Multilayer protective film

• US 6,164,739 A
• Filed: 09/24/1997
• Issued: 12/26/2000
• Est. Priority Date: 10/18/1993
• Status: Expired due to Term

• Current Assignee: The Dow Chemical Company (Dow, Inc.)
• Original Assignee: The Dow Chemical Company (Dow, Inc.)
• Inventors: Cahill, Glenda J., Danner, Mark C., Schulz, Thomas G., Tung, Harvey C.
• Primary Examiner(s): Safavi, Michael
• Application Number:
  US08/936,209
• Time in Patent Office: 1,189 Days
• Field of Search: 312/406, 312/401, 428/308.4, 428/317.1, 428/317.7, 428/319.3, 428/319.7, 428/319.9, 52/309.8, 52/309.9
• US Class Current: 312/406
• CPC Class Codes: B32B 2323/043 HDPE, i.e. high density polyethylene
• CPC Class Codes: B32B 2323/046 LDPE, i.e. low density polyethylene
• CPC Class Codes: B32B 27/28 comprising synthetic resins not wholly covered by any one of the sub-groups B32B27/30 - B32B27/42
• CPC Class Codes: B32B 27/32 comprising polyolefins comprising vinyl (co)polymers or acrylic (co)polymers B32B27/30
• CPC Class Codes: B32B 27/40 comprising polyurethanes
• CPC Class Codes: B32B 5/18 characterised by features of a layer of foamed material
• CPC Class Codes: B32B 7/04 Interconnection of layers
• CPC Class Codes: B32B 7/12 using interposed adhesives or interposed materials with bonding properties
• CPC Class Codes: F25D 2201/126 of cellular type
• CPC Class Codes: F25D 23/066 Liners
• CPC Class Codes: Y02B 40/00 Technologies aiming at improving the efficiency of home appliances, e.g. induction cooking or efficient technologies for refrigerators, freezers or dish washers
• CPC Class Codes: Y10T 428/249985 Composition of adhesive or bonding component specified
• CPC Class Codes: Y10T 428/249991 Synthetic resin or natural rubbers

Abstract

A multilayer protective film useful in insulated wall structures of appliances such as refrigerators, freezers, or boiler units, for example. The multilayer protective film has a substantially polyolefin protective layer. The multilayer protective film also has a substantially polyolefin surface capable of bonding to polyurethane foam without the use of an adhesive. The multilayer protective film bonds to and protects thermoplastic liners from attack by blowing agents used in the production of polyurethane foam. The multilayer protective film is also adaptable to be regrind-compatible into thermoplastic liners made of styrenic polymers.

Claims

1. An insulated structure consisting essentially of:

(a) an outer wall;

(b) a substantially styrenic polymer layer;

(c) an adhesive layer adjacent to said substantially styrenic polymer layer;

(d) a protective layer adjacent to said adhesive layer, said protective layer consisting essentially of polyethylene and up to about 16 weight percent talc based on the weight of said protective layer;

(e) a compatibilizing layer adjacent to said protective layer, said compatibilizing layer consisting essentially of polyethylene and a compatibilizer capable of compatibilizing blends of polyethylene and styrenic polymers; and

(f) a polyurethane foam disposed between said protective layer and said outer wall, said foam being adjacent to said compatibilizing layer and said outer wall.

2. An insulated structure according to claim 1, wherein said adhesive layer is permanently bonded to said styrenic polymer layer.

3. An insulated structure according to claims 1, wherein said adhesive layer is bonded to said styrenic polymer layer with an adhesive strength of at least about 7 ounces per inch of width.

4. An insulated structure according to claim 1, wherein the talc is present in an amount from about 6 percent to about 16 percent by weight of said protective layer.

5. An insulated structure according to claim 1, wherein the talc is present in an amount from about 6 percent to about 10 percent by weight of said protective layer.

6. A thermoformable liner consisting essentially of:

(a) a substantially styrenic polymer layer;

(b) an adhesive layer adjacent to said substantially styrenic polymer layer;

(c) a compatibilizing layer adjacent to said adhesive layer, said compatibilizing layer consisting essentially of polyethylene and a compatibilizer capable of compatibilizing blends of polyethylene and styrenic polymers; and

(d) a protective layer adjacent to said compatibilizing layer, said protective layer consisting essentially of polyethylene and up to about 16 weight percent talc based on the weight of said protective layer.

7. A thermoformable liner according to claim 6, wherein the talc is present in an amount from about 6 percent to about 16 percent by weight of said protective layer.

8. A thermoformable liner according to claim 6, wherein the talc is present in an amount from about 6 percent to about 10 percent by weight of said protective layer.

9. A thermoformable liner according to claim 6, wherein said adhesive layer is permanently bonded to said substantially styrenic polymer layer.

10. A thermoformable liner according to claim 6, wherein said adhesive layer is bonded to said substantially styrenic polymer layer with an adhesive strength of at least about 7 ounces per inch of width.

11. A multilayer protective film consisting essentially of:

(a) a protective layer consisting essentially of polyethylene and up to about 16 weight percent talc based on the weight of the protective layer;

(b) a compatibilizing layer adjacent to said protective layer, said compatibilizing layer consisting essentially of polyethylene and a compatibilizer capable of compatibilizing blends of polyethylene and styrenic polymers; and

(c) an adhesive layer adjacent to said compatibilizing layer, said adhesive layer comprising an adhesive polymer adapted to bond to styrenic polymer substrates.

12. The multilayer protective film of claim 11, wherein talc is present in an amount from about 6 percent to about 10 percent by weight of the protective layer.

13. The multilayer protective film of claim 11, wherein the compatibilizer in said compatibilizing layer is a copolymer selected from the group consisting of styrene-butadiene copolymers, styrene-butadiene-styrene copolymers, styrene-ethylene-butadiene copolymers, styrene-ethylene-butylene-styrene copolymers, styrene-isoprene copolymers, styrene-isoprene-styrene copolymers and maleic anhydride copolymers.

14. The multilayer protective film of claim 11, wherein the compatibilizer in said compatibilizing layer is a styrene-butadiene-styrene copolymer.

15. The multilayer protective film of claim 11, wherein the compatibilizer in said compatibilizing layer comprises from 10 percent to about 15 percent by weight of the multilayer protective film.

16. The multilayer protective film of claim 11, wherein said adhesive layer contains at least about 15 percent by weight of vinyl acetate.

17. The multilayer protective film of claim 16, wherein the vinyl acetate is in the form of EVA.

18. The multilayer protective film of claim 11, wherein the total thickness of the multilayer protective film is from about 1 mil to about 25 mils.

19. The multilayer protective film of claim 11, wherein the total thickness of the multilayer protective film is from about 6 mils to abut 15 mils.

20. The multilayer protective film of claim 11, wherein the thickness of said protective layer is from about 5 percent to about 65 percent of the thickness of the total film, the thickness of said compatibilizing layer is from about 30 percent to about 90 percent of the thickness of the total film, and the thickness of said adhesive layer is from about 5 percent to about 25 percent of the thickness of the total film.

21. The multilayer protective film of claim 11, wherein the thickness of said protective layer is from about 15 percent to about 30 percent of the thickness of the total film, the thickness of said compatibilizing layer is from about 45 percent to about 80 percent of the thickness of the total film, and the thickness of said adhesive layer is from about 5 percent to about 10 percent of the thickness of the total film.