Smoking article with liquid delivery material

1. A smoking article incorporating at least one liquid release component formed of a sustained-release liquid delivery material comprising:

a closed matrix structure comprising:

a polymer matrix defining a plurality of domains, wherein the polymer matrix is formed of one or more anionic polysaccharides cross-linked by multivalent cations and

a filler within the polymer matrix, the filler comprising one or more amphiphilic polysaccharides; and

a flavour composition that is trapped within the domains and is releasable from the closed matrix structure upon compression of the liquid release component,

wherein the one or more amphiphilic polysaccharides of the filler are selected from starch chemically modified to be amphiphilic and starch derivatives chemically modified to be amphiphilic, and

wherein the liquid delivery material comprises between 4 percent by weight and 15 percent by weight of the closed matrix structure and between 60 percent by weight and 90 percent by weight of the flavor composition, based on dry weight.

2. A smoking article according to claim 1 wherein the chemically modified starch includes octenyl succinic anhydride (OSA) starch.

3. A smoking article according to claim 1 wherein the amount of the filler in the closed matrix structure corresponds to between 10 percent and 30 percent by weight of the closed matrix structure, based on dry weight.

4. A smoking article according to claim 1 wherein the closed matrix structure further comprises a plasticiser.

5. A smoking article according to claim 1 wherein the one or more anionic polysaccharides in the polymer matrix include alginate.

6. A smoking article according to claim 5 wherein the alginate comprises at least 35 percent by weight guluronic acid residues.

7. A smoking article according to claim 1 wherein the amount of the anionic polysaccharide in the closed matrix structure is at least twice the amount of the amphiphilic polysaccharide, based on dry weight.

8. A smoking article according to claim 1 wherein the flavour composition comprises a flavourant mixed with one or more fats that are liquid at room temperature (22° C.).

9. A smoking article according to claim 8 wherein the flavour composition comprises menthol.

10. A smoking article according to claim 1 wherein the multivalent cations in the polymer matrix of the liquid delivery material are calcium ions.

11. A smoking article according to claim 1 wherein a concentration of multivalent cations in the closed matrix structure is highest in an outer region of the flavour release component where a degree of cross-linking is highest and decreases towards an inner core region of the flavour release component.

12. A filter for a smoking article incorporating at least one flavour release component formed of a sustained-release flavour delivery material, the sustained-release flavour delivery material comprising:

a closed matrix structure defining a plurality of domains, wherein the closed matrix structure comprises a polymer matrix of one or more anionic polysaccharides cross-linked by multivalent cations and a filler within the polymer matrix, the filler comprising one or more amphiphilic polysaccharides; and

a flavour composition that is trapped within the domains and is releasable from the closed matrix structure upon compression of the flavour release component,

wherein the one or more amphiphilic polysaccharides of the filler are selected from starch chemically modified to be amphiphilic and starch derivatives chemically modified to be amphiphilic, and

wherein the sustained-release flavour delivery material comprises between 4 percent by weight and 15 percent by weight of the closed matrix structure and between 60 percent by weight and 90 percent by weight of the flavor composition, based on dry weight.

13. A filter according to claim 12 wherein the one or more amphiphilic polysaccharides comprises octenyl succinic anhydride (OSA) starch.

14. A filter according to claim 12 wherein the amount of the filler in the closed matrix structure corresponds to between 10 percent and 30 percent by weight of the closed matrix structure, based on dry weight.

15. A filter according to claim 12 wherein the one or more anionic polysaccharides in the polymer matrix include alginate.

16. A flavour release component for a smoking article, wherein the flavour release component is formed of a flavour delivery material comprising:

a closed matrix structure defining a plurality of domains, wherein the closed matrix structure comprises a polymer matrix of one or more anionic polysaccharides cross-linked by multivalent cations and a filler within the polymer matrix, the filler comprising one or more amphiphilic polysaccharides; and

a flavour composition that is trapped within the domains and is releasable from the closed matrix structure upon compression of the material,

wherein the one or more amphiphilic polysaccharides of the filler are selected from starch chemically modified to be amphiphilic and starch derivatives chemically modified to be amphiphilic, and

wherein the flavour delivery material comprises between 4 percent by weight and 15 percent by weight of the closed matrix structure and between 60 percent by weight and 90 percent by weight of the flavor composition, based on dry weight.

17. A flavor release component according to claim 16 wherein the one or more amphiphilic polysaccharides comprises octenyl succinic anhydride (OSA) starch.

18. A flavor release component according to claim 16 wherein the amount of the filler in the closed matrix structure corresponds to between 10 percent and 30 percent by weight of the closed matrix structure, based on dry weight.

19. A flavor release component according to claim 16 wherein the one or more anionic polysaccharides in the polymer matrix include alginate.