The present invention relates to an adhesive composition or tie based on one or more ethylene polymers or copolymers, that can be used in an extrusion-coating process for application onto a support or in- an extrusion-lamination process to bond several supports, possibly being of the same or different nature, together, one of these supports possibly being, in particular,' aluminum. It is known to use ethylene/ (meth) acrylic acid •copolymers as a tie for extrusion-coating onto an aluminum support; however, these copolymers only adhere to a limited number of supports, and in particular do not adhere to oriented plastic films such as polyester (OPET), polypropylene (OPP) or polyamide (OPA). Document FR 98 13248' describes a tie of the ethylene/alkyl (meth)acrylate/glycidyl methacrylate (GMA) terpolymer type for bonding a polyester film such as corona-treated polyethylene terephthalate (PET) onto another substrate such as polyethylene (PE)? however, the versatility for bonding onto other substrates is limited. Document EP 444 865 describes ties of the sealable-peelable type for aluminum lids for plastic packaging, of which the compositions comprise, as a blend, ethylene/vinyl acetate (EVA) or ethylene/alkyl- (meth) acrylate copolymers, with ethylene/unsaturated acid or its anhydride/unsaturated ester terpolymers. These ties which must be sealable and peelable are not used as ties for extrusion-coating and extrusion-lamination between an aluminum support and a thermoplastic support. Document EP 1 136 536 describes a coextrusion tie comprising: 5 to 35 parts of a polymer (A) itself composed of a blend of 80 to 20 parts of a metallocene polyethylene (Al) and 20 to 80 parts of a non- metallocene LLDPE polyethylene (A2), the blend (Al) + (A2) being cografted by an unsaturated carboxylic acid; and 95 to 65 parts of a polyethylene (B) chosen from polyethylene homopolymers or copolymers and elastomers, the blend of (A) and (B) being such that the content of grafted unsaturated carboxylic acid is between 30 and 100 000 ppm. These compositions, which are very effective in coextrusion, are not very high-performance in extrusion-coating and extrusion-lamination technologies, on certain supports such as oriented polyethylene terephthalate (OPET). Document EP 222 789 describes a thermoplastic composition composed of a blend of an ethylene-based polymer or copolymer and an ethylene/alkyl (meth) acrylate/ maleic anhydride terpolymer; in the examples describing the use of this composition in coating an aluminum support, the terpolymer is used as a blend with 15 to 50 wt% of a radical polyethylene, which gives maleic anhydride contents between 1.4 and 2.5 wt%. This type of composition, due to its high maleic anhydride content, is very sensitive to moisture and, in addition, its adhesion properties to films made of OPET, OPA and OPP are mediocre. Document US 2002/0198323 Al describes a polymer blend used for high-speed coating of a polar substrate such as an aluminum foil, comprising low-density polyethylene (LDPE) (at least 55 wt%) and a copolymer having a low acid content which is an ethylene/(meth) acrylic acid copolymer, which may contain from 0 to 20 wt% of another ethylenically unsaturated comonomer. Preferably, this copolymer having a low acid content is an ethylene/(meth)acrylic acid/isobutyl acrylate terpolymer, having a content of the latter comonomer between 1 and 8 wt% of the terpolymer, namely at most 3.6% in the blend. This type of formulation only adheres to a limited number of supports such as aluminum, paper and polyethylene. The Applicant has found that it was possible, .'Surprisingly, to significantly improve the adhesion properties of an adhesive composition or tie, composed of at least one ethylene polymer or copolymer, applied to a support by an extrusion-coating process or to bond together supports of a different and varied nature by an extrusion-lamination process, while combining both a low content of reactive functions, which are of acid, anhydride or epoxide type, in an olefin matrix, and -a sufficient content of unsaturated carboxylic acid ester comonomers. The advantages of such a composition are, besides the versatility of the adhesion as a function of the supports, the " possibility of use over a wide temperature range between 220 and 330°C and at high operating speeds, the insensitivity to moisture uptake and also the reduced odor level emitted, both during its use and in the finished products. The present invention relates to an adhesive composition composed of at least one ethylene polymer or copolymer, this composition comprising at least one unsaturated carboxylic acid ester type comonomer, and at least one functional comonomer, that can be used in an extrusion-coating process for application onto a support or in an extrusion-lamination process for bonding several supports, having the same or a different nature, together, over a wide temperature range, characterized in that said composition has a content of unsaturated carboxylic acid ester type comonomer(s) greater than 5% by weight and that the functional comonomer is composed of at least one reactive function in the form of an acid, anhydride -or epoxide group, the level of which is less than 1% by weight of the composition. Preferably, the content of reactive function(s) is between 0.05% and 0.9% by weight relative to the composition. The term "ethylene copolymer" as used in the present description relates to polymers of ethylene and one or more comonomers, such as unsaturated monomers, in particular: a-olefins having 3 to 30 carbon atoms; - acetylene compounds; conjugated or nonconjugated dienes, such as for example 1,4-hexadiene; polyenes; carbon monoxide; unsaturated carboxylic acid esters, such as for example alkyl (meth)acrylates, the alkyl groups possibly having up to 24 carbon atoms; vinyl esters of saturated carboxylic acids, such as for example vinyl acetate or propionate; unsaturated epoxides; and unsaturated carboxylic acids, their salts and their anhydrides. Examples of unsaturated dicarboxylic acid anhydrides are especially maleic anhydride, itaconic anhydride, citraconic anhydride and tetrahydrophthalic anhydride. The ethylene copolymer or copolymers of the composition according to the invention may be diluted in a polyethylene homopolymer or copolymer such as especially low-density polyethylene, linear low-density Spolyethylene, very low-density polyethylene or metallocene polyethylene, which should result in a decrease of the adhesive characteristics of the compositions thus obtained; however, these adhesive characteristics may remain sufficient for the coating .or lamination onto certain envisaged supports. Preferably, the adhesive composition according to the invention is characterized in that the carboxylic acid ester type comonomer is chosen from alkyl (meth) ,