This invention relates to chemical compositions and in particular to silane-modified polymer containing compositions, e.g. coating and adhesive compositions.

Silane-grafted polymers have been widely suggested for use in the preparation of cable-jacketing, wire insulation, piping and liquid containers, and more recently they have been suggested for use in adhesive compositions.

The production of silane-grafted polymers is discussed in many publications, for example US-A-3646155, GB-A-1286460, GB-A-1347426, GB-A- 1406680, GB-A-1450934, GB-A-1542543 and GB-A-2197326.

Thus US-A-3646155 for example describes the production of such materials by the reaction of a polymer (e.g. polyethylene) with an unsaturated silane (e.g. vinyl triethoxy silane) in the presence of an initiator (e.g. a peroxide). A silanol condensation catalyst, e.g. dibutyl tin dilaurate, is incorporated into the grafted polymer and catalysed hydrolysis and cross-linking of the silane groups occurs to yield a cured end product. The reaction procedure may be represented as follows:

(A) Grafting

-(CH ₂ CH ₂ CH ₂ CH ₂ CH ₂ ) - + CH ₂ =CH.Si(OC^) ₃

peroxide -(CH2CH2CjHCH2CH ₀ 2)a-

C CHH ₂₂ CCHH ₂₂ SSii((0OCC ₂ H ₅ ) ₃ silane graft polymer

(B) Hydrolysis

-(CH ₂ CH ₂ CHCH ₂ CH ₂ ) _a - + 3 H _j O CH ₂ CH ₂ Si(OC ₂ H ₅ ) ₃

■> - CH ₂ CH ₂ CHCH ₂ CH ₂ ) _a - + 3 C ₂ H ₅ OH

CH ₂ CH ₂ Si (OH) ₃ (C) Cross-linking

- CH ₂ CH ₂ CHCH ₂ CH ₂ ) - - (CH ₂ CH ₂ CHCH ₂ CH ₂ )

- CH ₂ CH

The product of stage (A) above may also be produced by copolymerisation of ethylene with a suitable trialkoxysilyl monomer, e.g. 4-(trialkoxy- silγl)-but-l-ene. References hereinafter to silane- grafted or silane-modified polymers include such silane side chain materials produced by copolymerisation, which are indistinguishable from the materials produced by grafting.

The grafted but uncrosslinked polymers may be used as the basis for coating, adhesive or other compositions containing further ingredients such as organic fillers (which terms is also used herein to denote organic diluents and viscosity or tack modifiers and other organic components which serve

to fill out the cross-linked lattice of the cured composition) , inorganic fillers, colorants and plasticizers.

The present invention is based on the recognition that by using as such a further ingredient a material which contain groups which condense with silanols, the ingredient may be bound onto the modified polymer and, where it is polyfunctional, i.e. contains more ^" than one such reactive group per molecule, it may bind to two or more silanol groups and so be incorporated as part of the cross-linking lattice thereby modifying the physical properties and especially the temperature stability, flexibility, etc. of the cured composition. However even where such further ingredients are only monofunctional they may bond to the silane- modified polymer so reducing any undesirable tendency to leach out of the cured composition even under the adverse conditions - while many such further ingredients are relatively inert, their loss from composition after cross-linking has occurred may nonetheless adversely affect the physical properties, e.g. adhesion bond strength, flexibility, shrinkage and impact resistance, of the cured composition or may cause corrosion, discoloring or other damage to substrates which are in contact with the cured compositions; these effects will be particularly important where the composition is functioning as an adhesive or coating composition.

The present invention is thus based on the recognition that by utilizing as one or more such further components an organic material carrying silanol, alcohol, thiol or primary or secondary amino groups the component may be particularly effectively incorporated in the cross-linked structure of the cured composition as it is able to bond to the modified polymer when silanol formation occurs on hydrolysis of the silane- grafted but uncross-linked polymer.

Thus in one aspect the present invention provides a composition containing a silane modified, including silane-graf ed, polymer (hereinafter collectively SGP) further containing at least one organic filler, colorant or plasticizer compound which contains at least one and preferably a plurality of alcohol, thiol, silanol, primary amine or secondary amine groups.

In the compositions of the invention, which may for example be moulding compositions but preferably are adhesive or coating compositions (e.g. paint and other surface coating, jacketing or insulating compositions) , the organic filler conveniently is a wax or a polymeric filler, diluent or tack or viscosity modifier. The filler, colorant or plasticizer conveniently is a compound containing one or more alcohol groups.

Conventional alcohol, thiol, silanol or amine group containing compounds or compounds chemically modified to introduce alcohol, thiol, silanol or amine groups may be used as the filler, colorant or plasticizer compounds in the compositions of the invention. The compounds may be monofunctional but most preferably are polyfunctional as they may then take part in rather than hinder the cross- linking reaction. Particular mention in this regard may made of glycerol esters (for example glycerol esters of resins, e.g. Foral 85 available from Hercules) , glycol monoesters, polyols (e.g. diols and polyethylene glycols) , polyamines, 'OH' waxes (i.e. hydroxylated waxes e.g. Polywax OH alcohols available from Petrolite) ,

The alcohol, thiol, silanol and amine groups on the filler, colorant or plasticizer remain unreactive towards the silane groups until silane hydrolysis occurs and thus the properties of the uncured composition are not adversely affected by the filler, colorant or plasticizer. However when silane hydrolysis

occurs during curing the filler, colorant or plasticizer may then, if polyfunctional, react to produce a bridge between silanol groups so becoming incorporated into the cross-linking lattice, and if monofunctional the filler, colorant or plasticizer will bind to a silanol group on the silane modified polymer thereby hindering or preventing any subsequent leaching out and so avoiding the undesired effects of such leaching.

Migration of plasticizers from coating or adhesive compositions into polymeric substrates coated or adhered by such compositions, with consequent undesired modification of the rigidity of the substrate may particularly conveniently be reduced by the use of compositions according to the present invention containing plasticizers having alcohol, thiol or amine groups. Similarly, discoloration or chemical damage to porous or sensitive substrates may readily be reduced by the use of coating or adhesive compositions according to the invention in which in place of organic fillers or colorants which may cause such damage are used compounds having alcohol, thiol or amine groups.

The concentration of the alcohol, thiol, silanol or amine group containing compounds within the compositions of the invention will generally be within the ranges conventional for organic fillers, colorants and plasticizers in such compositions; the precise figures will of course depend on the nature of the particular component, and the properties desired for the cured and/or uncured composition. Generally however alcohol, thiol, silanol or amine group containing components will make up from 0.1 to 80%, preferably 1 to 40% and especially preferably 10-20% of the total composition.

The SGP, which conveniently constitutes up to 99.9%, preferably 10 to 50%, and especially preferably about 30% of the composition, may be

the product of the silane-grafting of a single homo- or copolymer or it may be a blend of two or more different homo- and/or copolymers or of ho o-and/or copolymers having molecular weights in two or more ranges. By suitable choice of the monomer/co onomer make up, of the molecular weights, and of the relative proportions of the polymers to be silane-grafted, the properties of the compositions of the invention may be selected to match the desired end use, e.g. by the use of polymers deriving from polar comonomers adhesion of the compositions to polar substrates such as glass, wood or metal may be enhanced. Thus, by blending polymers having different pre silane grafting MFIs and indeed by blending grafted polymers having different monomer make-ups (e.g. by blending silane-modified polypropylene with silane-modified polyethylene) , the performance profile of the final composition, for example in terms of wetting, strength, adhesion, flexibility, and ease of application, may be adjusted to suit its intended end use.

Thus in one embodiment the adhesive composition of the invention contains a blend of silane-grafted polymers for at least one of which the polymer has an MFI before silane grafting in the range 1 to 150, preferably 1 to 80, preferably 2-20, and for at least one other of which the polymer has an MFI before silane grafting in the range 150-2500, preferably 200-800.

It will be realized that where the silane- grafted polymer is a blend, silane-grafting can be effected on a blend of polymers or two or more silane-grafted polymers can be blended after grafting. Where a blend is used, the silane grafts may be the same or different, although for ease of post- blending grafting it will generally be preferred that the silane grafts be identical.

In general, the silane modified polymers which may be used in the compositions of the invention will preferably be silane-modified olefin, and especially C, _g α-olefin, homo- or copolymers, e.g. polyethylene, polypropylene, polybutylene, ethylene-propylene, EPDM (unsaturated ethylene- propylene terpolymer) ethylene-hex-1-ene, styrene- ethylene-butylene-styrene (SEBS) , ethylene-vinyl esters (e.g. ethylene-vinyl acetate (EVA)), ethylene- (meth)acrylic acid esters (especially ethylene- (C, . alkyl) (meth)acrylates (e.g. ethylene-ethyl acrylate (EEA) , ethylene-methyl acrylate (EMA) and ethylene-butyl acrylate (EBA) ) .

The silane side chains on the polymers are conveniently of general formula (I)

wherein A represents an optionally substituted divalent organic radical, preferably an optionally substituted alkylene, alkyleneoxy, alkylene-phenylene, or alkylene-oxy-alkylene chain; X represents a leaving group displaceable by hydrolysis, conveniently a halogen atom (e.g. chlorine) or a group R O-or

R COO- where R is a C ₁ _ _1Q , preferably C- ,, alkyl or alkoxyalkyl group; is 1, 2 or 3, preferably

2 or 3; and R represents a blocking group not displaceable by hydrolysis, for example a C, . alkyl group.

As mentioned above, the silane side chains may be present in a monomer which is compolymerised to produce the SGP. However the SGP component for inclusion in the compositions of the invention may also be prepared by reacting the polymer (or blend thereof) with an unsaturated silane of formula II

A ¹ -Si(R) J— _m mm _m m (ID

(where A represents an ethylenically unsaturated organic group corresponding to the divalent group A in formula I and R, m and X are as defined above) in the presence of a catalyst, conveniently a peroxide catalyst, for example using the reagents and conditions specified in the literature.

I Inn ffoorrmmuullaa III, A conveniently represents a group of formula

CH ₂ = | ₂ -<*

2 where p is 0 or 1; R represents hydrogen or C, ₄ alkyl; and R 3 represents a straight, branched or cyclic alkylene group, a phenylene group, a carbonyloxy group, a carbonyloxy alkylene) group, a (C, , _Q alkylene)carbonyloxy group or a

(C,_, _Q alkylene)carbonyloxy(C, , _Q alkylene) group, optionally carrying pendant glycidoxy groups.

Such compounds are described by Dart Industries in GB-A-1347426.

Particularly preferably however A represents a C ₂ _ ₅ monoalkenyl group, such as vinyl or allyl, or a (C ₂ _ ₃ alkenyl)carbonyloxy (C ₂ _ ₃ alkylene) group, such as a gammamethacryloxy-propyl group, and particularly preferred unsaturated silanes of formula II include vinyl trimethoxy silane, vinyl triethoxy silane and gamma-methacryloxy- propyl trimethoxy silane. unsaturated silanes of formula II are known or may be prepared by conventional methods.

The silane side chain need only constitute a minor part by weight of the SGP, e.g. up to 20%, generally 0.1-10%, preferably 0.5 to 6% and especially preferably about 2-4%, and the ratio of unsaturated silane to polymer used in the grafting reaction should be chosen accordingly, or alternatively the weight ratio of monomers where copolymerisation is used.

The catalyst used in the preparation of the SGPs is preferably a free-radical generating compound such as for example benzoyl peroxide, dicumyl peroxide or other such catalysts referred to by US-A-3646155. The free radical generator may conveniently be used in a concentration of about 0.01 to 3% relative to the weight of polymer used.

The silane grafting reaction is conveniently effected at a temperature of at least 140°C, preferably between 150°C and 250°C and may be performed in conventional apparatus such as a Ko-Kneader.

In the compositions of the invention, SGPs having a 3-membered or longer chain linking the silicon atoms with the polymer backbone will result after curing in a material having a generally more open structure than that achieved with only a 2- membered linking chain. The open structure may advantageously permit both a high degree of curing and the inclusion of relatively high concentrations of organic filler (e.g. tackifying resin) and other components in the uncured composition. In this way, the viscosity, tack and melting characteristics of the uncured composition may be tailored to particular desired levels, for example to permit the compositions to be used with of conventional melting, mixing and application apparatus.

As the catalyst for the SGP hydrolysis and cross-linking, a silanol condensation catalyst may be used. Many such materials are known to the art. Thus suitable catalysts include, for example, metal carboxylates, e.g. dibutyl tin dilaurate, organometallics, e.g. tetrabutyl titanate, organic bases, e.g. ethylamine, and mineral and fatty acids. Several such compounds are identified for example in US-A-3646155. Among suitable condensation catalysts, organotin compounds, such as dibutyl tin dilaurate are preferred. The catalyst, conveniently makes up from 0.005-0.2%, preferably about 0.02%, of the adhesive composition as a whole.

The nature and content of any further components in the composition of the invention will depend upon the intended end use of the composition. Thus for example where the composition is to be used as a hot melt adhesive it may contain conventional hot melt adhesive components (such as antioxidants, diluents, fillers, colorants, and tack and viscosity modifiers) in conventional or near conventional concentrations. Further discussion herein of compositions according to the invention will for the most part be in respect of adhesive compositions: it is however to be understood that the compositions of the invention may take other forms, e.g. coating or moulding compositions, and in these forms may contain components conventional to such forms in concentrations conventional or near conventional to such forms.

Where the composition is a hot melt adhesive composition it may contain as a tackifying resin component any suitable resin or resin mixture, for example those conventional for hot melt adhesives. The resin or resin mixture should however be selected to achieve the desired balance between compatibility with the SGP and the other components of the adhesive, the melt flow properties of the adhesive as a whole and the specific adhesion to the substrates intended to be bonded with the adhesive. In this respect, suitable tackifying resins may include: aromatic modified resins such as α-methyl styrene homopolymers or copolymers, e.g. Krystalex F100 (α-methyl styrene polymer) , Krystalex FR75 (a modified α-methyl styrene copoly er) or Piccotex (a vinyl toluene- α-methyl styrene copolymer) , all three available from Hercules Chemical Co. ; aliphatic petroleum hydrocarbon resins; styrene-modified hydrocarbon resins; and, particularly preferably, alicyclic hydrocarbon resins, e.g. Escorez 5300 (available from Exxon) .

The tackifying resin will conveniently make up from 5 to 40%, preferably 10-40%, and especially preferably about 30%-35%, of the adhesive.

Hot melt adhesive compositions according to the invention preferably contain at least one antioxidant. In this respect, conventional adhesives antioxidants, such as butylated hydroxytoluene (BHT) may be used. A preferred antioxidant is pentaerythritol-tetrakis-3-(3,5-di-tert.butyl-4- hydroxyphenyD-propionate, which is available under the trade name Irganox 1010 from Ciba-Geigy UK Ltd. of Manchester. The antioxidant will generally be present in the adhesive at about 0.1-2.5%, preferably 0.5-1%.

An SGP based adhesive system may if desired be formulated as two compositions which are not mixed until the adhesive is melted for application so as to avoid earlier contact between the SGP and the condensation catalyst. Thus according to a further aspect of the invention we provide a hot melt adhesive system comprising a first composition comprising at least one SGP as defined above and a second composition comprising a catalyst for the condensation of said SGP, wherein at least one of said first and second compositions contains an organic filler, colorant or plasticizer compound containing an alcohol, thiol, silanol, primary amine or secondary amine group, and wherein said first and second compositions are packed in separate containers.

The adhesive composition of the invention preferably also comprises a further polymer or polymer mixture. The further polymer or polymer mixture will be selected to achieve, inter alia, a balance between compatability with the catalyst and the other components of the adhesive and the viscosity and tack characteristics of the adhesive. Where the SGP is based on a (co)polymer deriving

from polar (co) onomers, the further polymers are preferably selected from compatible (co)polymers also deriving from polar (co)monomers, e.g. ethylene copolymers such as EVA, ethylene-methyl acrylate (EMA) , ethylene-ethyl acrylate (EEA) and ethylene butyl acrylate (EBA) , conveniently copolymers having polar comonomer residue contents of 12-40%, preferably 18-35% and especially preferably about 28% and MFIs of 1 to 2500, conveniently 5-800, preferably 20-500 and most preferably 150-400. Where the SGP is based on an polymer deriving from apolar monomers, the further polymers are preferably selected from homo- and polymers of apolar monomers, such as for example polythene, polypropylene, polybutylene, and SEBS, (for example low crystallinity range molecular weight homo-or copolymers, such as that available under the trade name Vestoplast 608 from Huls (UK) Limited of Manchester) , or low molecular weight polyethylene, such as polyethylene ACS or AC8 available from Allied Chemical Corporation International NV SA of Birmingham. Conveniently polymers having MFIs of 1 to 2500, conveniently 5-800, preferably 20-500 and most preferably 150- 400 are used. The further polymer conveniently constitutes up to 15%, preferably 1 to 10%, and especially preferably about 5%, of the adhesive of the invention and generally will be present at about half the concentration of the SGP.

The adhesive composition or system may also contain further components such as diluents or modifiers, conveniently as about 5-40%, preferably about 30%, of the total adhesive. These components may serve to regulate the viscosity, and setting speed of the adhesive and may be included to enhance the wicking of the adhesive into the substrates to be bonded. In this respect, conventional diluents and modifiers for hot melt adhesives, such as waxes (e.g. petroleum waxes such as paraffin waxes or

microcrystalline waxes such as Okerin 8981 from Astor Chemicals of West Drayton, Middlesex) , low molecular weight polyethylene, atactic polypropylene, hydrogenated animal or vegetable fats (e.g. hydrogenated castor oil or hydrogenated tallow) , and synthetic waxes, such as Fischer Tropsch waxes may be used.

Where waxes or low molecular weight polyethylenes are used as diluents, they should conveniently have softening temperatures in the range of 50- 120°C. Microcrystalline waxes. Fisher Tropsch waxes and paraffin waxes having softening temperatures in the ranges 65 to 94°C (e.g. 79°C) , 110 to 120°C and 54 to 72°C respectively are particularly suitable. A mixture of low molecular weight polyethylene, such as polyethylene AC6 or AC8, and a microcrystalline wax having a softening temperature of about 90°C, such as Micro 549 available from Holmes Chemical Company of Uxbridge, may also be particularly suitable, especially where the polyethylene and the wax constitute about 5 and about 15% by weight respectively of the adhesive.

Where the adhesive is formulated as a two part system, the SGP and the catalyst being separately packaged, the other components can appear in one or both of the separate compositions; the SGP-containing composition will however preferably contain the antioxidant and the tackifier and the catalyst- containing composition will preferably contain a further polymer; the plasticizers, diluents and modifiers may be in either or both compositions. In a two composition system, the catalyst containing composition particularly conveniently comprises about 99% of a polymer compatible with the SGP (e.g. EVA, EMA, EEA, EBA, polyethylene, polypropylene or SEBS) and 1% of a catalyst (e.g. dibutyl tin dilaurate) .

Where the adhesive of the invention is formulated as a single composition it will advantageously

be packaged in water-tight containers, for example aluminium cartridges, which containers advantageously will also include a desiccant, for example a sachet of silica gel at the end of a cartridge for a hot melt adhesive applicator. Thus, according to a further aspect of the invention we provide a hot- melt adhesive applicator cartridge comprising a water-tight container containing therein a desiccant and a hot-melt adhesive composition, said composition comprising an SGP as hereinbefore defined, a catalyst for the condensation thereof and at least one organic filler, colorant or plasticizer compound containing an alcohol, thiol, primary amine or secondary amine group.

Besides the components discussed above, it may be desirable to incorporate into the hot melt adhesive an inorganic colouring agent, for example a whitener such as titanium dioxide. Such colouring agents are particularly readily dispersed within the hot melt adhesive if introduced as solid dispersions in an polymer compatible with the SGP.

In use, the adhesive composition of the present invention will be heated to melting, generally to 100-200°C preferably about 110-170°C, mixed (e.g. in a cartridge loaded applicator or by the mixing in a mixer head of the two compositions of a two composition system) and applied to the substrates to be bonded, generally in a film thickness of up to about 3 mm, preferably up to about 1 mm, although this can be achieved by applying a larger amount and scraping off the excess. The adhesive characteristics of the system should be sufficient to maintain a bond between the substrates while the curing of the SGP component by hydrolysis and cross-linking occurs.

For the hydrolysis of the SGP, water is required. In general, the necessary water can be supplied by ambient moisture. However, if desired, the

adhesive may contain further components which gradually release moisture into the system, for example fillers with surface-bound moisture or moisture filled polymer microspheres such as those sold as paint opacifiers by Rohm and Haas Company under the trade name ROPAQUE OP-62 (see EP-A-119054 of Rohm and Haas) .

The adhesive of the invention may be used in most applications where hot melt adhesives have been used and where full bonding strength is not required immediately after the application of the adhesive. The adhesive of the invention is thus particularly suited to use in product assembly (for example in the furniture and automobile industries) , packaging and labelling.

Because of the silane cross-linking reaction, the compositions of the invention are capable of chemically bonding to the surfaces or many substrates. Thus the compositions of the present invention are particularly suitable for bonding to or coating of cellulosic and silicaceous substrates, for example paper and glass.

By the use according to the invention of plasticizers capable of reacting with silanol groups on the grafted polymer it may also be possible to produce compositions, especially moulding, jacketting or insulating compositions, which may be processed at lower temperatures than would be possible in the absence of a plasticizer. This is of particular interest for compositions which also contain moisture releasing components as by the use of lower processing temperatures premature moisture release can be reduced.

The SGP and catalyst components in the compositions of the present invention may be selected to achieve particular desired characteristics, for example rate or controlability of curing, and by varying the monomer make-up and the MFI of the polymer

precursor for the SGP, and by utilizing blends of SGPs, the formulation characteristics (such as viscosity, softening point, wetting ability, etc.), for the compositions may be controlled to give a readily processable material.

The following Examples are provided to illustrate the present invention further without limiting the scope of protection sought therefor (all percentages and parts referred to herein are by weight unless otherwise specified) :

Example 1

One part adhesive composition

The composition is the admixture of the following components:

SGEVA ⁺ 31.3% Catalyst/EVA blend (1% dibutyl tin dilaurate) 1.7%

Irganox 1010 (antioxidant) 1.0% Escorez 5300 (hydrogenated alicyclic hydrocarbon - tackifying resin) 26.0% Piccotex 100 (α-methyl styrene-vinyl toluene copolymer - tackifying resin) 10.0%

Hyvis 30 (polybutene - plasticizer) 20.0%

Polyethylene glycol PEG 400 10.0%

+ The SGEVA is the reaction product of vinyltrimethoxy- silane and a blend of EVAs having a total VA content of 28% and an MFI of 40, prepared with a silane content of about 2-3% using the procedure of US- A-3646155.

The composition is homogenized prior to the addition of the catalyst. The catalyst is then mixed in and the composition is filled into aluminium cartridge for a hot melt adhesive applicator. A silica gel sachet is placed in the filled cartridge which is then sealed.

Wingtack 10 liquid polyterpene (available from Goodyear) may be used in place of Hyvis 30.

Example 2

Coating Composition

The surface protecting coating composition is the admixture of the following components:

SGSEBS* 50%

Enerpar 11 (paraffinic plasticizer) 39.483%

Dibutyl tin dilaurate (catalyst) 0.017%

Irganox 1010 (antioxidant) 0.5%

Polyethylene glycol PEG 8000 (filler) 10%

*The SGSEBS is the reaction product of vinyltrimethoxysilan and SEBS (Kraton G-1650 available from Shell Chemical

Co. - Brookfield viscosity in toluene solution at 77% of 1500mPas) , prepared with a silane content of about 5% using the procedure of US-A-3646155.

The composition is mixed analogously to Example 1 and filled into containers.

Example 3

Coating Composition

The coating, e.g. jacketting or sheathing, composition is the admixture of the following components:

SGEVA* 75%

Catalyst/EVA blend ⁺ 5%

China clay (filler) 10%

Polyethylene glycol PEG 400 (plasticizer) 10%

* The SGEVA is the reaction product of vinyltrimethoxysilan and an EVA having an MFI of 1 and a vinyl acetate content of 12%, prepared with a silane content of about 2-3% using conventional processes.

The catalyst/EVA blend comprises 1% dibutyl tin dilaurate and 99% of an EVA having an MFI of 1 and a vinyl acetate content of 12%.

The composition is mixed analagously to Example 1 and filled into moisture- and air-tight containers. Silica gel sachets are placed in the filled containers which are then sealed.

Example 4

Two composition adhesive system

The first composition comprises the following components:

SGEVA* 80%

China clay (filler) 10%

Polyethylene glycol PEG 400 (plasticizer) 10%

* The SGEVA is the reaction product of vinyltrimethoxysilane and an EVA having an MFI of 1 and a vinyl acetate content of 12%, prepared with a silane content of about 2-3% using conventional processes.

The second composition comprises the following components:

28-800 EVA 94%

Ropaque OP-62 microspheres 5%

Dibutyl tin dilaurate 1%

In use, the first and second compositions are melted, mixed in a weight ratio of 98:2 and the mixture is applied to the substrates to be bonded.