GB2367556A

GB2367556A - Polysiloxane barrier coating composition

Info

Publication number: GB2367556A
Application number: GB0024367A
Authority: GB
Inventors: Patrick Merlin
Original assignee: Dow Corning SA
Current assignee: Dow Silicones Belgium SPRL
Priority date: 2000-10-05
Filing date: 2000-10-05
Publication date: 2002-04-10
Also published as: GB0024367D0

Abstract

A barrier coating composition comprising the reaction product of (a) an amino-functional cyclic siloxane comprising units of the formula [R<SP>1</SP><SB>2</SB>SiO<SB>2/2</SB>], wherein each R<SP>1</SP> is alkyl, substituted alkyl, amino, aryl, substituted aryl, arylalkyl or alkylaryl group, and (b) a reactive silane of the formula: (R<SP>4</SP>O)<SB>n</SB>(R<SP>5</SP>)<SB>3-n</SB> SiX wherein each R<SP>4</SP> is alkyl or acyl (RC(O)-), each R<SP>5</SP> is a hydrocarbon group, X represents an organic radical having at least one functional unit selected from epoxide, alkenyl, aldehyde, episulphide, acrylate, methacrylate, acrylamide, methacrylamide, isocyanate, isothiocyanate, halogen and an acid chloride and n is 1, 2 or 3; in a non-aqueous solvent, typically an alcohol. Preferably about 50% of R<SP>1</SP> substituents are tertiary amine groups and the remainder are alkyl groups containing one to four carbon atoms.

Description

BARRIER COATINGS

This invention relates to barrier coatings and in particular to cyclic aminosiloxane based polymers having barrier properties useful in packaging applications.

Coatings containing silane compounds can improve the adhesion and barrier characteristics with respect to the gas, oil, and flavour barrier performance of organic polymer film substrates and the performance of these coatings are typically further enhanced by exposing the coated film to electron beam radiation.

JP-A-7-18221 describes a surface treatment composition for gas barrier comprising an aminosilane and a compound having an aromatic ring or hydrogenated ring.

JP-A-7-323261 describes the use of compositions of silanes having amino groups and a compound having functional groups that can react with the amino group in said silane compound and their use as barrier coatings once applied to the substrate. However these compositions require prior hydrolysis of the silane.

It is well known that polysiloxane based polymers are very permeable to gases, as discussed in the book"Polymer Permeability" ; J Comyn (Ed)., pub. Chapman & Hall, 1985.

The present inventors have surprisingly discovered that certain modified cyclic aminosiloxane polymers significantly reduce the diffusion of permeant molecules at moderate relative humidity, and also display unique adhesive properties, once exposed to a certain level of moisture.

However, these compositions do not require pre-hydrolysis or an additional electron beam treatment to show effective barrier and adhesive properties.

The present invention provides a barrier coating composition comprising the reaction product of an aminofunctional cyclic siloxane comprising units of the formula

[R12SiO2], wherein each R1 may be the same or different and may be selected from the group consisting of : an alkyl, a substituted alkyl, an amine, an aryl, a substituted aryl, an arylalkyl and an alkylaryl group, each of which having from 1 to 18 carbon atoms, and a reactive silane or a mixture of reactive silanes of the formula: (R20) n (R3) 3-n SiX wherein each R2 group is the same or different and represents a radical selected from the group consisting of an alkyl group having from 1 to 4 carbon atoms and an acyl group (RC (O)-) having from 1 to 4 carbon atoms, each R3 group is the same or different and represents a hydrocarbon group with from 1 to 8 carbon atoms, X represents an organic radical having at least one functional unit selected from the group of an epoxide, an alkenyl, an aldehyde, an episulphide, an acrylate, a methacrylate, an acrylamide, a methacrylamide, an isocyanate, an isothiocyanate, a halogen atom and an acid chloride and n is 1,2 or 3; in a nonaqueous solvent.

The concept of"comprising"where used herein is used in its widest sense to mean and to encompass the notions of "include","comprehend"and"consist of".

Substituted alkyl and substituted aryl groups in R1 may include alcohol, amine, ether, ester, amide, alkoxy or urethane groups. In the case of amine groups these may be primary, secondary or tertiary and in the case of secondary and tertiary amines, N-alkyl and N-aryl groups may be further substituted with appropriate groups as described above, in particular with additional primary, secondary or tertiary amines, most preferably primary and/or secondary amines. Preferably at least 10% of R groups contain amino functionality in the form of one or more primary and/or

secondary and/or tertiary amines. More preferably at least 30 % of R1 groups contain amino functionality. Most preferably substantially each [R12SiO2/2] unit contains one group comprising a substituted alkyl group having one or more primary and/or secondary and/or tertiary amines (henceforth referred to as the amino R1 group) and the other R1 group in the unit is an alkyl group having from 1 to 4 carbon atoms, such that about 50% of all R1 groups are contain an amino functionality and the remaining R1 groups comprise alkyl groups having from 1 to 4 carbon atoms. Most preferably the alkyl R1 group is a methyl or ethyl group.

The amino R1 group preferably has the formula: -R'N (R') 2

wherein R4 is a linear, branched or substituted alkylene group and each R5 may be the same or different and may be hydrogen, an alkyl group or a substituted alkyl group. It is preferred for one R5 group to be hydrogen and the other to be a substituted alkyl group in the form of an aminoalkyl group. However it is to be understood that the aminoalkyl group may comprise anything from one primary amine group to a chain comprising a plurality of alkylene groups interspersed with secondary and or tertiary amine groups, preferably with terminal primary amine groups.

Optionally the amino-functional cyclic siloxane may additionally comprise units of the formula SiO4/2, R1SiO3/2 and R13SiOl/2 where Ru ils defined as above. This would cause the polymer chain to exhibit a certain amount of branching.

It is preferred that the Si04/2, R1SiO3/2 units should not exceed 10% of the total number of units thereby limiting the amount of branching that is taking place at the polymer level. More preferably no more than about 1% siloxane units causing branching should be present in the polymer.

Most preferably the amino Ri group is : - (CH2) CH (R) N (H) (R') (NHR7) qNH2 wherein R6 is hydrogen or an alkyl group with 1 to 4 carbon atoms and R7 is an alkylene or substituted alkylene group and R8 is an alkylene group having from 1 to 8 carbon atoms ; m is 0 to 8 and q is from 0 to 20. Preferably R6 is a methyl group, R8 is an ethylene group, m is 0, 1 or 2 and q is 0, a particularly preferred example of the amino Ri group is shown below :

- (CH2) 2-CH-NH- (CH2) 2-NH2 I CH3

The amino-functional cyclic siloxanes of the present invention preferably have molecular weights of from 200 to 2,000, 000, with about 400 to 100,000 preferred, and most preferred being from about 600 to 25,000, although it is to be noted that the use amino-functional cyclic siloxanes with higher molecular weights tends to reduce the degree of tackiness in the reaction product. Amino-functional cyclic siloxanes with molecular weights in the region of, or lower than the minimum given above can be further polymerised to form higher molecular weight polymers by methods well known in the art, such as by reaction with dialkyl halides (i. e. ethylene dichloride), diisocynates (e. g. tolydiisocyanate, hexamethylene diisocyanate), di (meth) acrylate esters (e. g. hexene diol diacrylate, pentaerythritol diacrylate), diepoxides (ethylene glycol diglycidyl ether, vinylcyclohexene diepoxide).

Additional groups may be introduced onto aminofunctional cyclic siloxanes using methods well known in the

art, to change the affinity of the coating to the substrate, or the adhesive properties. Such modification might include reactions with ethylene oxide based compounds (ethylene oxide, glycidol) to introduce hydroxyl groups, reactions with cyanides or aldehydes followed by hydrolysis to introduce carboxylic acid groups ("Strecker Synthesis"), reactions with phosphoric acid, carboxylic acid or sulphonic acid groups, and reactions with lipophilic alkyl chains using alkylating agents such as dimethyl sulphate.

Regarding the reactive silane, preferably n is either 2 or 3, most preferably n is 3. Preferably each R2 and R3 group is a methyl or ethyl group. Hence, when n is 2 or 3 the reactive silane is an alkyldialkoxysilane or a trialkoxysilane, the alkoxy groups of which may undergo a hydrolysis and/or condensation reaction subsequent to coating the composition of the present invention by adding water in-situ. The preferred reactive silanes contain a plurality of alkoxy groups, the presence of which may lead to cross-linking reactions with alkoxy groups of other reactive silanes. In such cases the resulting Si-O-Si bonds increase the cross-link density of the reaction product.

Specific examples of the reactive silane include gammaacryloxypropyltrimethoxysilane, gammamethacryloxypropyltrimethoxysilane, gammaglycidoxypropyltrimethoxysilane, gammaglycidoxypropyltriethoxysilane, chloropropyltrimethoxysilane, chloropropyltriethoxysilane, chloropropylmethyldimethoxysilane, chloropropylethyldimethoxysilane, epoxycyclohexylethyltrimethoxysilane, gammatrimethoxysilylpropylglycidyl ether, glycidoxypropylmethyldimethoxysilane, vinyltriethoxysilane, vinyltrimethoxysilane, gamma-isocyanatopropyltriethoxysilane and thiocyanopropyltrimethoxysilane.

The most preferred reactive silanes are chloropropyltrimethoxysilane, chloropropyltriethoxysilane and gamma-glycidoxypropyltrimethoxysilane.

Some of the reactive silanes may undergo modification prior to introduction onto the amino-functional cyclic siloxane, in that a spacer compound may be pre-reacted with the reactive silane prior to reaction with the amino

functional cyclic siloxane. An example of an appropriate p spacer is glycidyl methacrylate. The reaction of, for example, aminopropyltrimethoxysilane with glycidyl methacrylate gives a methacrylate functional silane that can be added onto the amino-functional cyclic siloxane by Michael addition.

For the preparation of the reaction product, the reactive silanes are preferably added in an amino-functional cyclic siloxane/reactive silane weight ratio of from 10: 1 to 1: 10, with a preferred ratio being from about 4: 1 to 1: 4 and most preferred ratio being from about 2: 1 to 1: 2.

The reaction product may be neutralised prior to use of the composition, for example, cases where the X group in the reactive silane contains a halo substituent for example when the reactive silane is chloropropyltrimethoxysilane. In these cases the reaction of the reactive silane with the amino functional cyclic siloxane, will result in the formation of a hydrochloride salt which is preferably neutralised to obtain the neutralised reaction product. Any appropriate base may be used for the neutralisation step, however a methanolic solution of sodium methoxide or an ethanolic solution of sodium ethoxide is preferred as the neutralisation process results in the production of a precipitate of sodium chloride which may be easily filtered off.

The non-aqueous solvent of the composition must be able to wet the substrate onto which the composition is to be applied. Preferably, the solvent is non-toxic, and does not extend the drying time of the layer beyond a commercially acceptable period. The amount of solvent may range from about 1 to about 99 parts by weight and is preferably from about 50 to about 95 parts by weight of the total composition. Water should be excluded from these solvents to ensure stability of the coating formulation. Preferred solvents (i) are alcohols for example, methanol, ethanol, npropanol, isopropanol, butanol, and 1-methoxy-2-propanol or mixtures thereof. Alternative solvents which may be utilised include an ether, for example diethyl ether, ether alcohols, an ester for example ethyl acetate, a hydrocarbon for example cyclohexane, and ether derivatives of mono or polyglycols, such as mono or polyalkylene oxides, for example, ethylene glycol dimethyl ether. The most preferred solvents are ethanol and isopropyl alcohol.

Optionally one or more additional cross-linking agents may be added to the reaction product. Cross-linking agents suitable for the present invention may be selected from the group of one or more multifunctional silanes and/or one or more organic cross-linkers.

As used herein the term"additional cross-linking agent"is defined as agents which can further chain extend and/or cross-link the amino-functional organic polymer/ reactive silane reaction product. The additional crosslinking agent may be added with a view to improving barrier properties, adhesive properties, reducing dewetting, and/or improving appearance. It is believed that a higher crosslink density causes these improved properties.

The multifunctional silane cross-linking agents may, for example be a reactive silane as defined above or a compound which imparts silane functionality and which can

further cause cross-linking to form a siloxane resin network through the condensation of the silane functionality, for example tetraethyl orthosilicate, polydiethoxysiloxane (PDEOS), and disilyl compounds for example, bis (trimethoxysilylpropyl) amine.

The organic cross-linking agents may be one or more compounds useful to chain extend and cross-link the reaction product. The reactive groups of such a cross-linking agent may be selected from the group of acrylates, methacrylates, epoxides, isocyanates, thiocyanates, acid halides, acid anhydrides, esters, alkyl halides, aldehydes or combinations thereof. Specific examples include, but are not limited to hexanediol diacrylate, glycidyl methacrylate, ethyleneglycoldiglycidyl ether, and tolyl di-isocyanate.

Particularly preferred are compounds which will undergo an acid catalyzed condensation reaction with the nitrogen atom of the amino-functional organic polymer, for example trismethylol phenol, formaldehyde, glyoxal, p-benzoquinone, and mixtures of formaldehyde and active methylene compounds that will undergo a Mannich reaction.

Various additional optional additives may also be added to the composition to improve various properties as required. These additives may be added in any suitable amount provided they do not degrade the performance of the barrier coatings as illustrated herein. Such additives include condensation catalysts, for example organo-tin, organo-titanium and organo-zirconium compounds or amines, which may be utilised to assist cure speed and fillers selected from, for example, silica, magnesium oxide, clay, diatomaceous earth, calcium carbonate, finely ground quartz and nanoparticles. Silicon containing nanoparticles such as silicates, for example exfoliated vermiculite, montmorillonite and apophyllite, may be added to the compound in order to reduce the thickness and/or weight of

the resultant coating. This would be particularly useful if the nanoparticles were exfoliated after having been thoroughly mixed into a compound or mixture prior to applying the layer to the substrate.

Other possible additives include anti-block and slip aids, for example stearamide, oleamide or polar additives, for example epoxides, acrylates, methacrylates, polyols, glycidol, glycidyl methacrylate, ethylene glycol diglycidylether, bisphenol A diglycidylether, or aminofunctional organic polymers, for example polyethylenimine and other silanes. Wetting agents, for example polyethoxylated phenol may also be added.

The present invention also provides a process for treating a surface of a substrate with the composition as described above, said process comprising applying the composition on to the substrate to form a layer and curing the layer by exposure to moisture.

In a process according to the invention the layer may be applied on to a wide variety of substrates, including, but not limited to polyolefins, including oriented polypropylene (OPP), cast polypropylene, polyethylene, polystyrene; polyolefin copolymers, including ethylene vinyl acetate, ethylene acrylic acid, ethylene vinyl alcohol (EVOH), ionomers, polyvinyl alcohol and copolymers thereof; polyacrylonitrile; polyvinyl chloride, polyvinyl dichloride, polyvinylidene chloride and polyacrylates.

Further alternative substrates include polyesters, for example, polyethylene terephthalate (PET) or polyethylene naphthalate (PEN) ; polyamides for example, nylon and MXD6 and polyimides.

Even further possible substrates include polysaccharides, for example, regenerated cellulose, glassine or clay coated paper, paperboard or Kraft paper or

metallised polymer films and vapour deposited metal oxide coated polymer films for example, Aloe, Sioux, or TiOx.

If desired, substrates used in a process according to the invention may be pretreated prior to application of the layer, for example, by corona treatment, plasma treatment, acid treatments and/or flame treatments, all of which are known in the art. Furthermore, any of the foregoing substrates may have a primer or primers applied thereon prior to application of the layer. The primers may be applied to the substrates by any appropriate process known in the art, for example, spray coating, roll coating, slot coating, meniscus coating, immersion coating, and indirect, offset, and reverse gravure coating and extrusion coating.

Suitable primers may include, but are not limited to carbodiimide, polyethylenimine, and silanes, for example, N 2-aminoethyl) -3-aminopropyltrimethoxy silane and aminopropyltriethoxysilane.

In a process in accordance with the invention the composition may be applied to the aforesaid substrates in the form of a film or sheet or molding. Alternatively, the substrate may be in the form of a rigid container made from materials for example, polyethylene, polypropylene, polystyrene, polyamide, PET, polymers of EVOH, or laminates containing such materials.

The layer may be applied onto a substrate in any desired amount, however, it is preferred that the layer be applied in an amount suitable to form a coating weight on

2 the substrate of from about 0. 05 to about 20 g/m2. Preferably the coating weight is from about 0.5 to about 10 g/m2, and most preferably is from 0.5 to 5g/m2. Coating weights may be determined by gravimetric comparison. The layer may be applied to the substrate by any conventional process, for example, spray coating, roll coating, slot

coating, meniscus coating, immersion coating, and direct, offset, and reverse gravure coating.

In a process according to the present invention a layer of the composition is cured by way of a condensation reaction, which preferably requires the presence of moisture. The moisture may, for example, be added through steam or in a high humidity oven (preferred Relative Humidity level: 40 to 100% most preferred: 60 to 80%). It is, however to be noted that wherever possible water should be excluded from the composition prior to commencement of the cure process to avoid premature curing (gelling).

The curing reaction may be accelerated by the application of heat, for example, by heating in an oven at temperatures up to a maximum of about 140oC. The curing process is preferably undertaken at temperatures of from

50 C to 120oC, temperatures from 60 C to 100oC being most preferred. Heating time is temperature and air-velocity dependent and the coating will reach tack free time in between one second and ten minutes depending on drying conditions. The heating step serves to evaporate the solvent, and accelerate the condensation reaction.

The composition may alternatively be used as a laminate adhesive, i. e. the composition may be applied to form a layer on a first substrate, partially cured and laminated to another substrate before complete drying. The composition in accordance with the invention may be applied as a coating or as an adhesive to a variety of substrates used in various applications, including laminated films for the packaging of food and non-food products and as barrier layers on a wide variety of packaging containers, such as pouches, tubes, bottles, vials, bag-in-boxes, stand-up pouches, gable top cartons, thermo-formed trays, brick-packs, boxes, cigarette packs and the like.

Of course, the present invention is not limited to just packaging applications, and may be used in any application wherein gas, or aroma barrier properties are desired, for example, in tires and buoyancy aids.

One major advantage of the present invention over recent prior art is that no ionising radiation, such as electron beam or ultra violet radiation is required to cure the layer.

In order that the invention may become clearer there now follows a detailed description of several coatings prepared in accordance with the present invention. Examples Example 1 The barrier results disclosed in Examples 1 to 6 were obtained using the following test method for analysis of ethyl acetate: The data was generated using a modification of ASTM standard E 96 recommended for the measure of water vapour transmission of materials. Test dishes having a mouth diameter of 35.68 mm (area 10 cm2) were used, and a minimum of 2 film samples were tested at the same time to determine reproducibility. Each dish was filled with 1 (+/-) 0.3 g of ethyl acetate, covered with the coated film, or laminate sample, sealed with Dow Corning High Vacuum silicone grease and lids were screwed tightly in order to prevent the escape of ethyl acetate other than through the coated film or laminate. The Weight of each sealed test dish containing ethyl acetate was recorded at the start of the test and thereafter is recorded every 24 hours until a constant weight loss was obtained.

The aroma barrier values for each film are given in units of grams of ethyl acetate lost per square meter of film within a 24 hours period (g/m2. d).

Example 1 is a comparative example identifying the results of the above test on a variety of uncoated substrates for comparative purposes with subsequent examples 3 to 5. All subsequent tests were carried out on a low density polyethylene (LDPE). Table 1. Uncoated Low Density Polyethylene (LDPE)

Substrate Thickness Ethyl Acetate (urn) Transmission Rate (EATR) (g/m2. d) Low density polyethylene (LDPE) 30 700 Example 2 In this example, the first in accordance with the invention, an amino-functional cyclic siloxane having the following repeating units:

which will henceforth be referred to as ACS was reacted with a number of epoxysilanes in isopropanol (IPA).

Example 2a) A solution was prepared by dissolving 30g of ACS in 93 g of HPLC grade isopropanol obtained from Aldrich. 10 g of

glycidoxypropyltrimethoxysilane (GPTMS) was added and the solution was stirred for 24 H. at room temperature to complete reaction.

Example 2b) A solution was prepared by dissolving 70 g of ACS in 275 g of HPLC grade isopropanol obtained from Aldrich. 48 g of epoxycyclohexylethyltrimethoxysilane (A-186 obtained from Witco) were added and the solution was stirred for 24 H. at room temperature to complete reaction.

In each case the resulting composition was either coated onto an LDPE sample to form a layer thereon and the layer was subsequently cured or was used as a laminate adhesive. Specific examples of the processes used to prepare the composition of the present invention used when using the composition as a laminating adhesive is described below: The composition was coated onto a freshly corona treated polyethylene film, using a &num;3 (green) meter bar obtained from RK. The coating was dried for 30 minutes before laminating to a second layer of freshly corona treated polyethylene. Lamination of this structure was done at a temperature of 60 C and nip pressure of 1. 17x10' kgm (40 psi), using a bench-top heated roll laminator from Chemsultants International Network.

The results for the above example and a number of other similarly prepared samples give excellent EATR results and are shown below in Table 3, wherein the figures within brackets refer to the mixing ratios, by weight, of the reaction ingredients and all compositions were made up in 30% solutions of isopropanol:

Table 2. Examples of an epoxysilane modified Cyclic Aminosiloxane (ACS) Reaction Product

Compositions EATR (g/m2. d) ACS/GPTMS (4: 3) 65 ACS/GPTMS (6: 1) 11 ACS/GPTMS (3: 1) 11 ACS/GPTMS (1: 1. 4) 8 ACS/A-186 (6: 1) 60 ACS/A-186 (3: 1) 57 ACS/A-186 (7: 4. 8) 5 Example 3 The result in the following example was achieved using the same ingredients and processes as described in Example 3 above with the exception of the fact that the reactive silane used was a thiocyanopropyltrimethoxysilane obtained from Aldrich (TCPTMS). The figures in the brackets refer to the mixing ratios, by weight, of the reaction ingredients.

Table 3. Example of Thiocyanopropyl Functional Silane modified Cyclic Aminosiloxane Reaction Products

Composition EATR (g/m2d) ACS/TCPTMS (7: 5) 94 Example 4 The result in the following example was achieved using the same ingredients as described in Example 3 above with the exception of the fact that the reactive silane used was chloropropyltrimethoxysilane (CPTMS). The method for

preparing the composition in this instance involved an additional step in that, the reaction product was neutralised before use as described the example below: A composition was prepared by dissolving 30 g of ACS in 86 g of HPLC grade isopropanol obtained from Aldrich. 10 g of chloropropyltrimethoxysilane (CPTMS) were added and the solution was heated to reflux for 24 H. to complete reaction. This solution was then neutralised with 9 g of 30% sodium methoxide solution in methanol and the resulting sodium chloride precipitate was filtered. Table 4. Chloropropyl Functional Silane modified Cyclic Aminosiloxane Reaction Product

Composition EATR (g/m2. d) Neutralised ACS/CPTMS (3: 1), 36 Example 5 This example is a comparative example with respect to a selection of reaction products based on reactive silanes and linear aminosiloxanes as opposed to the cyclic compounds previously exemplified. In each instance compositions were prepared using the methods described in Example 3. It will be noted that the results are comparative with the polyurethane adhesive of example 2 but as a group are significantly poorer than results produced when using the cyclic aminosiloxanes of the present invention. Table 5. Epoxy Functional Silane modified Linear Aminosiloxanes

Examples EATR (g/m2. d) di (aminopropyl) tetramethyldisiloxane 183 (DAPTMDS)/GPTMS (3.4 : 4.6) DAPTMDS/GPTMS (2 : 3) 164 DAPTMDS/A-186 (2: 3) 190 (dimethyl), (aminoethylaminoisobutyl, 251 methyl) siloxane (DMAEAIMS)/GPTMS (3: 1) DMAEAIMS/A-186 (1 : 1) 247

Claims

CLAIMS 1) A barrier coating composition comprising the reaction product of an amino-functional cyclic siloxane

comprising units of the formula [RSiO2/2], wherein each R1 may be the same or different and may be selected from the group consisting of: an alkyl, a substituted alkyl, an amine, an aryl, a substituted aryl, an arylalkyl and an alkylaryl group, each of which having from 1 to 18 carbon atoms, and a reactive silane or a

mixture of reactive silanes of the formula : (R n (R3) 3-n SiX wherein each R4 group is the same or different and represents a radical selected from the group consisting of an alkyl group having from 1 to 4 carbon atoms and an acyl group (RC (O)-) having from 1 to 4 carbon atoms, each Rs group is the same or different and represents a hydrocarbon group with from 1 to 8 carbon atoms, X represents an organic radical having at least one functional unit selected from the group of an epoxide, an alkenyl, an aldehyde, an episulphide, an acrylate, a methacrylate, an acrylamide, a methacrylamide, an isocyanate, an isothiocyanate, a halogen atom and an acid chloride and n is 1,2 or 3; in a non-aqueous solvent.
2) A barrier coating composition in accordance with claim 1 wherein about 50% of R1 groups comprise a substituted alkyl group having one or more primary and/or secondary and/or tertiary amines and the remaining R1 groups comprise alkyl groups having from 1 to 4 carbon atoms.
3) A barrier coating composition in accordance with claim 2 wherein the amino R1 group has the formula: - (CH2) mCH (R6) N (H) (R8) (NHR7) qNH2 wherein R6 is hydrogen or an alkyl group with 1 to 4 carbon atoms and R7 is an alkylene or substituted alkylene group and R8 is an alkylene group having from 1 to 8 carbon atoms; m is 0 to 8 and q is from 0 to 20.
4) A barrier coating composition in accordance with claim

3 wherein the amino R1 group has the formula :

- (CH2) 2-CH-NH- (CH2) 2-NH2 CH3
5) A barrier coating composition in accordance with any preceding claim wherein the amino functional cyclic siloxane has a molecular weight in the range of from about 600 to 25,000.
6) A barrier coating composition in accordance with any preceding claim wherein the reactive silane is selected from the group consisting of gamma acryloxypropyltrimethoxysilane, gamma methacryloxypropyltrimethoxysilane, gamma glycidoxypropyltrimethoxysilane, gamma glycidoxypropyltriethoxysilane, chloropropyltrimethoxysilane, chloropropyltriethoxysilane, chloropropylmethyldimethoxysilane, chloropropylethyldimethoxysilane, epoxycyclohexylethyltrimethoxysilane, gamma trimethoxysilylpropylglycidyl ether, glycidoxypropylmethyldimethoxysilane, vinyltriethoxysilane, vinyltrimethoxysilane, gamma isocyanatopropyltriethoxysilane and thiocyanopropyltrimethoxysilane.
7) A barrier coating composition in accordance with any preceding claim wherein the solvent is an alcohol.
8) The barrier coating composition in accordance with any preceding claim further comprising an additional cross linker selected from a further silane as described in claim 1, multifunctional acrylates, methacrylates, epoxides, isocyanates, thiocyanates, acid halides, acid anhydrides, esters, alkyl halides and aldehydes, and combinations thereof.
9) A barrier coating composition in accordance with any preceding claim wherein the composition further consists of an additive selected from the group consisting of anti-block and slip aids, polar additives, an acrylate or methacrylate, glycidyl methacrylate, glycidol, ethylene glycol diglycidylether, bisphenol A, diglycidylether and wetting agents.
10) A process for treating a surface of a substrate with a composition in accordance with any preceding claim comprising applying the composition on to the substrate to form a layer and curing the layer by exposure to moisture.
11) A process in accordance with claim 10, wherein the coated composition is disposed on one or more additional substrates to form a laminate.
12) A process in accordance with either claim 10 or 11 wherein the substrate is selected from the group consisting of polyolefins, including oriented polypropylene (OPP), cast polypropylene, polyethylene and polyethylene copolymer; polystyrene ; polyesters, including polyethylene terephthalate (PET), or polyethylene naphthalate (PEN); polyolefin copolymers, including ethylene vinyl acetate, ethylene acrylic acid and ethylene vinyl alcohol (EVOH), polyvinylalcohol and copolymers thereof; polyamides, including nylon, and MXD6; polyimides; polyacrylonitrile; polyvinylchloride; polyvinyl dichloride; polyvinylidene chloride; polyacrylates; ionomers; polysaccharides, including regenerated cellulose; silicone, including rubbers or sealants; natural or synthetic rubbers; glassine or clay coated paper; paper board; craft paper; and metallised films and vapor deposited metal oxide coated polymer films, including Aloe, Sioux, or TiOx.
13) A process in accordance with any one of claims 10 tol2 wherein prior to applying the composition the substrate is coated with a primer.
14) A process in accordance with any one of claims 10 to 13 wherein the layer is cured at a temperature of from 60 to 110oC upon exposure to moisture.
15) A coated substrate obtainable by the process in accordance with any one of claims 10 to 14.
16) Use of a composition in accordance with any one of claims 1 to 9 as a gas, aroma and/or flavour barrier coating for packaging.

16) Use of a composition in accordance with any one of claims 1 to 9 as a gas, aroma and/or flavour barrier coating for packaging. Amendments to the claims have been filed as follows 1) A barrier coating composition comprising the reaction product of an amino-functional cyclic siloxane

comprising units of the formula [R12SiO2/2], wherein each R1 may be the same or different and may be selected from the group consisting of: an alkyl, a substituted alkyl, an amine, an aryl, a substituted aryl, an arylalkyl and an alkylaryl group, each of which having from 1 to 18 carbon atoms, and a reactive silane or a mixture of reactive silanes of the formula:

2 3 (R20) n (R) 3-n Six wherein each R2 group is the same or different and represents a radical selected from the group consisting of an alkyl group having from 1 to 4 carbon atoms and an acyl group (RC (O)-) having from 1 to 4 carbon atoms, each R3 group is the same or different and represents a hydrocarbon group with from 1 to 8 carbon atoms, X represents an organic radical having at least one functional unit selected from the group of an epoxide, an alkenyl, an aldehyde, an episulphide, an acrylate, a methacrylate, an acrylamide, a methacrylamide, an isocyanate, an isothiocyanate, a halogen atom and an acid chloride and n is 1,2 or 3; in a non-aqueous solvent.

2) A barrier coating composition in accordance with claim 1 wherein about 50% of Ri groups comprise a substituted alkyl group having one or more primary and/or secondary and/or tertiary amines and the remaining Ru groups comprise alkyl groups having from 1 to 4 carbon atoms. 3) A barrier coating composition in accordance with claim

2 wherein the amino R1 group has the formula : - (CH2) mCH (R6) N (H) (R8) (NHRqNHz wherein R6 is hydrogen or an alkyl group with 1 to 4 carbon atoms and R7 is an alkylene or substituted alkylene group and R8 is an alkylene group having from 1 to 8 carbon atoms; m is 0 to 8 and q is from 0 to 20.

4) A barrier coating composition in accordance with claim

3 wherein the amino R1 group has the formula :

- (CH2) 2-CH-NH- (CH2) 2-NH2 \ CH3

5) A barrier coating composition in accordance with any preceding claim wherein the amino functional cyclic siloxane has a molecular weight in the range of from about 600 to 25,000.

6) A barrier coating composition in accordance with any preceding claim wherein the reactive silane is selected from the group consisting of gamma acryloxypropyltrimethoxysilane, gamma methacryloxypropyltrimethoxysilane, gamma glycidoxypropyltrimethoxysilane, gamma glycidoxypropyltriethoxysilane, chloropropyltrimethoxysilane, chloropropyltriethoxysilane, chloropropylmethyldimethoxysilane, chloropropylethyldimethoxysilane, epoxycyclohexylethyltrimethoxysilane, gamma trimethoxysilylpropylglycidyl ether, glycidoxypropylmethyldimethoxysilane, vinyltriethoxysilane, vinyltrimethoxysilane, gamma isocyanatopropyltriethoxysilane and thiocyanopropyltrimethoxysilane.

7) A barrier coating composition in accordance with any preceding claim wherein the solvent is an alcohol.

8) The barrier coating composition in accordance with any preceding claim further comprising an additional cross linker selected from a further silane as described in claim 1, multifunctional acrylates, methacrylates, epoxides, isocyanates, thiocyanates, acid halides, acid anhydrides, esters, alkyl halides and aldehydes, and combinations thereof.

9) A barrier coating composition in accordance with any preceding claim wherein the composition further consists of an additive selected from the group consisting of anti-block and slip aids, polar additives, an acrylate or methacrylate, glycidyl methacrylate, glycidol, ethylene glycol diglycidylether, bisphenol A, diglycidylether and wetting agents.

10) A process for treating a surface of a substrate with a composition in accordance with any preceding claim comprising applying the composition on to the substrate to form a layer and curing the layer by exposure to moisture.

11) A process in accordance with claim 10, wherein the coated composition is disposed on one or more additional substrates to form a laminate.

12) A process in accordance with either claim 10 or 11 wherein the substrate is selected from the group consisting of polyolefins, including oriented polypropylene (OPP), cast polypropylene, polyethylene and polyethylene copolymer; polystyrene; polyesters, including polyethylene terephthalate (PET), or polyethylene naphthalate (PEN); polyolefin copolymers, including ethylene vinyl acetate, ethylene acrylic acid and ethylene vinyl alcohol (EVOH), polyvinylalcohol and copolymers thereof; polyamides, including nylon, and MXD6; polyimides; polyacrylonitrile ; polyvinylchloride; polyvinyl dichloride; polyvinylidene chloride; polyacrylates; ionomers ; polysaccharides, including regenerated cellulose; silicone, including rubbers or sealants; natural or synthetic rubbers; glassine or clay coated paper; paper board ; craft paper; and metallised films and vapor deposited metal oxide coated polymer films, including AlOx, Sioux, or TiOx.

13) A process in accordance with any one of claims 10 tol2 wherein prior to applying the composition the substrate is coated with a primer.

14) A process in accordance with any one of claims 10 to 13 wherein the layer is cured at a temperature of from 60 to 110oC upon exposure to moisture.

15) A coated substrate obtainable by the process in accordance with any one of claims 10 to 14.