Adhesive compositions based on blends of grafted polyethylenes and non-grafted polyethylenes and styrene container rubber

• US 6,184,298 B1
• Filed: 06/16/1999
• Issued: 02/06/2001
• Est. Priority Date: 06/19/1998
• Status: Expired due to Term

• Current Assignee: Performance Materials NA, Inc. (Dow, Inc.)
• Original Assignee: E. I. du Pont de Nemours and Company (Corteva, Inc.)
• Inventors: Lee, I-Hwa
• Primary Examiner(s): Nutter, Nathan M.
• Application Number:
  US09/334,329
• Time in Patent Office: 601 Days
• Field of Search: 525/191, 525/240, 525/241, 156/327, 156/334, 428/474.4, 428/476.3, 428/500, 428/515
• US Class Current: 525/240
• CPC Class Codes: B32B 27/32 comprising polyolefins comprising vinyl (co)polymers or acrylic (co)polymers B32B27/30
• CPC Class Codes: B32B 7/12 using interposed adhesives or interposed materials with bonding properties
• CPC Class Codes: C08L 2666/02 Organic macromolecular compounds, natural resins, waxes or and bituminous materials
• 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: C08L 53/02 of vinyl-aromatic monomers and conjugated dienes
• CPC Class Codes: C09J 123/0815 Copolymers of ethene with aliphatic 1-olefins
• CPC Class Codes: Y10T 428/31725 Of polyamide
• CPC Class Codes: Y10T 428/3175 Next to addition polymer from unsaturated monomer[s]
• CPC Class Codes: Y10T 428/31855 Of addition polymer from unsaturated monomers
• CPC Class Codes: Y10T 428/31909 Next to second addition polymer from unsaturated monomers

Abstract

The invention relates to adhesive compositions having a modified polyethylene; an unmodified polyethylene of a certain density and a styrene-based elastomer. The styrene-based elastomer is present in a weight percentage of 10 to 45 wt. percent relative to the total weight of the elastomer plus the modified and unmodified polyethylenes. The adhesive composition is particularly useful in multilayer composite structures having polypropylene as one substrate and having bonded thereto a polyethylene or a layer which is made from an ethylene copolymer such as an ethylene/acid copolymer or an ethylene acid ionomer. In addition, the adhesive composition is particularly useful in multilayer structures having five layers wherein a single adhesive composition is needed as layer two and four and the other structural layers are, for example, polyethylene/ nylon/polypropylene or similar structures which would heretofore require two different polyolefin based adhesives.

Claims

1. An adhesive composition, consisting essentially of A) plus B),

wherein

A) is about 55 to 85 wt. % of a polyethylene polymeric blend selected from

i) an unmodified polyethylene of density 0.86 to 0.97 g/cc;

and

ii) a polyethylene of density 0.86 to 0.97 g/cc modified with an unsaturated carboxylic acid or derivative thereof;

wherein the amount of said unsaturated carboxylic acid or its derivative lo comprises 0.01 to 3 wt. % of A) plus B) and

B) is about 15 to 45 wt. % of an unmodified styrene-based elastomer having an immeasurable Mooney viscosity according to ASTM-D-15 or ASTM D1646 at ML 1+4 100°

C.

3. The adhesive composition according to claim 1 or 2 wherein the amount of unsaturated carboxylic acid or derivative thereof is 0.03 to 2 wt. % relative to the total weight of A) plus B).

4. The adhesive composition according to claim 1 or 2 wherein the wt. % of the styrene-based elastomer is 20 to 40%.

5. The adhesive composition according to claim 1 or 2 wherein the density range for the unmodified polyethylene ranges from 0.92 to 0.93 g/cc and the density range of the modified polyethylene ranges from 0.90 to 0.96 g/cc.

6. The adhesive composition according to claim 1 or 2 wherein the unmodified polyethylene or polyethylene to be modified is selected from a metallocene produced resin.

7. The adhesive composition according to claim 1 wherein the Mooney viscosity of the styrene-based elastomer is, at ML 1+4 150°

C., 2-200 according to ASTM D1646.

8. A multilayer composite structure having at least two structural and/or barrier layers wherein the adhesive composition according to claim 1 or 2 binds said layers.

9. A multilayer composite structure according to claim 8 wherein at least one of the structural layers is polypropylene.

10. A multilayer composite structure according to claim 9 wherein at least one of the barrier layers is selected from EVOH, polyamide or a combination of EVOH and polyamide.

11. A multilayer composite structure according to claim 9 or 10 wherein an additional structural layer is selected from polyethylene, or an ethylene acid copolymer or an ethylene acid ionomer or polypropylene.

12. A multilayer composite structure according to claim 11 wherein the polyethylene is a metallocene based resin.

14. A multilayer composite structure, comprising

a) a first non-polar polymeric layer;

b) an adhesive layer having the adhesive composition according to claim 1 or claim 2;

c) a polar metallic or non-metallic layer;

d) an adhesive layer having the same composition as layer b); and

e) a second non-polar polymeric layer wherein the second non-polar polymeric layer is different than the first non-polar polymeric layer.

15. The multilayer structure according to claim 14 wherein layer a) is selected from a polypropylene;

layer c) is selected from a polyamide or EVOH; and

layer e) is selected from a polyethylene or ethylene/acid copolymer or ionomer.

16. A multilayer composite structure according to claim 8 wherein the adhesive composition contains a metallocene polyethylene.

2. An adhesive composition, consisting essentially of,

A) about 55 to 85 wt. % of a polyethylene polymeric blend selected from

i) an unmodified polyethylene of density 0.86 to 0.97 g/cc with the proviso that an unmodified ethylene-alpha olefin within said polyethylene has a density of 0.91 to 0.97;

and

ii) a polyethylene of density 0.86 to 0.97 g/cc modified with an unsaturated carboxylic acid or derivative thereof; and

B) about 15 to 45 wt. % of an unmodified styrene-based elastomer wherein said composition binds incompatible structural or barrier layers in a multilayer structural element having at least three structural/barrier layers and wherein the Mooney viscosity of the styrene-based elastomer is, at ML 1+4 150°

C., 2-200 according to ASTM D1646.

13. A multilayer composite structure, comprising

a) a polypropylene layer;

b) an adhesive layer wherein the composition of said layer consists essentially of A) plus B), wherein;

A) is about 55 to 85 wt. % of a polymeric blend consisting essentially of

i) an unmodified polyethylene having a density of 0.86 to 0.97 g/cc and

ii) a polyethylene having a density of 0.86 to 0.97 g/cc modified with an unsaturated carboxylic acid or a derivative thereof, wherein the amount of said carboxylic acid or derivative thereof is 0.01 to 3 wt. % relative to A) plus B); and

B) is about 15 to 45 wt. % of a styrene-based elastomer having an immeasurable Mooney viscosity at ML 1+4 100°

C. according to ASTM-D15or ASTM D1646; and

c) a polymeric layer wherein the polymeric constituents of said layer are selected from polyethylene, or an ethylene/acid copolymer or an ethylene/acid ionomer or a polypropylene.