1. A structure comprising a poly(hydroxyalkanoic acid) layer, at least one tie layer, and at least one sealant layer wherein
the structure is a film or sheet;
the tie layer is selected from the group consisting of a modified polyethylene, a modified polypropylene, a modified ethylene alkyl(meth)acrylaye copolymer, and combinations of two or more thereof in which the ethylene alkyl(meth)acryliate copolymer contains, by weight of the copolymer, 4 to 28% repeat units derived from alkyl(meth)acrylate;
in the modified polyethylene, the modified polypropylene, or the modified ethylene alkyl(meth)acrylaye copolymer, the polyethylene, the polypropylene, or the ethylene alkyl(meth)acrylaye copolymer is modified with an acid, an anhydride, or an epoxide; and
the sealant layer is selected from the group consisting of ethylene alkyl(meth)acrylaye copolymer, ethylene acid copolymer, ethylene ionomer, and combinations of two or more thereof.
2-3. (canceled)
4. (canceled)
5. The structure of claim 1 wherein
the tie layer is the modified ethylene alkyl(meth)acrylaye copolymer; and
the modified ethylene alkyl(meth)acrylaye copolymer is an ethylene alkyl(meth)acrylaye copolymer grafted with an acid, anhydride, epoxide, or an ethylene alkyl(meth)acrylaye copolymer produced by copolymerizing a monomer of the polymer with the acid, anhydride, or epoxide.
6. The structure of claim 5 wherein the tie layer is the modified ethylene alkyl(meth)acrylaye copolymer modified with the anhydride or epoxide.
7. (canceled)
8. The structure of claim 6 wherein the structure is a coextruded film or sheet, the sealant layer is the ethylene ionomer or the ethylene alkyl(meth)acrylate copolymer, and the poly(hydroxyalkanoic acid) is a poly(lactic acid).
9. The structure of claim 8 wherein the sealant layer is capable of fusion bonding onto another layer by heat sealing.
10. The structure of claim 9 wherein the sealant layer is the ethylene ionomer and the poly(hydroxyalkanoic acid) layer is oriented.
11. The structure of claim 1 comprising layers of, in the sequential order, a polylactic acid, an anhydride modified ethylene acrylate, a polyethylene, a polyethylene, an anhydride modified ethylene acrylate, a polyamide, an ethylene vinyl alcohol, a polyamide, an anhydride modified ethylene acrylate, a polyethylene, and a sealant layer wherein the anhydride modified ethylene acrylate is the modified ethylene alkyl meth(acrylate).
12. An article comprising the multilayer structure of claim 1.
13. The article of claim 12 wherein
the poly(hydroxyalkanoic acid) is a poly(lactic acid);
the tie layer is the modified ethylene alkyl(meth)acrylate copolymer; and
the sealant layer is the ethylene ionomer.
14. The article of claim 13 wherein the article is a packaging and the structure is present in or as a lidding film of the article.
15. A process comprising coextruding a layer poly(hydroxyalkanoic acid) composition, a tie layer, and a sealant layer to produce a coextruded tubular multilayer structure; cooling the coextruded tubular multilayer structure in a first bubble; orienting the coextruded tubular multilayer structure under heating in a second bubble to produce an oriented tubular multilayer structure; and relaxing the oriented tubular multilayer structure under heating in a third bubble to produce a multilayer structure wherein each of the tie layer and the sealant layer is the same as recited in claim 1.
16. The process of claim 15 wherein
the poly(hydroxyalkanoic acid) is a poly(lactic acid);
the tie layer is a modified polymer; the polymer of the modified polymer is a polyethylene or ethylene alkyl(meth)acrylate copolymer; and the polymer is modified with an anhydride or epoxide; and
the sealant layer is an ethylene ionomer.
17. The process of claim 15 wherein the orienting, the relaxing, or both, is carried out at a temperature between the glass transition temperature and the melting point of the poly(hydroxyalkanoic acid) polymer composition.
18. The process of claim 16 wherein the orienting, the relaxing, or both, is carried out at a temperature between the glass transition temperature and the melting point of the poly(hydroxyalkanoic acid) polymer composition.
19. The process of claim 18 wherein the temperature 60\xb0 C. to 85\xb0 C.
20. (canceled)
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A method of knitting a tubular knitted fabric using a flat knitting machine provided with at least a pair of front and back needle beds such that a front knitted fabric belonging to the front needle bed and a back knitted fabric belonging to the back needle bed are continuously formed on both sides in a knitting width and such that the number of wales is different between the front knitted fabric and the back knitted fabric, comprising:
a step on one side of carrying out turning such that the knitted fabrics caught on the needle beds on both sides have an equivalent number of wales, in which between continuous portions between a knitted fabric having a larger number of wales and a knitted fabric having a smaller number of wales, the continuous portion on one side in the knitting width is positioned between the pair of front and back needle beds, the needle bed to which the knitted fabric having a smaller number of wales belongs catches the knitted fabric having a smaller number of wales, the continuous portion on the other side, and an end portion of the knitted fabric having a larger number of wales, and the needle bed to which the knitted fabric having a larger number of wales belongs catches the knitted fabric having a larger number of wales except for the end portion; and
a step on the other side of carrying out turning such that the knitted fabrics caught on the needle beds on both sides have an equivalent number of wales, in which between the continuous portions between the knitted fabric having a larger number of wales and the knitted fabric having a smaller number of wales, the continuous portion on the other side in the knitting width is positioned between the pair of front and back needle beds, the needle bed to which the knitted fabric having a smaller number of wales belongs catches the knitted fabric having a smaller number of wales, the continuous portion on the one side, and an end portion of the knitted fabric having a larger number of wales, and the needle bed to which the knitted fabric having a larger number of wales belongs catches the knitted fabric having a larger number of wales except for the end portion,
wherein the step on the one side and the step on the other side are alternately repeated,
the knitted fabric having a larger number of wales is provided with a joint, within a range in which the joint is caught on the knitted fabric having a larger number of wales in both of the step on the one side and the step on the other side,
in the step on the one side, in the knitted fabric having a larger number of wales, a portion on the one side from the continuous portion on the one side to the joint is knitted,
in the step on the other side, in the knitted fabric having a larger number of wales, a portion on the other side from the continuous portion on the other side to the joint is knitted, and
the portion on the one side and the portion on the other side in the knitted fabric having a larger number of wales are linked to each other at the joint.
2. The method of knitting the tubular knitted fabric of claim 1, wherein in at least one of the front knitted fabric and the back knitted fabric, a dart is formed in a middle portion in the knitting width by decreasing and then increasing the number of wales in accordance with progress of course knitting.
3. The method of knitting the tubular knitted fabric of claim 2, wherein even when the knitted fabric in which the dart is formed is the knitted fabric having a smaller number of wales, the knitted fabric is knitted separately in the step on the one side and the step on the other side, and linking is carried out at the joint,
the joint is formed so as to be positioned on the same straight line in a wale direction, and
in each of the portion on the one side and the portion on the other side in the knitted fabric, a line in which a narrowing line is continued to a widening line of the dart is formed at the same interval from a line constituted by the joint.
4. The method of knitting the tubular knitted fabric of claim 1, wherein in at least one of the front knitted fabric and the back knitted fabric, a swell is formed in a middle portion in the knitting width by increasing and then decreasing the number of wales in accordance with progress of course knitting.
5. The method of knitting the tubular knitted fabric of claim 1, wherein in at least one of the front knitted fabric and the back knitted fabric, the number of wales is increased or decreased in accordance with progress of course knitting.
6. The method of knitting the tubular knitted fabric of claim 1, wherein the joint provided in the knitted fabric having a larger number of wales is knitted so as to be positioned on the same wale such that the joint is spaced away from the continuous portions between the front knitted fabric and the back knitted fabric, within a range of the knitting width in which the joint is caught on the same needle bed in both of the step on the one side and the step on the other side.
7. The method of knitting the tubular knitted fabric of claim 2, wherein the joint provided in the knitted fabric having a larger number of wales is knitted so as to be positioned on the same wale such that the joint is spaced away from the continuous portions between the front knitted fabric and the back knitted fabric, within a range of the knitting width in which the joint is caught on the same needle bed in both of the step on the one side and the step on the other side.
8. The method of knitting the tubular knitted fabric of claim 3, wherein the joint provided in the knitted fabric having a larger number of wales is knitted so as to be positioned on the same wale such that the joint is spaced away from the continuous portions between the front knitted fabric and the back knitted fabric, within a range of the knitting width in which the joint is caught on the same needle bed in both of the step on the one side and the step on the other side.
9. The method of knitting the tubular knitted fabric of claim 4, wherein the joint provided in the knitted fabric having a larger number of wales is knitted so as to be positioned on the same wale such that the joint is spaced away from the continuous portions between the front knitted fabric and the back knitted fabric, within a range of the knitting width in which the joint is caught on the same needle bed in both of the step on the one side and the step on the other side.
10. The method of knitting the tubular knitted fabric of claim 5, wherein the joint provided in the knitted fabric having a larger number of wales is knitted so as to be positioned on the same wale such that the joint is spaced away from the continuous portions between the front knitted fabric and the back knitted fabric, within a range of the knitting width in which the joint is caught on the same needle bed in both of the step on the one side and the step on the other side.