WO2007140008A2

WO2007140008A2 - Insulative composite materials including a coated, water-resistant paper layer

Info

Publication number: WO2007140008A2
Application number: PCT/US2007/012636
Authority: WO
Inventors: Lee Baker
Original assignee: Dow Reichhold Specialty Latex, Llc
Priority date: 2006-05-26
Filing date: 2007-05-29
Publication date: 2007-12-06

Abstract

The present invention provides a composite insulation material. The material includes a layer of an insulation, such as foam or fiberglass, and a paper layer. The paper layer is coated with a moisture vapor barrier, using a coating composition that includes a resin latex and a component having a crystalline platelet structure. Suitable resin latexes include poly(meth)acrylates, carboxylated or non-carboxylated butadiene-acrylonitrile, polystyrene, styrene-acrylonitrile, styrene-acrylonitrile-butadiene, styrene acrylates, styrene-butadiene, carboxylated styrene butadiene, polyvinyl chloride, polyvinyl acetate, waterborne polyurethanes, vinyl acrylics, polyvinylidene chloride, ethyl vinyl chloride, vinyl acetate- ethylene copolymers, and copolymers, terpolymers, and blends thereof. A suspending agent for the crystalline platelet component can be present, and is typically a hydrophilic polymer. The coating compositions can include wax, or can be essentially devoid of wax. A hydrophobic agent other than wax can optionally be added. The crystalline platelet structure can be unmodified, or modified to increase its hydrophobicity. The composite material can also be in the form of a foil/scrim/Kraft paper laminate, which can be combined with a layer of insulation if desired. The insulation materials can be used, for example, to insulate pipes and ductwork, or other aspects of buildings.

Description

Insulative Composite Materials Including A Coated, Water-Resistant Paper Layer

Field of the Invention

The invention is generally in the area of composite materials used for providing insulation, which materials include a paper layer which is treated to improve its. water- resistance and/or grease resistance.

Background of the Invention

Insulation is a non-structural material used to reduce heat transfer. Typically, insulation is in the form of rigid sheets, flexible blankets, and loose fill. The insulation is provided by a low-density material, such as fiberglass or rock wool fibers, cellulose (paper) fibers, and of foams. Open spaces can be insulated with loose fill, such as blown cellulose, and gaps between studs can be filled with a polyurethane foam, and neither of these require a backing layer. In contrast, certain insulative materials are designed to be capable of being wrapped around an object, such as a pipe, or fitted into a particular space, or provided in roll form for ease of storage and/or application. In these latter materials, the insulation, whether foam or fiberglass, is typically provided with a backing layer formed from plastic, foil, and/or a fibrous material, and often with a reinforcing layer, such as a scrim layer. A limitation of a plastic layer is that the tape used to seal seams often has problems adhering to the plastic. For this reason, and for reasons of cost, fibrous materials such as paper are often used.

The fibrous material can be in sheet and roll form, and can be paper, paperboard, fabric or other fiber-based materials. Typically, such fibrous layers are subject to poor resistance to water vapor, gases, oil, solvents and greases. In those insulative materials that include a fibrous layer, it advantageous to provide water and/or grease resistance to the fibrous layer, for example, by providing a suitable water and/or grease resistant coating. It would further be desirable that this coating be removable during repulping operations, and/or be able to be printed, coated and bonded (e.g., using adhesive or glue) to another similar or dissimilar substrate. The present invention provides such fibrous layers and composite materials. Summary of the Invention

Composite insulation materials comprising a layer of an insulative material, a fibrous layer coated with a moisture resistant barrier, such as a coated paper layer, and, optionally, a reinforcing layer, and articles of manufacture coated with the insulative material, such as coated pipes, coated ductwork, and the like, are disclosed.

The composite insulation materials typically include a layer of a low density insulative material and a fibrous layer, such as a paper layer, and optionally include a reinforcing layer, such as a scrim layer, between the insulation and the fibrous layer. The low density materials can include one or more types of foam, fiberglass, and the like. The types of fibrous materials that can be used include paper, for example, Kraft paper, paperboard, cardboard, and the like. An adhesive is typically used to adhere the insulation, paper, and scrim layers.

The term "paper" includes paper of all weights and types, paperboard, coated paper, printed paper and the like. The coated fibrous substrate has excellent moisture vapor and/or grease-resistant properties. Additionally, the fibrous substrate can be repulped without the problems associated with wax coatings during a repulping process.

The fibrous layer is coated with a moisture vapor barrier coating composition. The coating composition includes a resin latex and a crystalline platelet structure, such as mica, clay, talc, kaolin, silica or the like, which can be modified to increase its hydrophobicity, or can be untreated.

Suitable resin latexes include poly(meth)acrylates, carboxylated or non-carboxylated butadiene-acrylonitrile, polystyrene, styrene-acrylonitrile, styrene-acrylonitrile-butadiene, styrene acrylates, styrene-butadiene, carboxylated styrene butadiene, polyvinyl chloride, polyvinyl acetate, waterbome polyurethanes, vinyl acrylics, polyvinylidene chloride, ethyl vinyl chloride, vinyl acetate-ethylene copolymers, and copolymers, terpolymers, and blends thereof.

Hydrophobic agents that can be added to the coating composition include fluorochemicals and fluoropolymers, including fluorinated telomers and oligomers; silicones, functionalized silicones (e.g., ether, amino epoxy, etc), silanes and siloxanes; hydrocarbon polymers, including polyolefins such as polyethylene and polypropylene, fatty acids and modified fatty acids (e.g. fatty esters, fatty amides, and salts of fatty acids, such as calcium stearate); fatty alcohols; fats; lipids; oils; polymers based on styrene maleic anhydride half esters or diesters, and hybrids of the above (e.g., hydrocarbon/flourocarbon polymers).

The crystalline platelet structure can be suspended in a suspending means, for example, a hydrophilic polymer such as a highly carboxylated acrylate polymer or a fully hydrolyzed polyvinyl alcohol. Representative hydrophilic polymers include highly carboxylated polymers, including polycarboxylated acrylics such as Morcryl® 132, colloids, cellulosics, starches, polyethylene oxide, polyethylene glycol, and fully hydrolyzed polyvinyl alcohol.

A representative type of insulative material is a laminate of a metal foil, a scrim, and kraft paper (FSK laminate), which is primarily designed to impart ignition resistance to fiberglass pipe jacketing, and to serve as a moisture barrier. FSK laminates are wrapped in such a way that the paper side is exposed to the elements. When used in high heat and humidity environments, the coated paper facing will not absorb moisture and swell, unlike uncoated paper, thus avoiding the 'dimpling' problems that occur with uncoated FSK laminates. Further, the coated paper layer is repulpable, and the moisture barrier properties of the coated paper equal that of plastic alternatives.

The insulative materials described herein can be used for a variety of applications, including tube or sheet insulation for pipe and ductwork. Additional examples include insulation for metal buildings, such as warehouses, industrial buildings, office buildings, retail stores, churches, athletic facilities, sports arenas, walls, and ceilings.

The coated insulation materials described herein have wide application in the production of insulation materials with water and/or grease resistance, low slip, hot melt glueability and moisture vapor barrier characteristics. Advantageously, the coating compositions may also be used as overprint varnishes on preprinted linerboard substrates to impart additional scuff resistance to the coated substrate surface.

The coated paper layer is readily repulped and recycled. The coated paper can be mixed with regular waste paper streams such as recycled newsprint and office waste for recycling purposes. The aqueous coatings described herein break up and disperse with the paper fibers when the material is run through a standard hydropulper under alkaline conditions. Detailed Description

The present invention will be better understood with reference to the following detailed description. As stated above, the coatings can be applied to various fibrous substrates, and particularly paper, as part of a composite material including a coated paper layer.

As used herein, the term "water-repellant" merely refers to the hydrophobic character of the coating and its tendency to repel, block or not significantly absorb or transmit water in normal use. Thus, the term "water-repellant" is intended to include "water-resistant" and other terminology which connotes substantial as opposed to total or complete water blocking properties, and refers to a water-blocking property which is sufficient for the intended use requiring a degree of water-repellency.

I. Coating Composition

The coating composition includes a resin latex and a crystalline platelet structure, ideally includes a suspending means for the crystalline platelet structure, and may optionally include a hydrophobic agent. The crystalline platelet structure can be unmodified, or modified to provide hydrophobicity.

The coating is applied at any suitable rate, which may be expected to vary depending on the base sheet. However, in one embodiment, the application rate is between about 2 and about 3 pounds dry per 1,000 sq. ft. of paper/paperboard at a viscosity in the range of 400 to 700 cps, such that the coating will comprise from about 2 to about 3 percent of the total weight of the board.

The degree of penetration of the coatings into the substrate surface is dependent on the viscosity of the composition as well as the type of substrate used. Generally the coating compositions have a viscosity in the range of 50-2500 cps and a solids content greater than 35%, for example, around 60% solids content. The low viscosities of the compositions results in little penetration into the substrate surface, but enough for adhesion or binding of the coating to the substrate surface. Optionally, a primer such as polyvinylidiene chloride can be applied before the barrier coat to seal a porous substrate surface. Examples of other suitable primers include a water-based dispersion of a polymer selected from the group comprising acrylic polymers, polyvinyl acetate, polyvinyl alcohol, vinyl acetate-ethylene, ethylene vinyl chloride copolymers, styrenebutadiene copolymers, polyvinylidene chloride or starch. The primer coat may further include a wax component, for example, one including between about 5 and 30 wt. % of the primer coat. The primer coat may further include pigments or mineral fillers, such as, but not limited to, aqueous dispersions of clay, calcium carbonate or mica. Typically, substrates used in the invention, which are preferably linerboards having a weight of 26-90 lbs/msf, do not require a primer coat. In all embodiments the barrier coating adheres or binds to the substrate surface to form a continuous film.

The cross-linking reaction occurs in the process of drying the coated board which may be carried out using forced hot air and conventional can-dryers as by threading the web with the coating thereon through a stack of rotating cans, which advance the web through the dryers alternatively exposing opposite faces of the web to the hot surfaces of the cans. Preferably, the coated board is pre-dried before contacting the surfaces of the dryer cans by non-contact heating such as forced hot air (temp. 200-400⁰F) for around 5 to 15 seconds or more to dry the coating to at least a substantially non-sticky state prior to contact drying at the can dryers.

The ionic bonding is believed to provide the coating with a polymer matrix represented generally by the formula P-S-CO₂ -M-O₂ C-S-P, wherein P represents the polymer as in the preferred styrene-butadiene polymer, S represents a polymer side chain, CO₂ and O₂C represent carboxylic groups and M represents a metal, such as zinc, from the cross-linking agent (such as zinc ammonium complexes, such as zinc ammonium carbonate) providing the ionic cross-link or bridge between adjacent polymer chains.

The coating forms a substantially pin-hole free continuous film on the paper layer. The film is comprised of an interlocking network of polymer and crystalline platelet structures. The platelet structures can be aligned parallel to the substrate surface due to the stress applied to the coating during the application process. The rod or blade coating can essentially shear the coating and doctor the excess material off the surface. Under high shear between the rod or blade and the paper layer, the platelet structures can be mostly aligned parallel to the substrate surface.

Resin Latexes Suitable resin latexes include poly(meth)acrylates, carboxylated or non-carboxylated butadiene-acrylonitrile, polystyrene, styrene-acrylonitrile, styrene-acrylonitrile-butadiene, styrene acrylates, styrene-butadiene, carboxylated styrene butadiene, polyvinyl chloride, polyvinyl acetate, waterbome polyurethanes, vinyl acrylics, polyvinylidene chloride, ethyl vinyl chloride, vinyl acetate-ethylene copolymers, and copolymers, terpolymers, and blends thereof.

The resin latex typically comprises from about 60 to 80 percent by weight, preferably about 60 to 75 percent by weight of the barrier composition although conventionally formulations are based on 100 parts of resin. The resin may also include additional comonomers such as monocarboxylic acid monomers, dicarboxylic acid monomers, unsaturated monocarboxylic ester monomers (e.g., acrylates and methacrylates), acrylamide- based monomers, half esters of unsaturated dicarboxylic acid monomers including mono esters of maleic acid or fumaric acid (e.g., monomethyl maleate), and blends and mixtures thereof. A particularly suitable resin is a styrene butadiene blend having a small amount of monomethyl maleate.

The polymer component of the formulations generally comprise from about 25 to 75 percent by weight of the coating application (% by weight —dry basis), for example, around 60 percent by weight. A preferred polymer for use in the coating is a styrene-butadiene (SB) copolymer polymerized with monomers having carboxylic acid pendant groups, e.g., acrylic acid and methacrylic acid. An especially preferred SB polymer for use in the invention is the carboxylated styrene-butadiene latex available under the trade name RAP 314NA from Dow Chemical Company of Midland, Mich. Another similar SB polymer which may be used is available under the tradename 654NA, also from Dow Chemical Company. Styrene-butadiene polymers sold by Dow Reichhold Specialty Latex, Inc., such as Tykote 1004, Tykote 1024, and Tykote 1046, are also particularly preferred. The physical characteristics and properties of these commercially available materials are further described in their respective technical data sheets, which are incorporated herein by reference.

Other ionically cross-linkable polymers which may be used include, by way of example and not by way of limitation, polymers selected from the group consisting of vinylidene chloride/vinyl chloride, styrene-acrylic, styrene-butadiene, acrylic polymers, polyvinyl acetate, polyvinyl alcohol, vinyl acetate-ethylene, ethylene vinyl chloride copolymers, polyvinylidene chloride and starch.

The polymers utilized in the coating compositions are carboxylated by copolymerizing with a monomer having carboxylic acid pendant groups. The monomers are generally an acrylate based monomer selected from the group consisting of an acrylic acid, methaciylic acid, itaconic acid, maleic (cis) acid, fumaric (trans) acid and other acrylate based monomers. Carboxylic acid pendent groups are necessary for the crosslinking reaction to occur. The polymer molecules utilized in the compositions are typically commercially available as carboxylated polymers.

The polymer chains are ionically cross-linked through pendent carboxylic acid groups with a crosslinking agent. The essentially ionic character of the carboxylate bridge between the polymer chains is believed to confer a high degree of stability to acids and water (essentially neutral) to form a superior water repellant and substantially continuous film on the paperboard which is not readily attacked by conditions of normal use. The crosslink is also believed to increase the effective glass transition temperature of the coating, so that contiguous sheets of the coated paperboard are less likely to block.

The crosslinking agent component of the coating is selected from the group consisting of zinc ammonium complexes, and zirconium ammonium complexes. Preferably, a complex such as the zinc ammonium carbonate complex available under the trade designation Zinplex 15 from Ultra Additives, Inc. of Paterson, NJ. is used. Other suitable crosslinking agents include ammonium zirconium carbonate crosslinkers such as the ammonium zirconium carbonate composition available under the trade name HTI Insolubilizer 5800 M from Hopton Technologies, Inc. Albany, Oreg. The crosslinking component may comprise 2 to 30 parts by weight of the coating and preferably makes up about 2-10 percent of the coating by weight (dry basis).

In an alternate embodiment, under certain conditions, the crosslinking agent can be excluded from the coating formulation.

Crystalline Platelet Structures

Although the Applicants do not wish to be bound by one theory, Applicants believe that the crystalline platelet structure is aligned in the barrier resulting in a tortuous path for any moisture to go through the barrier. This results in the barrier properties being a bulk property rather than a surface property such as is present in wax-coated paper or in the use of wax dispersion in a latex. Moreover, such a structure is less susceptible to interruption of the barrier such as caused by creasing or lamination to another layer. Additionally, it is believed that the component having a crystalline platelet structure has a high aspect ratio, and can be fully dispersed on recycling.

Suitable components having a crystalline platelet structure are mica, talc, silica, clay, and kaolin. Mica is a preferred component. The mica employed in the present invention may be a natural mica such as muscovite, paragonite, phlogopite, biotite, and Syrian mica, or a synthetic mica such as fluorine-contained phlogopite, fluorine/silicone-contained mica, and taeniolite. The resin is typically present in an amount ranging from about 20 to 85 parts of the crystalline platelet structure, such as mica, preferably 30 to 45 parts based on 100 parts of resin. Additionally, the component preferably has a particle size of less than 100 μm.

In one embodiment, around 25 to around 35 parts by weight of the mica is used, for example, around 30 parts by weight. At higher levels, there may be a dropoff of the MVTR values than when resin alone is used, and this tends to provides poor results. When uncoated paper is used, the results are even worse.

The components having a crystalline platelet structure can be modified to provide them with hydrophobicity. For example, mica can be treated with calcium stearate. Typically, the calcium stearate is added at a 1 to 4 percent by weight level onto a 5 μm particle size mica. One example of a hydrophobically-treated mica is Kalsitex®, available from Engelhard of Hartwell, Ga. The resin comprises from about 20 to 85 parts of the mica, preferably 30 to 45 parts based on 100 parts of resin. Additionally, the component preferably has a particle size of less than 100 μm.

Suitable pigments include aluminum trihydrate, barium sulfate, calcium carbonate, mica (potassium aluminum silicates), nepheline syenite (sodium potassium aluminosilicate), finely ground silica sand and other natural and synthetic type of silicates, talc (magnesium silicates), wollastonite (calcium metasilicates), bentonite (montmorillonite, smectite) and clay.

The pigments are generally available commercially under various tradenames and from various manufacturers. Representative pigments that may be used include, but are not limited to, MicaWhite 200, available from Franklin Minerals, Denver, Colo.; Mica C-4000, available from KMG Minerals, Kings Mountain, N.C.; Vantalc 6H and PDX 181 slurry, both talcs which are available from R. T. Vanderbilt, Norwalk, Connecticut; Black Hills Bond, bentonite, available from Black Hills Bentonite, Mills, Wyo.; and Opazil AS, bentonite, available from Albion Kaolin Co., Hephziban, Ga. Another representative example is Gimsheen 40, sold by Georgia Industrial Minerals, Inc. (Sandersville, GA). This pigment has a mean particle size of 34.0 - 44.0 microns and a bulk density of around 8-12 lbs/ cubic ft. The physical characteristics and properties of these commercially available materials are further described in their respective technical data sheets, which are incorporated herein by reference.

Preferred pigments incorporated into the formulations include mica, talc, clay and bentonite and are considered "platelet" type of pigments based on their particle shape, however, other types of pigments may also be used. When platelet type pigments are incorporated into the composition formulations improved water vapor barrier properties of the coatings is observed. This is believed to be due to the presence of a "tortuous path" created by the pigments.

The pigments, when present, incorporated into the formulations are generally present in the amount of 25 to 60% (% by weight—dry basis). The composition of the pigment dispersion is typically as follows:

The crosslinking agent, in the amount of 2-10%, is preferably added to the pigment dispersion to prevent gelling. The % solids of the pigment dispersion is generally 35-60%. Types of pigment dispersants include polyacrylates, complex phosphates or mixtures of both. The particle size of the pigments are of the size that 85-90% pass through a 325 mesh, which is a wire mesh consisting of 325 wires per inch.

Suspending Means

In one embodiment, the unmodified crystalline platelet structure is suspended in a suspending means, such as a hydrophilic polymer. Representative hydrophilic polymers include highly carboxylated polymers, including polycarboxylated acrylics such as Morcryl® 132, colloids, cellulosics, starches, polyethylene oxide, polyethylene glycol, and fiilly hydrolyzed polyvinyl alcohol, such as PVOH 103 or PVOH 325 available from Air Products, Allentown, Pa. The suspending means, in addition to facilitating the application of the coating, does not adversely affect the water resistant properties of the barrier.

The suspending means is used at an amount of about 0.5 to about 3 parts by weight, such as between about 1 to about 2 parts by weight, including about 1.5 parts by weight, based on 100 parts of resin. The means for suspending must be capable of suspending the crystalline platelet structure, while not adversely affecting the moisture barrier properties of the overall barrier composition. A particularly suitable means for suspending is a highly carboxylated polymer such as Morcryl® 132.

Hydrophobic Agents

In addition to the latex and mica or other crystalline platelet structure, the compositions can also include a hydrophobic agent. Hydrophobic agents that can be added to the coating composition include fluorochemicals and fluoropolymers, including fluorinated telomere and oligomers; silicones, functionalized silicones (e.g., ether, amino epoxy, etc), silanes and siloxanes; hydrocarbon polymers, including polyolefins such as polyethylene and polypropylene, fatty acids and modified fatty acids; fatty alcohols; fats; lipids; oils; styrene maleic anhydride polymers; and hybrids of the above (e.g., hydrocarbon/flourocarbon polymers). Another representative hydrophobic agent is SMA® 2625 by Sartomer, a partially esterified, low molecular weight polymers of styrene maleic anhydride esters or half-esters.

In one embodiment, the hydrophobic component is wax. The wax is preferably provided by a low molecular weight paraffin-polyethylene emulsion such as a mixture of a polyethylene (molecular weight in the range of from about 500 to about 2000), paraffin wax and an emulsifying agent. The polyethylene may comprise from about 1 to about 10 weight percent of the wax emulsion and the paraffin wax may comprise from about 30 to about 25 weight percent (wet basis). The emulsifying agent may comprise up to 7 weight percent, with the balance water (50-70%). The wax emulsion can comprise from about 10 to about 30 weight percent of the coating (% by weight— dry basis). The % solids by weight of the coating and wax emulsion are as follows:

A particularly preferred wax emulsion is the paraffin/polyethylene emulsion available under the trade name Mobilcer 136 from Mobil Oil Corporation of Fairfax, Va. Other suitable wax emulsions include paraffin/microcrystalline wax emulsions such as the wax emulsion sold under the trade designation Mobilcer J of Mobil Oil Corporation of Fairfax, Va. and the wax emulsion available under the trade name Mobilcer MTD 216 from the Mobil Oil Company or a paraffin wax emulsion, Mobilcer XMTD241, also available from Mobil Oil Company. Nopcote DSlOl, a synthetic wax emulsion, available from Henkel Corporation, Charlotte, N.C., may also be used. Nopcote DSlOl is composed of 30-50% synthetic wax, up to 7% of emulsifying agents and 50-65% water (% by weight—wet basis). In addition, wax emulsions based on carnauba wax, carnauba/paraffin wax, camauba/microcrystalline and camauba/polyethylene resin may be used. The physical characteristics and properties of these commercially available materials are further described in technical data sheets which are incorporated herein by reference.

The hydrophobic agent is used at an amount of about 0.5 to about 2 parts by weight, such as between about 0.75 to about 1.5 parts by weight, including about 1 part by weight, based on 100 parts of resin.

As used herein, the term "modified fatty acids" specifically includes esters, amides, and salts of fatty acids, including calcium stearate and calcium salts of other fatty acids.

Optional Components

The barrier composition may also include a number of other components such as biocides, defoamers, pigments, thickeners, crosslinking agents, flame retardants, catalysts, dispersing agents, wetting agents, and the like.

The coating composition can further include thickeners to modify the viscosity of the composition for application of the coating. A suitable thickener is the cellulose gum theological property modifier available under the trade designation Admiral 3089FS available from Aqualon Company of Wilmington, Del. Sodium or ammonium polyacrylates may also be used as thickeners for the composition.

In addition, organic silicone free or silicone-based defoamers may be used. Preferred defoamers are an organic, silicone-free defoamer available under the trade name Colloid 682 from Rhone-Poulenc of Marietta, Ga. and an organic, silicone-free defoamer available from Witco Chemical of New York, N.Y. under the trademark BubbleBreaker 748. These defoamers are preferably used in an amount ranging from about 0.05 to about 0.5 percent by weight based on the total weight of the coating. Color pigments may also be added, such as to impart a whitish color for aesthetics.

Methods of Preparing the Coating Compositions:

The following description describes the general procedure for producing the coating compositions.

In one embodiment, water is charged to a mill equipped with high shear and intensive grinding capability, such as a Kady mill as sold by Kinetic Dispersion Corporation, Scarborough, Me. Agitation is initiated, and a dispersant and polymer are added to the Mill. In another embodiment, a previously prepared latex dispersion is added, rather than adding water first and a dispersant and polymer separately.

A crosslinking agent, for example, an ionic crosslinking agent such as a zinc ammonium carbonate complex (15% solids), is then added. The mixture is stirred for approximately 3 minutes. Finally, the particles of the crystalline platelet component, such as MicaWhite, are added, and the mixture is stirred for around an additional 15 minutes, although longer or shorter stir times can be used. The dispersion is then ready for blending with other components to form the final coating formulation. Representative additional components include a defoamer, such as Colloid 682 from Rhone-Poulenc, Marietta, Ga., a polymeric binder, i.e. Dow 314, a wax emulsion, i.e. Nopcote DS-101, and a cellulosic gum thickener, i.e. Admiral 3089FS from Aqualon, Wilmington, Delaware. Although the procedure has been described using specific materials the compositions are not limited to such and other suitable materials may be substituted.

The following are more specific examples of the preceding method, in which specific quantities of the components are disclosed.

In one embodiment, one begins with a neat latex dispersion (58.8 parts dry). Mica is slowly added (30 parts) under constant agitation. Zinc ammonium carbonate crosslinker (3 parts) is added, followed by Morcryl 132 (1.5 parts), Bostex 732R (1.5 parts), TiO₂ (5 parts), and Alcogum VEP-I (0.2 parts).

In another embodiment, water, approximately 250 lbs, is charged to a Kady mill (volume 55 gallons) by Kinetic Dispersion Corporation, Scarborough, Me., which is equipped with high shear and intensive grinding capability. Agitation is initiated and the dispersant which is approximately 0.6 lbs of tetrasodiumpyrophosphate (TSPP) and 0.6 lbs of polyacrylate is added to the Kady Mill. The crosslinking agent, 25 lbs of Zinplex 15 which is a zinc ammonium carbonate complex (15% solids), is then added. The mixture is stirred for approximately 3 minutes. Finally, the particles of the crystalline platelet component, such as MicaWhite 200-250 lbs, are added and stirred for 15 minutes. The dispersion is then ready for blending with other components to form the final coating formulation, including a defoamer, i.e. Colloid 682 from Rhone-Poulenc, Marietta, Ga., the polymeric binder, i.e. Dow 314, the wax emulsion, i.e. Nopcote DS-101, and a cellulosic gum thickener, i.e. Admiral 3089FS from Aqualon, Wilmington, Delaware. Although the procedure has been described using specific materials the compositions are not limited to such and other suitable materials may be substituted.

II. Insulative Materials

The insulation typically comprises a foam and/or a fiberglass layer, a paper coating layer, and, optionally, a scrim layer, a foil layer, and/or a pressure-sensitive adhesive layer.

Foams

The insulation, when in the form of a foam, is typically in the form of an elastomeric or thermoplastic foam. The foam can be of any size or shape.

Thermoplastic polymer foams are particularly well suited for use as thermal insulators. Thermoplastic materials are those that soften and flow upon application of pressure and heat. Thermoplastic foams are defined, generally, as foams made from thermoplastic resins. Because thermoplastic materials regain their original properties upon cooling, most thermoplastic materials can be remolded many times.

Examples of thermoplastic resins include polyvinyl chloride), polyethylene, polystyrene, acrylate resins, and poly(ethylene terephthalate). Suitable resins include any thermoplastic material. Preferred materials include polystyrene polymers (amorphous) such as styrene-acrylonitrile copolymers, olefinic polymers (semicrystalline) such as polyethylene, polycarbonate polymers, and polyester polymers (semicrystalline) such as poly(ethylene terephthalate). Suitable foams include, but are not limited to, polyolefin, polyurethane, polystyrene, open-cell, and closed-cell foams. Each foam has its particular R-value associated with the material formulation and thickness of the foam.

When it is desired to provide a composite material that allows vapor to pass through the foam, the foam is preferably an open-cell foam. Alternatively, the foam can be perforated to provide breathability.

The thermoplastic foams can also include additives to enhance the overall desirability of the foam. One such additive would add fire retardant characteristics to the foam. Other additives could also be added, such as to affect the color of the final product. HI. Foil and Scrim Materials

One example of an insulating material that includes a paper layer coated with the coating composition described herein is an "FSK" laminate. This is a laminate which includes a metal foil bonded to a scrim layer, such as a non-woven glass fiber paper-like layer, which in turn is coated with a Kraft paper layer.

A fibrous web or scrim can be used. This web or scrim can be of conventional construction, including 1 , 2, 3 or more plies (multi-ply), forming a composite material. The scrim can be formed from a thermoplastic material, and thus, when heated, be used to adhere the paper layer to the insulation. Alternatively, or additionally, the scrim can comprise fiberglass.

Fiberglass scrim is an alkali resistant fiberglass net or fabric. Fiberglass scrim is typically made from C-glass or E-glass fiber, which is treated with acrylic and/or bitumen. Fiberglass scrim offers properties such as alkali resistance, high strength, chemical stability, and fire resistance. Particularly when a vapor barrier is applied to duct wraps in HVAC systems, and there is a need for a material to meet the requirements of a rigorous fire rating, it can be advantageous to use a fiberglass scrim, versus a polymer scrim. The base paper can include up to about 30% fiberglass by weight, and is typically in the range of about 10% to about 30% fiberglass by weight.

The metal foil can be aluminum foil or other equivalent metal foils, and typically has a thickness in the range of about of 0.0007 in. to about 0.005 in., more typically, about 0.001 in. The non-woven glass fiber paper-like material typically has a thickness in the range of about 0.010 in. to about 0.500 in, more typically, around 0.015 in. The metal foil layer can be adhered to the scrim layer using a latex adhesive, or any other suitable adhesive. One type of suitable adhesive is a plasticized vinyl acetate-ethylene co-polymer emulsion, such as SRD870 by American Finish and Chemical Co. of Chelsea, Mass. Other representative adhesive materials include vinyl acetate homo-polymers which use plasticizers, such as phthalate esters, or phosphate esters, to soften the film and improve flexibility of the resulting laminate. Products such as DL259, a butadiene-vinylidene chloride polymer, can contribute to ignition resistance.

U. S. Patent No. 4,348,450 to Shaw, the contents of which are hereby incorporated by reference, discloses insulating material formed of a metal foil-nonwoven glass fabric. This laminate can then be bonded to a paper layer, such as corrugated cardboard. The paper layer can be coated with the coating compositions described herein to form a water-resistant, grease-resistant, and fϊre-retardant insulating material.

IV. Adhesives

The fibrous layer, such as a paper layer, can be secured to the insulating material over substantially the entirety of the contiguous surfaces of the paper layer and the insulating material. Alternatively, only portions of the paper layer may be secured to the insulating material by, for example, intermittent use of adhesive.

The adhesive can be applied as a separate layer between the insulating material and the paper layer. The adhesive used will depend, at least in part, on the composition of the paper and insulating materials as well as on the particular application for which the composite is to be used. For example, when the insulating material is a foam, suitable adhesives include, but are not limited to, hot melt adhesives (e.g., styrene block copolymer adhesives, ethylene- vinylacetate copolymer adhesives, and poly-alpha-olefϊn based adhesives), and water-based or solvent-based adhesives (e.g., acrylates and vinyl acetates). When it is desired to provide a composite material that allows vapor to pass therethrough, the adhesive is preferably a breathable adhesive such as a foamable adhesive (e.g., an adhesive that incorporates a blowing agent).

Representative pressure-sensitive adhesives include those based on acrylic (Fastbond™ 49, 3 M Switzerland AG, CH-8803 Ruschlikon) or based on a thermoplastic rubber (ALFA H 3000/0 ALFA Klebstoffe AG, CH-8454 Buchberg). V. Fibrous Substrates

The coating composition described herein is applied to a fibrous layer, such as a paper layer, which forms the outermost layer of the composite insulation materials. The term "paper" includes paper of all weights and types, paperboard, coated paper, printed paper and the like. The paper layer can include a variety of coated and uncoated paper and paperboard, including bleached or unbleached hardwood or softwood, virgin or recycled and clay-coated or uncoated forms of paper or paperboard.

The fibrous layer, once coated with the coating compositions described herein, has excellent moisture vapor properties. Additionally, the fibrous layer can be repulped without the problems associated with wax coatings during repulping process.

VI. Optional Backing Layer for the Insulation

In one embodiment, the composite material comprises a backing material, attached to the insulation on the side opposite that of the paper layer. This backing material can be breathable and moisture-resistant (e.g., TYVEK®). Examples of suitable backing materials include, for example, polymeric sheets, foils, and paper.

VII. Methods of Preparing the Composite Materials

The composite materials can be formed by adhering an insulating material and a paper layer such that the paper layer is in a generally superposed, contiguous relation to the insulating material, optionally with a scrim or other reinforcing layer between the paper layer and the insulation material.

In one embodiment, the composite material is formed by passing the insulating material and the paper layer through a nip formed between two drums or rolls. The paper and/or insulating materials are optionally preheated prior to being fed between the drums.

The paper layer can be coated either before or after the paper layer is applied to the insulation material. The coating is applied as an aqueous formulation which is dried to provide the water-repellant coating on the paper layer. Generally, the coating compositions can be applied by a number of different methods, including using a rod coater, blade coater or air knife coater. The coating is preferably dried thoroughly after the application in order to prevent any sticking or blocking within the coated rolls.

The paper layer can be preprinted before applying coating/film layer. This overcoat layer, which may or may not include a pigment component, further provides scuff resistance to the coated surface. A preferred way of applying the barrier coating on a preprinted substrate is to apply the coating in an overprint varnish station on the printing press apparatus. The overprint varnish station may be a rod or blade coater with subsequent drying capabilities.

When manufacturing the foil/scrim/paper laminates described herein, the foils and/or the scrim can be provided as rolls, ideally rolls of substantially equal width. For example, a foil web can be passed over a resilient rubber roller, over which is disposed a knife to knife- coat a layer of adhesive on the foil web as it passes under the knife. Those of skill in the art can determine the appropriate settings to apply a suitable amount of adhesive to the foil. A roll containing the scrim can be set above the foil web. After the adhesive is applied to the metal foil, the scrim can be mated with the foil web, thus forming a laminate. This laminate can be heated under pressure to cure the adhesive and flatten the laminate. The laminate can then be rolled up on a take-up reel. Then, an adhesive can be applied, and a Kraft paper layer applied. Once the Kraft paper layer is applied, it can be coated using the coating compositions described herein.

The laminated rolls can be formed into sheets for large applications, or can be die cut into discrete shapes, if desired. The resulting laminate can be used for insulating purposes and for its light and heat reflecting properties.

VlJLl. Methods of Using the Composite Materials

The composite materials can be used to insulate a pipe, ductwork, or an entire structure, such as an entire building, or a portion thereof, such as a ceiling, wall, or floor. The composite material can be wrapped over at least a portion of the pipe, structure, or other article to be insulated. The article to be insulated is ideally wrapped so that the composite material covers substantially all of the exterior surfaces of the article with the insulating material adjacent the article. The composite materials are optionally secured to the articles using any of a variety of techniques. For example, the composite materials can be nailed or tacked to the article. Alternatively, an adhesive coating can be applied to the composite material along at least a portion of the surface of the composite material that contacts the structure to facilitate attachment of the composite material to the structure.

The composite material can be provided in the form of tube or sheet insulation materials for insulating pipe and ductwork. Insulated pipe materials are described, for example, in United States Patent No. 6,823,899 to Weibel et al., the contents of which are hereby incorporated by reference.

The insulated pipe arrangement comprises a pipe body, which is enclosed by an insulating layer made of foam and/or fiberglass, a protective paper layer arranged around the insulating layer, and optionally a scrim or other reinforcing layer between the insulating layer and the paper layer. The paper layer is coated using the coating composition described herein.

EX. Repurpabilitv of the Coated Paper Layer

Under alkaline conditions, such as when contacted with repulping liquors containing NaOH or ammonia solutions, the ionic bonds in the coating disassociate to permit the film to be broken up in a more highly divided form for enhanced repulpability as compared with conventional (wax) coatings.

Examples

The following examples illustrate specific embodiments of the present invention. In the examples and throughout the specification, all parts and percentages are by weight, unless otherwise indicated Example 1: Representative Coating Formulation:

In this representative example, the formulation contains the following:

Synthemul® 18106 (DRSL) - styrerie acrylic binder chosen for barrier & UV stable properties.

Unmodified Mica (GA Industrial Minerals) - for moisture and oil/gτease barrier properties. Barrier properties tend to drop gradually at levels below 35%, then fall dramatically at levels below 25%.

Zinc Ammonium Carbonate ("ZAC") - crosslinker that interacts with the styrene acrylic polymer chain, reduces blocking potential.

Morcryl® 132 (Rohm & Haas) - a mid range molecular weight, solid grade, styrene/acrylic resin, used to help pigment wetting, helps keep the mica in suspension. Potential crosslinking with ZAC.

Bostex 732R (Akron Dispersions) - antioxidant package, for heat and color stability.

Uvitex® OB (Ciba) - fluorescent optical brightener for bluish whitening effects. Tinuvin® 477 (Ciba)- experimental aromatic UV absorber. Tiθ2 - opacity and whiteness/brightness.

Alcogum® VEP-I (Alco) - sodium polyacrylate thickener - gives compound some body, helps slow mica settling.

Blue pigment - extremely small amount, used to shift the final coating color away from yellowish tint

The amounts of the components are provided in Table 1, below:

Table 1

Example 2: Application of the Coating to an FSK Laminate

A laminate of bleached kraft paper, fiberglass scrim, and aluminum foil was prepared, for use in imparting ignition resistance to fiberglass pipe jacketing and to serve as a moisture barrier. The FSK laminate was wrapped in such a way that the paper side was exposed to the elements.

The composition provided in Example 1 was applied to the FSK laminate. When applied, the composition holds out moisture on levels equal to a plastic laminate, while allowing for tape adhesion. The barrier coating was effective down to 32°F at adhering tape.

While various embodiments have been disclosed and described herein, it will be appreciated that various changes and modifications can be made by those skilled in the art without departing from the true spirit and scope of the invention, as defined in the following claims.

Claims

We claim:

1. An composite insulation material comprising: a) a layer of foam or fiberglass insulation, and . b) a paper layer adhered to the layer of foam or fiberglass insulation, wherein the paper layer is coated with a coating composition comprising latex and a crystalline platelet structure.

2. The composite insulation material of Claim 1, wherein the foam is a thermoplastic or elastic foam.

3. The composite insulation material of Claim 1, wherein the resin latex is selected from the group consisting of latexes of poly(meth)acrylates, carboxylated or non-carboxylated butadiene-acrylonitrile, polystyrene, styrene-acrylonitrile, styrene-acrylonitrile-butadiene, styrene acrylates, styrene-butadiene, carboxylated styrene butadiene, polyvinyl chloride, polyvinyl acetate, waterbome polyurethanes, vinyl acrylics, polyvinylidene chloride, ethyl vinyl chloride, vinyl acetate-ethylene copolymers, and copolymers, terpolymers, and blends thereof.

4. The composite insulation material of Claim 1, wherein the resin latex includes a comonomer selected from the group consisting of monocarboxylic acid monomer, dicarboxylic acid monomers, unsaturated monocarboxylic ester monomers, acrylamide-based monomers, half esters of unsaturated dicarboxylic acid monomers, and blends and mixtures thereof.

5. The composite insulation material of Claim 1, wherein the insulation is fiberglass insulation.

6. The composite insulation material of Claim 1, wherein the paper layer is Kraft paper.

7. The composite insulation material of Claim 1, wherein the crystalline platelet structure is selected from the group consisting of mica, clay, talc, kaolin, and silica.

8. The composite insulation material of Claim 1, wherein the crystalline platelet structure is modified to increase its hydrophobicity.

9. The composite insulation material of Claim 8, wherein the crystalline platelet structure is calcium stearate-modifϊed mica.

10. The composite insulation material of Claim 1, wherein the foam is a thermoplastic or elastic foam.

1 1. The composite insulation material of Claim 1 , wherein the coating composition further comprises wax.

12. The composite insulation material of Claim 1, wherein the coating composition further comprises a hydrophobic agent other than wax.

13. The composite insulation material of Claim 12, wherein the hydrophobic agent other than wax is selected from the group consisting of fluorochemicals, fluoropolymers, silicones, functionalized silicones, silanes, siloxanes, hydrocarbon polymers, fatty acids, modified fatty acids, fatty alcohols, fats, lipids, oils, styrene maleic anhydride polymers, and hybrids of the above.

14. The composite insulation material of Claim 1, wherein the layer of foam or fiberglass insulation foam has two sides, one of which is coated with the paper, and the other of which is coated with a metal foil.

15. The composite insulation material of Claim 14, wherein the foil is aluminum foil.

16. The composite insulation material of Claim 1 , wherein the layer of foam or fiberglass insulation foam has two sides, one of which is coated with the paper, and the other of which is coated with a metal foil.

17. An composite insulation material comprising: a) a layer of a metal foil, b) a scrim layer adhered to the layer of metal foil, and c) a paper layer adhered to scrim layer on the side opposite the metal foil, wherein the paper layer is coated with a coating composition comprising latex and a crystalline platelet structure.

18. The composite insulation material of Claim 17, wherein the paper layer is Kraft paper.

19. The composite insulation material of Claim 17, wherein the crystalline platelet structure is selected from the group consisting of mica, clay, talc, kaolin, and silica.

20. The composite insulation material of Claim 17, wherein the crystalline platelet structure is modified to increase its hydrophobicity.

21. The composite insulation material of Claim 20, wherein the crystalline platelet structure is calcium stearate-modified mica.

22. The composite insulation material of Claim 17, wherein the coating composition further comprises wax.

23. The composite insulation material of Claim 17, wherein the coating composition further comprises a hydrophobic agent other than wax.

24. The composite insulation material of Claim 23, wherein the hydrophobic agent other than wax is selected from the group consisting of fluorochemicals, fluoropolymers, silicones, functionalized silicones, silanes, siloxanes, hydrocarbon polymers, fatty acids, modified fatty acids, fatty alcohols, fats, lipids, oils, styrene maleic anhydride polymers, and hybrids of the above.

25. The composite insulation material of Claim 17, further comprising a layer of foam or fiberglass insulation.

26. Pipes coated with the composite insulation material of any of Claims 1-25.

27. Building materials coated with the composite insulation material of any of Claims 1-25.

28. Ductwork coated with the composite insulation material of any of Claims 1-25.

29. A method of making a composite insulation material which comprises: a) providing a layer of foam or fiberglass insulation, b) applying a layer of paper to the surface of the foam or fiberglass insulation, and c) applying a coating composition to the topmost surface of the paper, wherein the coating composition comprises latex and a crystalline platelet structure.

30. The method of Claim 29, wherein the foam is a thermoplastic or elastic foam.

31. The method of Claim 29, wherein the resin latex is selected from the group o consisting of latexes of poly(meth)acrylates, carboxylated or non-carboxylated butadiene- acrylonitrile, polystyrene, styrene-acrylonitrile, styrene-acrylonitrile-butadiene, styrene acrylates, styrene-butadiene, carboxylated styrene butadiene, polyvinyl chloride, polyvinyl acetate, waterbome polyurethanes, vinyl acrylics, polyvinylidene chloride, ethyl vinyl chloride, vinyl acetate-ethylene copolymers, and copolymers, terpolymers, and blends thereof.

32. The method of Claim 29, wherein the resin latex includes a comonomer selected from the group consisting of monocarboxylic acid monomer, dicarboxylic acid monomers, unsaturated monocarboxylic ester monomers, acrylamide-based monomers, half esters of unsaturated dicarboxylic acid monomers, and blends and mixtures thereof.

33. The method of Claim 29, wherein the insulation is fiberglass insulation.

34. The method of Claim 29, wherein the paper layer is Kraft paper.

35. The method of Claim 29, wherein the crystalline platelet structure is selected from the group consisting of mica, clay, talc, kaolin, and silica.

36. The method of Claim 29, wherein the crystalline platelet structure is modified to increase its hydrophobicity.

37. The method of Claim 36, wherein the crystalline platelet structure is calcium stearate-modified mica.

38. The method of Claim 29, wherein the foam is a thermoplastic or elastic foam.

39. The method of Claim 29, wherein the coating composition further comprises wax.

40. The method of Claim 29, wherein the coating composition further comprises a hydrophobic agent other than wax.

41. The method of Claim 40, wherein the hydrophobic agent other than wax is selected from the group consisting of fluorochemicals, fluoropolymers, silicones, functionalized silicones, silanes, siloxanes, hydrocarbon polymers, fatty acids, modified fatty acids, fatty alcohols, fats, lipids, oils, styrene maleic anhydride polymers, and hybrids of the above.

41. The method of Claim 29, wherein the layer of foam or fiberglass insulation foam has two sides, one of which is coated with the paper, further comprising coating the other side with a metal foil.