MXPA01004464A - In-press process for coating composite substrates - Google Patents

Abstract

An improved process for manufacture of polymer coated composite substrates is described. A coated composite substrate is prepared in the press by applying a layer of a primer coating composition to the surface of a compressible mat comprising fibers and/or particles and a resin binder. The primer coating composition is formulated preferably as a fast setting polymer latex capable of forming a chemically crosslinked polymer matrix when applied to the surface of a compressible mat. A thermosetting top coat composition can be applied directly over the wet primer coating composition before heat-processing the mat to improve surface quality and release characteristics. Compressing and heating the coated mat produces a primed composite substrate directly out of the press.

Description

PRESS PROCESS TO COVER COMPOSITE SUBSTRATES FIELD OF THE INVENTION This invention relates to the manufacture of composite building materials. More particularly, this invention is directed to a low cost method for the manufacture of compressed, coated composite substrates, wherein the coating is formed as a formaldehyde-free primer coating of the composite substrate in a press. Compressed press-ready substrates, manufactured in accordance with this invention, have a smooth, hard, low porosity surface, which exhibits excellent water resistance and blocking, and is ready, without further treatment, to receive final finishing coating compositions .

BACKGROUND AND BRIEF DESCRIPTION OF THE INVENTION The demands of the construction industry for low-cost, multifunctional building materials have led to the expanded use of composite substrates formed in general by compression and heating of a particulate mesh and / or REF: 129234 fibers combined with a resin and wax binder. While the most common fiber / particle components for such compounds are cellulosic materials such as particles, fibers, flakes or chips, of wood, there has also been significant research and development directed towards the use of fibers / particles from other sources such as glass, synthetic polymers, carbon and inorganic fillers such as talc, alumina, silica, calcium carbonate, and cementitious materials that include ash dust and Portland cement. The most common composite substrates for use in today's construction are those formed from particles, fibers, chips, flakes or other fragments of wood, for the production of cardboard, medium density hardboard, cardboard oriented strands , particleboard, plywood, and paper-coated composites. Such compounds are typically manufactured from a mixture of particles, fibers, flakes or chips, of wood, with a binder typically a thermosetting resin. The mixture is formed into a mesh under wet-dry or dry process conditions, and then compressed under heat and pressure into a dense composite substrate, typically in the form of a sheet or sheet. In some applications, such as the manufacture of door liner, the mesh is molded into a desired shape and / or provided with a smooth or textured surface during the thermal compression process. In the related manufacturing processes, the paper is glued to the meshing surface in the press. The manufacture of composite, compressed substrates for use in the construction industry is well known in the art. See, for example, U.S. Patent Nos. 3,164,511; 3,391,223; 3,940,230; and 4,241,133. An important aspect of composite substrates intended for use in the construction industry is the quality and the nature of the substrate surface. Many composite substrates are used in applications that require the surface substrate to be suitable for receiving finish coatings. Thus, it is desirable that the surface of the substrate be hard, and substantially free of cracks, void spaces and porosities. Much effort has been directed to the development of manufacturing techniques to obtain and secure high quality surfaces, ready for finishing, on composite substrates. Thus, for example, in the manufacture of finished door linings or outdoor chipboard sheets, a mesh comprising wood pulp, resin binder and additives is compressed in a press between the hot metal plates (plates). ) at a temperature of about 149 ° C (300 ° F) to about 254 ° C (490 ° F) at a pressure of about 36.5 kg / cm2 (500 psi) to about 109.5 kg / cm2 (1500 psi) for about 20 seconds to approximately 2 minutes. The resin binder is typically a thermosetting resin such as urea / formaldehyde resins, phenol / formaldehyde resins, melamine / formaldehyde resins, acrylic resins, polyisocyanates or urethane resins. Meshing is typically treated with a pre-press sealer to provide release from the hot platen of the press and thereby optimize surface smoothness and minimize buildup on press platens. (metal plates) . After the meshing is pressed, typically at a predetermined stop thickness, the resulting board is subsequently processed in a series of steps, including rehumidification, dressing, stacking, and transportation to a pick-up line for the dresser application, and the subsequent cure of the sizing composition applied. With such current manufacturing techniques there are significant labor costs involved in the transportation of composite board substrates from the press to the dressing and cure stations. In addition, there are significant capital and fuel costs associated with the required reheat and cure step of sizing or sizing boards. Responding to current needs for reduced costs and improved quality of composite substrate construction materials, manufacturers of such materials have invested in significant research and development efforts to improve composite substrate manufacturing. One goal of such efforts has been to develop a manufacturing process for composite substrates, particularly those formed from particulates and wood fibers, wherein the composite is formed with a polymer coated surface on the press, thereby they eliminate the subsequent steps of the dressing and curing application, which are standard in current wood composite manufacturing operations. A process of this type is described in U.S. Patent No. 5,635,248 wherein a polymeric latex is applied as a foam on the meshing surface, the foam is dried on a hardened layer which is thereafter ground and hardened during the pressing of the mesh in a reconsolidated, coated substrate. While it is said that the methodology produces a composite board primed directly from the press, the method requires an extra foaming step with latex, and this requires a step of í * _B _----------.

Warming extra time / consuming costs to current manufacturing processes. The present invention provides a low-cost manufacturing process for the manufacture of polymer-coated composite substrates (sizing) directly from the press without any latex processing step or heating / drying, extra. In accordance with one embodiment of this invention, an improved process for manufacturing composite substrates having a surface coated with high quality polymer, directly from the press is provided. A quick-hardening formaldehyde-free primer coating composition is applied to the surface of the compressible mesh or glued paper to the mesh surface. The quick hardening coating composition exhibits excellent "persistence" on the meshing surface during subsequent compression of the mesh between the hot metal surfaces in a press. The sizing coating composition is formulated to form a chemically crosslinked polymer matrix, when or as it is applied to the surface. The pressing of the coated mesh under standard conditions of high temperature and pressure produces a composite substrate having a smooth surface of low porosity, ideal for the reception of the finishing coatings compositions. The present invention also makes it possible to manufacture coated paper where a fiber mesh is coated and pressed on coated paper, as part of the papermaking process. The sizing (or sizing) coating composition comprises either a thermosetting polymer, or a thermoplastic polymer and is otherwise formulated for rapid crosslinking / gel formation after application to the meshing surface. In an embodiment of the invention, the coating composition is formulated to undergo ionic cross-linking after application to the compressible mesh. In a preferred embodiment, the coating composition comprises an anionically stabilized thermoplastic latex, which undergoes an ion-crosslinking reaction, dependent on the pH, of gel formation, as applied to the surface of the mesh. Alternatively, the sizing surface may be a two-component composition, wherein the first and second components are capable of forming a gel through ionic cross-linking when applied, for example, through a dual channel sprayer. In yet another embodiment of the invention, a topcoating composition is applied, over the coating composition, applied, before the application of heat and pressure to the mesh, to form the coated polymeric substrate. In one embodiment, the topcoating composition is a thermosettable latex composition that improves the surface properties of the substrate of the produced polymer coated composition and facilitates the release of the compound from hot metal surfaces in the press. The topcoat is preferably a thermosetting coating at low temperature, and free of formaldehyde, which functions as a release agent and as an anti-marking coating with metals. In yet another embodiment of the invention, a release coating composition comprising a re-paintable silicone polymer or a surfactant is applied over the coating coating composition to facilitate the release of the polymer-coated composite substrate, from the press . In still another embodiment of the invention, the polymer-coated composite substrate of this invention is prepared by a film transfer process. In this process, the sizing coating composition is applied to a hot press platen, optionally on a first layer of a release agent and / or a thermosetting latex topcoat composition, and the hot metal platen is thereafter contacting under pressure with a compressible mesh optionally pretreated with an adhesive composition, to provide a composite substrate coated with polymer, compressed. The priming film transfer process can be employed with particular advantage in the manufacture of composite substrates in continuous band processes.

DETAILED DESCRIPTION OF THE INVENTION According to this invention there is provided an improved process for the manufacture of polymer-coated composite substrates, more typically those formed from a compressible mesh comprising fibers or cellulosic particles, and / or chopped or flaked wood. Such composite, wood substrates are commonly used in a wide variety of building construction applications, many of which dictate that the composite substrate have smooth, hard, high-quality surfaces suitable for the reception of finished coating compositions. The present invention makes possible the low cost manufacturing of such high quality composite substrates. It also provides the methodology for the efficient manufacture of coated papers, where the composite substrate is a mesh of cellulosic fiber, in general much thinner than those used for the manufacture of chipboard, which have optional wax components, filler and binder. The compressible mesh from which the substrate is formed is first coated with a fast hardening coating dressing composition, which allows the production of a high quality polymer coated composite substrate directly from the press. Meshing can optionally be covered with a sheet of paper typically glued to the meshing surface and thereafter coated with the quick hardening primer composition. In one embodiment, this invention includes the step of applying a quick hardening primer coating with excellent "persistence" of the coating to the compressible mesh, optionally applying a topcoat of thermosetting or thermoplastic coating on the quick hardening coating layer, and compressing the meshing with the applied coating or coatings, between the hot metal plates (platens) under standard conditions of heat and pressure to produce an improved polymer-coated composite substrate of this invention. The metal plates can be flat and smooth (or encrusted to provide a predetermined pattern on the surface of the composite sheets produced), or the plates can be in the form of complementary molds that function to compress the mesh into a three-dimensional molded shape, such like those used in the manufacture of door linings. The polymeric coating on the composite substrate produced in this way shows ideal physical characteristics such as low porosity, surface smoothness, surface hardness, and flexibility - a particularly important feature when the composite substrate is molded to a predetermined shape during compression of the mesh. The composite substrate coating also exhibits favorable chemical properties, including excellent blocking resistance and moisture resistance, and good adhesion to the finished coating compositions, applied. The primer coating composition used in accordance with the present invention typically comprises a thermosetting or thermoplastic polymer dispersible in water. The composition is formulated to form a chemically crosslinked polymer matrix, for example, a three dimensional gel when, or according to, it is applied to the surface of the compressible mesh. Any of a wide variety of polymeric latexes, either as one- or two-component compositions, can be used with the proviso that they are formulated to provide a rapid hardening chemistry that enables rapid chemical cross-linking of the polymer as it is applied to the compressible mesh. The coating coating composition can be formulated so that the crosslinking bond can occur rapidly through the ionic or covalent bond as it is applied to the mesh. Thus, in one embodiment of the invention, the coating coating composition is formulated to form an ionically crosslinked polymer matrix, when applied to the surface of the compressible mesh. Such coating compositions are known in the art; however, its unique application in the manufacture of polymer-coated composite substrates, as described herein, is novel and provides significant advantage in the manufacture of polymer-coated composite substrates, in press. Exemplary of the coating compositions formulated for rapid curing via ionic crosslinking of the polymer component are those written in PCT International Application No. PCT / US96 / 00802, published July 25, 1996 as International Publication No. WO 96 / 22338, the description of which is incorporated by reference herein. The aqueous coating composition described in this publication comprises from 95 to 99 weight percent, based on the weight of the dry materials in the composition, of an anionically stabilized aqueous emulsion, of a copolymer having a Tg of -10 °. C at 50 ° C. The copolymer comprises in polymerized form a polymerization mixture containing two or more ethylenically unsaturated monomers wherein, based on the total weight of all the ethylenically unsaturated monomers in the polymerization mixture, from 0 to 5 weight percent of the monomers they are alpha, beta-ethylenically unsaturated carboxylic acid monomers; 0.2 to 5 weight percent of a polyimine having a molecular weight of 250 to 20,000; and from 0.2 to 5 weight percent of a volatile base; wherein the composition has a pH of from about 10.3 to about 12, more typically from about 8 to about 11, and wherein a voided film of the composition has a rate or rate of cure rate measurement of at least 5 to 20. minutes after emptying under ambient conditions of temperature up to 30 ° C and relative humidity not less than 50%. The composition is optionally pigmented and is described as particularly useful as an aqueous, fast curing traffic paint. The quick hardening latex composition can also be formulated to include standard coating excipients such as defoamers, wetting agents, dispersants, release agents, pigments and fillers, such as organic fillers, inorganic fillers, organic fibers, inorganic fibers or mixtures of the same. The composition is optionally pigmented and is described as particularly useful as an aqueous, fast curing traffic paint. The volatile base component of fast hardening latex includes an organic or inorganic compound which is a weak or strong base or which has sufficiently high vapor pressure and tendency to evaporate or otherwise volatilize from the aqueous coating composition, with which results in a reduction in the pH and concomitant ionic crosslinking of the polyimine and the carboxylic polymer components of the composition. Examples of volatile bases include ammonium hydroxide and organic amines containing up to 4 carbon atoms, including, for example, dimethylamine, diethylamine, aminopropanol, ammonium hydroxide, and 2-amino-2-methyl-1-propanol with hydroxide of ammonium which is the most preferred. The volatile base typically comprises about 0.3 to about 1.5 weight percent of the coating composition. A polymeric coating composition utilizing such chemistry is commercially available from the Dow Chemical Company as a fast hardening 50% solids latex sold under the trade name Dow DT 211 NA. There are, of course, many other polymeric compositions that can be formulated and applied to provide the fast hardening ion chemistry, to provide a polymer gel matrix that exhibits the high "persistence" property required, important for the provision of polymeric substrates. polymer coated, in press, of high quality, in accordance with this invention. In this wayIt is possible to prepare polymeric backbones having cationic and anionic moieties in the same polymeric molecule with one of the ionic species modified by environmental pH control. See, for example, the polymer systems described in U.S. Patent No. 5,674,934, specifically incorporated by reference herein. The polymer system is designed so that after application of the coating, a pH change dependent on the application, for example that effected by the loss of carbon dioxide, re-ionizes the neutralized ionic species to provide an ionically cross-linked system through the anionic and cationic protruding groups, resulting in the rapid formation of an ionically crosslinked polymeric matrix or gel. Alternatively, an ionically crosslinked polymeric gel matrix can be formed on the surface of a compressible mesh, in the embodiment of the method of this invention by the application of an anionic latex system, co-sprayed, for example, using a spray gun. double channel spray, with a cationic polyamine or polyimine or a cationic latex system to form a three-dimensional, ionically crosslinked polymeric gel matrix, after application to the meshing surface. Alternatively, an anionic latex system can be co-sprayed with a water soluble salt containing di- or multi-valent cationic species, eg, zinc or calcium salts, to effect ionic crosslinking and gel formation after of the application to a compressible mesh, in carrying out the method of this invention. The fast hardening latex may be substantially thermoplastic, or this may include other functional groups recognized by those skilled in the art as imparters of thermosetting functionality to the polymer latex. In yet another embodiment of the present invention, the coating coating composition is formulated to provide a covalently crosslinked, fast hardening, matrix-like polymer on the surface of the compressible mesh. The formation of such covalently crosslinked polymeric compositions on the surface of the compressible mesh before the formation of the coated composite substrates is preferably achieved using two-component systems which when combined provide a level of covalent cross-linking reactivity sufficient to allow the minus the partial covalent crosslinking of the polymer formulation applied prior to compression of the coated mesh between the hot plates in a press. Thus, for example, conventional, two-component, epoxy, urethane or ethylenically unsaturated polymers / oligomers / monomers (where a radical initiator is co-applied with the radical-crosslinkable composition) can be used in the formation of a matrix crosslinked polymer on the surface of the mesh. The two-component systems can be applied to the mesh, for example, as separate components through a double-channel spray gun, or these can be mixed together immediately before application to the mesh and applied as a homogeneous, reactive polymer composition. . The nature of the reactive components of the two component compositions is not critical, and such a reactive polymer composition can be optimized by routine experimentation to provide a sufficient level or reactivity to provide at least partial covalent crosslinking of the formulation on the surface of the mesh. , before compression of the mesh under heat and pressure to form the current polymer-coated composite substrates. The quantity of the coating coating composition required for the optimal manufacture of substrates coated with high quality polymer, directly from the press according to this invention, is dependent on the nature of the components of the coating coating composition, the crosslinking chemistry, the solids content of the primer and the nature of the components of the compressible mesh same. In one embodiment, the sizing composition for use in the manufacture of agglomerate sheetboard can have a solids content of about 30 to about 80 weight percent. In yet another embodiment, a sizing composition for the production of coated paper has a solids content of about 20 to about 70 weight percent. When the coating composition is formulated as a polymer latex that uses the pH-dependent coacervation chemistry or the ionic crosslinking chemistry for the formation of the polymeric matrix on the surface of a mesh prepared for hardboard, particle board, board of shredding, or fabrication of door plates or liners, the sizing composition can be applied at a ratio of about 7 g to about 40 g, more typically from about 10 g to about 20 g per 0.093 m2 (one square foot) of meshing surface . The amount of sizing composition can be adjusted within that range or it can be used at higher application rates if. it is necessary to optimize the quality of the polymeric coating on the composite substrate coated in the press. Typically, the apportion application rates are less in paper coating operations, for example, about 1 to about 10 grams per 0.093 m2 (square foot). The technology forming the basis of this invention, for example, the use of a thermoplastic or thermosetting composition, of high "persistence", of rapid pre-hardening, optionally in combination with a topcoating of thermosetting, applied wet on Wet, cured to a finished surface coating during contact with a hot metal surface, can be used to form high quality durable coatings on a wide variety of porous and non-porous substrates, including not only the compressible meshes as described above, but also the pre-compressed composite substrates, paper-coated substrates and other commercially important building materials. In one embodiment of the present invention, the quality and functionality of the polymeric coating on the composite substrates coated with the polymer in press, of this invention, are enhanced by the application of a layer of a polymer-containing topcoat composition on the chemically crosslinked polymer matrix, on the compressible mesh before compression of the mesh in the press. The topcoating composition is preferably a thermosetting or thermoplastic polymer latex. In a preferred embodiment of the invention, the topcoating composition comprises a thermosettable polymeric latex, for example, an acrylic latex formed from unsaturated monomers including hydroxyl and / or glycidyl functional groups and carboxyl functional group. The topcoating composition is applied at a ratio generally lower than that of the coating coating composition, and typically less than one medium of that of the dresser, for example, about 0.5 to about 10 g, more typically about 3 to about 7. g, by 0.093 m2 (square foot) in the manufacture of the composite board. The topcoat latex composition typically comprises about 25 to about 60% solids and, as the primer coating composition, can be formulated using standard coating excipients including but not limited to defoamers, dispersants, wetting agents, pigments, release agents and fillers, such as silica, talc, kaolin, calcium carbonate and the like. The thermosetting top coating composition not only functions to improve the surface hardness and strength of the mesh to the coated composite substrates, prepared in accordance with this invention, but also functions to provide a thermoset "liner" on the coating coating composition, to facilitate the release of coated composite substrates, from metal surfaces in the press.

In addition to, or as an alternative to, the step of applying a thermosetting topcoating composition onto the chemically crosslinked, sizing polymer matrix, a separate release composition can be applied to facilitate the release of the coated composite substrates. from the press. Release compositions are well known in the art and can be formulated to include recognized release agents, alone or in combination to provide the desired release characteristics. In one embodiment of the invention, a release coating composition comprising a thermoplastic or thermosetting silicone polymer or a surfactant, is applied onto the chemically crosslinked polymer matrix, before pressing the matrix coated mesh, between the hot metal plates . In still another embodiment of the invention, a thermosetting topcoat latex composition is applied to the crosslinked polymer matrix and a release coating composition is applied to the topcoat composition prior to pressing the coated mesh between the hot metal plates. . The release composition, when used in the present process for the manufacture of press-coated composite substrates, is typically applied at minimum usage levels, sufficient to facilitate the release of the coated compounds from the mold plates. Release compositions, when used in the embodiment of the process of this invention, are typically applied at less than 3 g per 0.093 m2 (square foot), more preferably less than 1 g per 0.093 m2 (square foot). The use of excessive amounts of release agents may adversely affect the adhesion of the finished coating to the polymeric surface of the coated composite substrates, in accordance with this invention. In accordance with one embodiment of this invention, there is provided a process for manufacturing a press-coated composite substrate, comprising the steps of forming a laminate of the wet coating composition comprising (1) a layer of a coating composition. a doctor comprising a water-dispersible thermosetting or thermoplastic polymer, the dressing coating layer is formed as a chemically crosslinked polymer matrix, and (2) a layer of a topcoating composition including a thermoplastic or thermosetting polymeric latex composition; contacting the primer coating layer with a surface of a compressible mesh comprising fibers or particles and a resin binder composition; the compression of the mesh and the coating laminate between the hot metal surfaces in a press; and the release of the polymer-coated composite substrate, compressed, from the press. That process can be carried out using any of the various alternative protocols. Thus, as generally described above, the laminate of the wet coating composition can be formed on the surface of the compressible mesh, firstly by applying a layer of the coating composition to the mesh, and applying a layer of the top coating composition on the layer of the coating composition before compressing the mesh and the coating laminate applied in a press. The sizing coating composition and the top coating composition can be applied to the mesh using the recognized application techniques in the art, including conventional spray without air or aided air, curtain coating, and direct roller coating. The coating composition is typically applied immediately on the still wet coating composition., on the surface of the mesh, and meshing with the laminate of the coating composition still wet on its surface, is compressed and / or molded into the press to form the composite substrate currently coated with polymer. In an alternative embodiment, a release composition is applied, typically by spray as on the top coating composition layer, to facilitate the release of the polymer coated substrate, from the press. In an alternative embodiment of the invention, the coating laminate is prepared by applying its component layers to the hot metal surface of the press (in reverse order of its application to the mesh), and the coating laminate is transferred to the mesh, optionally having a paper cover, as it is compressed with the metal surface coated with the laminate, in the press. In a priming film transfer process, the meshing surface (or paper) for receiving the coating laminate may be coated with an adhesive to promote adhesion of the coating laminate to the compressed mesh during the compression / heating step. In this way, using the protocol of the film transfer process, the coating laminate is prepared by applying to the hot platen of the press, in sequence, a layer of a release coating composition, a layer of a composition of top coating, and a layer of a coating coating composition. Optionally, an adhesive layer may be applied to the coating layer on the hot plate, to optimize the adhesion of the laminate of the film transferred to the composite substrate of this invention. In one embodiment of the invention, a feeder transfer method is used to produce a door sill or sheet, sizing or sizing. A light film of a water-based release agent is applied to the hot caulking plate (149 ° C) (300 ° F)). This dries instantaneously. The primer is then applied by spray (9 g wet / 0.093 m2 (one square foot) -equivalent to 25.4 microns (1 thousandth of an inch) dry) to 60% solids by weight (40% by volume) directly to the plate of hot caulking. The priming composition dries almost instantaneously. The fiber mesh is placed in direct contact with the dry primer with the caulking. Meshing is pressed to 31.7 mm (1/8") stops for 90 seconds at 149 ° C (300 ° F) The transfer of the primer to the caulking plate to the door liner takes place under a variety of pressing cycles The press is open to release the squeezed door liner that you see ? _ ^^^^ ___- very similar to the door linings produced in a conventional manner. An advantage of applying the release agent and the dresser to the caulking plate is that the amount of the applied dresser is essentially the same as that applied in the normal dressing operations. In fact, it has been found that using the primer transfer method, the polymer-coated composite substrates (door linings) having surface properties similar to those achievable using normal press-out dressing applications, can be achieved using only 90% of the quantity of the sizing composition (or with sizing). While the aforementioned appendage transfer method can be used in manufacturing operations of agglomerated sheet metal of standard workpiece, the method of transfer of aprestador has particular application in the processes of manufacture by continuous press (Conti-press) for the manufacture of agglomerated sheet metal / fibreboard. In the continuous press method, the press consists of a hot, continuous steel strip, which is brought into contact and at the end compressibly in contact with the meshing through a series of rollers behind the band, so that according to the Mesh moves continuously through the process, the band and the roller apply heat and increase the pressure to the mesh. At the end of the continuous press, a laminate of agglomerated sheet or fiber board of solid form is produced having the physical characteristics very similar to the laminate of normal agglomerated sheet. The appendage transfer method is only adapted for the application to the continuous press manufacturing processes for the manufacture of the composite substrate. The coating laminate can be formed on the web by applying the release coating, the topcoat and / or the primer coating sequentially to the hot steel strip by any means, but more practically by direct roller coaters before the coating. band comes into contact with the mesh, so that there is little or no waste as would typically be incurred in spray applications.

Example 1 A wooden fiber mesh or a reconsolidated wood fiber mesh for the manufacture of linings or door panels was coated with the rapid hardening primer formulation described below (at approximately 15 g / 0.03 m2 (one square foot) ). Followed by the formulation of superior anti-marking coating with metal (approximately 3 g / 0.093 m2 (one square foot)). The coated mesh was then placed in a press at a temperature from about 121 ° C (250 ° F) to about 258 ° C (490 ° F) for about 20 seconds to about 120 seconds at a pressure of about 65.7 kg / cm2 ( 900 psi). The press can be either flat or in the form of a die with the feature of deep drawing. After the pressing, a sheet or door liner with top coating prepared in mold / anti-marking with metals, was released from the press. The aesthetic characteristics of this door sill or sheet metal prepared in mold, are very much comparable to those of a conventional door sill or sheet that is prepared in a finishing line after the pressing line.

Neogen DGH (Kaolin Dry Branch / filler) 3.10 Example 2 A wooden fiber mesh or a reconsolidated wood fiber mesh for the production of door sheet is coated with a polymeric adhesive before moving towards the press. The hot top plate of the press as described in Example 1 is spray coated first with a release agent, followed by the anti-marking coating with metals and then the coating primer. During the pressing cycle, the laminated coating film was released from the upper plate and glued on the mesh. A door plate prepared in a mold and with an anti-marking upper coating with metals that has excellent surface properties is released from the mold.

Example 3 Continuous wood fiber mesh or reinforced wood fiber meshing for the production of door or cardboard sheets or particle boards is spray coated with the coating preparation formulation (15 g / 0.093 m2 (square foot)) followed by the superior anti-marking coating with metals (5 g / 0.093 m2 (square foot)). The ready meshing is passed through a hot continuous press, to produce a line of sheet for door ready "in press" which can then be cut into pieces for boarding. This press-sizing board can also be made through a film transfer process as described in Example 2 above, in a continuous press line. It is noted that in relation to this date, the best method known to the applicant to carry out the aforementioned invention, is that which is clear from the present description of the invention.

Claims (50)

CLAIMS Having described the invention as above, the content of the following claims is claimed as property:

1. A process for the manufacture of a press-coated composite substrate, characterized in the process, comprising the steps of: forming a laminate of the coating composition comprising: 1) a layer of a coating coating composition comprising a polymer of thermosetting or thermoplastic dispersible in water, the coating coating layer is formed as a chemically crosslinked polymer matrix, and 2) a layer of a top coating composition including a thermoplastic or thermosetting polymeric latex composition; contacting the coating layer with a surface of a compressible mesh comprising fibers or particles and a resin binding composition; the compression of the mesh and the laminate of the coating between the hot metal surfaces in a press; and the release of the composite substrate, coated with polymer, compressed, from the press.

2. The process according to claim 1, characterized in that the fibers or particles used to form the mesh are selected from cellulose, glass, synthetic polymers and carbon.

3. The process according to claim 2, characterized in that the meshing further comprises an inorganic cementitious composition.

The process according to claim 1, characterized in that the coating laminate is formed by applying a layer of the coating composition to the surface of the mesh, and applying a layer of the top coating composition on the layer of coating coating before compressing the mesh.

The process according to claim 4, characterized in that the topcoating composition comprises a thermosetting polymer and the coating laminate further comprises a layer of a release composition in contact with the topcoat layer, the release composition comprises a silicone polymer or a surfactant.

The process according to claim 1, characterized in that the topcoating composition comprises a thermosetting polymer and the coating laminate further comprises a layer of a release composition in contact with the topcoat layer, the release composition comprises a silicone polymer or a surfactant.

The process according to claim 6, characterized in that the coating laminate is prepared by applying, in sequence, a layer of a release coating composition, a layer of a topcoating composition and a layer of a topcoat composition. coating composition, to a hot metal surface of the press, and the mesh is compressed between the metal surface coated with the laminate, and a second metal surface in a press.

The method according to claim 7, characterized in that the hot metal surface is a continuous band.

The method according to claim 7, characterized in that an adhesive is applied to the surface of the mesh or of the coating layer before the mesh is compressed between the metal surface coated with the laminate and the second metal surface in the press.

10. A process for manufacturing a composite substrate coated with polymer, in press, the process is characterized in that it comprises the steps of: applying a layer of a coating composition to the surface of a compressible mesh comprising fibers or particles and a resin binder, the coating coating composition comprises a thermosetting polymer or a thermoplastic polymer, and is formulated to form a chemically crosslinked polymer matrix when applied to the surface of the compressible mesh and before heating the mesh; the compression of the mesh and the chemically crosslinked polymer matrix between hot metal surfaces in a press to form the polymer-coated composite substrate; and the release of the polymer-coated composite substrate from the press.

11. The process according to claim 10, characterized in that the polymer matrix on the surface of the compressible mesh comprises an ionically crosslinked polymer.

12. The process according to claim 11, characterized in that the ionically crosslinked polymer comprises a thermoplastic polymer.

13. The process according to claim 10, characterized in that the polymer matrix on the surface of the compressible mesh comprises a covalently cross-linked polymer.

The process according to claim 10, characterized in that it further comprises the step of applying a layer of a topcoat composition containing polymer on the chemically crosslinked polymer matrix, on the compressible mesh before compression of the mesh in the press .

15. The process according to claim 14, characterized in that the top coating composition comprises a thermosetting polymer latex.

16. The process according to claim 10, characterized in that it further comprises the step of applying a release coating composition comprising a silicone polymer or a surfactant, on the chemically crosslinked polymer matrix on the compressible mesh before compression of the meshing in the press.

17. In a process for the manufacture of a polymer-coated composite substrate including the step of pressing a compressible mesh comprising fibers or particles and a resin binder, between the hot metal plates in a press to form a compressed composite substrate, the improvement is characterized in that it comprises the steps of: applying a polymer-containing sizing composition to the surface of the compressible mesh before pressing it between the hot metal plates, the polymer-containing sizing composition is formulated to provide an ionically crosslinked polymer matrix , as it is applied on the surface of the compressible mesh; and thereafter the matrix coated mesh is pressed between the hot metal plates, to form a composite substrate coated with polymer.

18. The improvement according to claim 17, characterized in that the polymer-containing sizing composition comprises an anionically stabilized thermoplastic latex.

19. The improvement according to claim 17, characterized in that the sizing composition comprises a thermoplastic polymer latex.

20. The improvement according to claim 17, characterized in that the priming composition comprises a thermosetting polymer latex.

21. The improvement according to claim 17, characterized in that it further comprises the step of applying a layer of a topcoat latex composition, of thermosetting on the crosslinked polymer matrix before pressing the mesh coated by the matrix between the metal plates hot

22. The improvement according to claim 21, characterized in that it further comprises the step of applying a release coating composition comprising a silicone polymer or surfactant on the top coating composition prior to pressing the matrix coated mesh, between the hot metal plates.

23. A composite substrate coated with polymer, characterized in that it is prepared according to the process according to claim 1.

24. A composite substrate coated with polymer, characterized in that it is prepared according to the process according to claim 10.

25. The composite substrate coated with polymer, according to claim 23, characterized in that the compressible mesh comprises cellulose fibers or particles and a binder of thermosetting resin.

26. The polymer-coated composite substrate according to claim 24, characterized in that the compressible mesh comprises cellulose fibers or particles and a binder of thermosetting resin.

27. The process according to claim 1, characterized in that the compressible mesh further comprises a sheet of paper forming the surface of the mesh in contact with the coating coating layer.

28. The process according to claim 10, characterized in that the compressible mesh further comprises a sheet of paper forming the surface of the mesh to which the layer of the dressing is applied.

29. The improvement according to claim 17, characterized in that the compressible mesh further comprises a sheet of paper forming the surface of the mesh to which the dressing composition is applied.

30. A process for the manufacture of a porous substrate coated by another, characterized the process because it comprises: the application of a polymer-containing sizing composition to the surface of a porous substrate, the sizing composition is formulated to provide an ionic polymer matrix reticulated, as it is applied on the surface; and contacting the coated substrate with the matrix, with a hot surface.

31. The process according to claim 30, characterized in that the sizing composition comprises an anionically stabilized thermoplastic latex.

32. The process according to claim 30, characterized in that the sizing composition comprises a thermosetting latex.

33. The process according to claim 30, characterized in that it further comprises the step of applying a layer of a topcoat composition of thermosetting latex on the crosslinked polymer matrix before the surface is brought into contact with the hot surface. .

34. The process according to claim 10, characterized in that the composite substrate is paper.

35. The process according to claim 17, characterized in that the composite substrate is paper.

36. The process according to claim 30, characterized in that the coated porous substrate is paper.

37. A process for manufacturing a composite substrate coated in a press, the process is characterized in that it comprises the steps of: selecting or forming a film comprising a chemically cross-linked polymer matrix, free of formaldehyde, for transfer to a mesh compressible comprising fibers or particles and a resin binder composition; contacting the film with a compressible mesh surface; the compression of the mesh and the film between the hot surfaces of a press; and the release of the composite substrate, coated on polymer, compressed, from the press.

38. The process according to claim 37, characterized in that an adhesive is applied between the film and the surface of the compressible mesh.

39. The process according to claim 37, characterized in that the film comprises an upper coating and a coating layer or sizing primer.

40. The process according to claim 37, characterized in that the film consists essentially of a cross-linked polymer.

41. The process according to claim 40, characterized in that an adhesive is applied between the film and the surface of the compressible mesh.

42. A process for manufacturing a composite substrate coated with polymer, in press, the process is characterized in that it comprises the steps of applying a coating composition to the surface of a compressible mesh, or to the paper that is glued to the surface of the meshing, the sizing coating composition comprises a polymer formulated to form, without heating, a chemically crosslinked polymer matrix when applied to the meshing or the paper surface, and compressing the meshing and the reticulating polymer matrix sizing coating, while heats the mesh.

43. The process according to claim 42, characterized in that the coating coating composition is formulated to form an ionically crosslinked polymer matrix, as it is applied to the mesh or to the paper surface.

44. The process according to claim 42, characterized in that the coating coating composition is formulated to form a covalently crosslinked polymer matrix as it is applied to the mesh or paper surface.

45. A polymer-coated composite substrate, in press, characterized in the substrate because it comprises a heat-compressed mesh of fibers or particles and a resin binder, the polymer coating is formed in a press from a coating coating composition, formulated to form a chemically crosslinked polymer matrix, as it is applied to the mesh, and before the compression by heat of the mesh.

46. The coated composite according to claim 45, characterized in that the coating coating composition is formulated to form an ionic cross-linked polymer matrix as it is applied to the mesh.

47. The coated composite according to claim 45, characterized in that the coating coating composition is formulated to form a covalently cross-linked polymer matrix, as it is applied to the mesh.

48. A process for the manufacture of paper coated with polymer, the process is characterized in that it comprises the steps of coating a fiber mesh with a coating coating composition formulated to form a chemically crosslinked polymer matrix, as it is applied to the mesh, without heating; and compression of the coated mesh with heating to form the polymer coated paper.

49. The process according to claim 48, characterized in that the coating coating composition comprises a polymer and is formulated to form an ionically crosslinked polymer matrix as it is applied to the mesh.

50. The process according to claim 48, characterized in that the coating coating composition comprises a polymer and is formulated to form a covalently cross-linked polymer matrix as it is applied to the mesh.