WO2018211440A1

WO2018211440A1 - Moisture barrier compositions

Info

Publication number: WO2018211440A1
Application number: PCT/IB2018/053451
Authority: WO
Inventors: Mathew James CAIRNS; James Howard Johnston; Behudin MESIC
Original assignee: New Zealand Forest Research Institute Limited
Priority date: 2017-05-19
Filing date: 2018-05-17
Publication date: 2018-11-22

Abstract

A packaging or building material comprising a coated cellulosic or plastic sheet, web, or film substrate at least partially coated with a cured coating comprising an elastomer matrix having nanoparticles of silicon dioxide dispersed within the matrix, and compositions and methods for making same. The method comprises (a) providing a coating composition comprising an aqueous dispersion of an elastomer having one or more silicon alkoxides dispersed within the elastomer, the weight ratio of the silicon alkoxides to the aqueous dispersion of the elastomer being at least about 1 : 250 to about 1 : 10 on a wet basis, (b) applying the coating composition to the substrate to at least partially coat the substrate, and (c) curing the coating composition.

Description

MOISTURE BARRIER COMPOSITIONS

FIELD OF THE INVENTION

[0001] The invention relates to moisture barrier compositions for building and packaging substrates, such as cellulosic and plastic substrates, including paper, paperboard, and other wood fibre products, and in particular to moisture barriers comprising an elastomer and silicon dioxide.

BACKGROUND OF THE INVENTION

[0002] The provision of moisture barrier properties to packaging materials can lead to improved material life and ultimately reduced spoilage and improvements in the shelf life of perishable goods such as foodstuffs. If the packaging material is a naturally adsorbent material such as paperboard, ingress of moisture can lead to loss of mechanical strength of the package and damage to the goods contained therein.

[0003] The provision of moisture barrier properties to building materials is beneficial for interior and exterior cladding or lining exposed to moisture where contact with moisture and ingress of moisture into the building material and surrounding structure can lead to loss of mechanical strength and establishment of unwanted organisms.

[0004] The application of a barrier layer in liquid form is desirable, as high speed reel-to-reel application techniques may be employed for the coating process, as developed by the printing industry.

[0005] It is an object of the invention to provide improved or alternative moisture barrier compositions.

SUMMARY OF THE INVENTION [0006] The present invention broadly relates to packaging or building materials at least partially coated with an elastomer matrix comprising dispersed nanoparticles of silicon dioxide.

[0007] Accordingly, in one aspect the invention relates to a packaging or building material comprising a coated substrate, the substrate comprising a cellulosic or plastic sheet, web, or film, the substrate being at least partially coated with a cured coating comprising an elastomer matrix having

nanoparticles of silicon dioxide dispersed within the matrix. [0008] In another aspect the invention relates to a composition for coating a packaging or building material, the composition comprising an aqueous dispersion of an elastomer having one or more silicon alkoxides dispersed therein, the weight ratio of the one or more silicon alkoxides to the aqueous dispersion of the elastomer being at least about 1 : 250 to about 1 : 10 on a wet basis.

[0009] In another aspect the invention relates to a method of coating a substrate, preferably comprising a sheet, web, or film, to form a packaging or building material, the method comprising

(1) providing a coating composition comprising an aqueous dispersion of an elastomer having one or more silicon alkoxides dispersed therein, the weight ratio of the one or more silicon alkoxides to the aqueous dispersion of the elastomer being at least about 1 : 250 to about 1 : 10 on a wet basis,

(2) applying the coating composition to the substrate to at least partially coat the substrate, and (3) curing the coating composition.

[0010] In another aspect the invention relates to a coated substrate prepared by the methods described herein.

[0011] The following embodiments may relate to any of the above aspects in any combination. [0012] In various embodiments the nanoparticles of silicon dioxide may be dispersed throughout, preferably substantially evenly throughout the matrix.

[0013] In various embodiments the elastomer matrix may comprise coalesced particles of elastomer. [0014] In various embodiments the elastomer matrix and the nanoparticles of silicon dioxide together may be in the form of a substantially anhydrous gel with the nanoparticles of silicon dioxide dispersed throughout, preferably substantially evenly throughout the matrix. [0015] In various embodiments the elastomer matrix may comprise a continuous elastomer phase with the nanoparticles of silicon dioxide dispersed throughout, preferably substantially evenly throughout the matrix, such that the elastomer matrix and the nanoparticles of silicon dioxide together form a substantially anhydrous gel. [0016] In various embodiments the nanoparticles of silicon dioxide may be less than about 50, 30, 40, 20, 10, 8, 6, 4, 2, or 1 nm in size, preferably as determined by scanning electron microscopy or transmission electron microscopy, and useful ranges may be selected between any of these values (for example about 1 to about 50, about 1 to about 40, about 1 to about 30, about 1 to about 20, about 1 to about 10, or about 1 to about 8 nm).

Preferably the nanoparticles of silicon dioxide may be less than about 20 nm or 10 nm, more preferably less than about 8 nm, or most preferably less than about 6 nm in size. Size may be median size, geometric mean size, or average size, for example. [0017] In various embodiments the weight ratio of the silicon dioxide to the elastomer may be at least about or up to about 1:200, 1:195, 1:190, 1:185, 1:180, 1:175, 1:170, 1:165, 1:160, 1:155, 1:150, 1:145, 1:140, 1:135, 1:130, 1:125, 1:120, 1:115, 1:110, 1:105, or 1:100 on a dry basis, and useful ranges may be selected between any of these values (for example, about 1:200 to about 1:100, about 1:190 to about 1:100, about 1:180 to about 1:100, about 1:170 to about 1:100, about 1:160 to about 1:100, about 1 : 150 to about 1 : 100, about 1 : 140 to about 1 : 100, or about 1 : 130 to about 1 : 100). Preferably the ratio is at least about or up to about 1 : 140 to about 1:100, or more preferably at least about or up to about 1:130 to about 1:100. [0018] In various embodiments the coating may comprise at least about 0.50, 0.51, 0.53, 0.54, 0.56, 0.57, 0.59, 0.61, 0.63, 0.65, 0.67, 0.69, 0.71, 0.74, 0.77, 0.80, 0.83, 0.87, 0.91, 0.95, or 1 % by weight silicon dioxide on a dry basis, based on the combined weight of the elastomer and silicon dioxide, and useful ranges may be selected between any of these values (for example, about 0.5 to about 1, about 0.53 to about 1, about 0.56 to about 1, about 0.59 to about 1, about 0.63 to about 1, about 0.67 to about 1, about 0.71 to about 1, about 0.77 to about 1, about 0.83 to about 1, or about 0.91 to about 1 %). Preferably the amount of silicon dioxide is at least about or up to about 0.71 % to about 1 %, or more preferably at least about or up to about 0.77 % to about 1 % by weight.

[0019] In various embodiments, providing a coating composition may comprise providing an aqueous dispersion of an elastomer and adding one or more silicon alkoxides, along with one or more steps in any order selected from

1) adding one or more fillers,

2) adding one or more additives,

3) adding water,

4) holding, to de-aerate or de-foam, for example,

5) mixing, and

6) any combination of any two or more thereof.

[0020] In various embodiments, the total solids content of the coating composition may be about 30 to about 70 % by weight before application to the substrate.

[0021] In various embodiments applying the coating composition to the substrate to at least partially coat the substrate may comprise a batch process or a continuous process. [0022] In various embodiments curing the coating composition may comprise heating the coated substrate at a temperature of at least about 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 105, 110, 115, 120, 125, 130, 135, 140, 145, or 150 °C, and useful ranges may be selected between any of these values (for example, about 50 to about 150, or about 50 to about 120 °C). Preferably heating is at a temperature of about 50 to about 90 °C, or more preferably about 60 to about 80 °C. [0023] In various embodiments heating may be conducted for at least about 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, or 12 milliseconds, about 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, or 12 seconds, about 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, or 12 minutes, or about 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, or 12 hours, and useful ranges may be selected between any of these values (for example, about 1 to about 12, or about 1 to about 10 milliseconds, about 1 to about 12, or about 1 to about 10 seconds, about 1 to about 12, or about 1 to about 10 minutes, about 1 to about 12, or about 1 to about 10 hours). In various embodiments the heating may be conducted in one, or two, or three, or four, or more stages. Preferably heating may be at a temperature discussed herein, for a time discussed herein, where the heat is applied for the time, one, or two, or three, or four, or more times. In various embodiments, heating is conducted until the elastomer has substantially coalesced.

[0024] In various embodiments the one or more silicon alkoxides may be present in the aqueous dispersion in the form of dispersed droplets, or dispersed molecules.

[0025] In various embodiments the weight ratio of the one or more silicon alkoxides to the aqueous dispersion of the elastomer may be at least about or up to about 1:250, 1:240, 1:230, 1:220, 1:210, 1:200, 1:190, 1:180, 1:170, 1:160, 1:150, 1:140, 1:130, 1:120, 1:110, 1:100, 1:90, 1:80, 1:70, 1:60, 1:50, 1:40, 1:30, 1:20, 1:18, 1:15, or 1:10 on a wet basis, and useful ranges may be selected between any of these values (for example, about 1:250 to about 1:10, about 1:220 to about 1:10, about 1:200 to about 1:10, about 1:180 to about 1:10, about 1:170 to about 1:10, about 1:160 to about 1:10, about 1:150 to about 1:10, about 1:140 to about 1:10, or about 1:130 to about 1 : 10). Preferably the ratio is at least about or up to about 1 : 170 to about 1:15, or more preferably at least about or up to about 1:130 to about 1:18.

[0026] In various embodiments the coating composition may comprise at least about or up to about 0.40, 0.42, 0.43, 0.45, 0.48, 0.50, 0.53, 0.56, 0.59, 0.63, 0.67, 0.71, 0.77, 0.83, 0.91, 1, 1.11, 1.25, 1.43, 1.67, 2, 2.50, 3.33, 5, 5.56, 6.67, or 10 % by weight silicon alkoxide on a wet basis, based on the combined weight of the elastomer and silicon alkoxide, and useful ranges may be selected between any of these values (for example, about 0.4 to about 10, about 0.45 to about 10, about 0.5 to about 10, about 0.56 to about 10, about 0.59 to about 10, about 0.63 to about 10, about 0.67 to about 10, about 0.71 to about 10, or about 0.77 to about 10 %). Preferably the amount of silicon dioxide is at least about or up to about 0.59 % to about 6.67%, or more preferably at least about or up to about 0.77 % to about 5.56 % by weight.

[0027] In various embodiments the one or more silicon alkoxides may comprise a compound of formula Si(OR²)4 or of formula SiRHOR²)3 or a combination thereof wherein R² is a CI to C4 alkyl and R¹ is phenyl.

[0028] In various embodiments R² may be methyl, ethyl, propyl, isopropyl, cyclopropyl, butyl, sec-butyl, isobutyl, tert-butyl, or cyclobutyl.

[0029] In various embodiments the one or more silicon alkoxides may comprise tetramethyl orthosilicate, tetraethyl orthosilicate, tetrapropyl orthosilicate, tetrabutyl orthosilicate, phenyl triethoxysilane, or any combination of any two or more thereof.

[0030] In various embodiments the coating composition may have a pH of about 6, 7, 8, or 9, and useful ranges may be selected between any of these values (for example about 6 to about 9, or about 6 to about 8).

[0031] In various embodiments the silicon dioxide may be an amorphous silicon dioxide.

[0032] In various embodiments the elastomer may have a glass transition temperature of less than about 0, 5, 10, 15, 20, 25, 30, or 35 °C, and useful ranges may be selected between any of these values (for example, about 10 to about 35 °C).

[0033] In various embodiments the elastomer may comprise a styrene butadiene co-polymer, a polyisoprene, a polybutadiene, a chloroprene, a polychloroprene, an isobutylene isoprene co-polymer, a butadiene acrylonitrile copolymer (NBR), an ethylene propylene co-polymer, an ethylene propylene diene ter-polymer, an epichlorohydrin rubber, a polyacrylic rubber, a silicone rubber, a fluorosilicone rubber, a fluroroelastomer, a perfluoroelastomer, a polyether block amide, a chlorosulfonated polyethylene, an ethylene-vinyl acetate, a polyurethane, a latex, a natural rubber, or any combination of any two or more thereof. Preferably the elastomer comprises a styrene butadiene co-polymer.

[0034] In various embodiments the elastomer may be substantially free of or lack carboxyl groups, or the mole percent of carboxyl groups in the elastomer may be less than about 1, 5, 10, 15, 20, 25, or 30 %, or the mole percent of a carboxyl-containing monomer in the elastomer may be less than about 1, 5, 10, 15, 20, 25, or 30 %, or the acid value of the elastomer may be less than about 30, or less than about 20.

[0035] In various embodiments the aqueous dispersion of the elastomer may comprise aggregates, droplets, and/or particles of elastomer in an aqueous carrier.

[0036] In various embodiments the aqueous dispersion of the elastomer may comprise at least about 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, or 80 % by weight elastomer, and useful ranges may be selected between any of these values (for example, about 20 to about 80, about 30 to about 70, or about 40 to about 60 %). Preferably the aqueous dispersion comprises about 40 to about 60 % by weight elastomer, more preferably about 45 to 55 % by weight.

[0037] In various embodiments the aqueous dispersion of the elastomer may comprise elastomer aggregates, droplets, and/or particles. In various embodiments the aqueous dispersion of the elastomer may comprise elastomer aggregates, droplets, and/or particles having a size or diameter of about 40, 50, 60, 70, 80, 90, 125, 150, 175, 200, 250, 300, 350, 400, 450, 500, 600, 700, 800, 900, or 1000 nm, and useful ranges may be selected between any of these values (for example, about 40 to about 1000, about 40 to about 500, about 40 to about 200, or about 40 to about 100 nm).

Preferably the size or diameter is about 40 to about 200 nm, more preferably about 40 to 100 nm, most preferably about 50 to about 90 nm. [0038] In various embodiments the coating or coating composition may further comprise one or more fillers. In various embodiments the coating or coating composition may further comprise about 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, or 80 % by weight of the one or more fillers, and useful ranges may be selected between any of these values (for example, about 0.5 to about 80, about 0.5 to about 70, about 5 to about 70, about 10 to about 70, about 20 to about 70, about 0.5 to about 10, about 0.5 to about 8, to about 1 to about 8 %), preferably about 30 to about 70 %, or about 1 to about 6 % by weight. [0039] In various embodiments the one or more fillers may comprise a phyllosilicate or a platy mineral, or any combination of any two or more thereof.

[0040] In various embodiments the one or more fillers may comprise a plate-like mineral filler with an aspect ratio of about 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 105, 110, 115, 120, 125, 130, 135, 140, 145, or 150, and useful ranges may be selected between any of these values (for example, about 5 to about 150, about 10 to about 150, or about 25 to about 150), preferably at least about 30.

[0041] In various embodiments the one or more fillers may comprise a plate-like mineral filler with an average particle size of about 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, or 5 microns, and useful ranges may be selected between any of these values (for example, about 0.5 to about 5, or about 0.5 to about 2 microns), preferably less than about 2 microns.

[0042] In various embodiments the phyllosilicate or platy mineral may comprise kaolin, talc, bentonite, vermiculite, montmorillonite, nontronite, beidellite, volkonskoite, hectorite, saponite, laponite, sauconite, magadiite, kanyaite, ledikite, halloysite, nacrite, illite, attapulgite, muscovite, zeolite or any combination of any two or more thereof.

[0043] In various embodiments the filler forms or provides a torturous path in the coating, or form or provides a structure defining a torturous path in the coating. [0044] In various embodiments the composition has a viscosity of less than about 800, 750, 700, 650, 600, 550, 500, 450, 400, 350, 300, 250, 200, 150, 100, or 50 centipoise (mPa-s), and useful ranges may be selected between these values (for example, about 50 to about 800, about 100 to about 800, about 50 to about 600, about 100 to about 600, or about 50 to about 200, about 100 to about 200 centipoise). Preferably the composition has a viscosity of less than about 600, more preferably less than about 200 centipoise.

[0045] In various embodiments the substrate or packaging or building material may comprise lignocellulose and/or cellulose. [0046] In various embodiments the substrate or packaging or building material may comprise or may be a plastic comprising polypropylene, polyethylene, polyethylene terephthalate, high density polyethylene, low density polyethylene, polyvinyl chloride, polyvinylidene chloride, polyester, polystyrene, polyamide, polyacrylate, polyurethane, co-polymers thereof, polymer blends thereof, or any combination of any two or more thereof.

[0047] In various embodiments the substrate or packaging or building material may comprise or may be a cellulosic substrate comprising paper, paperboard, linerboard, cardboard, plasterboard, or may comprise or may be an engineered wood product, or a plastic, or any combination of any two or more thereof.

[0048] In various embodiments the engineered wood product may comprise fibreboard, medium density fibreboard (MDF), particleboard, flakeboard, hardboard, oriented strand board, or plywood, or any combination of any two or more thereof. [0049] In various embodiments the coated substrate may have a liquid water uptake of less than about 5, 10, 15, 20, 25, 30, 35, 40, 45, or 50 g/m² after 30 minutes water contact time according to standard AS/NZS

1301.411s: 2004/ISO 535: 1991, and useful ranges may be selected between any of these values (for example, about 5 to about 50, about 5 to about 40, about 5 to about 30, or about 10 to about 50 g/m²). [0050] In various embodiments the coated substrate may have a water vapour transport rate of less than about 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 105, 110, 115, 120, 125, 130, 135, 140, 145, or 150 g nr² d^"1 according to standard AS 1301.419s : 1989 at 23 °C and 50 % relative humidity, and useful ranges may be selected between any of these values (for example, about 10 to about 150, about 25 to about 150, about 10 to about 100, or about 25 to about 100 g nr² d^"1).

[0051] In various embodiments the coated substrate may have a grammage of from about 1, 5, 10, 15, 20, 25, 30, 35, 40, 45, or about 50 g nr² according to TAPPI test method T410 om-98, and useful ranges may be selected between any of these values (for example, about 1 to about 50 g nr ²).

[0052] In various embodiments the dry thickness of the coating may be from about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, or 100 μιη, and useful ranges may be selected between any of these values (for example, about 1 to about 100, about 10 to about 100, or about 20 to about 100 μιη).

[0053] In various embodiments the coating may comprise one or more additives. Additives can include, but are not limited to, dispersants, colouring agents, crosslinkers, slipping agents, defoamers, pH control agents, plasticizers, thickeners, water-retention aids, fire retardants, pesticides, fungicides, and any combination of any two or more thereof. In various embodiments the coating may comprise about 0.1 to about 10 % by weight of one or more additives on a dry basis. Preferred additives include a defoamer and/or a pH control agent. A preferred defoamer is an ethylene oxide- propylene oxide defoamer. A preferred pH control agent is sodium hydroxide.

[0054] It is intended that reference to a range of numbers disclosed herein (for example, 1 to 10) also incorporates reference to all rational numbers within that range (for example, 1, 1.1, 2, 3, 3.9, 4, 5, 6, 6.5, 7, 8, 9 and 10) and also any range of rational numbers within that range (for example, 2 to 8, 1.5 to 5.5 and 3.1 to 4.7) and, therefore, all sub-ranges of all ranges expressly disclosed herein are hereby expressly disclosed. These are only examples of what is specifically intended and all possible combinations of numerical values between the lowest value and the highest value enumerated are to be considered to be expressly stated in this application in a similar manner. [0055] In this specification where reference has been made to patent specifications, other external documents, or other sources of information, this is generally for the purpose of providing a context for discussing the features of the invention. Unless specifically stated otherwise, reference to such external documents is not to be construed as an admission that such documents, or such sources of information, in any jurisdiction, are prior art, or form part of the common general knowledge in the art.

[0056] The invention may also be said broadly to consist in the parts, elements and features referred to or indicated in the specification of the application, individually or collectively, in any or all combinations of two or more of said parts, elements or features, and where specific integers are mentioned herein which have known equivalents in the art to which the invention relates, such known equivalents are deemed to be incorporated herein as if individually set forth.

BRIEF DESCRIPTION OF THE DRAWINGS [0057] Figure 1 is a flow diagram depicting processes of the invention.

[0058] Figure 2a is a bar graph showing direct water contact barrier performance (Cobb 1800 s) values (bars) for three different styrene butadiene elastomers (DL966 - solid dark bars; SPD92 - light bars; and DL629 - diagonal striped bars) applied at different coat grammage (DL966 - solid line; SPD92 - dashed line; DL629 - dotted line) and silicon alkoxide concentrations of 1 : 132 or 1 : 88.

[0059] Figure 2b is a bar graph showing direct WVTR values (bars) for three different styrene butadiene elastomers (DL966 - solid dark bars; SPD92 - light bars; and DL629 - diagonal striped bars) applied at different coat grammage (DL966 - solid line; SPD92 - dashed line; DL629 - dotted line) and silicon alkoxide concentrations of 1 : 132 or 1 : 88. DETAILED DESCRIPTION

[0060] The inventors have discovered that an aqueous styrene-butadiene latex dispersion coating containing in-situ formed silicon dioxide, provided by an in-situ processed silicon alkoxide such as tetraethyl orthosilicate (TEOS), applied on paperboard demonstrated improved water barrier performance. Coatings containing TEOS equivalent to 0.8% S1O2 (dry basis) exhibited water vapour performance of < 25 g nr² d^"1 (23 °C, 50% relative humidity), and liquid water barrier performance (Cobb 1800 s) of < 6 g nr², when applied as a single-layer 18 g nr² coating, and 11 g nr² at coat weights of 7 - 10 g nr². Fillers such as kaolin improved the vapour barrier properties of the coating but were not critical to the liquid water barrier properties.

1. Definitions

[0061] The term "comprising" as used in this specification and claims means "consisting at least in part of". When interpreting statements in this specification and claims which include the term "comprising", other features besides the features prefaced by this term in each statement can also be present. Related terms such as "comprise" and "comprised" are to be interpreted in similar manner. [0062] The term "substantially free" as used in this specification in relation the disclosed formulations means less than about 1, 0.8, 0.6, 0.4, 0.2, 0.1, or 0.05 % by weight of the stated substance, group, component or compound.

2. Coating compositions

[0063] The present invention broadly relates to packaging or building materials at least partially coated with an elastomer matrix comprising dispersed nanoparticles of silicon dioxide. The disclosed compositions are useful to increase the water barrier performance of plastic or cellulosic substrates.

[0064] As described above, in one aspect the invention relates to a packaging or building material comprising a coated substrate, the substrate comprising a cellulosic or plastic sheet, web, or film, the substrate being at least partially coated with a cured coating comprising an elastomer matrix having nanoparticles of silicon d ioxide dispersed within the matrix. [0065] As a lso described above, in another aspect the invention relates to a composition for coating a packag ing or build ing material, the composition comprising a n aqueous dispersion of a n elastomer havi ng one or more silicon alkoxides dispersed therein, the weight ratio of the one or more silicon alkoxides to the aqueous dispersion of the elastomer being at least a bout 1 : 250 to about 1 : 10 on a wet basis.

[0066] Coating compositions useful herei n a re described a bove a nd exemplified below.

[0067] The coati ng compositions comprise na noparticles of silicon dioxide once cured, preferably less tha n 50 nm in size, with the silicon dioxide dispersed throug hout, preferably substantia lly evenly throughout the elastomer matrix, where the elastomer matrix comprises coalesced pa rticles of elastomer. Without wishing to be bound by theory, it is believed the elastomer matrix and the na noparticles of silicon dioxide together form a substantially anhydrous gel. In particular, it is believed the elastomer matrix comprises a continuous elastomer phase with the na noparticles of silicon dioxide dispersed throug hout, preferably substa ntial ly evenly throughout the matrix.

[0068] In the cured coating, the weight ratio of the silicon d ioxide to the elastomer may be at least about or up to a bout 1 : 200 to about 1 : 100 on a dry basis (a bout 0.50 to about 1 % by weight silicon dioxide on a dry basis, based on the combined weight of the elastomer and silicon dioxide).

[0069] Before curing, the total solids content of the coating composition may be about 30 to a bout 70 % by weight before application to the substrate, where the one or more silicon alkoxides may be present in the aqueous dispersion in the form of dispersed droplets, or dispersed molecules and the weight ratio of the one or more silicon alkoxides to the aqueous d ispersion of the elastomer may be at least a bout or up to about 1 : 250 to about 1 : 10 on a wet basis (about 0.40 to about 10 % by weight silicon alkoxide on a wet basis, based on the combined weight of the elastomer and silicon alkoxide).

[0070] As described in more detail above, the one or more silicon alkoxides may comprise a compound of formula Si(OR²)4 or of formula SiRHOR²^ or a combination thereof wherein R² is a CI to C4 alkyl and R¹ is phenyl. A preferred silicon alkoxide is tetraethyl orthosilicate (TEOS).

[0071] The elastomer may comprise any suitable elastomer known in the art, particularly those described above and exemplified below. Preferably the elastomer comprises a styrene butadiene co-polymer. Suitable characteristics of the elastomer are also described above and exemplified below.

[0072] In some situations an elastomer with a lower hydrophilicity may be desired, and so the elastomer selected may be substantially free of or lack carboxyl groups, or have a low proportion of carboxyl groups as described above. [0073] In various embodiments the coating or coating composition may further comprise one or more fillers, including about 0.5 to about 80 % by weight of one or more fillers, particularly fillers such as a phyllosilicate or a platy mineral. Such fillers are described above. The role of the filler is to form or provide a torturous path in the coating, or form or provide a structure defining a torturous path in the coating, reducing or preventing the ingress of water or other liquids.

[0074] For efficient application, it may be useful for the composition to have a viscosity of less than about 800 to about 50 centipoise (mPa-s), preferably less than about 600, more preferably less than about 200 centipoise. [0075] The coatings described herein, once cured on a substrate, may provide benefits including a liquid water uptake of less than about 5 to about 50 g/m² after 30 minutes water contact time according to standard AS/NZS 1301.411s: 2004/ISO 535: 1991, and/or a water vapour transport rate of less than about 10 to about 150 g nr² d^"1 according to standard AS

1301.419s: 1989 at 23 °C and 50 % relative humidity. [0076] Once cured on a substrate, the coated substrate may have a grammage of from about 1 to about 50 g nr² according to TAPPI test method T410 om-98, and the dry thickness of the coating may be from about 1 to about 100 μιτι, or more. [0077] As described above, the coating may comprise one or more additives. Additives may be useful to impart additional properties to the coating, or aid with its formulation and/or application. As discussed above, useful additives can include, but are not limited to, dispersants, colouring agents, crosslinkers, slipping agents, defoamers, pH control agents, plasticizers, thickeners, water-retention aids, fire retardants, pesticides, fungicides, and any combination of any two or more thereof. In various embodiments the coating may comprise about 0.1 to about 10 % by weight of one or more additives on a dry basis.

3. Substrates [0078] The substrate may be any substrate usefully needing a modified or improved liquid water uptake and/or a water vapour transport rate. As described above, the substrate may comprise or may be a plastic or a cellulosic. Such substrates are common in the packaging and building industries. Preferred substrates include paper, paperboard, linerboard, cardboard, plasterboard, an engineered wood product, or a plastic, or substrates that combine those materials. Preferred substrates are paperboard, linerboard, cardboard, plasterboard.

[0079] Substrates for high throughput processing are generally in the form of a sheet, web, or film. However, substrates may be in the form of fully assembled products, whether packaging or elements for use in construction.

4. Methods of coating

[0080] As described above, and with reference to Figure 1, the invention also relates to a method of coating a substrate, preferably comprising a sheet, web, or film, to form a packaging or building material, the method comprising (1) providing 1 a coating composition comprising an aqueous dispersion of an elastomer having one or more silicon alkoxides dispersed therein, the weight ratio of the one or more silicon alkoxides to the aqueous dispersion of the elastomer being at least about 1 : 250 to about 1 : 10 on a wet basis, (2) applying 2 the coating composition to the substrate to at least partially coat the substrate, and

(3) curing 3 the coating composition, to form a coated packaging or building material 4.

[0081] The step of providing 1 a coating composition may comprise providing an aqueous dispersion of an elastomer 5 and adding one or more silicon alkoxides 6, along with one or more steps in any order selected from

1) adding one or more fillers 7, such as those discussed above and

exemplified below,

2) adding one or more additives 8, such as those discussed above and exemplified below,

3) adding water 9, preferably to obtain or maintain a total solids content of about 30 to about 70 % by weight, and/or to obtain a viscosity of, or maintain the viscosity at less than about 600, more preferably less than about 200 centipoise,

4) holding 10, to de-aerate or de-foam, for example,

5) mixing 11, and

6) any combination of any two or more thereof.

[0082] In various embodiments, the total solids content of the coating composition provided 1 may be about 30 to about 70 % by weight before application 2 to the substrate.

[0083] In various embodiments applying 2 the coating composition to the substrate to at least partially coat the substrate may comprise a batch process or a continuous process. A batch process may comprise spray, roll, dip, rod, or doctor blade application, for example, or alternatively any other suitable batch technique known in the art. A continuous process is preferably a high speed application and drying process, and may comprise extrusion coating, dipping, dispersion coating, air-knife, blade, rod, spray, curtain coating, surface sizing, film coating, printing, flexographic printing, or gravure printing, for example, or alternatively any other suitable continuous technique known in the art.

[0084] The coating may be applied as a single 13 or multiple 14 coating, through recycle or use of multiple coating stations in series. A flexible approach such as flexographic printing, may be used to apply single or multiple layers in a specific pattern. The substrate may be surface sized 12 or otherwise treated as known and necessary in the art given the intended use prior to application of the coating. Coatings with different formulations may be applied in different layers. Subsequent coating formulations, such as pigment coatings, can also be applied to impart other properties.

[0085] In various embodiments curing 3 the coating composition may comprise heating the coated substrate at a temperature of at least about 50 to about 150 °C for at least about 0.5 milliseconds to about 12 hours, as necessary, conducted in one, or two, or three, or four, or more stages, as required. Preferably heating may be conducted at about 50 to about 100 °C, for about 0.5 milliseconds to 1 second, one, or two, or three, or four times. Preferably heating is conducted until the elastomer has substantially coalesced. [0086] As described above, and exemplified below, the resulting coated substrate may have improved barrier properties including reduced liquid water uptake and water vapour transport rate compared to the uncoated substrate, including a liquid water uptake of less than about 5 to about 50 g/m² after 30 minutes water contact time according to standard AS/NZS

1301.411s: 2004/ISO 535: 1991, and/or a water vapour transport rate of less than about 10 to about 150 g nr² d^"1 according to standard AS

1301.419s: 1989 at 23 °C and 50 % relative humidity.

[0087] Various aspects of the invention will now be illustrated in non- limiting ways by reference to the following examples. EXAMPLES

GENERAL PROTOCOL

[0088] Unless otherwise stated, the following general protocol was followed . Materials

[0089] Kraft linerboard substrate of 175 g nr² grammage was obtained from the Kinleith mill (Oji Fibre Solutions Ltd (Tokoroa, New Zealand)) .

[0090] All binders (DL966, DL629 & SPD92) used in this study were aqueous poly(styrene butadiene) dispersions at 50% solids content obtained from Styron Indonesia, a subsidiary of Dow Chemical Company.

[0091] Kaolin clay was the usual filler material used (Eckalite 2 brand, nominally 2.33 μιτι x 0.067 μιτι obtained from IMERYS, Australia).

Alternatively, talc (Steaplus HAR T77 from IMERYS) was used.

[0092] A poly(ethylene oxide-propylene oxide) defoamer DF122, obtained from Nopco was added to all dispersions.

[0093] Tetraethylorthosilicate (TEOS), 98% was obtained from Sigma Aldrich, and ethanol, 96%, was obtained from Merck. Deionised water was used for all dilutions.

Preparation of Coating Formulation

[0094] Binder/filler mixtures were prepared by adequately dispersing the filler component, where present, in a binder suspension. Unless otherwise indicated, the DL966 poly(styrene-butadiene) binder was used. A defoamer, sodium hydroxide solution for pH adjustment, and additional water for control of total solids content were also added. When kaolin was used as the filler component, a dry mass ratio of 53 :47 was used for latex: kaolin, and the solids content of the formulation was adjusted to 53%. Clay-latex dispersions were allowed to stand in an air-tight container overnight to permit foam to disperse, before the mixture was gently re-dispersed at 600-800 rpm for 30 minutes before continuing with addition of TEOS.

[0095] For typical batches of 400 - 500 g wet mass, the components were mixed with a high-shear mixer for at least 60 minutes before entrained air was removed by allowing the mixture to stand overnight.

[0096] A solution of TEOS in ethanol was added to the binder/filler formulation and moderate mechanical mixing was provided for 15 minutes. The formulation was removed from the mixer and subsamples withdrawn for characterisation of parameters such as viscosity, pH, and total solids.

[0097] Application of the formulation to linerboard was usually commenced within 10 minutes after mixing ceased. Coating operations with a single batch were completed within 2 hours. [0098] The TEOS content of the batches was usually designated as a mass ratio of S1O2 to wet binder, assuming that the TEOS component was completely reacted with water according to the equation : Si(OEt)4 + 2 H2O →

[0099] Batches of 6-8 linerboard samples of 30 cm x 30 cm or 29 cm x 19 cm were coated using a bench coater (K Coater M202, RK Print-Coat

Instruments Ltd., Royston, U .K.) equipped with wire-wound metering rods. A single layer coating was applied with a close-wound rod (# 1 to #5), depending on the desired grammage. Nominally, these rods apply a wet coat thickness of 6 m (# 1) - 50 pm (#5) on a non-adsorbent substrate. Typically, a #3 rod was used. This rod applies coatings with a (nominal) wet thickness of 24 m on a non-absorbent substrate. Coating speed was controlled at 12 m min^-1. Coated sheets were usually dried at 20°C until dry to touch (5 - 10 minutes) before drying at 105 °C against a glossy metal plate for 1 minute. The dry weight of the coating layers was determined gravimetrically. [00100] In some cases, when small scale < 50 g formulation was prepared, a manual bar coating method was used. In this case, paper substrates were affixed to a flat glass plate, and coatings of nominal 75 pm wet thickness were drawn down by hand using a bar coater. Coated area was 100 (w) x 200 mm (I). Linerboard samples were air dried at room temperature. As the samples were not hot-pressed, the Cobb water adsorption value of samples prepared using this method were generally higher than those of samples prepared with the standard rod-based coating method. Coatings prepared using this procedure were characterised for WVTR performance at 20 °C, 40% RH.

Characterisation Methods

[00101] Water barrier performance of the coated papers was undertaken in an atmosphere of 50% relative humidity, 23 °C. Direct water contact barrier performance (Cobb) measurements were undertaken in accordance with AS/NZS 1301.411s: 2004/ ISO 535 : 1991, with a water contact duration of 1800 s. Water vapour barrier performance was measured according to AS 1301.419s-89, and coat grammage of the barrier coating was determined according to TAPPI test method T410 om-98. Results are reported as mean ± standard deviation of 6 measurements.

[00102] Scanning electron microscopy (SEM) and x-ray energy dispersive spectroscopic (EDS) analysis of the coated samples was undertaken on either JEOL 6500F or JEOL 6610LA electron microscopes. Samples were sputter coated with carbon prior to analysis.

EXAMPLE 1 - TEOS addition to latex dispersions

[00103] The improvement in water barrier performance upon addition of TEOS to latex dispersions was investigated. Formulations were prepared at varying pH levels and with filler composition according to the information in Table 1.

Table 1: Variation of pH and filler content for TEOS (Si02)-containing formulations.

Grammage/ g nr 8 ± 1 8± 1 9 ± 2 9± 2 11 ± 1

[00104] The TEOS additive i n the coating increased WVTR barrier

performa nce. Electron microgra phs of the samples (not provided) showed that major crack defects were largely a bsent from the TEOS-containi ng coating . By compa rison, coatings lacking TEOS showed la rge crack defects penetrating the full depth of the coating to the paper substrate.

EXAMPLE 2 - variation of binder component

[00105] Formulations were prepared in which either the binder or the TEOS content were va ried as shown in Table 2a . Three styrene-butad iene binders were tested : DL966, DL629, conta ining a higher proportion of butadiene, and SPD92, a latex with the same styrene-butadiene ratio as DL966, but having a greater degree of surface carboxylation . Two series of sa mples at different coat weig hts were prepared for each formulation, one at 7-8 g nv² a nd another one at 20-23 g nr². Results are shown in Table 2b and Figures 2a and 2b.

Table 2a: Variation of binder com osition in coatin formulation

Table 2b: results of variation of binder composition in coating formulation.

[00106] The results indicate that similar barrier performance is obtained across a modest variation in TEOS content, with Si02: wet latex binder ratio of either 1:132 or 1:88. Higher surface carboxylation can impact on barrier performance.

EXAMPLE 3 - variation of coating grammage

[00107] A series of formulations was prepared with DL966 latex according to the Si02: wet binder composition of 1:132 as given in Table 2a. A series of coated paper samples were subsequently prepared from this formulation at increasing coat grammage. The coated paperboard samples were dried against a hot plate at 105 °C for 1 minute. The procedure was repeated for four separate preparations of the coating formulation.

[00108] Good barrier performance (Cobb 1800 s < ca. 10 g nr²) was achieved for coating grammage in excess of 10 g nr², with optimal water barrier performance achieved at a coat grammage in the range of 17-22 g nr². Increasing the grammage beyond the optimal value resulted in deterioration in both barrier properties.

[00109] In addition, one series of medium grammage coatings for each formulation, as detailed in Table 2a, was dried at varied temperature, from 20 °C through to 120 °C. The samples dried at 20 °C were not dried against a hot plate; all other samples were dried against the plate at required temperature for 1 minute.

[OOl lO] Cobb barrier performance is significantly improved with increased drying temperature, with the best barrier properties obtained when the coatings were dried in excess of 70 °C. Vapour barrier performance was not significantly affected by the drying conditions used.

EXAMPLE 4 - variation of filler component

[00111] Formulations were prepared with talc as the sole filler component and combined talc/kaolin fillers (Table 3). Table 3: Variation of filler com osition

[00112] Formulation 3A had poor barrier performance (>70 g nr²) and water barrier performance (>240 g nr² d^"1). Formulations 3B to 3D all had a barrier performance (Cobb) of less than 15 g nr² and water vapour transmission ratio of less than 50 g nr² d^"1. Combining kaolin and talc did not provide any additional barrier performance.

[00113] In micrographs of the coatings (not provided), the TEOS-free coating exhibited significant crack defects penetrating to the paper substrate, which accounted for the poor barrier performance of the coating. The coatings containing talc and TEOS show a similar morphology to the TEOS-kaolin coatings discussed above. In the TEOS-containing coatings, surface defects in the coating layer are minimal, and do not extend the full depth of the coating . Similar to the earlier TEOS-kaolin coatings, good Cobb barrier performance is obtained for the TEOS-talc coatings.

[00114] Coatings were prepared with varying talc content (Table 4). Cobb barrier performance was largely independent of talc filler content in the coating, and was similar to the filler-free pH 6.6 TEOS-containing coating from Table 1, with Cobb-1800 s values of < 10 g nr². Water vapour barrier performance improved with increasing filler content, from >50 g nr² d^"1 for formulation 4A to >40 g nr² d^"1 for formulation 4F. All water barrier properties of these coatings were significantly improved with respect to the TEOS-free latex/talc coating (3A, Table 3).

Table 4: Variation of talc filler content in coating formulation.

Sam les re ared with a SiC : wet binder ratio of 1: 139.

EXAMPLE 5 - variation of TEOS content

[00115] A series of formulations was prepared with varying mass ratio of Si02:wet latex (Table 5). The sodium quantity of hydroxide added to the formulations provides a final pH of 9.0. Table 5 In-situ coating formulations prepared with varying TEOS content.

[00116] A series of coated paperboard samples were prepared from these coatings using the bar coating procedure. In cases where the ratio of Si02: latex in the coating is in excess of 1 : 200, good barrier performance is achieved (Cobb less than about 15 g nr²). Formulations with a S1O2 : latex ratio in excess of 1 : 100 exhibit increased viscosity.

[00117] Given a nominal 100 nm particle size of the DL966 latex (50% solids) and a cross-sectional area for TEOS of 0.57 nm², the amount of TEOS required for monolayer coverage of the latex is approximately a S1O2 : latex ratio of 1 : 182. Papers coated from formulations with TEOS content in excess of this ( 1 : 100, 1 : 50, 1 : 20) exhibited low Cobb values (less than about 5 g nr 2).

EXAMPLE 6 - use of other silicon alkoxides

[00118] Formulations were prepared from DL966 or a polyurethane latex, Kamthane K-5000 and silicon alkoxides, as shown in Table 6. In all cases, 0.2 g equivalent of S1O2 was added to 20 g of the wet latex.

Table 6 Formulation composition of in-situ coatings prepared with

|EtOH 0.75 mL |0.80 mL |0.75 mL |l.O mL |

[00119] The polyurethane latex used for mixture 5A had a higher pH value of 8.7, compared to a pH value of 6.8 in the DL966 latex. For mixture 5B, the phenyl derivative of TEOS, PhSi(OEt)3 was used. For mixture 5C, a 3 : 1 molar ratio of TEOS to PhSi(OEt)3 was used. In the case of mixture 5D, the rate of Si(OBu)4 adsorption by the latex was significantly slower than the rate of TEOS adsorption. No gelling was observed in the Si(OBu)4 coating after several days, or in the polyurethane-TEOS coating.

[00120] Coatings were applied to paperboard using the bar-coating procedure 10 minutes after addition of the final component. The exception to this general rule was for coating 5D for which an additional coating was applied after 4 hours. All samples drawn down with a 75 μιη bar and air dried at room temperature. Measurement conditions were 40% RH, 20 °C.

Table 7 WVTR measurement of sam les.

[00121] Samples prepared with silicon alkoxides do show improved WVTR values. Under similar measurement conditions, a TEOS-latex formulation without clay has a WVTR value of 25-30 g nr² d^"1.

INDUSTRIAL APPLICABILITY

[00122] The products and processes of the present invention have

application in the building and packaging industries.

[00123] Those persons skilled in the art will understand that the above description is provided by way of illustration only and that the invention is not limited thereto.

Claims

WHAT WE CLAIM IS

1. A packaging or building material comprising a coated substrate, the

substrate comprising a cellulosic or plastic sheet, web, or film, the substrate being at least partially coated with a cured coating comprising an elastomer matrix having nanoparticles of silicon dioxide dispersed within the matrix.

2. The packaging or building material of claim 1, wherein the nanoparticles of silicon dioxide are dispersed throughout the matrix.

3. The packaging or building material of claim 1 or 2, wherein the elastomer matrix comprises coalesced particles of elastomer.

4. The packaging or building material of any one of claims 1 to 3, wherein the elastomer matrix and the nanoparticles of silicon dioxide together are in the form of a substantially anhydrous gel with the nanoparticles of silicon dioxide dispersed throughout the matrix.

5. The packaging or building material of any one of claims 1 to 3, wherein the elastomer matrix comprises a continuous elastomer phase with the nanoparticles of silicon dioxide dispersed throughout the matrix, such that the elastomer matrix and the nanoparticles of silicon dioxide together form a substantially anhydrous gel.

6. The packaging or building material of any one of claims 1 to 5, wherein the nanoparticles of silicon dioxide are less than about 50 nm in size, as determined by scanning electron microscopy.

7. The packaging or building material of any one of claims 1 to 5, wherein the nanoparticles of silicon dioxide are less than about 10 nm in size, as determined by scanning electron microscopy.

8. The packaging or building material of any one of the claims 1 to 7,

wherein the weight ratio of the silicon dioxide to the elastomer is at least about 1 : 200 to about 1 : 100 on a dry basis.

9. A composition for coating a packaging or building material, the

composition comprising an aqueous dispersion of an elastomer having one or more silicon alkoxides dispersed therein, the weight ratio of the one or more silicon alkoxides to the aqueous dispersion of the elastomer being at least about 1 :250 to about 1 : 10 on a wet basis.

10. A method of coating a substrate to form a packaging or building material, the method comprising a) providing a coating composition comprising an aqueous dispersion of an elastomer having one or more silicon alkoxides dispersed therein, the weight ratio of the one or more silicon alkoxides to the aqueous dispersion of the elastomer being at least about 1 : 250 to about 1 : 10 on a wet basis, b) applying the coating composition to the substrate to at least

partially coat the substrate, and c) curing the coating composition.

11. The method of claim 10, wherein curing the coating composition

comprises heating the coated substrate at a temperature of at least about 50 °C to about 150 °C for at least about 0.5 milliseconds to about 12 hours. 12. The composition or method of any one of claims 9 to 11, wherein the one or more silicon alkoxides comprises a compound of formula Si(OR²)4 or of formula SiR¹(OR²)3 or a combination thereof wherein R² is a CI to C4 alkyl and R¹ is phenyl.

13. The composition or method of claim 12, wherein R² is methyl, ethyl,

propyl, isopropyl, cyclopropyl, butyl, sec-butyl, isobutyl, tert-butyl, or cyclobutyl.

14. The composition or method of any of claims 9 to 13, wherein the one or more silicon alkoxides comprise tetramethyl orthosilicate, tetraethyl orthosilicate, tetrapropyl orthosilicate, tetrabutyl orthosilicate, phenyl triethoxysilane, or any combination of any two or more thereof.

15. The composition or method of any of claims 9 to 14, wherein the coating composition has a pH of about 6 to about 9. 16. The packaging or building material, composition, or method of any one of claims 1 to 15, wherein the silicon dioxide is amorphous silicon dioxide.

17. The packaging or building material, composition, or method of any one of claims 1 to 16, wherein the elastomer comprises styrene butadiene copolymer, polyisoprene, polybutadiene, chloroprene, polychloroprene, isobutylene isoprene co-polymer, butadiene acrylonitrile copolymer

(NBR), ethylene propylene co-polymer, ethylene propylene diene ter- polymer, epichlorohydrin rubber, polyacrylic rubber, silicone rubber, fluorosilicone rubber, fluroroelastomer, perfluoroelastomer, polyether block amide, chlorosulfonated polyethylene, an ethylene-vinyl acetate or polyurethane, or any combination of any two or more thereof.

18. The packaging or building material, composition, or method of any one of claims 1 to 17, wherein the coating or coating composition further comprises about 0.5 to about 70 % by weight of one or more fillers.

19. The packaging or building material, composition, or method of claim 18, wherein the one or more fillers comprises a phyllosilicate or a platy mineral, or any combination of any two or more thereof.

20. The packaging or building material, composition, or method of claim 18 or 19, wherein the one or more fillers comprises a plate-like mineral filler with an aspect ratio of about 5 to about 150. 21. The packaging or building material, composition, or method of claim 18, 19 or 20, wherein the one or more fillers comprises a plate-like mineral filler with an average particle size of about 0.5 to about 5 microns.

22. The packaging or building material, composition, or method of any one of claims 19 to 21, wherein the phyllosilicate or platy mineral comprises kaolin, talc, bentonite, vermiculite, montmorillonite, nontronite, beidellite, volkonskoite, hectorite, saponite, laponite, sauconite, magadiite, kanyaite, ledikite, halloysite, nacrite, illite, attapulgite, muscovite, zeolite or any combination of any two or more thereof. 23. The packaging or building material or composition or method of any one of claims 1 to 22, wherein the substrate or packaging or building material comprises lignocellulose and/or cellulose.

24. The packaging or building material or composition or method of any one of claims 1 to 23, wherein the substrate or packaging or building material comprises or is a plastic comprising polypropylene, polyethylene, polyethylene terephthalate, high density polyethylene, low density polyethylene, polyvinyl chloride, polyvinylidene chloride, polyester, polystyrene, polyamide, polyacrylate, polyurethane, co-polymers thereof, polymer blends thereof, or any combination of any two or more thereof. 25. The packaging or building material or composition or method of any one of claims 1 to 24, wherein the substrate or packaging or building material comprises or is a cellulosic substrate comprising paper, paperboard, linerboard, cardboard, plasterboard, or comprises or is an engineered wood product, or a plastic, or any combination of any two or more thereof.

26. The packaging or building material or composition or method of claim 25, wherein the engineered wood product comprises fibreboard, medium density fibreboard (MDF), particleboard, flakeboard, hardboard, oriented strand board, or plywood, or any combination of any two or more thereof.

27. A coated substrate prepared by the method of any one of claims 10 to 26.

28. The packaging or building material or method or coated substrate of any one of claims 1 to 8 and 10 to 27, wherein the coated substrate has a liquid water uptake of less than about 10 to about 50 g/m² after 30 minutes water contact time according to standard AS/NZS

1301.411s:2004/ISO 535: 1991.

29. The packaging or building material or method or coated substrate of any one of claims 1 to 8 or 10 to 28, wherein the coated substrate has a water vapour transport rate of less than about 25 to about 150 g nr² d^"1 according to standard AS 1301.419s: 1989 at 23 °C and 50 % relative humidity.

30. The packaging or building material or method or coated substrate of any one of claims 1 to 8 or 10 to 29, wherein the coated substrate has a grammage of from about 1 to about to about 50 g nr² according to TAPPI test method T410 om-98.

31. The packaging or building material or method or coated substrate of any one of claims 1 to 8 or 10 to 30, wherein the dry thickness of the coating is from about 1 to about 100 μιη.