Claims
- 1. A process of making a biaxially-oriented multilayer film, comprising:(A) extruding a tubular multilayer tape comprising: (i) a first layer comprising a composition consisting essentially of a first polyamide and a second polyamide, wherein the first polyamide is a crystalline polyamide and wherein the second polyamide is a crystalline copolyamide, wherein the second polyamide has a different crystal structure than the first polyamide, and the first layer has a thickness of from about 2 to 12 percent, based on a total thickness of the tape; (ii) a second layer comprising a first polyolefin; (iii) a third layer which is an O2-barrier layer comprising at least one member selected from the group consisting of ethylene/vinyl alcohol copolymer, polyvinylidene chloride, and polyalkylene carbonate, the third film layer having a thickness of less than about 15 percent, based on a total thickness of the tape; (iv) a fourth layer comprising a second polyolefin; (B) inflating the tape so that the tape is biaxially oriented by stretching in a transverse direction and machine direction, so that a tubular multilayer film is formed.
- 2. The process according to claim 1, wherein the composition comprises the first polyamide in an amount of from about 10 to 95 percent, based on the weight of the composition.
- 3. The process according to claim 1, wherein the composition comprises the first polyamide in an amount of from about 60 to 95 percent, based on the weight of the composition.
- 4. The process according to claim 1, wherein the composition comprises the first polyamide in an amount of from about 85 to 95 percent, based on the weight of the composition.
- 5. The process according to claim 1, wherein the O2-barrier layer comprises ethylene/alcohol copolymer, and wherein the second layer is between the third layer and the fourth layer, and the fourth layer is an inside layer of the tubing.
- 6. The process according to claim 5, wherein:the first polyolefin comprises at least one member selected from the group consisting of polyethylene homopolymer, polypropylene homopolymer, polybutylene homopolymer, ethylene/alpha-olefin copolymer, propylene/alpha-olefin copolymer, butene/alpha-olefin copolymer, ethylene/unsaturated ester copolymer, ethylene/unsaturated acid copolymer; and the second polyolefin comprises at least one member selected from the group consisting of polyethylene homopolymer; polypropylene homopolymer, polybutylene homopolymer, ethylene/alpha-olefin copolymer, propylene/alpha-olefin copolymer, butene/alpha-olefin copolymer, ethylene/unsaturated ester copolymer, ethylene/unsaturated acid copolymer.
- 7. The process according to claim 6, wherein the tube further comprises the fifth layer which comprising a third polyolefin which comprises at least one member selected from the group consisting of ethylene/alpha-olefin copolymer, ethylene/unsaturated ester copolymer, and ethylene/unsaturated acid copolymer, and wherein the third layer is between the fourth layer and the fifth layer.
- 8. The process according to claim 7, wherein the tube further comprises a sixth layer and a seventh layer, wherein:the sixth layer comprises at least one member selected from the group consisting of anhydride grafted polyolefin and acid modified polyolefin; the seventh layer comprises at least one member selected from the group consisting of anhydride grafted polyolefin and acid modified polyolefin; and the sixth layer is between the second layer and the third layer, and the seventh layer is between the third layer and the fifth layer.
- 9. The process according to claim 8, wherein the third layer is between the fourth layer and the fifth layer.
- 10. The process according to claim 1, wherein biaxial orientation is carried out at an orientation temperature of from about 180° F. to 280° F.
- 11. The process according to claim 10, wherein biaxial orientation is carried out at an orientation temperature of from about 160° F. to 205° F.
- 12. The process according to claim 11, wherein the tube is heated in hot water immediately before biaxial orientation.
- 13. The process according to claim 12, wherein biaxial orientation is carried out at an orientation temperature of from about 180° F. to 205° F.
- 14. The process according to claim 13, wherein the tube is heated with water having a temperature of from about 185° F. to 212° F., for a time of from about 3 to 50 seconds.
- 15. The process according to claim 14, wherein the film has a total free shrink of from about 5 to 140 percent.
- 16. The process according to claim 15, wherein the film has a total free shrink of from about 10 to 80 percent.
- 17. The process according to claim 16, wherein the film has a total free shrink of from about 20 to 60 percent.
- 18. The process according to claim 1, further comprising the step of coating an outside surface of the tubular multilayer film with oil.
- 19. The process according to claim 1, wherein the second polyamide is selected from the group consisting of nylon 6/12, nylon 6/69, nylon 66/610, and mixtures thereof.
Parent Case Info
This is a Divisional Application of application Ser. No. 08/480,635 filed Jun. 7, 1995, now abandoned, which is a Continuation-in-Part of application Ser. No. 07/893,638, filed Jun. 5, 1992, now abandoned.
US Referenced Citations (34)
Foreign Referenced Citations (22)
Number |
Date |
Country |
90 07 334 |
Apr 1991 |
DE |
0 149 321 A1 |
Jul 1985 |
EP |
0 170 385 |
Feb 1986 |
EP |
0 269 325 A2 |
Jun 1988 |
EP |
0 325 151 A2 |
Jul 1989 |
EP |
0 325 151 |
Jul 1989 |
EP |
0 331 509 A2 |
Sep 1989 |
EP |
0 331 509 |
Sep 1989 |
EP |
0 358 038 |
Mar 1990 |
EP |
0 358 038 A1 |
Mar 1990 |
EP |
0 386 759 A2 |
Sep 1990 |
EP |
0 408 390 |
Jan 1991 |
EP |
0 451 977 A1 |
Oct 1991 |
EP |
0 465 931 |
Jan 1992 |
EP |
0 465 931 A2 |
Jan 1992 |
EP |
0 467 039 |
Jan 1992 |
EP |
0 573 306 |
Dec 1993 |
EP |
222632 |
Jul 1989 |
NZ |
232235 |
Apr 1991 |
NZ |
WO 9003414 |
Apr 1990 |
WO |
WO 9215641 |
Sep 1992 |
WO |
WO 9303093 |
Feb 1993 |
WO |
Non-Patent Literature Citations (4)
Entry |
Journal of Polymer Science, Wild et al., vol. 20, pp. 441-455, “Determination of Branching Distributions in Polyethylene and Ethylene Copolymers”. |
ASTM Standard 2732, pp. 368-371, “Standard Test Method for Unrestrained Linear Thermal Shrinkage of Plastic film and Sheeting”. |
Dr. Siggi Schaaf, “Polyamides (Nylons) -the most important engineering plastics”. |
X-ray Diffraction Methods in Polymer Science, Alexander, Leroy E. John Wiley & Sons, New York, pp. 491-494, 1969. |
Continuation in Parts (1)
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Number |
Date |
Country |
Parent |
07/893638 |
Jun 1992 |
US |
Child |
08/480635 |
|
US |