MXPA01001140A - High temperature polyolefin based adhesive film with improved polarity for adhering to polyurethane foams - Google Patents

Abstract

Adhesion promoters, adhesive compositions, and adhesive films that adhere well to polar materials contain the product of a reaction between a polyolefin grafted with an ethylenically unsaturated carboxylic acid and/or an ethylenically unsaturated carboxylic acid anhydride, and a polymeric and/or oligomeric polyamine. The reaction product may be blended with an ethylene polymer, such as a low density polyethylene, to form an adhesive composition that bonds well to polar substrates, such as polyurethane foam. The adhesive compositions may be extruded or cast to form adhesive films.

Description

ADHESIVE FILM ON ^ POLIOLEPHINE BASE, AT ELEVATED TEMPERATURE, WITH IMPROVED POLARITY TO ADHER TO EOLIURETANE FOAMS Field of the Invention This invention relates to adhesive films and, more particularly, to adhesive films that are formulated to better adhere to polar materials.

BACKGROUND OF THE INVENTION It is known that copolymers of ethylene acrylic acid (EAA) and polymers modified with maleic anhydride (MAH) adhere well with polar materials. However, adhesive films prepared with high amounts of EAA copolymers or MAH polymers tend to be more expensive for everyday use in many applications, such as in the production of automotive parts as titrators In an attempt to provide adhesive films of lower cost that exhibit good adhesive properties with polar materials, others have mixed polymers that exhibit good adhesion to polar materials with less expensive olefin polymers. However, these blends still tend to be too expensive for many applications or exhibit unacceptable adhesion to polar materials. , or both The incorporation of a catalytic amount of an acidic agent or a basic agent into a -S? ¿?, £ MllíL * .ü ',:. , -. > -.... ^ .- .., M? - -aaa polyolefin inserted with object of improving accession. The catalytic acid is selected from monoalkyl phosphates, dialkyl phosphates, monoalkylamines, dialkylamines, trialkylamines, heterocyclic amino compounds, carboxylic acids and salts of such acids. Examples of amines include tributylamine and trioctylamine. A disadvantage in the use of these amines, both of relatively low molecular weight and catalytic agents, is that they tend to volatilize, especially at temperatures necessary to cast-mix the catalytic agents with EAA copolymers, polymers modified with MAH or both. The volatilization of amino catalysts can present health, safety and environmental problems, all of which are desirably avoided. The reaction of the primary ultraviolet (UV) absorbents, substituted with amino or hydro-acids, with some or all of the anhydride groups of the polymers or copolymers containing anhydrides to form acid or imide acid groups, substituted with stabilizer is also known in the art. pending. An amic acid results from a reaction between an anhydride and an amine wherein the amine attacks a carbonyl group of anhydride to produce an amide while leaving a second unreacted carbonyl group as a carboxylic acid. The resulting polymer stabilizers can be used as such or as concentrates to stabilize other polymer systems. Polymer or polymer binding stabilizers are not lost from a polymer system by volatilization, migration or extraction, even at elevated temperatures. Although polymeric stabilizers by themselves are not subject to volatilization, they are prepared from a primary amino substituted 2-hydroxybenzophenone, an ester of salicylic acid substituted with primary amino, an amide of oxalic acid substituted with primary amino, all which are low molecular weight molecules that could be volatilized when mixed by fusion with polymers or copolymers containing anhydride. It is not known that polymeric stabilizers prepared by the reaction of primary amino compounds with anhydride-containing polymers or copolymers are used as adhesives or adhesion promoters. US-A-4822688 discloses an adhesive composition consisting essentially of polypropylene modified by grafting with an acid anhydride to subsequently react with a compound containing at least two groups capable of reacting with the anhydride, preferably a polyol or a polyamine. US 4,735,992, the US equivalent to EP-A-0177401, describes polymers resulting from the association of two reactive components having a low melt viscosity, characterized in that one of the components is a modified polypropylene by grafting a monomer unsaturated having an acid anhydride group and the other is a compound R having at least two groups that are reactive toward its anhydride group. JP-A-061 28429 describes a composite composition ifl > »- of a polypropylene-based polymer, an olefin-based elastomer and a polyoxyalkyleneamide and exhibiting high adhesion to a coating material based on a urethane resin or an amino resin, without requiring a surface treatment. EP-A-0344138 discloses an adhesive composition containing a thermoplastic elastomeric polymer which includes ethylene propylene rubber, ethylene propylene diene monomer, polyisobutylene butyl rubber, ethylene vinyl acetate graft copolymers thereof , with C3 to C10 unsaturated mono- and polycarboxylic acids, an adherent resin and a di- and poly-amine degrading agent having 2-10 carbon atoms, which is useful as a pressure sensitive adhesive or Hot melt that has improved properties at higher temperature.

SUMMARY OF THE INVENTION A first aspect of this invention is an adhesion promoter or adhesive which is a product of a reaction between a first reagent which is a polyolefin inserted with an insertable monomer which is an ethylenically unsaturated carboxylic acid, an acid anhydride ethylenically unsaturated carboxylic acid or both and a second reagent which is a polymeric polyamine, an oligomeric polyamine or both. A second, but related, aspect of the invention, is an adhesion composition comprising from 50 percent «Ug < l - HBt-to < - ~ * * ¿Yes¡ & to up to 80 weight percent (percent weight) of an ethylene polymer that is substantially free of graft modification and from 20 to 50 weight percent of the adhesion promoter or adhesive of the first aspect. The adhesive composition has sufficient polarity to allow it to bind effectively to polar materials, such as polyurethane foam. A third, also related, aspect of the invention is an adhesive film prepared from the adhesive composition of the second aspect. The invention also relates to methods for preparing adhesives, adhesive compositions and films by using the adhesion promoter of the first aspect or by reacting it with another component. The invention further relates to a method for adhering a first substrate to a second substrate, the method comprising a first step of applying the adhesive composition of the first aspect to a surface of at least one of the substrates and a step of conducting at least one surface of each substrate as a whole, such that the adhesive composition is placed at an interface between such surfaces.

DETAILED DESCRIPTION OF THE PREFERRED MODALITY The adhesive or adhesion promoter is the product of a reaction between two components. A first component is a polyolefin that is inserted with a carboxylic acid ethylenically not Éf¿ saturated, an anhydride ethylenically-. not saturated or both. A is a polymeric polyamine, an oligomeric polyamine, or both. The inserted polyolefin can be formed by grafting an ethylenically unsaturated monomer onto a polyolefin by using known methods such as those described in the U.S. Patent. No. 4,61 2, 1 55. Polyolefins suitable for use as base polymers for grafting include ethylene homopolymers and copolymers of ethylene and an alpha-olefin (α-olefin). A preferred grafted polyolefin, with respect to its relatively low cost and commercial availability, as well as excellent performance in the adhesive compositions and films of this invention, is a linear, low density polyethylene, modified with MAH (MAH-g-LLDPE) . An appropriate commercially available MAH-g-LLDPE is sold under the name Bynel ™ 4104 by E. I. du Pont de Nemours and Company. Other polyolefins that may be inserted include copolymers of ethylene and a vinyl alkanoate, such as ethylene / vinyl acetate (EVA) copolymers; ethylene / alkyl (meth) acrylate copolymers including ethylene / methacrylate copolymers, ethylene / methyl acrylate (EMA) copolymers, ethylene / butyl acrylate copolymers (EBA) and ethylene / methyl methacrylate (EMMA) copolymers; ethylene / carbon monoxide copolymers (ECO); ethylene / vinyl alkanoate / carbon monoxide terpolymers; such as ethylene / acetate terpolymers • "-" ta iifi - vinyl / carbon monoxide (EVACO); and ethylene / alkyl (meth) acrylate / carbon monoxide terpolymers, such as ethylene / butyl acrylate / carbon monoxide (EBACO) terpolymers. Such copolymers are known in the art and many are commercially available. The monomer grafted to the polyolefin is at least one ethylenically unsaturated monomer selected from ethylenically unsaturated carboxylic acids and ethylenically unsaturated carboxylic acid anhydrides. Examples of such acids and anhydrides include mono-, di- or polycarboxylic acids such as acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, crotonic acid, itaconic anhydride, N-methyl-anhydride ™ (anhydride isomers) methyl-bicyclo [2.2.1] heptene-2,3-dicarboxylic acid, Allied Chemical Corporation), MAH materials and substituted with MAH, such as dimethyl MAH. Suitable polymeric and oligomeric polyamines include dimers, trimers and tetramers (collectively known as oligomers) and polymers (macromolecules comprised of five or more monomers). The polymeric and oligomeric polyamines include at least two amino groups per molecule. The polyamines used to prepare the adhesive films of this invention preferably contain from 20 to 1000 percent by weight of amine-containing monomer, more preferably at least 50 percent by weight of amine-containing monomer, based on the weight of -. ? aa - «- ato. .- .. the polyamine. The polymeric and oligomeric polyamines employed in the practice of this invention preferably have an average molecular weight (Mw) of at least 250 daltons, more preferably at least 500 daltons and more preferably at least minus 1,000 daltons. A suitable polymeric polyamine is a copolymer of N, N'-bis (2,2,6,6) -tetramethyl-4-pipepdinyl-1,6-hexadiamine with 2,4-dichloro-6- (4-morpholinyl) - 1, 3,5-triazine (a commercially available amine type UV stabilizer available under the designation commercial Cyasorb® UV-3346 from Cytec Industries). Any utility of such polyamine as a UV stabilizer in compositions of the present invention is merely incidental, since basically, if not exclusively, it is used to improve the adhesion of the inserted polyolefins and polymer blends containing such polyolefins inserted. The polymeric and oligomeric polyamines can be prepared, for example, by the solution polymerization, in aqueous medium, of at least one ethylenically unsaturated monomer that includes an amino group, either with or without a comonomer ethylenically unsaturated which does not contain an amino group. The monomers containing an amino group include ammoalkyl vinyl esters or sulfides wherein the alkyl groups are straight chains or branched chains and the nitrogen atom is a primary, secondary or tertiary nitrogen atom. The specific examples include beta (β) -aminoethyl vinyl ether, β-vinyl sulphide amino-ethyl, vinyl ether or vinyl sulfide of N-monomethyl, vinyl ether or vinyl sulfide of N-monoethyl ether, vinyl ether or vinyl sulfide of N-monobutyl ether and vinyl sulfide or vinyl sulphide N-monoethyl-3-aminopropyl. Other suitable monomers containing an amino group include acrylamides and aminoalkyl (methyl) acrylates, such as dimethylaminoethylacrylate or methacrylate, β-aminoethyl acrylate or methacrylate, N-β-aminoethyl acrylamide or methacrylamide, N- (monomethylaminoethyl) acrylamide or methacrylamide , N- (mono-n-butyl) -4-aminobutyl, methacryloxyethoxyethylamine and acryloxypropoxypropylamine acrylate or methacrylate. The monomers containing an amino group also include N-acryloxyalkyl oxazolidines and N-acryloxyalkyltetrahydro-1,3-oxazines and corresponding components in which the alkyl linkage is replaced by an alkoxyalkyl or a poly (alkoxyalkyl). Examples include oxazolidinylethyl methacrylate, oxazolidinylethyl acrylate, 3- (gamma-methacryloxypropyl) -tetrahydro-1,3-oxazine, 3- (β-methacryloxyethyl) -2,2-penta-methylene-oxazolidine, 3- (β-methacryloxyethyl-2- methyl-2-propyloxazolidine, N-2- (2-acryloxyethoxy) ethyl-oxazolidine, N-2- (2-methacryloxyethoxy) ethyloxazolidine, N-2- (2-methacryloxyethoxy) ethyl-5-methyl-oxazolidine, N-2 - (2-acryloxyethoxy) ethyl-5-methyl-oxazolidine, 3- [2- (2-methacryloxyethoxy) ethyl)] - 2,2-penta-methylene-oxazolidine, 3- [2- (2-methacryloxyethoxy) ethyl) ] -2,2-dimethyloxazolidine, 3- [2 (methacryloxyethoxy) ethyl] -2-phenyl-oxazolidine. The monomers that easily generate amines by hydrolysis are also useful ^^^ Ml Examples of such monomers include acryloxy-ketimines and acryloxy-aldimines, with illustrative compounds including 2- [4- (2,6-dimethylheptylidene) -amino] -ethyl methacrylate, 3- [2- (4-methylpentylidine methacrylate. ) -amino] -propyl, β- (benzylideneamino) -methyl methacrylate, 3- [2- (4-methylpentylidene) -amino] -ethyl methacrylate, 2- [4- (2,6-dimethylheptylidene) acrylate - amino] -ethyl, 12- (cyclopentylidene-amino) -dodecyl methacrylate, N- (1,3-dimethylbutylidene) -2 (2-methacryloxyethoxy) -ethylamine, N- (benzylidene) -methacryloxyethoxyethylamine, N- (1, 3 -dimethylbutylidene) -2- (2-acryloxyethoxy) -ethylamine, N- (benzylidene) -2- (2-acryloxyethoxy) ethylamine. Polymeric and oligomeric polyamines can be prepared by polymerizing any of the ethylenically unsaturated amine-containing monomers, set forth above, either alone, with each other, or with an ethylenically unsaturated comonomer lacking an amino group. Examples of amine-free comonomers include alkyl acrylates (esters of acrylic acid with an alcohol containing 1 to 1 8 carbon atoms (C? -C? 8), especially C 1-4 alcohols or alkanols), styrene, vinyl toluene, vinyl acetate, vinyl chloride, vinylidene chloride, substituted styrenes, butadiene, substituted butadienes, ethylene and the nitriles and amides of acrylic and methacrylic acid The inserted polyolefins used in the preparation of adhesives and adhesion promoters do not need have a particular content of carboxylic acid or carboxylic acid anhydride «Fc. hbts ^ áA The inserted polyolefin preferably contains a total amount of 0.001 percent up to 5 percent by weight, based on the weight of the inserted polyolefin, the carboxylic acid groups, the carboxylic acid anhydride groups, or both. The amounts 5 below 0.001 weight percent lack the desired adhesive properties. Amounts greater than 5 weight percent do not provide significant additional benefits and amounts substantially greater than 5 weight percent may retract from the adhesive properties. The polymeric polyamines, oligomeric polyamines or both are present in an amount that depends both on the desired properties and on the monomer content containing the amino group of such polyamines. The amount and type of polyamine preferably provides an excess of acid group Ethylenically unsaturated carboxylic acids, ethylenically unsaturated carboxylic acid anhydride groups or both. Generally, the amount and type are selected to produce a proportion of carboxylic acid groups, carboxylic acid anhydride groups or both and amino groups from 10: 1 to 3: 2; preferably from 3: 1 to 2: 1. The adhesive or adhesion promoter has a weight ratio of inserted polyolefin and pohamine of from 20 1 to 400: 1. The adhesive or adhesion promoter can be used alone or, more preferably, can be combined with an ethylene polymer that has not been modified by grafting to form a composition Adhesive suitable for use in the production of an adhesive film. In a preferred aspect of this invention, the adhesive compositions comprise polymer blends of from 50 weight percent to 80 weight percent of an ethylene polymer that has not been modified by grafting and from 20 weight percent to 50 percent by weight of the adhesive or adhesion promoter described above, based on the weight amounts of the composition and the total at 100 percent. Adhesive compositions can be prepared by combining an ethylene polymer that has not been modified by grafting and the adhesion promoter in a conventional melt mixing apparatus, such as in an extruder. An alternate procedure combines the unmodified ethylene elastomer with those components that, when they react, they form the adhesive or adhesion promoter in such an apparatus. Regardless of the process, the blends typically have a polyamine content of from 0.1 to 1 weight percent, based on the total weight of the mixture. The "ethylene polymer", as used herein, refers to homopolymers of ethylene and copolymers of ethylene and at least one other ethylenically unsaturated monomer. Examples of ethylene copolymers include copolymers of ethylene and at least one higher α-olefin monomer (from 3 to 20 carbon atoms (C3-C20), preferably C3-C8) such as propylene, butene-1, hexene-1 and octene-1, copolymers of ethylene and a vinyl alkanoate such as EV-* Ab copolymers of ethylene and alkyl (meth) acrylate copolymers. Preferred ethylene polymers, taking into account their relatively low cost, commercial availability and satisfactory performance in the compositions and adhesive films of this invention, are low density polyethylenes (LDPE). A commercially available LDPE, particularly suitable, is LDPE 6201 (The Dow Chemical Company). Other suitable ethylene polymers include those identified above as suitable base polymers for grafting. The adhesive compositions of this invention can and, preferably in fact contain, an antiblock concentrate of silicon dioxide (SiO2). A suitable anti-block concentrate of SiO2 is CN 734 (Southwest Plastics, Houston Texas). The antiblock concentrate can be used in an amount of up to 7.5 weight percent, based on the weight of the adhesive composition. Other adhesives, such as colorants, antioxidants and UV stabilizers, can be added in minor amounts, as desired. The adhesive compositions described above can be melted or extruded through a nozzle to form adhesive films exhibiting improved polarity as determined by contact angle measurements by the use of a Tantee ™ contact angle meter model CAM-FILM, and Improved adhesion with polar substrates as determined by measuring the adhesive strength of adhesive films bonded to foam é ^ ».» J polyurethane. The adhesive compositions of this invention exhibit improved adhesion (relative to adhesive films made from mixtures of EAA resin and LLDPE) to polar substrates and can be advantageously used to adhere or bond a first substrate to a second substrate, especially when at least one of the substrates has a polar surface. The adhesive compositions of this invention are especially useful for adhering a polyurethane material to another material, which can or can also not be a polar material, and which may or may not be polyurethane. An illustration of the latter involves the joining of a layer of polyurethane foam to another layer of an automotive interior panel, such as an automotive titrator. The adhesive composition is preferably applied to a substrate surface as a preformed film. The following example illustrates certain aspects of the invention and does not limit the scope of the invention described in the specification and claims. EXAMPLE A dry mixture of resin beads is prepared polymer containing 70 weight percent LDPE (LDPE 6201, The Dow Chemical Company), 20 weight percent MAH-g-LLDPE (BYNEL® 41 04, EY du Pont de Nemours and Company), 5 percent by weight of an antiblock concentrate (CN-734, Southwest Plastics) consisting of 85 percent by weight of LDPE and 1 5 percent by weight weight of S? O2 and 5 percent by weight of an additive concentrate (CN- to? j S0 »L ^? * < s? mi¿w * iñ ?? 720, Southwest Plastics) consisting of 87 weight percent LDPE, 10 weight percent of an oligomeric hindered amine that sometimes serves as a UV stabilizer (CYRASORB® 3346), 2 weight percent of a phosphite antioxidant (MARK® 21 12) and 1 weight percent of an hindered phenolic antioxidant (CYANOX® 1790). The percentages of the dry mix are based on the weight of the mixture and the percentages of concentrate in the weight of the concentrate. In each case, the percentages make a total of 100 percent by weight. The dry mix is extruded into a round profile having a diameter of 0.21 inches (in) (0.53 centimeters (cm)) by the use of a single 2-inch (5.1 cm) screw extruder press. The extruder is operated at a speed of 20 revolutions per minute (rpm) by using the following temperature profile: Cylinder zone (BZ) 1 -332 ° Fahrenheit (° F) (166.7 ° C (° C)), BZ2 - 346 ° F (174.4 ° C), BZ3 - 366 ° F (1 85.5 ° C), Zone 4 (gate) - 370 ° F (187.8 ° C), Gate / adapter - 371 ° F (88.3 ° C) C) and Transfer Line - 371 ° F (88.3 ° C). This profile results in an extrusion melting temperature of 381 ° F (1 93.9 ° C) and a cylinder pressure of 2690 pounds per square inch (psi) (1 8.5 megapascal (Mpa)). The extrudate is pressed between films of polyethylene terephthalate (PET) (Mylar®, EY du Pont de Nemours and Company) at a temperature of 340 ° F (1 71 .1 ° C), by using an applied pressure of 1 5,000 pounds (Ibs) (6804) kilograms (kg)), during 2 m inutes and then the extrudate is cooled while maintaining the applied pressure for 2 minutes. Additional films are pressed as identified in the table below shown under the same conditions. The pressed extruded films are removed from the PET films and their water contact angle is tested on a pressed extruded film surface by the use of a goniometer. See, S. Wu, Polvmer Interface and Adhesion, Marcel Deker, Inc., New York and Basel, (1992) p. 178-181 for calculations of surface tension and methodology. Measurements of the contact angle at room temperature are made by the use of bubbles of deionized water in a bubble vertex with a contact angle meter tantee model CAM-FILM. The results shown in the following table represent an average of three measurements. FILM CONTACT ANGLE 6201 LDPE 82.7 ° + 4.2 ° Bynel® 4104 60.0 ° + 0 ° CN-734 78.0 ° + 2.0 ° CN-720 50.0 ° + 10.0 ° Composition of the invention 65.3 ° + 1 .2 ° The above results show that an adhesive film prepared from an adhesive composition according to this invention, which contains a relatively high amount (70 weight percent) of non-wettable LDPE and amounts relatively low material-polar (Bynel® 4104 and CN-720), is very polar. By way of contrast, the measurements of the contact angle of a film lacking a polyamine (concentrate 5 additive CN-720) averages 82.7 ° + 2.52 °. The corona discharge treatment on one side of the film up to 42 dynes / centimeter reduces the contact angle at 72.0 ° + 0.0 °. The composition of the film is 64 weight percent LDPE, 30 weight percent MAH-g-LLDPE and 6 weight percent antiblock concentrate (CN-10 734), all percentages based on the weight of the composition and making a total of 100 percent by weight. The above results demonstrate that the presence of an oligomeric polyamine (contained in the additive concentrate CN-720) provides a significant reduction in the contact angle. This equates to a significant increase in polarity relative to films lacking an oligomeric polyamine, a polymeric polyamine, or both. The results show that the inclusion of a polyamine provides a greater reduction of the contact angle than that resulting from a corona discharge treatment. 20 Adhesion tests are conducted by joining rigid polyurethane foam to a fabric lined with flexible polyurethane foam. with a pressed extruded film, as detailed above, by the use of a 25 Sentinel thermal seal bar set at 280 ° F (1 37 8 ° C) and an applied force of 30 psi * -? artm? l Mü? aJt &St? &? - • > -Me? H * rilffifel - (206.8 kilopascals (Kpa)) for 20 seconds. Test strips (1 inch or 2.5 cm in width) are cut from the bonded foams and the foams are stripped apart by the use of an Instron tension testing machine. The following table contains numerical values that represent an average of values of five test samples. Maximum Load 2.13 Ib + 0.27 Ib (0.97 + 0.1 2 kg) Average load between limits 1 .76 Ib + 0.23 Ib (0.80 + 0.10 kg) Failure Mode Cohesive The above results demonstrate that the adhesive films of this invention exhibit excellent adhesion to polar substrates such as polyurethane foams, the non-adhesive failure mode being cohesive. It will be apparent to those skilled in the art that various modifications may be made to the preferred embodiment of the invention as described herein, without departing from the spirit or scope of the invention, as defined by the appended claims.

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Claims (10)

1. CLAIMS An adhesion promoter composition consisting essentially of a product of a reaction between a first reagent that is a polyolefin inserted with an insertable monomer 5 which is an ethylenically unsaturated carboxylic acid, an ethylenically unsaturated carboxylic acid anhydride or both, being selected said polyolefin from the group consisting of ethylene homopolymers, copolymers of ethylene and a vinyl alkanoate, ethylene / alkyl (meth) acrylate copolymers, copolymers of 10 ethylene / carbon monoxide, ethylene / vinyl alkanoate / carbon monoxide terpolymers and ethylene / alkyl (meth) acrylate / carbon monoxide terpolymers, and a second reagent which is a polymeric polyamine, an oligomeric polyamine or both; the composition having a proportion of the first reagent 15 relative to the second reagent of from 20: 1 to 400: 1 and a proportion of carboxylic acid groups, carboxylic acid anhydride groups or both with respect to amino groups of from 10: 1 to 3: 2. 2. The adhesion promoter according to claim 1, characterized in that the first reagent is linear low density polyethylene modified with maleic anhydride. 3. The adhesion promoter according to claim 1, characterized in that the polyolefin of the first reagent is selected from the group consisting of copolymers of ethylene and a 25 vinyl alkanoate, ethylene / alkyl (meth) acrylate copolymers, ethylene / carbon monoxide copolymers, ethylene / vinyl alkanoate / carbon monoxide terpolymers and ethylene / alkyl (meth) acrylate / carbon monoxide terpolymers. The adhesion promoter according to claim 1, characterized in that the insertable monomer is selected from the group consisting of acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, crotonic acid, itaconic anhydride, nadic anhydride, anhydride Maleic and substituted maleic anhydrides. The adhesion promoter according to claim 1, characterized in that the second reagent has an amine-containing monomer content of from 20 percent to 100 percent by weight, based on the weight of the second reagent. 6. The adhesion promoter according to claim 1, characterized in that the polyamine has a molecular weight of at least 250 daltons. The adhesion promoter according to claim 1, characterized in that the polyamine is a copolymer of N, N'-bis (2, 2,6,6) -tetramethyl-4-piperidinyl-1,6-hexadiamine with 2,4 -dichloro-6- (4-morpholinyl) -1, 3, 5-triazine. The adhesion promoter according to claim 1, characterized in that the first reagent has an insertable monomer content of from 0.001 percent up to 5 weight percent, based on the weight of the first reagent. 9. An adhesive composition comprising from 50 weight percent up to 80 weight percent of an ethylene polymer that is substantially free from graft modification and from 20 weight percent to 50 weight percent of the adhesion promoter according to any of claims 1 -8. The adhesive composition according to claim 9, characterized in that the ethylene polymer that is substantially free of graft is selected from the group consisting of a low density polyethylene (LDPE), a copolymer of ethylene and at least one monomer of alpha-olefin, a copolymer of ethylene carbon monoxide, an ethylene / vinyl alkanoate / carbon monoxide terpolymer. eleven . The adhesive composition according to claim 9, further characterized in that it comprises an antiblock concentrate.
2. 2. A method of adhesion to a surface of a first substrate to a surface of a second substrate, characterized in that it comprises: applying the adhesive composition according to claim 9 to the surface of at least one of the substrates, first and second; and driving at least one surface of each substrate together in such a manner that the adhesive composition is placed at an interface between such surfaces. The method according to claim 1 2, characterized in that at least one of the substrates comprises a polar material 14. An adhesive film made from the adhesive composition according to claim 9.