Coextrusion tie for polyester based on cografted metallocene polyethylene and LLDPE and on metallocene polyethylene

• US 20050019516A1
• Filed: 09/26/2003
• Published: 01/27/2005
• Est. Priority Date: 09/27/2002
• Status: Active Grant

• Current Assignee: SK Geo Centric Company Limited
• Original Assignee: Arkema France (Arkema)
• Inventors: Chopinez, Fabrice, Pradel, Jean-Laurent, Rauline, Damien, Robert, Patrice
• Granted Patent: US 7,794,806 B2
• Time in Patent Office: Days
• US Class Current: 428/35.700
• CPC Class Codes: C08L 2205/02 containing two or more polymers of the same C08L -group
• CPC Class Codes: C08L 23/0815 Copolymers of ethene with aliphatic 1-olefins
• CPC Class Codes: C08L 2314/06 Metallocene or single site catalysts
• CPC Class Codes: C08L 2666/24 Graft or block copolymers according to groups C08L51/00, C08L53/00 or C08L55/02; Derivatives thereof
• CPC Class Codes: C08L 51/06 grafted on to homopolymers or copolymers of aliphatic hydrocarbons containing only one carbon-to-carbon double bond
• CPC Class Codes: Y10T 428/13 Hollow or container type article [e.g., tube, vase, etc.]
• CPC Class Codes: Y10T 428/1303 Paper containing [e.g., paperboard, cardboard, fiberboard, etc.]
• CPC Class Codes: Y10T 428/1352 Polymer or resin containing [i.e., natural or synthetic]
• CPC Class Codes: Y10T 428/1359 Three or more layers [continuous layer]
• CPC Class Codes: Y10T 428/139 Open-ended, self-supporting conduit, cylinder, or tube-type article
• CPC Class Codes: Y10T 428/31909 Next to second addition polymer from unsaturated monomers
• CPC Class Codes: Y10T 428/31913 Monoolefin polymer

Abstract

A subject matter of the invention is a coextrusion tie, which comprises: 5 to 35% by weight of a polymer (A) itself composed of a blend of 80 to 20% by weight of a metallocene polyethylene (A1) with a density of between 0.863 and 0.915 and of 20 to 80% by weight of a non-metallocene LLDPE polyethylene (A2) with a density of between 0.900 and 0.950, the blend of polymers (A1) and (A2) being cografted; 95 to 65% by weight of metallocene polyethylene (B) homo- or copolymer, the comonomer of which comprises 3 to 20 carbon atoms, preferably 4 to 8 carbon atoms, the density of which is between 0.863 and 0.915 and the MFI of which is between 0.5 and 30, preferably between 3 and 15, g/10 min; the total forming 100%, the blend of (A) and (B) being such that its MFI is between 0.1 and 15, preferably between 1 and 13, g/10 min.

Claims

1. A coextrusion tie, which comprises:

5 to 35% by weight of a polymer (A) itself composed of a blend of 80 to 20% by weight of a metallocene polyethylene (A1) with a density of between 0.863 and 0.915 and of 20 to 80% by weight of a non-metallocene LLDPE polyethylene (A2) with a density of between 0.900 and 0.950, the blend of polymers (A1) and (A2) being cografted by a grafting monomer chosen from unsaturated carboxylic acids and their derivatives, the content of the grafting monomer in said blend being between 30 and 100 000 ppm, preferably between 600 and 5 000 ppm;

95 to 65% by weight of metallocene polyethylene (B) homo- or copolymer, the comonomer of which comprises 3 to 20 carbon atoms, preferably 4 to 8 carbon atoms, the density of which is between 0.863 and 0.915 and the MFI, melt flow index, of which, measured under 2.16 kg at 190°

C. according to Standard ASTMD 1238, is between 0.5 and 30, preferably between 3 and 15, g/10 min;

the total forming 100%, the blend of (A) and (B) being such that its MFI is between 0.1 and 15, preferably between 1 and 13, g/10 min.

2. The tie as claimed in claim 1, the adhesive strength of which is increased by 5 to 50% between the time t=0 corresponding to its application immediately after its extrusion and the time t=8 days.

3. The tie as claimed in claim 1, wherein the grafting monomer is maleic anhydride.

4. The tie as claimed in claim 1, which additionally comprises an ethylene/alkyl (meth)acrylate copolymer (C).

5. The tie as claimed in claim 1, wherein the MFI of A is between 0.1 and 5 g/10 min (ASTMD 1238 at 190°

C. under 2.16 kg).

6. A multilayer structure, which comprises a layer (L) comprising the tie of any one of the preceding claims and a layer (E) directly attached to one of the two faces of said layer (L), said layer (E) being a polyolefin or polyester layer.

7. The multilayer structure as claimed in claim 6, wherein a layer (F) is directly attached to the second face of the layer (L), the layer (L) being sandwiched between the layers (E) and (F), said layer (F) being either a polymer layer, the polymer being chosen from the group of the polyamides, saponified copolymers of ethylene and of vinyl acetate (EVOH), polyolefins and polyesters, or a metal layer.

8. The multilayer structure as claimed in claim 7, wherein the layer (E) is a polyester copolymer layer and the layer (F) is an EVOH layer.

9. An object, which comprises a structure as in claim 1.

10. The object as claimed in claim 9, which is a bag, a bottle, a container, a pipe or a hose.

11. Use of the structure as claimed in claim 6 for manufacturing films or sheets.