Title of Invention

"ADHESIVE COMPOSITION BASED ON ETHYLENE COPOLYMERS, USEFUL FOR EXTRUSION-COATING AND EXTRUSION LAMINATION ON A VARIETY OF SUPPORTS"

Abstract The invention concerns an adhesive composition consisting of at least one ethylene polymer or copolymer, said composition comprising at least one unsaturated carboxylic acid ester comonomer, and at least one functional comonomer, useful in an extrusion-coating process for application on a support or in an extrusion-lamination process for bonding together several supports of different type or not, in a wide temperature range. The invention is characterized in that said composition has an unsaturated carboxylic acid ester content, higher than 5 wt. % and in that the functional comonomer consists of at least one reactive function in the form of an acid group, anhydride or epoxy, whereof the proportion is less than 1 wt. % of the composition. Said composition has advantageous uses, in particular for bonding together substrates selected among aluminum, paper or cardboard, cellophane, films based of polyethylene, polypropylene, polyamide, polyester, poluvinyl chloride (PVC) polyvinylidene chloride (PVDC), poly-acrylonitrile (PAN) resins, oriented or not, metal-coated or not, Physically or chemically treated or not and films coated with a thin inorganic barrier layer, such as polyester (PET, SiOx or AlOx)
Full Text 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) , Examples of alkyl acrylate or methacrylate are especially methyl acrylate, ethyl acrylate, n-butyl lacrylate, isobutyl acrylate and 2-ethylhexyl acrylate.
In particular, methyl acrylate and n-butyl acrylate are used.
Preferably, the adhesive composition is characterized in that the functional comonomer is chosen from acid, anhydride or epoxide groups.
Preferably, the group is chosen from compounds of carboxylic acids or their unsaturated carboxylic acid anhydride derivatives.
Examples of unsaturated dicarboxylic acid anhydrides are especially maleic anhydride, itaconic anhydride, •citraconic anhydride, and tetrahydrophthalic anhydride. Preferably, it is maleic anhydride that is used.

However, the functional comonomer may comprise an
unsaturated epoxide type function.
Examples of unsaturated epoxides are especially:
aliphatic glycidyl esters and ethers, such as allyl glycidyl ether, vinyl glycidyl ether, glycidyl maleate and itaconate, glycidyl methacrylate (GMA) and acrylate; and
alicyclic glycidyl esters and ethers, such as glycidyl l-cyclohex-2~ene ether, diglycidyl 4,5-cyclohexene dicarboxylate, glycidyl 4-cyclohexene carboxylate, glycidyl 5~norbonene-2-methyl-2-carboxylate and diglycidyl endocis-bicyclo[2.2,1] hept-5-ene-2,3-dicarboxylate.
•Unsaturated monocarboxylic or dicarboxylic acid type functions, such as (meth)acrylic acid may also be used.
These functional comonomers are preferably attached to the preceding ethylene polymers or copolymers by copolymerization, especially of the high-pressure radical type, however they may also be attached by grafting.
However, these functional comonomers may be copolymerized directly with ethylene or other ethylene comonomers, especially by high-pressure radical polymerization, or grafted to ethylene polymers.
Preferably, the functional comonomer is chosen from unsaturated carboxylic acid anhydrides, and preferably is maleic anhydride.
In particular, the adhesive composition is characterized in that the content of maleic anhydride is between 0.15% and 0.6% by weight of the composition.
Preferably, this adhesive composition is characterized in that the content of alkyl (meth)acrylate type

comonomer is between 6 and 40% by weight, and preferably between 10 and 25% by weight, of the composition.
According to another embodiment, the invention relates to a multilayer structure obtained by use of the adhesive composition as described previously, in an extrusion-coating process for application onto a support, said support being chosen from aluminum, paper or board, cellophane, films based on polyethylene, polypropylene, polyamide, polyester, polyvinyl chloride (PVC), polyvinylidene chloride (PVDC) or polyacrylonitrile (PAN) resins, these films being oriented or unoriented, metallized or unmetallized, treated or untreated by physical or chemical means, and films coated with a thin inorganic barrier layer, such as polyester (PET SiOx or AlOx).
According to another embodiment, the invention relates to a multilayer structure obtained by use of the adhesive composition of the invention, in an extrusion-lamination process to bond several supports, of different nature, together, characterized in that these supports are chosen from aluminum, paper or board, cellophane, films based on polyethylene, polypropylene, polyamide, polyester, polyvinyl chloride (PVC), polyvinylidene chloride (PVDC) or polyacrylonitrile (PAN) resins, these films being oriented or unoriented, metallized or unmetallized, treated or untreated by physical or chemical means, and films coated with a thin inorganic barrier layer, such as polyester (PET SiOx or AlOx).
In addition, the invention also relates to a method for producing the adhesive composition of the invention, consisting of the high-pressure radical polymerization of all the comonomers in a single step.

The invention also relates to another method of producing the adhesive composition according to the invention, in which at least two ethylene copolymers obtained separately by high-pressure radical polymerization, of which one at least comprises the functional comonomer, are melt-blended.
In this case, it matters little whether this blend has been made prior to the extrusion-coating or extrusion-lamination step, or during this step by dry-blending granules of different compounds comprising the various comonomers.
The adhesive composition of the invention may contain, in addition, other additives, such as antiblocking agents, slip agents, antioxidants, fillers, pigments, dyes and processing aids to facilitate the implementation of this composition in extrusion-coating or extrusion-lamination. Some of these additives may be introduced into the composition in the form of masterbatches.
EXEMPLARY EMBODIMENTS:
General conditions:
Adhesives of different compositions (the characteristics of which are specified in Table 1) were coextruded with one layer of radical low-density polyethylene (rLDPE) and layered on various supports •using a COLLIN extrusion-coating line. The operating conditions were chosen so as- to impose a draw ratio (ratio of the drawing speed to the speed of the molten polymer exiting the die) of 5.8.
It will be noted that in the composite structures obtained that are described in the following examples, the polyethylene layer may be completely formed by

extrusion or partially by lamination on a polyethylene film.
Strips having a width of 15 mm were cut out from the center of the width and along the extrusion direction. The polymer coating was manually separated from the support over a distance of a few centimeters, then the two sections thus released (respectively aluminum and polymer coating) were then each placed in one of the two jaws of -an MTS SYNERGIE 200 tensile testing machine. The peel strength was then assessed with a peeling rate of 200 mm/min. Five testpieces were tested per adhesive reference. The tests were carried out in the 15 minutes following the implementation (peel at t0) and also after conditioning for one month at 23°C and 50% relative humidity.
Table 1

(Table Removed)
The low-density polyethylene (LDPE) was LACQTENE® LD 304 from Total Petrochemicals .
Resin 1 was the ethylene/butyl acrylate/maleic anhydride (MAH) terpolymer sold under the trademark LOTADER® 3210 by Arkema.
Resin 4 was the ethylene/butyl acrylate/maleic anhydride (MAH) terpolymer sold under the trademark LOTADER® 3410 by Arkema.
Resins 2, 3, 5 to 8 were compositions according to the invention.
Resin 2 was obtained by blending an ethylene/butyl •acrylate copolymer containing 18.6 wt% of acrylate with an ethylene/methyl acrylate (17.7 wt%)/maleic anhydride (1 wt%) terpolymer, in a weight ratio of around 70/30, in a FAIREX 45/26 D type single-screw extruder, having a rotation speed of 50 rpm, at a temperature of 150°C.
:Resins 3, 5 and 6 were ethylene/methyl acrylate/maleic anhydride terpolymers obtained by high-pressure radical polymerization.
Resin 7 was obtained by blending, in an extruder as for 'resin 2, an ethylene/methyl acrylate copolymer containing 20 wt% of acrylate with an ethylene/butyl acrylate (6 wt%)/methacrylic acid (1.5 wt%) terpolymer, in a weight ratio of around 70/30.
Resin 8 was obtained by blending, in an extruder as for the preceding resin, an ethylene/methyl acrylate copolymer containing 24 wt% of acrylate with an ethylene/methyl acrylate (25 wt%)/glycidyl methacrylate (8 wt%) terpolymer, (sold under the trademark LOTADER® AX 8900 by Arkema), in a weight ratio of around 90/10.
The abbreviations MeA, BuA, MAH, MAA and GMA denote methyl acrylate, butyl acrylate, maleic anhydride, methacrylic acid and glycidyl methacrylate respectively.
MFI is the melt flow index measured at a temperature of 190°C under a load of 2.16 kg (according to standard ASTM D 1238).
Example 1:
The support used was an aluminum film having a thickness of 37 µm. The structure produced was: aluminum (37 µm) /adhesive (10 µm) / rLDPE (100 µm). Two extrusions temperatures (290-300°C and 310-320°C respectively) were assessed for each of the adhesives tested (including those being used as comparative adhesives).
The results obtained are given in Table 2 below (the values measured are followed by the standard deviation):
Table 2



(Table Removed)
In particular, the improved adhesion characteristics of the compositions according to the 'invention (resins 2,-3 and 7} were observed, especially after aging, relative to the normal adhesives used in extrusion (resins 1 and 4,.comparative tests).
In addition, the blend of resin 1 with LDPE, according to the teaching of Examples 9 to 13 of Patent EP 222 789, cited as prior art, gave even lower 'adhesion values than with resin 1 used alone.
Example 2:
For this example, two oriented polyethylene
terephthalate (OPET) supports of reference MYLAR 813
(14 µm thick)and MYLAR 800 (12 µm) from DuPont Teijin were used.
In the case of MYLAR 813, the adhesive was deposited onto the side of the film that had not been treated by physical or chemical means (by a "primer"), and in both cases a corona treatment was applied in-line to the PET film just before the deposition of the adhesive.
• The structure produced was: PET film/adhesive (10 µm) / rLDPE (30 µm) . The results obtained are given in Table 3 below:
Table 3

(Table Removed)
The highly improved adhesion characteristics of the Scompositioris according to the invention (resins 5, 6, 7 and 8) were observed relative to the comparative resins 1 and 4.
Example 3:

In this example, the adhesives were deposited onto an oriented nylon-6 film having a thickness of 25 µm. The structure of the samples was the following: OPA film/ adhesive (10 µm) /rLDPE (85 µm) . The results obtained are given in Table 4 below:
Table 4
(Table Removed)
Resin 6 according to the invention also had improved adhesion characteristics on this type of substrate made from oriented polyamide.
In all the tests, a large reduction in the odors emitted during the processing of the resins according to the invention, and in the final products, was also observed relative to conventional resins.
In addition, the resins of the invention in granule form have a remarkable insensitivity to moisture.





We claim:
1. An adhesive composition based on at least one ethylene copolymer, this ethylene copolymer
being polymers from ethylene and from at least one comonomer, this composition comprising at
least one unsaturated carboxylic acid ester type comonomer and at least one functional
comonomer, wherein:
- the at least one unsaturated carboxylic acid ester type comonomer is chosen from alkyl (meth)acrylates, the alkyl group comprising from 1 to 24 carbon atoms,
- the content of alkyl (meth)acrylate type comonomer is between 6 and 25% by weight of the composition; and
- the functional comonomer is composed of at least one reactive function selected from the group consisting of an acid, anhydride or epoxide group, the level of which is less than 1 % by weight of the composition.
2. The adhesive composition as claimed in claim 1, wherein the content of alkyl (meth)acrylate
type comonomer is between 10 and 25% by weight of the composition.
3. The adhesive composition as claimed in claim 1 or 2, wherein the content of reactive
function(s) is between 0.05% and 0.9% by weight relative to said composition.
4. The adhesive composition as claimed in any one of claims 1 to 3, wherein the functional comonomer is chosen from unsaturated carboxylic acid anhydrides, and in particular is maleic anhydride.
5. The adhesive composition as claimed in claim 4, wherein the content of maleic anhydride is between 0.15% and 0.6% by weight of the composition.
6. A multilayer structure obtained by use of the adhesive composition as claimed in any one of claims 1 to 5, in an extrusion-coating process for application onto a support, wherein said support is chosen from aluminum, paper or board, cellophane, films based on polyethylene, polypropylene, polyamide, polyester, polyvinyl chloride (PVC), polyvinylidene chloride (PVDC) or polyacrylonitrile (PAN) resins, these films being oriented or unoriented, metallized or unmetallized, treated or untreated by physical or chemical means, and film's coated with a
thin inorganic barrier layer, such as polyester (PET SiOx or AlOx).
7. A multilayer structure obtained by use of the adhesive composition as claimed in any one of claims 1 to 5, in an extrusion-lamination process to bond several supports, having the same or a different nature, together, wherein these supports are chosen from aluminum, paper or board, cellophane, films based on polyethylene, polypropylene, polyamide, polyester, polyvinyl chloride (PVC), polyvinylidene chloride {PVDC) or polyacrylonitrile (PAN) resins, these films being oriented or unoriented, metallized or unmetallized, treated or untreated by physical or chemical means, and films coated with a thin inorganic barrier layer, such as polyester (PET SiOx or AlOx).
8. A method for producing the adhesive composition, as claimed in any one of claims 1 to 5, wherein it consists of the high-pressure radical polymerization of all the comonomers in a single step.

9. A method for producing the adhesive composition as claimed in any one of claims 1 to 5, wherein at least two ethylene copolymers obtained by high-pressure radical polymerization, of which one at least comprises the functional comonomer, are melt-blended.
10. Blend comprising the adhesive composition as-claimed in any one of claims 1 to 5 and polyethylene homopolymer or copolymer.
11. Blend as claimed in claim 10, wherein the polyethylene homopolymer is chosen from low-density polyethylene, linear low-density polyethylene, very low-density polyethylene and metallocene polyethylene.
12. Adhesive composition as claimed in any of the preceding claims, as and when 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.

Documents:

5051-delnp-2007-abstract.pdf

5051-delnp-2007-Claims-(01-10-2012).pdf

5051-DELNP-2007-Claims-(11-11-2011).pdf

5051-delnp-2007-claims.pdf

5051-DELNP-2007-Correspondence Others-(11-11-2011).pdf

5051-delnp-2007-Correspondence-Others-(01-10-2012).pdf

5051-delnp-2007-correspondence-others.pdf

5051-delnp-2007-description (complete).pdf

5051-delnp-2007-form-1.pdf

5051-DELNP-2007-Form-13-(11-11-2011).pdf

5051-delnp-2007-form-2.pdf

5051-delnp-2007-form-3.pdf

5051-delnp-2007-form-5.pdf

5051-delnp-2007-pct-210.pdf

5051-DELNP-2007-Petition-137-(11-11-2011).pdf


Patent Number 255550
Indian Patent Application Number 5051/DELNP/2007
PG Journal Number 10/2013
Publication Date 08-Mar-2013
Grant Date 02-Mar-2013
Date of Filing 29-Jun-2007
Name of Patentee ARKEMA FRANCE
Applicant Address 4-8, COURS MICHELET, F-92800 PUTEAUX, FRANCE.
Inventors:
# Inventor's Name Inventor's Address
1 CHOPINEZ, FABRICE 40 B, RUE DE PANNETTE, RESIDENCE PARIS SOLEIL, F-27000 EVREUX, FRANCE.
2 RAULINE, DAMIEN LA COCHONNIERE, F-27270 SAINT-QUENTIN-DES-ISLES, FRANCE.
3 PASCAL, JEROME LE BEURON, F-27410 GRANDCHAIN, FRANCE.
PCT International Classification Number C09J 123/08
PCT International Application Number PCT/FR2005/003110
PCT International Filing date 2005-12-13
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 0413384 2004-12-16 France