Multilayer structures, packages, and methods of making multilayer structures
View Patent ↗Multilayer structures, methods of making the same and packages made therefrom are provided. The multilayer structures are useful for packaging bone-in meat or other like products. More specifically, the multilayer structures have sufficient rigidity and strength to contain bone-in meat or other like products. In addition, multilayer structures can easily seal to themselves or to other structures. Moreover, the multilayer structures are biaxially oriented and heat-shrinkable.
1. A package comprising a multilayer structure and bone-in meat, the multilayer structure comprising:
an outer layer comprising polyethylene wherein the volume percent of the outer layer is between 5% and 25% of the multilayer structure;
a first polyamide layer, wherein said first polyamide layer comprises a blend of between 91% by weight and 99% by weight semi-crystalline polyamide and 1% by weight to 9% by weight amorphous polyamide, wherein the volume percent of the first polyamide layer is between 15% and 25% of the multilayer structure;
a first tie layer disposed between and in contact with each of said outer layer and said first polyamide layer, wherein the volume percent of the first tie layer is between 2% and 15% of the multilayer structure;
a second tie layer comprising polyamide disposed in contact with said first polyamide layer;
a second polyamide layer disposed in contact with said second tie layer, wherein said second polyamide layer comprises a blend of between 91% by weight and 99% by weight semi-crystalline polyamide, and between 1% by weight and 9% by weight amorphous polyamide, wherein the volume percent of the second polyamide layer is between 15% and 25% of the multilayer structure;
a sealant layer, wherein the sealant layer comprises polyethylene, wherein the volume percent of the sealant layer is greater than the volume percent of the outer layer; and
a third tie layer disposed between and in contact with each of said sealant layer and said second polyamide layer, wherein the volume percent of the third tie layer is between 2% and 15% of the multilayer structure,
wherein the multilayer structure is biaxially oriented,
wherein the multilayer structure has a low oxygen transmission rate due to the first and second polyamide layers, and
the package comprises a bone-in meat contained therein, where a bone of the bone-in meat protrudes from the meat and contacts the multilayer structure,
wherein the multilayer structure does not comprise a double wall or patch, is heat-shrinkable, annealed and has rigidity, strength, oxygen barrier and puncture resistance to hold the bone-in meat.
2. The multilayer structure of claim 1 wherein said first and said second polyamide layers comprise an equal percent by volume of the multilayer structure.
3. The multilayer structure of claim 1 wherein said sealant layer is between 25% by volume and 30% by volume of the multilayer structure and the outer layer is between 15% by volume and 20% by volume of the multilayer structure.
4. A bone-in meat package comprising:
a first wall comprising a multilayer structure comprising:
an outer layer comprising polyethylene wherein the volume percent of the outer layer is between 5% and 25% of the multilayer structure;
a first polyamide layer, wherein said first polyamide layer comprises a blend of 91% by weight to 99% by weight semi-crystalline polyamide and 1% by weight to 9% by weight amorphous polyamide, wherein the volume percent of the first polyamide layer is between 15% and 25% of the multilayer structure;
a first tie layer disposed between and in contact with each of said outer layer and said first polyamide layer, wherein the volume percent of the first tie layer is between 2% and 15% of the multilayer structure;
a second tie layer comprising polyamide disposed in contact with said first polyamide layer;
a second polyamide layer disposed in contact with said second tie layer, wherein said second polyamide layer comprises a blend of 91% by weight to 99% by weight semi-crystalline polyamide and 1% by weight to 9% by weight amorphous polyamide, wherein the volume percent of the second polyamide layer is between 15% and 25% of the multilayer structure;
a sealant layer, wherein said sealant layer comprises polyethylene, wherein the volume percent of the sealant layer is greater than the volume percent of the outer layer;
a third tie layer disposed between and in contact with each of said sealant layer and said second polyamide layer, wherein the volume percent of the third tie layer is between 2% and 15% of the multilayer structure;
wherein the multilayer structure is biaxially oriented,
wherein the multilayer structure has a low oxygen transmission rate due to the first and second polyamide layers,
wherein the multilayer structure is heat-shrunk around a bone-in meat and a bone of the bone-in meat protrudes from the meat and contacts the multilayer structure, and
wherein the multilayer structure is annealed and has rigidity, strength, oxygen barrier and puncture resistance to hold the bone-in meat and does not comprise a double wall or patch.
5. The package of claim 4 wherein said first and second polyamide layers comprise an equal percent by weight of the multilayer structure.
6. The package of claim 4 wherein said sealant layer is between 25% by volume and 30% by volume of the multilayer structure and the outer layer is between 15% by volume and 20% by volume of the multilayer structure.
7. A method of making a package comprising a multilayer structure and bone-in meat, the method comprising the steps of:
coextruding a multilayer structure comprising
an outer layer comprising polyethylene, wherein the volume percent of the outer layer is between 5% and 25% of the multilayer structure;
a first polyamide layer, comprising a blend of between 91% by weight and 99% by weight semi-crystalline polyamide and 1% by weight to 9% by weight amorphous polyamide, wherein the volume percent of the first polyamide layer is between 15% and 25% of the multilayer structure;
a first tie layer disposed between and in contact with each of said outer layer and said first polyamide layer, wherein the volume percent of the first tie layer is between 2% and 15% of the multilayer structure;
a second tie layer comprising polyamide disposed in contact with said first polyamide layer;
a second polyamide layer disposed in contact with said second tie layer comprising a blend of between 91% by weight and 99% by weight semi-crystalline polyamide, and between 1% by weight and 9% by weight amorphous polyamide, wherein the volume percent of the second polyamide layer is between 15% and 25% of the multilayer structure;
a sealant layer comprising polyethylene wherein the volume percent of the sealant layer is greater than the volume percent of the outer layer; and
a third tie layer disposed between and in contact with each of said sealant layer and said second polyamide layer, wherein the volume percent of the third tie layer is between 2% and 15% of the multilayer structure;
biaxially orienting said multilayer structure using a tubular process whereby each layer of the multilayer structure is coextruded together as a bubble, cooled, then reheated and oriented in both the longitudinal and transverse directions; and
annealing said multilayer structure,
wherein the multilayer structure has a low oxygen transmission rate due to the first and second polyamide layers, and
placing bone-in meat within the package and
heat shrinking the package around the bone-in meat, wherein a bone of the bone-in meat protrudes from the meat and contacts the multilayer structure, and
wherein the multilayer structure has rigidity, strength, oxygen barrier and puncture resistance to hold the bone-in meat and does not comprise a double wall or patch.
8. The method of claim 7 wherein the sealant layer is between 25% by volume and 30% by volume of the multilayer structure and the outer layer is between 15% by volume and 20% by volume of the multilayer structure.
9. The method of claim 7 further comprising a step of irradiating said multilayer structure to promote crosslinking between the layers of said multilayer structure, prior to the placing step.
10. The method of claim 7 further comprising a step of irradiating said multilayer structure to promote crosslinking within a layer of said multilayer structure, prior to the placing step.
11. The method of claim 7 further comprising a step of moisturizing said multilayer structure by applying water to said multilayer structure, prior to the placing step.
12. The method of claim 7 wherein the tubular process comprises a double bubble process.
13. The method of claim 12 , wherein the multilayer structure is oriented in the second bubble of the double bubble process.