KR20070022204A - Composite fiber cement article with radiation curable component - Google Patents

Abstract

The building composite article of the present invention is structured to have one or more subsurface interface zones provided for the purpose of improving the durability of the article. Each subsurface interface zone consists of a matrix of fiber cement and radiation curable material. The radiation curable material forms an interlocking network with the fiber cement to provide an interfacial zone against entry of environmental materials that can degrade the article. The number, structure and distribution of subsurface interfacial zones can vary depending on the desired characteristics of the final product. In addition, the subsurface interface zone can be formed integrally with the outer coating layer as well as the substrate, thereby improving the adhesion between the substrate and the outer coating.

Radiation curable components, composite fiber cement articles.

Description

COMPOSITE FIBER CEMENT ARTICLE WITH RADIATION CURABLE COMPONENT}

FIELD OF THE INVENTION The present invention generally relates to such composite articles, including methods and formulations for the preparation of building composite articles, in particular building composite fiber cement articles incorporating one or more radiation curable components.

Fiber-reinforced cement (FRC) products are becoming more and more widely used in various construction fields and in different areas of climate. FRC products have the advantage of inherent fire resistance, water resistance, disease resistance and fungal resistance, as well as general affordability. However, wet-dry cycles, freeze-thaw cycles, and periodic exposure to UV and atmospheric carbon dioxide can cause physical and chemical changes to the FRC product over time. In addition, FRC building materials may be physically damaged during handling, shipping, and installation.

Coatings and laminates have been developed that protect the FRC product to reduce the deleterious effects of exposure and handling, while at the same time providing a decorative surface for the FRC product. When processing fiber cement articles by applying surface coatings, often the final product is still susceptible to degradation in both physical and chemical ways. Coatings and laminates are inherently surface treated materials and are prone to loss of adhesion or peeling from the substrate upon repeated exposure. Although it is known to use adhesion promoters or coatings or adhesives that chemically react with the substrate to improve adhesion, such as when exposed outdoors for many years in a humid environment experiencing extreme weather or severe conditions, such as many freeze / thaw cycles. Strategies are difficult to maintain successfully at all times. Means are needed to maintain the decorative surface on the FRC material even in extreme conditions.

Similar to environmental damage, mishandling during installation can adversely affect the useful life of FRC products. Misoperation can cause cracking, rupture or abrasive damage or peeling of the applied surface coating or laminate. If the integrity of the surface coating or laminate is weakened, repeated exposure to extreme environments can impair adhesion and damage the underlying FRC substrate. Means are needed to maintain FRC product integrity despite surface damage to the coating or laminate.

Based on the above, there is a need for FRC composites with decorative or functional surfaces that provide a means to maintain the appearance and integrity of the surface even in extreme environments and at the same time maintain the integrity of the composite even if the surface is damaged or weakened. exist. In addition, there is a need to substantially reduce the number of treatments required for the composite to achieve the required level of performance in a given field. To this end, in particular, there is a need for FRC products that have high resistance to damage caused by long exposure to freeze / thaw conditions, wear resistance and water resistance, and can achieve these performance characteristics while substantially reducing materials and costs. do.

It is therefore an object of the present invention to provide composite articles and methods of making such articles that overcome or mitigate one or more of the disadvantages of the prior art.

Summary of the Invention

In one aspect, a preferred embodiment of the present invention provides a building composite article having a first zone comprising predominantly fiber cement, a second zone comprising predominantly radiation curable material, and a subsurface interfacial zone sandwiched between these zones. . Preferably, the subsurface interface zone comprises an interlocking matrix formed of radiation curable material and fiber cement and is structured to increase the durability of the building article. Preferably, the interfacial zone is present through the cross section of the composite article to a specified degree. The radiation curable material is from the group consisting of epoxy, urethane, polyester, acrylate, methacrylate, thiol-acrylate, unsaturated polyester, polyester epoxy, urethane acrylic material, styrene and functionalized styrene or mixtures thereof Can be selected. In one embodiment, the thickness of the subsurface interfacial zone is determined by the porosity of the first zone, the viscosity of the carrier solution to the radiation curable material, the viscosity of the radiation curable material itself, the wet behavior of the radiation curable material, and the radiation curable material and the first zone material. It can be adjusted by modifying a feature selected from the group consisting of the reactivity of. In one embodiment, the first zone comprises a fiber cement substrate having a porosity of about 2% to 80% by volume, more preferably about 20% to 40% by volume. In another embodiment, the entire cross section of the building composite article includes subsurface interface zones. In another embodiment, the subsurface interface zone is formed integrally with the first zone and the second zone, and has a thickness of about 1 μm to 1,000 μm. Preferably, the radiation curable material in the subsurface interface zone is substantially free of catalyst and is mainly curable by radiation. Preferably, the composite building material is selected from the group consisting of cladding panels, sheets, boards, flanks, trims, columns and pipes.

In another aspect, a preferred embodiment of the present invention provides a building article wherein at least a portion of the matrix of the building article comprises a network formed of fiber cement and a radiation curable material. Preferably, the network structure is structured to increase the durability of the building article. In one embodiment, the fiber cement and the radiation curable material are scattered throughout the matrix of building material. Preferably, the radiation curable material is present in fiber cement material pores having an average pore size of greater than 0.01 micron. In another embodiment, the building article further comprises reinforcing fibers wherein at least a portion of the fibers are treated with a radiation curable material. In another embodiment, the building article further includes an outer coating formed primarily of radiation curable material. Preferably, the outer coating is integrally formed with the network to increase the adhesion between the matrix of the building article and the outer coating. In alternative embodiments, the building article includes an exterior coating applied to one or more surfaces.

In still another aspect, a preferred embodiment of the present invention provides a method of forming a building product. The method includes applying a radiation curable material to a fiber cement substrate, where the radiation curable material extends to the substrate in a controlled manner and forms an area comprising a mixture of the radiation curable material and the fiber cement. The method further includes forming a three dimensional network of radiation cured material and fiber cement by applying radiation to cure the radiation curable material in the substrate. Preferably, electron beam radiation is applied to cure the radiation curable material. Preferably, the radiation curable material is in direct contact with the fiber cement substrate. In another embodiment, the radiation curable material is cured in a multistep process.

In still another aspect, a preferred embodiment of the present invention provides a method of forming a building product. The method comprises combining a radiation curable material with a component for forming a fiber cement composite material, forming a green sheet in which the radiation curable material is distributed over at least a portion of the green sheet, and curing the green sheet to cure the fiber cement. And forming a building article containing a network of radiation curable materials. In one embodiment, the method further includes bonding the green sheet to the uncured fiber cement substrate prior to curing the green sheet. In another embodiment, the method further comprises applying a coating to one or more surfaces of the building product.

1 is a cross-sectional view of a building composite article of one preferred embodiment, showing a subsurface interface zone formed in the article.

2 is a cross-sectional view of an architectural composite article of another embodiment, showing two subsurface interface zones formed in the article.

3 is a cross-sectional view of another embodiment of the building composite article having a subsurface interface zone formed adjacent to an exterior face of the building article.

4 is a cross-sectional view of another embodiment of the building composite article having a separate subsurface interface zone formed on the substrate of the article.

5 is a cross-sectional view of another embodiment of the building composite article having two different types of subsurface interface zones formed on the substrate of the article.

6 is a cross-sectional view of a building hollow composite article incorporating a subsurface interface zone adjacent to an exterior surface of the building article.

7 is a cross-sectional view of an architectural hollow composite article incorporating two different types of subsurface interface zones in an article.

8 illustrates a method of forming a building composite article of a preferred embodiment of the present invention.

9 is a chart comparing the ILB results after the freeze-thaw cycles of the compressed FRCs of one preferred embodiment with the results of equivalent compressed FRC sheets without any interfacial band.

10A and 10B are photographs showing the FRC article of one preferred embodiment after a cleavage and freeze-thaw cycles.

Detailed Description of the Preferred Embodiments

Preferred embodiments of the present invention provide a building composite article having at least one subsurface interface zone formed from an interlocking network of fiber cement and radiation curable material. As will be described in detail below, the interface zone is preferably formed integrally with the outer surface and the substrate of the building article to provide an effective interface to the entry of environmental materials and to improve the durability, weather resistance, strength and toughness of the building article. .

Reference is now made to the drawings, wherein like numerals refer to like parts throughout the figures. 1 schematically illustrates a cross-sectional view of an architectural composite article 100 of one preferred embodiment of the present invention. As shown in FIG. 1, a building article 100 is generally formed of a substrate 102 formed primarily of fiber cement, an outer layer 104 formed primarily of radiation curable material, and a network of fiber cement and radiation curable material. Subsurface interface zone 106. The term "mainly" as used herein, means to include greater than 50% by weight.

Preferably, the substrate 102 of the building composite article 100 in FIG. 1 is porous and / or hydrophilic. The substrate may be composed of a variety of different materials, such as gypsum composites, cement composites, geopolymer composites or other composites including inorganic binders. Preferably, the substrate is a low density fiber cement plate having a porosity of about 40% to 80% by volume, a medium density fiber cement plate having a porosity of about 20% to 40% by volume, or about 2% to 20% by volume. High density / compressed fiber cement plate with a porosity of%. As will be described in detail below, it is also possible to modify the porosity of the substrate by mechanical or chemical treatment to control the formation of interfacial zones. The porosity of the substrate can be divided into five main groups as follows.

i) air voids (about 100-10 microns). These relate to large voids created by poor packing, fiber clumping, dehydration, and the like. Sometimes they are also referred to simply as cracks or interlayer voids.

ii) fiber voids (10-1 micron). They are particularly concerned with inherent voids in lignocellulosic fibers that occur due to their tubular structure and four-wheel like shape.

iii) Meso voids (1-0.1 micron).

iv) capillary pores (0.1-0.01 micron). These are related to the voids that occur when the free water is depleted in the matrix.

v) gel pores (0.01-0.001 micron). These voids relate to cement or ten binder micropores, which are very small in size and difficult to deform.

While not wishing to be bound to any particular theory, Applicants believe that voids in construction articles, in particular from 0.01 microns to 100 microns, most particularly from 1 micron to 100 microns, in which the properties of the substrate 102 are produced, particularly durability in extreme climatic conditions. It is assumed that it can be involved in modifying or processing pores with an average pore size of.

Substrate 102 may be sanded, mechanized, extruded, molded or formed into any desired shape. Substrate 102 may be in a fully cured, partially cured or uncured "green" state. Various different fiber cement compositions and methods of making fiber cement substrates can be used in these applications, for example those described in Australian patent AU515151, PCT application WO 0168547 and PCT application W09845222, which are hereby incorporated by reference in their entirety. It is cited in the literature.

Preferably, the subsurface interface zone 106 illustrated in FIG. 1 is formed integrally with the substrate 102 and includes an intimate blend of fiber cement and one or more radiation curable components. The radiation curable component interpenetrates the gaps and voids in the fiber cement and mechanically interacts with the fiber cement to form a subsurface three-dimensional network structure that is substantially resistant to the entry of environmental materials, such as water. Preferably the radiation curable component is present in pores having an average pore diameter of greater than 0.01 micron, more preferably 0.1 to 100 microns. Most preferably, the radiation curable component is present in the pores having an average pore diameter of 1 to 100 microns. In addition, in some embodiments, the radiation curable component is chemically bonded to the void walls and / or reinforcing fibers of the substrate 102. Because the interfacial zone 106 is integrally formed with the substrate 102, it is much less susceptible to degradation and damage than conventional protective coatings or laminates formed on the exterior surface of a building article. The number, shape, distribution and thickness of the interfacial zones can be selected based on the intended end use of the composite article. In one embodiment, the interfacial zone 106 constitutes substantially the entire thickness of the composite article. In another embodiment, the interfacial zone 106 has a thickness of about 1 to 1,000 μm, preferably about 5 to 500 μm, more preferably about 10 to 200 μm.

Preferably, the radiation curable component in the interfacial zone 106 is substantially free of catalyst and is mainly cured by radiation such as UV, IR, NIR microwave or gamma radiation, more preferably electron beam (EB) radiation. do. Radiation curable components may include polymeric materials such as epoxy, urethanes, polyesters, acrylates, methacrylates, and compounds having multifunctional types such as polyester epoxy and urethane acrylic materials, It is not limited to this. In an embodiment, the radiation curable component can be a monomer, oligomer or polymer. Oligomers are isocyanates, hydroxyls, polyethers, epoxies, carboxylic acids, free radical systems such as thiolenic (polyfunctional thiols and unsaturated polyenes such as vinyl ethers, vinyl sulfides, allyl ethers and Based on the reaction of bicyclic ene), amine-ene based (based on the reaction of polyfunctional amines and unsaturated polyenes), acetylene based, other vinyl based (eg , Styrene), acrylamide, allyl, itaconate and crotonate, and cationic curing systems such as onium salt-derived vinyl ethers and epoxy-reacted by ring opening It can be prepared from a range of monomers having functionalities including, but not limited to, late stages, and others based on compounds having reactive ends. In fact, almost any functional group that is cured by irradiation, heat or other means and does not adversely affect the desired properties of the cured composition (ie oxidation, heat and hydrolytic stability and moisture resistance) is suitable for the radiation curable component 106. Is considered. When the radiation curable component is cured in air, a radiation curable component comprising thiylene is particularly preferred.

In addition, the radiation curable component 106 may comprise acrylate or methacrylate functionalized alcohols, diols and polyols, acrylate or methacrylate functional ethoxylated and / or propoxylated alcohols, diols and polyols, and acrylates or Methacrylate functional ethylene and propylene glycol and ethylene and propylene polyglycol, and other ethylene unsaturated monomers such as styrene, and monomers including but not limited to functionalized styrene. Other monomers effective to prepare such complexes include derivatives of unsaturated carboxylic acids and diacids, such as maleate and fumarate esters, and vinyl-based functional materials such as vinyl ethers, and vinyl pyrrolidone Including but not limited to. In addition, blends or mixtures of the radiation curable components described herein can also be used. In addition, additives such as pigments, mineral extenders, surfactants, anti-wetting agents, dyes, plasticizers, stabilizers, dustproofers, insulations, and flame retardants can be added to the radiation curable components to ensure the physical properties of the finished product. Can improve chemical properties

Preferably, the radiation curable component is 100% solids and has a low VOC content. Alternatively, the radiation curable component may be dissolved, suspended or emulsified in an organic solvent, water, a supercritical fluid, such as but not limited to C0 ₂ . Preferably, the radiation curable component has a solids content of greater than about 50%, more preferably greater than about 70%, even more preferably from about 80% to 100%. In addition, in some implementations, the radiation curable component may contain viscosity modifiers, surfactants or inorganic fillers. It has been found that 100% solid compositions are advantageous for forming the interfacial zone. Preferably, the viscosity of the high solids composition is manipulated to obtain the specified distribution in the fiber cement matrix and voids. In one embodiment, monomers can be used to modify the viscosity of the high solids radiation curable component. Preferably, the curable component having a high solid ratio is 1% to 60% by weight, more preferably 2% to 40% by weight, more preferably less than 40% by weight and 5% by weight, 10% by weight, 15 Have a monomer content of greater than 20%, 20%, 25%, or 30% by weight. When using an emulsion based system, it is desirable to manipulate the emulsion particle size to facilitate void filling.

The outer layer 104 of the building article 100 of FIG. 1 includes a layer of a protective coating, such as a radiation curable coating, or a heat curable coating, primer, sealer, or the like. In some embodiments, outer layer 104 comprises the same radiation curable material as incorporated in interfacial zone 106. As will be described in detail below, the outer layer 104 may be integrally formed with the interface zone 106 to enhance the adhesion between the outer layer 104 and the substrate 102. Advantageously, the continuous outer layer 104 together with the fiber cement 106 and subsurface three-dimensional network of radiation curable material improves the aesthetics of the product and improves the long term durability of the product in extreme conditions. In addition, the continuous outer layer can serve as a means of delivering to the subsurface curable material energy or starting species that is difficult to reach by the primary radiation source.

It will be appreciated that the number, location, and structure of subsurface interface zones in a building article may vary based on design and desired purpose. Single or multiple interfacial zones may be incorporated in building articles in which each interfacial zone contains one or more radiation curable components. 2-7 schematically illustrate various embodiments of a building article having one or more subsurface interface zones distributed in the article in various ways.

2 schematically illustrates a cross-sectional view of the architectural composite article 200 of one such embodiment. The building article 200 is composed of a fiber cement substrate 202, two opposing outer layers 204a and 204b, and two integrally formed sandwiched between the fiber cement substrate 202 and the outer layers 204a and 204b, respectively. It has subsurface interface zones 206a and 206b. Preferably, the outer layers 204a and 204b are coated with a protective coating such as a radiation curable sealer.

3 illustrates a cross-sectional view of an architectural composite article 300 of another embodiment. The building article 300 has a fiber cement substrate 302 and subsurface interface zones 306a-d formed adjacent each side of the article 300. In addition, outer protective layers 304a-d that primarily comprise a radiation curable material are formed on each side of the article 300. Preferably, subsurface interface zones 306a-d are integrally formed with outer layer 304a-d and substrate 302.

4 illustrates a cross-sectional view of an architectural composite article 400 of another embodiment. The building article 400 has a fiber cement substrate 402 and a plurality of subsurface interface zones 406 distributed throughout the substrate 402. Each subsurface interface zone 406 has a circular cross section and extends along the length of the article.

FIG. 5 shows a building article 500 having a fiber cement substrate 502 and a first plurality of separate subsurface interface zones 506 distributed throughout the substrate 502. The building article 500 also has a second plurality of subsurface interface zones 508 formed in the substrate 502 adjacent the outer layer 504. Preferably, the outer layer 504 mainly comprises a radiation curable material. In one embodiment, the radiation curable material incorporated in the first subsurface interface zone is different from that in the second interface zone.

The building articles shown schematically in FIGS. 1-5 provide a variety of different building products, such as building plates, sheets, flanks, trims, shakes, cladding panels, suitable for application to the interior and exterior surfaces of a building. One preferred embodiment of the present invention has been developed for use in the production of high performance compressed fiber cement sheets having subsurface interfacial zones and radiation cured coatings specifically structured for use as exterior or interior building cladding and lining panels.

6-7 show that the theory can also be applied to building articles having annular bodies, for example pipes or columns. 6 is a cross-sectional view of a hollow pipe 600 having integrally formed subsurface interface zones 606a, 606b and a fiber cement core 602 positioned adjacent the outer surfaces 604a, 604b of the pipe 600. Preferably, a radiation curable coating is applied to the outer surfaces 604a and 604b of the pipe 600. FIG. 7 shows that a second set of subsurface interface zones 706 can be distributed in the fiber cement core 602 of the hollow pipe 600 in FIG. 6.

Subsurface Interfacial Zone Formation Method

As will be described in detail below, the subsurface interface zone in the fiber cement article is characterized by (a) applying the radiation curable component to the cured fiber cement matrix in a controlled manner, and (b) uncuring the radiation curable component in a controlled manner. Applied to the fiber cement matrix, (c) prior to formation of the green form, the radiation curable component is mixed into the fiber cement mixture, and (d) the radiation curable material is incorporated into components, such as fibers, fillers and / or inorganics of building articles. Applying to the binder, (e) prefabricating a mixture of fiber cement and radiation curable material, and then forming together into an architectural article having an uncured fiber cement material that does not contain radiation cured components. Can be formed by a number of different methods.

In each preferred embodiment, the radiation curable component is in direct contact with the fiber cement matrix and polymerized in contact with the fiber cement to form a network that mechanically interacts with the voids and crevices of the fiber cement. Preferably, the application rate and concentration of the radiation curable material is selected to provide a suitable concentration of polymerizable compounds in the interfacial zone to fill the voids and gaps in the fiber cement matrix to a specified degree.

Single layer application

In certain preferred embodiments, no additional layer of other coating material is interposed between the radiation curable material and the fiber cement to ensure that the polymerized radiation curable material is in contact with the fiber cement. In one embodiment, the layer of radiation curable material is preferably applied to one or more surfaces of the fiber cement substrate, but retains a substantially defect-free adhesive film on each surface. Subsequently, the layer of radiation curable material is transferred to the substrate in a controlled manner to form an integral interface zone after curing. As such, a single layer of radiation curable material is sufficient to provide a continuous protective coating that is formed integrally with the fiber cement matrix.

Thickness control of subsurface interface zone

In addition, in certain preferred embodiments, the thickness of the subsurface interfacial zone can also be adjusted or tailored to specific product performance criteria. In one embodiment, the preselected thickness is obtained by controlling the migration of the radiation curable component to the fiber cement matrix. For example, the thickness of the interfacial zone can be controlled by modifying the porosity of the fiber cement matrix to a target volume to control the rate and amount of radiation curable component migration to the fiber cement matrix. Alternatively, the viscosity of the radiation curable component can be modified by combining this component with a specified amount of reactive monomer. In some embodiments, the thickness of the interfacial zone is further increased by using a solvent or carrier that allows the dissolved radiation curable component to penetrate into the fiber cement.

Curing of Radiation Curable Components in Subsurface Interface Zones

In order to ensure hardening of an interface zone, it is preferable to use the hardening method which can harden the component deep in an interface zone. Preferably, the curing of the radiation curable component in the subsurface interface zone is carried out mainly using radiation, more preferably EB radiation. Since the radiation curable component of certain preferred embodiments does not contain a significant amount of catalyst, EB radiation curing is preferred because it has a high energy and provides good penetration into the curable component in the interface zone to provide an increased thickness of the interface zone. . In addition, since the EB curable compound tends to be stable even in the presence of heat and UV, it can be easily activated when necessary. The high energy of electrons in these beams allows the beam to penetrate to significant depths and initiate reactions at greater depths.

While not wishing to be limited to any particular implementation, the inventors have found suitable curing using an EB source of 50 KeV to 200 KeV at 10 mA in a fiber cement substrate having a density of about 1.33 for an interfacial zone thickness of every 30 microns. It was found that can be performed. For example, a 180 micron thick interface band can be cured by using an EB source of 10 mA to 150 mA and a thicker interface band using a corresponding higher energy EB source. Alternatively, the interfacial zone can be cured using thermal means following the EB radiation of the above described capacities. In some embodiments, the curing method includes more than one mechanism, such as EB and UV, EB and thermal means, and the like.

8 shows a process 800 for producing a building composite article of a preferred embodiment of the present invention. In this figure, the building composite article is a compressed building cladding panel. As shown in FIG. 8, process 800 begins with step 802 where an FRC green sheet is manufactured according to known fiber cement compositions and manufacturing techniques. In one embodiment, commonly used fiber cement compositions fall within the ranges shown in Table 1 below.

Formulation for FRC Sheet Dry Ingredients (General) Dry Ingredient (Preferred Embodiment) Acceptable range (dry weight%) Preferred range (dry weight percent) Binder cement About 20-60% About 23.5-26.5% Aggregate Silica About 0 to 60% About 62-65% fiber Cellulose pulp About 0.1 to 15% About 7-9% additive Alumina About 0-5% About 2.5-4.5%

The binder may include conventional Portland cement type 1, and may also include other inorganic binders such as gypsum, geometric polymers, or other inorganic cements. The aggregates are rolled quartz, amorphous silica, pearlite, vermiculite, synthetic calcium silicate hydrate, diatomaceous earth, rice bran, coal ash, bottom ash, blast furnace slag, chain slag, steelmaking slag, inorganic oxide, inorganic Hydroxides, clays, magnasites or dolomite, polymer beads, metal oxides and hydroxides, or mixtures thereof.

Preferred fibers include various forms of cellulose fibers, such as bleached or unbleached kraft pulp. However, it will be appreciated that other types of fibers may also be used. In a particularly preferred embodiment, the fiber is cellulose wood pulp. Other examples of suitable fibers include ceramic fibers, glass fibers, inorganic wool, steel fibers, and synthetic polymer fibers such as polyamide, polyester, polypropylene, polymethylpentene, polyacrylonitrile, polyacrylamide, viscose, nylon , PVC, PVA, rayon, glass ceramics, carbon or any mixture thereof. The fibers may also include hydrophobic treated, biocide treated cellulose fibers, or those disclosed, for example, in PCT patent applications WO 0228796 and WO0228795, which are hereby incorporated by reference in their entirety.

In addition, density modifiers, dispersants, silica fume, geothermal silica, fire retardants, viscosity modifiers, thickeners, pigments, colorants, dispersants, blowing agents, flocculating agents, waterproofing agents, organic density modifiers, aluminum powder, kaolin, hydroxide It should also be noted that additional additives, including but not limited to alumina, mica, metakaolin, calcium carbonate, wollastonite, polymeric resin emulsions or mixtures thereof, may optionally be incorporated into the fiber cement composition.

In one preferred method, the sheets are made using the Hotschek method. In general, hot check methods known in the art employ a series of rotating drum sieves to deposit a continuous layer of dehydrated slurry onto an absorbent conveyor and accumulate on a size roll until the desired sheet thickness is obtained. However, it will be appreciated that green sheets can also be produced using other known methods, such as extrusion, casting, molding, Mazza, Magnini, Fourdrinier and roll press methods. .

A preferred manufacturing process is set up to produce a plurality of green sheets of a particular size, then one is stacked over another and then optionally densified in a press or embossed in a pattern. In step 804, the green sheet is cured in an autoclave or using a number of other conventional techniques, including air curing, moisture curing, or drying.

When curing is complete, the sheet is optionally cut at step 806 by sizing it using any of various cutting, sawing or scoring techniques.

In step 808, the radiation curable material is applied to one or more sides of the FRC sheet. A substantial portion of the radiation curable component extends from one or more sides of the FRC sheet into the fiber cement matrix, filling voids and gaps therein, and in direct contact with the fiber cement. A radiation curable material, for example a radiation curable sealer, in some preferred forms of the present invention is applied to all six sides (front and mounting faces are two main faces, with four ends) of the finished FRC sheet. This can be done by first manually roll coating or spraying a roll coating or spray sealer at the end of the stack of FRC sheets, and then roll coating the sealers individually at the front and back of the FRC sheet using conventional roll coatings. Alternatively, the sealer may be applied by other conventional methods such as spraying, curtain coating or powder coating. Preferably, the combined thickness of the outer layer and the subsurface interface zone is in the range of about 15 to 1000 microns, more preferably 15 to 100 microns.

Preferably, the radiation curable material is applied directly to the fiber cement surface and transferred to the FRC sheet or substrate in a controlled manner to form the interfacial zone of step 810. In a particular embodiment, a continuous defect free film is applied to the fiber cement in a single pass. In other embodiments, the surface of the FRC sheet is further treated to facilitate controlled movement of the radiation curable material. In addition, mechanical and chemical treatments may be applied to affect the porosity of the substrate which affects the movement of the radiation curable component to the substrate. The surface of the fiber cement may be sanded, machined or chemically etched prior to application of the radiation curable component, which may provide an effect of increasing the thickness and improving the uniformity of the interface zone.

In one preferred embodiment, the radiation curable component is a radiation polymerizable compound applied to the surface of the FRC as a dispersion in an amount sufficient to ensure that at least a portion of the dispersion penetrates the pores of the FRC substrate to create a subsurface interface zone. In an alternative embodiment, the radiation curable component is applied to the FRC green sheet to penetrate the surface of the FRC green sheet, thereby subsurface interfacial zone in the thickness range of about 15 to 1000 microns, more preferably 15 to 100 microns before FRC sheet curing. To form.

In other embodiments, the blend of uncured FRC and radiation curable components may be distributed or located in one or more designated areas within the bulk matrix of uncured fiber cement that does not contain radiation curable materials. Furthermore, in a further alternative embodiment, some polymerizable compounds may be added in solution, followed by application of the same or different polymerizable or copolymerizable compounds to the surface. Further, in another alternative embodiment, two or more different blends of radiation curable material and fiber cement are located or distributed in one or more designated zones in the bulk matrix of uncured FRC that do not contain radiation curable material. In another alternative embodiment, the fibers are treated with a radiation curable material and distributed or carefully placed in one or more designated areas in the bulk matrix of uncured fiber cement that do not contain radiation curable materials.

Next, in step 812, the FRC sheet is cured using conventional EB radiation at a suitable designated strength and duration determined by the special sealer formulation. Preferably, an EB source with an output of about 50 to 1000 KeV, more preferably about 75 to 500 KeV, even more preferably 150 to 300 KeV is used. Preferably, the strength of the EB cure is maintained in a constant amount relative to the surface during the cure period to substantially reduce product defects and any of a number of suitable tests known in the art (eg solvent rub, coating Hardness, water or monomer content, etc.) to achieve the specified amount of cure. Preferably, the cured radiation curable component has less than about 1 weight percent reactive monomer or reactive volatile component remaining after curing. More preferably, the cured radiation curable component has less than about 0.1 weight percent reactive monomer or reactive volatile component remaining after curing.

FIG. 9 shows improved freeze thaw resistance compared to equivalent compressed FRC panels without interfacial bands of compressed FRC panels formed using interface bands adjacent to all six faces. As shown in FIG. 9, an FRC panel formed using an interfacial zone can maintain a relatively constant ILB at about 2.0 Mpa as the number of freeze-thaw cycles increases, while the ILB of a typical compressed FRC panel is substantially high freezing. -Decrease in the thawing cycle; The freeze-thaw cycle is operated according to the method described in ASTM C666-92 modified to fit a sample size of 415 × 57 × 9 mm.

10A and 10B are photographs showing peel resistance of building FRC composite articles having subsurface interface bands. Articles under 1,000 freeze thaw cycles were scored deeper to deeper than the interfacial zone. As shown in FIGS. 10A and 10B, the degree of peeling was limited to a relatively small area even after a large freeze thaw cycle. This shows that the radiation cured zone not only tightly binds to the fiber cement zone that resists delamination, but also improves the integrity of the FRC article even under severe freeze thawing conditions.

Preferred embodiments of the invention are further described with reference to the following illustrative examples.

Example 1-Medium Density Hot Check Sheet for External Use

7/16 "medium density fiber cement sheets were formed by hot check method. Flanks were of the type commonly used for external use. Spray coating all sides with EB curable urethane acrylate resin having a solids content of about 80%, The resin was cured by exposure to EB radiation The resin thickness was about 50 microns The resin zone strongly adhered to the sheet and had a substantially flat appearance The cross-sectional examination of the material revealed three distinct zone-bottom fiber cement zones, It shows the presence of the resin coating and the subsurface interfacial zone, which shows that the amount of fibrous material embedded in the resin is significant, with the cured resin forming the network of the cured polymer continuously in the voids of the subsurface interfacial zone. The subsurface interface zone was integral with both the resin and fiber cement regions.

Example 2 External Low Density Extruded Articles

A fiber cement article of nominal 2 "x 4" rectangular cross section of low density fiber cement of suitable formulation for external use was extruded. The material was spray coated in green with radiation curable resin and then cured to each surface using EB radiation. Similar results were recorded as above. Excellent subsurface interfacial zones were formed, but did not withstand the use of very high solid formulations. The green article was then air cured to obtain an article that was more durable than the article without this coating.

Example 3-Fiber cement articles comprising cellulose fibers with an EB curable resin coating.

Sheets of unbleached kraft fiber were refined with a degree of freedom of about 350 CSF and added to water to produce about 11% by weight fiber solution. An aqueous dispersion of EB curable acrylic urethane was added to the fibers at a dosage rate of about 0.5% resin per fiber weight. The fibers were then combined with cement and ground silica in solution to form a sheet of fiber cement about 1 mm thick. While the fiber cement component of the sheet was kept green, the radiation curable component in the sheet was cured using EB radiation. This fiber cement sheet was then laminated to the top and bottom of the stack of green fiber cement sheets that did not contain a radiation curable component to form a composite. The composite laminate was cured at about 180 ° C. in an autoclave to further cure the fiber cement sheet. The resulting sheet had less moisture permeability through the outer surface than the fiber cement sheet containing no fibers treated with the radiation curable resin.

Example 4 Medium Density Fiber Cement Articles Having Epoxy-Based Radiation Curable Components

About 60% w / w bifunctional bisphenol A based on epoxy acrylate resin, about 15% tripropylene glycol diacrylate monomer, about 20% w / w extender (combination of talc and calcium carbonate) and about 5% w / An epoxy based radiation curable component (RCC) comprising w additive was rolled onto a medium density fiber cement plate to form a continuous film on the surface and subsurface interfacial zone of approximately 5 to 15 microns thick. The total RCC application amount was about 39 g / m 2. The average wet film thickness was determined to be 30 μm using a comb gauge. The RCC was cured using an electron beam curing unit (manufactured by Advanced Electron Beam, 150 kV, 10 mA laboratory unit). The unit was set to 150 kV, 10 mA and 50 ft / min. The unit was purged with nitrogen to obtain an oxygen concentration of about 200 ppm in the chamber. The adhesion of the continuous surface film was tested using a cross-blind tape test. Adhesion to the plate was scored as 10 out of 10 possible.

Example 5 Medium Density Fiber Cement Articles Having Urethane-Based Radiation Curable Components.

Urethane RCCs consisting of 80% w / w aliphatic difunctional urethane acrylate resins and 20% tripropylene glycol diacrylate monomers were rolled onto medium density fiber cement plates to provide continuous on the surface and subsurface interface zones approximately 5 to 30 microns thick. A film was formed. The total RCC application amount was about 78 g / m 2. The RCC was cured using an electron beam curing unit (manufactured by Advanced Electron Beam Co., Ltd., 150 kV, 10 mA laboratory unit). The unit was set to 150 kV, 10 mA and 50 ft / min. The unit was purged with nitrogen to obtain an oxygen concentration of 200 ppm in the chamber. The adhesion of the continuous surface film was tested using a cross-blind tape test. Adhesion to the plate was perfect (grade 10/10)

Example 6 Medium Density Fiber Cement Articles Having a Polyester-Based Radiation Curable Component.

60% w / w bifunctional polyester acrylate resin, 15% tripropylene glycol diacrylate monomer, 20% w / w pigment and extender (combination of titanium dioxide talc and barium sulfate) and 5% w / w Polyester RCCs consisting of additives (flowing agents, dispersants, thixotrope and antifoaming agents) were rolled onto medium density fiber cement plates to form continuous films on the surface and subsurface interface zones approximately 5 to 30 microns thick. The total RCC application amount was about 78 g / m 2. The average wet film thickness was determined to be 60 μm using a comb gauge. The RCC was cured using an electron beam curing unit (manufactured by Advanced Electron Beam Co., Ltd., 150 kV, 10 mA laboratory unit). The unit was set to 150 kV, 10 mA and 50 ft / min. The unit was purged with nitrogen to obtain an oxygen concentration of 200 ppm in the chamber. The adhesion of the continuous surface film was tested using a cross-blind tape test. Adhesion to the plate was perfect (grade 10/10)

Example 7 Medium Density Fiber Cement Articles Having a Polyester-Based Radiation Curable Component.

45% w / w difunctional polyester acrylate, 15% w / w metal acrylate, 15% 1,6 hexanediol diacrylate, 20% w / w pigment and extender (a combination of titanium dioxide talc and barium sulfate Water) and 5% w / w additives (fluidizers, dispersants, thixotropes and antifoams) were rolled onto medium density fiber cement plates to produce continuous films on the surface and subsurface interface zones approximately 5-20 microns thick. Formed. The total RCC application amount was about 52 g / m 2. The average wet film thickness was determined to be 40 μm using a comb gauge. The RCC was cured using an electron beam curing unit (manufactured by Advanced Electron Beam Co., Ltd., 150 kV, 10 mA laboratory unit). The unit was set to 150 kV, 10 mA and 50 ft / min. The unit was purged with nitrogen to obtain an oxygen concentration of 200 ppm in the chamber. The adhesion of the continuous surface film was tested using a cross-blind tape test. Adhesion to the plate was perfect (grade 10/10)

Example 8 Medium Density Fiber Cement Articles Having a Thiolene-Based Radiation Curable Component.

RCC consisting of 30% w / w 6-functional aliphatic urethane acrylate, 20% w / w tri-functional polyester acrylate and 50% w / w pentaerythritol tetrakis (3-mercaptopropionate) It was applied to medium density fiber cement plates to form continuous films on the surface and subsurface interfacial zones approximately 5 to 30 microns thick. The RCC was cured using an electron beam curing unit (manufactured by Advanced Electron Beam Co., Ltd., 150 kV, 10 mA laboratory unit). The unit was set to 150 kV, 10 mA and 50 ft / min under air. The continuous surface film was non-tacky and the adhesion was tested using a cross-stitch tape test (after drying and soaking in water for 1 hour). Adhesion to the plate was perfect for both (grade 10/10).

Example 9-Medium Density Fiber Cement Articles Having Pigmented Thiylene-Based Radiation Curable Components.

20% w / w 6 functional aliphatic urethane acrylate, 14% w / w trifunctional polyester acrylate, 35% w / w pentaerythritol tetrakis (3-mercaptopropionate), 30% w / w pigment And an RCC topcoat consisting of a bulking agent (a combination of titanium dioxide talc and barium sulfate) and 1% w / w additive (fluidizing agent, dispersant, thixotropy and antifoaming agent) on a medium density fiber cement plate to approximately 5-20. Continuous films on the micron thick surface and subsurface interface zones were formed. The total RCC application amount was about 52 g / m 2. The average wet film thickness was determined to be 40 μm using a comb gauge. The RCC was cured using an electron beam curing unit (manufactured by Advanced Electron Beam Co., Ltd., 150 kV, 10 mA laboratory unit). The unit was set to 150 kV, 10 mA and 50 ft / min under atmospheric conditions. The continuous surface film was non-tacky and the adhesion was tested using a cross-stitch tape test (after drying and soaking in water for 1 hour). Adhesion to the plate was perfect for both (grade 10/10).

Example 10 Medium Density Fiber Cement Articles with RCC Treated Interface Zones with Improved Wet Adhesion.

Urethane RCC consisting of 80% w / w aliphatic difunctional urethane acrylate and 20% tripropylene glycol diacrylate is rolled onto the surface of a medium density fiber cement plate to provide continuous on the surface and subsurface interface zones of approximately 5 to 30 microns thick. A film was formed. The total RCC application amount was about 78 g / m 2. The average wet film thickness was determined to be 60 μm using a comb gauge. The RCC was cured using an electron beam curing unit (manufactured by Advanced Electron Beam Co., Ltd., 150 kV, 10 mA laboratory unit). The unit was set to 150 kV, 10 mA and 50 ft / min. The unit was purged with nitrogen to obtain an oxygen concentration of 200 ppm in the chamber. Next, the wet adhesion of the continuous surface film was tested. This was done by immersing the test panel completely in water for 2 hours at room temperature. The panel was then recovered and dried by tapping lightly with a cloth so that there was no residual moisture that would interfere with the adhesive force of the tape. Then, the cross-stitch tape test was used to immediately check the adhesion of the coating. Adhesion to the plate was perfect (grade 10/10)

Example 11: Medium Density Fiber Cement Articles with RCC Treated Interfacial Zones Showing Reduced Surface Permeability

The urethane RCC consisted of 80% w / w aliphatic difunctional urethane acrylate and 20% tripropylene glycol diacrylate. This coating was rolled to all four ends, fronts and backs of the medium density fiber cement to form a continuous film on each surface and subsurface interfacial zone approximately 5 to 30 microns thick. The total RCC application amount was about 78 g / m 2. The average wet film thickness was determined to be 60 μm using a comb gauge. The RCC was cured using an electron beam curing unit (manufactured by Advanced Electron Beam Co., Ltd., 150 kV, 10 mA laboratory unit). The unit was set to 150 kV, 10 mA and 50 ft / min. The unit was purged with nitrogen to obtain an oxygen concentration of 200 ppm in the chamber. The moisture permeability of the coating was tested using a water column placed under pressure of 2 bar for 7 minutes. The test panel was weighed before and after exposure to the pressurized water column. The sample was recovered from the test column, dried and reweighed. The panel showed no weight change after exposure to the pressurized water column.

Embodiments of FRC building articles having subsurface interfacial zones comprising such radiation curable components improve the long term durability of FRC materials in extreme environments, such as freeze thawing, and generally wet and dry adhesion of surface films. To demonstrate substantial improvement. The radiation curable component is added to the fiber cement in the form of an entire batch of fiber cement forming material or in the form of added bands of material including both fiber cement and the curable material and applied to the fiber cement or the fiber cement forming substrate. Can be. In this way, a subsurface interfacial zone is prepared in which the curable compound and the fiber cement are intimately mixed. For example, a zone of fiber cement may be laid, and a zone in which a mixture of fiber cement and a curable compound is present is applied thereon. The fiber cement product is then cured to produce a fiber cement article having a polymerizable compound in the upper zone intimately mixed with the fiber cement material. An additional zone of the curable compound can be added on top of it, and then the mixture is cured, for example with an electron beam. The EB curable material in the top zone will crosslink with other crosslinkable components in the top zone and also with crosslinkable components in the prefabricated subsurface interface zone. In this way, the subsurface interface zone is specially formed by applying a mixture of the fiber cement zone and the resin component. The advantage of using an EB curable compound is that it is stable even in the presence of heat and UV and can be activated more easily if necessary.

Advantageously, the composite building article of the preferred embodiment of the present invention provides a high resistance to external atmospheric materials, heat, moisture, in particular scratching or polishing, compared to similar sheets made using conventional surface coatings, It can be used in the construction field as the covering of the outer surface. They can also be used in applications where chemical resistance is a problem, for example pipes. The addition of cured subsurface interfacial zones provides a weathering tendency, in particular freeze / thaw damage or differential carbonation reduction, in composite articles compared to the fiber cement products present.

Although the foregoing description of the preferred embodiments of the present invention has shown, described and pointed out novel features of the invention, various omissions, substitutions and changes in the form of the details of the invention as well as the exemplified embodiments thereof, It will be appreciated that it may be made by one skilled in the art without departing from. In particular, it will be appreciated that preferred embodiments of the present invention may be found in other shapes and structures suitable for the end use of articles made therefrom.

Claims (21)

A first zone comprising predominantly fiber cement, a second zone predominantly comprising radiation curable material, and an interlocking matrix formed of radiation curable material and fiber cement and structured to increase durability of the building composite article A building composite article having a subsurface interface zone sandwiched between a first zone and a second zone. The building composite article of claim 1, wherein the subsurface interface zone is integrally formed with the first zone and the second zone. The building composite article of claim 2, wherein the first zone comprises a fiber cement substrate having a porosity of about 20% to 40% by volume. The building composite article of claim 1, wherein the radiation curable material in the subsurface interface zone is substantially free of catalyst and is primarily curable by radiation. The building composite article of claim 1, wherein the thickness of the subsurface interface zone is adjusted by modifying a feature selected from the group consisting of porosity of the first zone, viscosity of the radiation curable component, and combinations thereof. The building composite article of claim 1, wherein the subsurface interface zone has a thickness of about 1 μm to 1,000 μm. The method of claim 1 wherein the radiation curable material is epoxy, urethane, polyester, acrylate, methacrylate, polyester, polyester epoxy, thiylene acrylic material, urethane acrylic material, styrene, functionalized styrene and A composite article for construction, selected from the group consisting of mixtures thereof. The building composite article of claim 1 selected from the group consisting of cladding panels, sheets, boards, flanks, trims, shakes, and pipes. At least a portion of the matrix of the building article is formed of fiber cement and radiation curable material and comprises a network structure structured to increase durability of the building article. 10. The building article of claim 9, wherein the radiation curable material is scattered throughout the matrix of the building article. 10. The building article of claim 9 wherein at least a portion of the fibers further comprise reinforcing fibers treated with a radiation curable material. 10. The building article of claim 9, further comprising an outer coating formed primarily of a radiation curable material and integrally formed with the network to increase adhesion between the matrix and the outer coating of the building article. The building article of claim 1, wherein said radiation curable material is a carbonation reduction sealer. Applying to the fiber cement substrate a radiation curable material that extends to the fiber cement substrate in a controlled manner and forms an area comprising a mixture of the radiation curable material and the fiber cement, Applying radiation to cure a radiation curable material in the substrate to form a three dimensional network of radiation cured material and fiber cement Building product forming method comprising a. 15. The method of claim 14, wherein electron beam radiation is applied to cure the radiation curable material. 15. The method of claim 14, wherein the radiation curable material is in direct contact with a fiber cement substrate. 15. The method of claim 14 wherein the radiation curable material is cured in a multi-step process. 15. The method of claim 14, wherein the radiation curable material is applied to the fiber cement substrate using a method selected from the group consisting of roll coating, spraying, curtain coating and soaking. Combining the radiation curable material with the components for forming the fiber cement composite material, The radiation curable material forms a green sheet distributed over at least a portion of the green sheet, Curing the green sheet to form a building product containing a network of fiber cement and radiation curable material Construction product forming method comprising a. 21. The method of claim 20, further comprising bonding the sheet to an uncured fiber cement substrate prior to curing the green sheet. 21. The method of claim 20, further comprising applying a coating of radiation curable material to the building product.

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