizable protective coating is applied onto the substrate overlying the basecoat and the pattern. The protective coating seals the substrate and is adapted for accepting a colorant to be applied by an end user. The protective coating is then polymerized. Additionally, if a porous substrate is provided, a sealer is applied prior to the liquid basecoat and is then cured.

Description:
This application is a divisional of U.S. application Ser. No. 08/800,798 filed Feb. 18, 1997, now U.S. Pat. No. 5,989,681, which is a divisional of U.S. application Ser. No. 08/448,880 filed May 24, 1995, now U.S. Pat. No. 5,597,620, which is a divisional of U.S. application Ser. No. 08/163,798 filed Dec. 9, 1993, now abandoned. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates generally to semi-finished wood simulating products and methods, and more particularly to semi-finished products capable of accepting wood stain, paint or varnish as applied by an end user at an installation site and methods of manufacturing semi-finished wood simulating products. 
     BACKGROUND OF THE INVENTION 
     There is a need to substitute wood simulating products for solid or real wood products to reduce material costs. This need to substitute simulated wood products for real wood is particularly acute for hardwood products. These hardwoods include woods such as lauan mahogany, and other woods of that same family, the bulk of which come from the Philippines and other pacific and forest locations. Over the last ten years, the availability of such woods has greatly diminished, and the remaining supply has diminished markedly in quality. There are also substantial environmental issues and concerns affecting both the quality and quantity of the real wood supply, in part, because these woods come from “rain forest” areas which have been “harvested” over the years as part of a general land clearing program which did not include replanting, etc. 
     A traditional method of manufacturing simulated wood products such as paneling, or door-skins for hollow core doors, involves utilizing a non-solid wood substrate such as a wood composite or fiberboard substrate and overlaying this substrate with a paper overlay and then applying a protective coating to the paper overlay. Vinyl overlays may also be used. There are numerous problems inherent in the traditional methods. These problems include the risk of the paper or vinyl overlay product peeling from the substrate. Another problem is that bubbles and blisters sometimes occur in the overlay process. Other problems are that the protective coating is not cleanable with a solvent or capable of being sanded to eliminate surface imperfections and scratches which occur during shipping and handling. Most importantly, the type of wood being simulated and the color of its stain must be determined at the manufacturing facility and is not changeable by the user at the installation site. 
     OBJECTS AND SUMMARY OF THE INVENTION 
     It is, therefore, an object of the present invention to provide a product and method for manufacturing semi-finished wood simulating products which eliminate or obviate the above mentioned problems. 
     It is another object of the present invention to provide a product capable of accepting stain, paint, or varnish as applied by an end user at the installation site. 
     It is another object of the present invention to provide a product that simulates the visual appearance and tactile qualities of real wood. 
     It is another object of the present invention to provide a product that is more durable than existing products and can be lightly sanded to eliminate scratches and surface imperfections. 
     It is another object of the invention to provide a product that can be cleaned with a solvent. 
     It is yet another object of the present invention to provide a semi-finished wood simulating product which is simple in construction, effective in use and economical to manufacture. 
     These objects are achieved by providing a substrate having at least one surface to be finished. A liquid basecoat is applied on the substrate and dried. A wood grain pattern is deposited, in liquid form, on the basecoat. Some of the pattern is transferred from the originally deposited position on the basecoat to a subsequent position. The pattern is then cured. A polymerizable protective coating is applied onto the substrate overlying the basecoat and the pattern. The protective coating seals the substrate and is adapted for accepting a colorant to be applied by an end user. The protective coating is then polymerized. Additionally, if a porous substrate is provided, a sealer is applied prior to the liquid basecoat and is then cured. 
     These and other objects of the present invention will become apparent from the following detailed description and appended claims. 
     The invention may best be understood with reference to the accompanying drawings wherein illustrative embodiments are shown. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a schematic illustration according to the present invention depicting a conveyor line for manufacturing a semi-finished wood simulating product; 
     FIG. 2 is an exploded cross-sectional view showing a porous substrate and various layers of coatings applied to the porous substrate; 
     FIG. 3 is an exploded cross-sectional view showing a non-porous substrate and various layers of coatings applied to the non-porous substrate; 
     FIG. 4 a  is a side elevational view of a high pressure roller; and 
     FIG. 4 b  is a front elevational view of the high pressure roller of FIG. 4 a.   
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring first to FIG. 2, semi-finished wood simulating product  100  includes a substrate  102 , a sealer  108 , a top or base coat  110 , a printed wood grain pattern (not shown), and a protective coating  112 . Substrate  102  may be a composite wood material, such as pressboard or medium density fiberboard, having a porous composite layer  104  and a backing layer  106 . Sealer  108  is applied to a porous surface  114  of substrate  102  to create a uniformly impermeable surface on which to apply subsequent materials. A thick, colored, viscous basecoat  110  is roller applied to sealed surface  114 , with the color selected to reflect the general “background ambient color” of the wood being simulated. A wood grain pattern (not shown) chosen to simulate a particular wood, is then printed on basecoat  110 . A protective coating  112  is applied to protect the wood grain pattern. The protective coating  112  is transparent/translucent so that the printed wood grain pattern is visible through protective coating  112 . Protective coating  112  is sufficiently porous so as to be stainable by the end user at the installation site. Protective coating  112  is also hard enough to allow the product to be stacked and shipped horizontally, without substantial degradation occurring to the outer surface of protective coating  112 . 
     A second embodiment of the present invention is shown in FIG. 3. A semi-finished wood simulating product  120  includes a non-porous substrate  122 , such as sheet metal, a thick, colored, viscous basecoat  110  applied thereon, a wood grain pattern printed (not shown) on basecoat  110 , and a protective coating  112  applied to protect the wood grain pattern. 
     Sealer  108  is used to avoid blotching when a substrate having a porous surface to be finished is going to be stained by the end user at the installation site, and is therefore not necessary with the product  120  and its non-porous substrate  122 . Stain or colorant applied by the end user may penetrate the entire protective layer  112  and even the basecoat  110  and, but for sealer  108 , into the porous surface  114 . Because t he hardness/absorbability of the underlying composite wood materials is non-uniform (i.e., varies throughout a given sheet), the stain would be able to penetrate the underlying porous surface in some places and not in others, and thus create a blotchy look. Basecoat sealer  108  is not necessary when using a non-porous substrate, or if only varnish or paint is to be applied by the end user. 
     The method of manufacturing a semi-finished wood simulating product can best be understood with reference to FIG.  1 . It should be understood that the layout shown is for illustrative purposes only and the layout and size of each of the elements is not meant to be limited. For purposes of completeness, the method of manufacturing will be described with reference to a product utilizing a composite wood substrate  102 . It will be understood that the product could also be manufactured using a non-porous substrate  122  by eliminating some of the process steps required to process a product using a composite wood substrate. 
     Substrate  102  enters a horizontal conveyor system C at multi-brush cleaning station  10  with surface  114  facing upwardly. Surface  114  of substrate  102  is cleaned using multi-rotary brushes, which clean the surface; adhesion of the subsequent layers may be adversely affected if surface  114  is not clean. 
     Conveyor portion  12  transports clean substrate  102  to direct roll coating station  14  where liquid sealer  108  is applied to surface  114 . Sealer  108  is an acrylic sealer, preferably from AKZO Coatings, Inc. under their product number 641-Y029-42. Conveyor system C then transports substrate  102  having sealer  108  to an infrared oven  16 , which cures and sets sealer  108 . 
     Substrate  102  having a dry sealer  108  then enters a first direct roll coating station  22  where liquid basecoat  110  is applied. Basecoat  110  is a low volatile organic content (“VOC”) water based vinyl acrylic copolymer having a viscosity of 38 seconds on a # 2  Zahn cup, and is available from AKZO Coatings, Inc. under their product number 651-W029-12. 
     A conveyor portion  20  then transports substrate  102  having wet basecoat  110  to a second direct roll coating station  22 . Due to the length of conveyor portion  20 , the first layer of basecoat begins to level on account of the dwell time. A second layer of the basecoat is then applied on the first layer of basecoat, each layer having a thickness of approximately 0.003 inches. The second layer of basecoat is then allowed to level while being transported on conveyor portion  24 . 
     The controlled viscosity of basecoat  110  causes the basecoat  110  to have the tactile qualities, when dry, of raw wood. Because the basecoat is applied in two coats, then the resulting thickness must be controlled. If the basecoat is too thick, it may crack and thus be unusable for the resulting product. Because the basecoat  110  is applied in two coats, then if sealer  108  is not covered by the first layer of basecoat  110  it will be covered by the second layer of basecoat  110 . 
     The conveyor portion  24  then transports substrate  102  having two coats of wet basecoat  110  to two sequential dual high velocity ovens  26  and  28 . Oven  26  is set to approximately 250° F., in order to prevent the basecoat  110  from forming a skin, and oven  28  is set to approximately 375° F. The dwell time of substrate  102  in dual ovens  26  and  28  is approximately 15 seconds, with the surface temperature when exiting the oven  28  being at about 131° F. The ovens  26  and  28  are each convection ovens, which cause the solvent to be moved relatively rapidly away from the substrate. The ovens  26  and  28  dry and set the two layers of the basecoat. 
     A conveyor portion  30  then transports substrate  102  from oven  28  to a brush station  32 . The basecoat  110  layers are allowed to cool in ambient air during the transport because of the dwell time achieved. Basecoat  110  should be dry and hard so that basecoat  110  is not malleable. At brush station  32 , the outer surface of the second layer of basecoat  310  is burnished with high speed rotary brushes which remove grooves in the basecoat  110  and any fibers and the like lying upon the surface. 
     A conveyor portion  34  then transports substrate  102  to a rotogravure print station  36 . While on conveyor portion  34 , the burnished surface of basecoat  110  cools to remove the heat from the burnishing operation. Substrate  102  is sequenced prior to entering print station  36  in preparation for wood grain printing. A wood grain pattern, such as of mahogany, teak, or oak, is applied using conventional rotogravure technique at print station  36 . The wood grain pattern is printed with an acrylic print ink available from AKZO Coatings, Inc. under their product number 699-C029-370A. 
     Print station  36  includes a 48 inch print cylinder (not shown) underneath which rolls substrate  102 . Substrate  102  has a length of about 80.5 inches, and each substrate  102  is sequenced for entry into print station  32  so that no two print patterns are exactly the same. The pattern is randomly printed on basecoat  110  by timing entry of the input edge of each substrate  102  relative to the print drum. Thus, each substrate  102  has certain unique properties and characteristics, which, although subtle, enhance the real wood look and feel. 
     A conveyor portion  38  then transports the substrate having a wood grain pattern printed thereon to a rotary print transfer station  40 . During this approximately 9 second transport, the print ink begins to dry and portions become tacky. As best shown in FIGS. 4 a  and  4   b , rotary print transfer station  40  includes a high pressure roller assembly  42  including a roller  44  and a screw jack pressing mechanism  46 . Roller  44  is approximately six inches in diameter, and is made of a modified polyvinyl-type rubber having a 45-50 durometer. Roller  44  rolls relative to lead or input edge of substrate  102  to the opposite or exit edge. Screw jacks  46  press roller  44  against the drying wood grain pattern so that the wet or tacky ink on the surface of basecoat  110  is picked up by roller  44  and then transferred to a circumferentially spaced location where the wet and tacky portions are then reapplied to basecoat  110 . Thus the print pattern has voids and skips which enhance the uniqueness of the product because no two appear exactly alike. The finish achieved resembles distressed wood. 
     A conveyor portion  60  then transports substrate  102  to a direct roll coater  62 . While on conveyor portion  60 , the print ink of the grain pattern dries. Direct roll coater  62  applies a first layer of a protective coating  112 . Protective coating  112  is an acrylic/amino low volatile organic content, high solids, pigmented temperature converted or polymerizable coating available from AKZO Coatings, Inc., under their product number G81-C029-123. The viscosity of protective coating  112  is 22 seconds on a #2 Zahn cup. Protective coating  112  includes a methane sulfonic acid catalyst available from AKZO Coatings, Inc., under their product number G49-PJ029-23. The catalyst is 9% by volume of protective coating  112 . The first layer of protective coating has a thickness of approximately 0.003 inches. 
     A conveyor portion  64  then transports the substrate  102  to a second direct roll coater  66  where a second layer of the protective coating  112  is applied. Because protective coating  112  is applied in two coats, it is ensured that, if the wood grain pattern is not covered by the first layer of protective coating  112 , then it will be covered by the second layer of protective coating  112 . 
     A conveyor portion  68  transports substrate  102  having two uniform layers of protective coating  112  applied thereon to two dual high velocity ovens  70  and  72 . Substrate  102  remains on conveyor portion  68  for approximately 3 seconds to allow protective coating  112  to level. 
     Dual high velocity ovens  70  and  72  set the coating  112  and remove the low volatile organic content cosolvents therefrom. Oven  70  is set to approximately 275° F., and oven  72  is set to approximately 300° F. The entering temperature of substrate  102  to oven  70  is about 92° F., and the surface temperature when exiting oven  72  is about 185° F. 
     Conveyor C then transports substrate  102  having two layers of protective coating  112  thereon to an infrared oven  74 . Oven  74  is set at approximately 1,700° F., so that full polymerization of coating  112  is achieved. Full polymerization occurs at a temperature of about 300° F., and occurs at the surface of protective coat  112  at a transport speed of 200 feet per minute. Satisfactory polymerization is achieved at a surface temperature of 220° F. Polymerization of protective/stainable coating  112  occurs while substrate  102  is in oven  74 . 
     A conveyor portion  76  then transports substrate  102  having a polymerized protective coating  112  thereon to a combination chiller-humidifier  78 . During this time, product  100  is allowed to cool in ambient air. Chiller-humidifier  78  rapidly reduces the temperature of product  100  to about 124° F., and rehumidifies the product prior to stacking. 
     A conveyor portion  80  then transports product  100  from chiller-humidifier  78  to a stacking station  82  where product  100  is stacked. The stacks may be lifted by a fork lift for transfer to a flat bed or the like so that the resulting semi-finished products  100  may be transported to the end user. 
     It should be understood that two layers of stainable/protective coating  112  produce a coating which is both durable and thick enough to permit the surface to be lightly sanded so that imperfections and scratches which may occur can be removed. The end user can finish the outer surface of stainable/protective coating  112  to whatever color is desired, which is something that the user cannot do with any of the other alternatives and is otherwise only available from real wood. Because the coating  112  is colorable by the end user, either by staining or painting, then the end user may select the finished color. The end user coloring does not, however, completely mask the wood grain pattern. 
     It should also be understood that the outer surface of backing  106  is frequently textured. This means that the textured back of the next to the bottom product being stacked in stacking station  82  presses against the outer surface of the bottom product with a force of as much as 4,000 lbs. throughout the shipping process. The disclosed coating formulation and application process creates a surface which is hard enough to withstand the shipping process, and yet porous enough to be readily stained and finished on site. 
     It should be noted that the process results in a product which has the look and feel of an unfinished piece of wood, which may then be used to manufacture a hollow core door or the like which is then sold unfinished to the user. This allows the end user to either paint the doors as he might any other wood door, or in the alternative to varnish the door, or to stain the doors and then apply protective varnish coat over the stain surface. Alternatively, the semi-finished product of the invention may be used to create paneling, veneers, and like wood-appearing surfaces. 
     While this invention has been described as having a preferred design, it is understood that it is capable of further modifications, uses, and/or adaptations thereof following in general the principles of the invention and including such departures that have been known or customary practice in the art to which the invention pertains.