A GLASS COMPOSITION

Abstract

An aerosol-generating device is provided, including: a heater, a component of the heater including a coating, the coating being formed from a glass composition including: between about 30 percent by weight and about 70 percent by weight silicon oxide, between about 0.1 percent by weight and about 10 percent by weight aluminium oxide, between about 2 percent by weight and about 30 percent by weight boron oxide, between about 2 percent by weight and about 40 percent by weight lithium oxide, between about 0.1 percent by weight and about 5 percent by weight magnesium oxide, and one or more of calcium oxide, gallium oxide, potassium oxide, samarium oxide, strontium oxide, and titanium oxide. An aerosol-generating system including an aerosol-generating article and the aerosol-generating device is also provided.

Claims

1.-15. (canceled)

16. An aerosol-generating device, comprising: a heater, wherein a component of the heater comprises a coating, wherein the coating is formed from a glass composition comprising: between about 30 percent by weight and about 70 percent by weight silicon oxide, between about 0.1 percent by weight and about 10 percent by weight aluminium oxide, between about 2 percent by weight and about 30 percent by weight boron oxide, between about 2 percent by weight and about 40 percent by weight lithium oxide, between about 0.1 percent by weight and about 5 percent by weight magnesium oxide, and one or more of calcium oxide, gallium oxide, potassium oxide, samarium oxide, strontium oxide, and titanium oxide.

17. The aerosol-generating device according to claim 16, wherein the glass composition further comprises at least 0.1 percent by weight calcium oxide.

18. The aerosol-generating device according to claim 17, wherein the glass composition further comprises between about 0.1 percent by weight and about 5 percent by weight calcium oxide.

19. The aerosol-generating device according to claim 18, wherein the glass composition further comprises between about 0.1 percent by weight and about 2.5 percent by weight calcium oxide.

20. The aerosol-generating device according to claim 16, wherein the glass composition further comprises at least 0.1 percent by weight gallium oxide.

21. The aerosol-generating device according to claim 16, wherein the glass composition further comprises between about 0.1 percent by weight and about 10 percent by weight gallium oxide.

22. The aerosol-generating device according to claim 16, wherein the glass composition further comprises at least 0.1 percent by weight samarium oxide.

23. The aerosol-generating device according to claim 16, wherein the glass composition further comprises at least 0.1 percent by weight strontium oxide.

24. The aerosol-generating device according to claim 16, wherein the glass composition further comprises at least 0.1 percent by weight titanium oxide.

25. The aerosol-generating device according to claim 16, wherein the glass composition further comprises between about 40 percent by weight and about 60 weight percent by weight silicon oxide.

26. The aerosol-generating device according to claim 16, wherein the component of the heater is a heating element.

27. The aerosol-generating device according to claim 26, wherein the heating element is a heating blade.

28. An aerosol-generating system, comprising: an aerosol-generating article; and an aerosol-generating device according to claim 16.

Description

[0121] FIG. 1 illustrates schematically an example of an aerosol-generating device including a heater, wherein a component of the heater has a coating formed from a glass composition as described herein; and

[0122] FIG. 2 illustrates schematically a cross-section view of the component of the heater shown in FIG. 1.

[0123] Aerosol-generating systems for delivering an aerosol to a user typically comprise an aerosol-generating device and an aerosol-generating article. An aerosol-generating device may comprise an atomiser configured to generate an inhalable aerosol from an aerosol-forming substrate provided in the aerosol-generating article. Some known aerosol-generating devices comprise a heater such as an electric heater or an inductive heating device. The heater is configured to heat and vaporise the aerosol-forming substrate to generate an aerosol. Typical aerosol-forming substrates for use in aerosol-generating systems are nicotine formulations, which may be liquid nicotine formulations comprising an aerosol former such as glycerine and/or propylene glycol.

[0124] During use of an aerosol-generating device, waste residue can build up on a surface of the atomiser. Therefore, atomisers, particularly heaters, should be cleaned regularly to keep them in good working order. However, if a component of an atomiser has a rough surface then the surface of that component becomes difficult to clean effectively and waste residue can be left behind after the component has been cleaned. Over time, this waste residue builds up on the atomiser surface, which leads to the performance of the atomiser deteriorating.

[0125] Aerosol-generating devices that have a heater may be particularly susceptible to the problem of waste residue building up on a surface of the heater. Aerosol-generating devices having a heating blade type heater may be more likely to experience a build-up of waste residue on their surface compared to other types of heaters.

[0126] It would be desirable to provide an aerosol-generating system in which a component or part of the heater is easy to clean.

[0127] The present inventors realised that the outer surface of one or more components of the heater can be coated in a glass composition in order to provide a smoother surface. For example, glass compositions are used for similar reasons in dental applications. However, such glass compositions need to be fired at a temperature above 900? C. Firing a component of a heater at such a high temperature can cause partial melting of parts of the heater, such as the gold and silver containing heating tracks. This partial melting may generate defects such as small bubbles on the surface of a glass coating, which may impact the smoothness of the coating and thus make the heater more difficult to clean.

[0128] It would therefore be desirable to provide a glass composition that can be used to provide a smooth outer coating, and that can also be fired at a relatively low temperature compared to conventional glass compositions.

[0129] The example of FIG. 1 shows a portion of an aerosol-generating device 1000.

[0130] The aerosol-generating device 1000 includes a heater 1010. The heater 1010 is for heating an aerosol-generating substrate contained within an aerosol-generating article. In the example of FIG. 1 the heater 1010 includes a heating blade 1020. In other examples, the heater 1010 may include an alternative heater arrangement.

[0131] In the example of FIG. 1, the heater 1010 is mounted within a receiving chamber.

[0132] The aerosol-generating device 1000 defines a plurality of air holes 1030 for allowing air to flow into an aerosol-generating article engaged with the aerosol-generating device 1000 and received within the receiving chamber.

[0133] The aerosol-generating device 1000 has a power supply. In the example of FIG. 1, the power supply is a battery 1040.

[0134] The aerosol-generating device 1000 includes control electronics 1050 for controlling operation of the aerosol-generating device 1000. The control electronics 1050 may include a processor or the like.

[0135] The example of the aerosol-generating device 1000 illustrated in FIG. 1 is designed to be engaged by an aerosol-generating article in order for an aerosol-forming substrate contained within the aerosol-generating article to be consumed.

[0136] In use, once an aerosol-generating article is engaged with the aerosol-generating device 1000, a user activates the heater 1010. The heater 1010 heats the aerosol-forming substrate to a temperature of about 375 degrees Celsius. At this temperature, volatile compounds are evolved from the aerosol-forming substrate. These compounds condense to form an aerosol. The user then draws on a mouth-end of the aerosol-generating article and the aerosol is drawn through a filter provided in the aerosol-generating article and into the user's mouth.

[0137] The example of FIG. 2 shows a cross-section view of the heating blade 1020 of FIG. 1.

[0138] The heating blade 1020 has a coating 1060 on at least part of its external surface. In some examples, the heating blade 1020 has a coating 1060 on all of its external surface.

[0139] The heating blade 1020 also includes one or more electrical tracks 1070.

[0140] The coating 1060 is formed from a glass composition. In one example, the glass composition includes between about 30 percent by weight and about 70 weight percent by weight silicon oxide; between about 0.1 percent by weight and about 10 percent by weight aluminium oxide; between about 2 percent by weight and about 30 percent by weight boron oxide; between about 2 percent by weight and about 40 percent by weight lithium oxide; between about 0.1 percent by weight and about 5 percent by weight magnesium oxide; and one or more of: calcium oxide, gallium oxide, potassium oxide, samarium oxide, strontium oxide and titanium oxide. In some examples, the glass composition also include fluorine.

[0141] Example compositions of the glass composition according to the invention (Examples A, B, C, D and E) are prepared having the compositions shown in Table 1.

TABLE-US-00001 TABLE 1 A B C D E Component Weight % Weight % Weight % Weight % Weight % Silicon Oxide SiO.sub.2 40.8 52.0 51.1 59.8 46.0 Aluminium Oxide Al.sub.2O.sub.3 4.5 1.0 1.8 1.8 5.0 Boron Oxide B.sub.2O.sub.3 19.6 9.2 9.1 4.0 18.6 Lithium Oxide Li.sub.2O 22.0 20.5 19.5 24.8 5.9 Magnesium Oxide MgO 2.5 2.0 0.8 2.2 2.5 Calcium Oxide CaO 2.5 2.2 1.7 0.5 0.2 Gallium Oxide Ga.sub.2O.sub.3 1.2 0.9 1.0 3.2 3.9 Potassium Oxide K.sub.2O 0.5 0.1 3.8 2.5 6.2 Samarium Oxide Sm.sub.2O.sub.3 2.2 1.2 1.9 0.2 2.5 Strontium Oxide SrO 2.0 4.0 3.5 0.1 0.3 Titanium Oxide TiO.sub.2 1.2 6.0 5.0 0.4 6.5 Fluorine F.sub.2 1.0 0.9 0.8 0.5 2.4

[0142] The compositions of Examples A, B, C, D and E form deep multicomponent eutectics, which combine fusibility with high hardness.

[0143] A coating 1060 having a glass composition of Examples A, B, C, D and E is prepared and applied to a heating blade 1020 by: [0144] mixing the starting materials together (see Table 2 below); [0145] pouring the mixed starting materials into a crucible able to sustain very high temperatures, such as a crucible formed from aluminium oxide or silicon oxide; [0146] melting the starting materials by heating the crucible to 1200? C.-1300? C. for 30-60 minutes in an electric furnace; [0147] granulating the melted material; [0148] drying and milling the granulated material in a ball mill; [0149] sieving the milled material to remove particles larger than 30 ?m; [0150] mixing the sieved material with an organic liquid to form a fluid; [0151] spray coating the fluid onto the surface of the heating blade to form a coating; [0152] drying the coating by placing the heating blade in a drying oven for 10 minutes at 150? C. and then for 20 minute at 300? C.; and [0153] firing the heating blade in a furnace for 20 minutes at 595? C. to 620? C.

[0154] In some examples, instead of being spray coated, the fluid may be screen printed on to the heating blade 1020.

[0155] Accordingly, glasses having the compositions of Examples A, B, C, D and E are formed at temperatures that are around 250? C. below the firing temperature of conventional glass.

[0156] Glasses formed from the glass compositions of Examples A, B, C, D and E are able to be used as smooth coatings with a Vickers micro hardness of between 750 and 780 kg/mm 2.

[0157] The starting materials for the glass compositions of Examples A, B, C, D and E include the following materials shown in Table 2.

TABLE-US-00002 TABLE 2 Oxides Carbonates Fluorides Silicon SiO.sub.2 Lithium Li.sub.2CO.sub.3 Lithium LiF Aluminium Al.sub.2O.sub.3 Potassium K.sub.2CO.sub.3 Potassium KF Gallium Ga.sub.2O.sub.3 Calcium CaCO.sub.3 Calcium CaF.sub.2 Samarium Sm.sub.2O.sub.3 Strontium SrCO.sub.3 Magnesium MgF.sub.2 Titanium TiO.sub.2 Aluminium AlF.sub.3 Calcium CaO Samarium SmF.sub.3 Magnesium MgO

[0158] Table 3 shows the roughness of the Example glass compositions A, B, C, D and E.

TABLE-US-00003 TABLE 3 A B C D E Roughness 0.05 0.002 0.02 0.06 0.09 (Ra, ?m)

[0159] A baseline roughness (Ra) of industrial glass is 0.135 ?m.

[0160] Accordingly, the data of Table 3 shows that the glass compositions of all of the Examples A, B, C, D and E form glasses having a roughness that is much lower than industrial glass. Indeed, the glasses formed from the glass compositions of Examples B and C have the smoothest surfaces of the Examples.

[0161] Glass that is made using the glass compositions of the Examples A, B, C, D and E may therefore provide a smooth, hard surface that is defect-free and can be formed at a relatively low firing temperature. Thus, when the glass is used as a coating on a component of a heater of an aerosol-generating device, the resulting smooth surface allows for the component to be easier to clean. The relatively low firing temperature, which is about 250? C. below typical firing temperatures, means that delicate electrical tracks within the heater are not damaged during the firing process. This also improves the resulting smoothness of the outer surface of the component. By making a component of the heater easier to clean, deterioration of the heater is reduced, which improves the overall performance of the aerosol-generating device.

[0162] The examples described above are not intended to limit the scope of the claims. Other examples consistent with the exemplary examples described above will be apparent to those skilled in the art. Features described in relation to one example may also be applicable to other examples.