Stemware manufacturing method and stemware

Abstract

To provide a method for manufacturing stemware which can be optically produced, can be easily manufactured, and is hard to break even though it is made of glass. [Solution] A glass pool 11 is formed at the bottom of a ball portion 1, white glass C is inserted into the glass pool 11, and then the glass pool 11 is stretched along the longitudinal direction of the white glass C to form a stem portion 2. Thereafter, a plate portion 3 is formed at the end of the stem portion 2 to manufacture stemware A.

Description

[Technical field]

[0001] The present invention relates to a method for manufacturing stemware, and to stemware. More specifically, the present invention relates to a method for manufacturing stemware that is capable of optical presentation, can be easily manufactured, and is not easily broken despite being made of glass, and to the stemware. [Background technology]

[0002] Stemware is a drinking glass with a handle at the bottom, typically a wine glass or champagne glass. Stemware consists of a bowl into which the drink is poured, a stem that serves as a handle, and a plate that serves as the base.

[0003] Wine, champagne, and the like are everyday drinks, but are also enjoyed at festive occasions such as celebrations and parties, and are therefore often placed on colorfully decorated tables.

[0004] However, most stemware is not only simple in shape but also made of a single material, transparent glass, which makes it lacking in glamour. This makes it unsuitable for a party or other occasion.

[0005] In order to solve this problem and create an optical atmosphere, a "luminous glass" with a luminous member attached inside the stem has been disclosed, as shown in Patent Document 1. That is, this luminous glass has a luminous member with a chemical luminescent agent as a light source disposed inside the stem. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 8-299144 Summary of the Invention [Problem to be solved by the invention]

[0007] However, the luminous glass described in Patent Document 1 needs to have a hollow stem in order to insert the luminous member, and it is difficult to manufacture it from glass material. In addition, it is difficult to ensure the strength of a hollow stem, and even if it could be manufactured, it would be very fragile.

[0008] Incidentally, the luminous glass described in Patent Document 1 (luminous glass having a hollow stem portion) can be manufactured from materials other than glass (e.g., plastic materials, etc.), which makes manufacturing easier and ensures strength; however, plastic materials, etc. are inferior to glass materials in terms of gloss and brilliance.

[0009] The present invention has been devised in consideration of the above points, and aims to provide a method for manufacturing stemware that is capable of optical presentation, is easy to manufacture, and is not easily broken despite being made of glass, as well as a stemware manufacturing method. [Means for solving the problem]

[0010] In order to achieve the above-mentioned object, the manufacturing method of stemware of the present invention includes a ball portion forming step of forming a ball portion of a predetermined shape having a glass pool portion made of molten transparent glass at the bottom; an insertion step of inserting colored glass into the glass pool portion; a stem portion forming step of melting the colored glass inserted into the glass pool portion and then stretching the glass pool portion with the colored glass contained therein to form a stem portion; and a plate portion forming step of attaching molten transparent glass to the end of the stem portion to form a plate portion of a predetermined shape.

[0011] Here, by using the ball portion forming process to form a ball portion of a specified shape having a glass pool portion made of molten transparent glass at the bottom, a glass pool portion can be formed at the bottom of the ball portion to serve as a base for inserting colored glass in the insertion process described below.

[0012] Furthermore, by the insertion step of inserting colored glass into the glass pool, the colored glass can be disposed inside the transparent glass of the glass pool (the transparent glass of the glass pool can contain the colored glass). In this case, "contained" does not only refer to the case where "all" of the colored glass is placed inside the glass reservoir, but also includes the case where "part" of the colored glass is placed inside the glass reservoir (i.e., the case where "another part" of the colored glass is placed outside the glass reservoir).

[0013] In addition, the colored glass inserted in the glass pool is melted, and then the glass pool is stretched while containing the colored glass to form a stem portion in a stem formation process, which makes it possible to form "a stem portion having a central portion made of colored glass and a peripheral portion made of clear glass arranged around the central portion" at the bottom of the ball portion.

[0014] Here, because of "the stem portion having a central portion made of colored glass and a peripheral portion made of transparent glass arranged around the central portion," when light is shone on it from above, the stem portion appears to glow (specifically, the colored glass itself appears to emit light). In addition, the "stem portion having a center portion made of colored glass and a peripheral portion made of transparent glass arranged around the center portion" gives the stem portion a special aesthetic look, even when no light is shining on it, creating a gorgeous appearance.

[0015] On the other hand, when the stem portion is made up of "only colored glass" (no transparent glass) or when the stem portion is made up of "only transparent glass" (no colored glass), the stem portion is unlikely to appear to glow even when light is shone on it from above. Furthermore, when the stem portion is made up of "only colored glass" (no clear glass) or when the stem portion is made up of "only clear glass" (no colored glass), even when no light is shining on it, the stem portion has a simple structure (only colored glass, only clear glass) and is unable to create a gorgeous appearance.

[0016] Furthermore, by stretching the glass reservoir portion while it contains colored glass (in other words, by stretching the glass reservoir portion while it is solid), the stem portion can be formed relatively easily (at least compared to the case where a hollow stem portion is formed, the stem portion can be formed easily).

[0017] Furthermore, by stretching the glass pool at the bottom of the ball portion to form the stem portion (in other words, by forming the stem portion integrally with the ball portion), there is no joint (seam) between the ball portion and the stem portion, and a visually beautiful stemware with physical integrity can be obtained.

[0018] Furthermore, if the "ball portion of a specified shape" and the "stem portion of a specified shape" are manufactured separately and then joined together, the joint (seam) will be noticeable and the joint will be large (thick), resulting in a loss of physical integrity.

[0019] Furthermore, the plate portion can be formed integrally with the stem portion through the plate portion forming process, in which molten transparent glass is attached to the end of the stem portion to form a plate portion of a specified shape. This means that there is no joint (seam) between the stem portion and the plate portion, and a visually beautiful stemware product with physical integrity can be obtained.

[0020] Furthermore, if the "stem portion of a specified shape" and the "plate portion of a specified shape" are manufactured separately and then joined together, the joint (seam) will be noticeable and the joint will be larger (thicker), resulting in a loss of physical integrity.

[0021] Furthermore, when the insertion process involves inserting white glass, which is a colored glass containing sodium silicofluoride at a ratio of 1.3 wt% to 3.5 wt% relative to the weight (total weight) of the transparent glass, it is possible to form a "stem portion having a central portion made of white glass and a peripheral portion made of transparent glass arranged around the central portion," and when light is shone on it from above, the stem portion appears to shine even more.

[0022] When a beverage (e.g., wine) is poured into the bowl and light is shone on it from above, light reflecting the color of the beverage enters the stem. If the center is made of "white glass," the stem will appear to glow in the color of the beverage (specifically, the white glass itself will appear to glow in the color of the beverage).

[0023] Here, if the proportion of sodium silicofluoride relative to the weight (total weight) of the transparent glass is less than 1.3 wt %, the white glass becomes too close to colorless transparency (too little whiteness) and the transmittance of the white glass becomes too high, making it difficult for diffuse reflection of incident light to occur within the white glass and making the stem shiny and difficult to see.

[0024] On the other hand, if the proportion of sodium silicofluoride exceeds 3.5 wt% relative to the weight (total weight) of the transparent glass, the white glass becomes too close to white (too white) and the transmittance of the white glass becomes too low, making it difficult for incident light to enter the white glass and making the stem shiny and difficult to see.

[0025] Furthermore, when the insertion step involves inserting white glass, which is a colored glass containing sodium silicofluoride at a ratio of 2.0 wt% to 3.5 wt% relative to the weight (total weight) of the transparent glass, it becomes easier to form the white glass in a straight line within the stem portion.

[0026] Here, if the ratio of sodium silicofluoride to the weight (total weight) of the transparent glass is less than 2.0 wt %, when the glass reservoir portion containing colored glass (white glass) is stretched to form the stem portion, the white glass is likely to become irregularly distorted and assume a crooked shape.

[0027] Furthermore, the higher the proportion of sodium silicofluoride, the less likely the white glass will become irregularly distorted and crooked, and the more likely it is that the stem will be finished into a straight, beautiful stem. However, as mentioned above, if the proportion of sodium silicofluoride exceeds 3.5 wt% relative to the weight of the transparent glass (total weight), the stem will become shiny and difficult to see.

[0028] Furthermore, when the insertion process involves inserting a rod-shaped body of colored glass into a glass pool, and the stem formation process involves stretching the glass pool in the longitudinal direction of the rod-shaped body of colored glass to form the stem, it becomes easier to stretch the glass pool in a linear manner, making it relatively easy to form the stem.

[0029] For example, by placing the colored glass in the center of the glass pool (the center in a plane perpendicular to the longitudinal direction of the colored glass) so that the "longitudinal direction of the colored glass" coincides with the "pulling direction of the glass pool," and focusing on making the colored glass form a straight line, the glass pool can be easily stretched in a linear manner.

[0030] Furthermore, if the insertion process involves heating the rod-shaped colored glass to an extent that it can maintain its shape, and then inserting the colored glass into the glass pool, the colored glass can be easily inserted into the desired position (for example, the center in a plane perpendicular to the longitudinal direction of the colored glass), and after insertion, the glass pool can be stretched. That is, since the colored glass is rod-shaped, it can be easily inserted into the desired position. Also, the colored glass is preheated (but only to the extent that it can maintain its shape), and after it is inserted into the glass pool (molten transparent glass), the heat transferred from the glass pool also helps to melt the colored glass sufficiently, so that the glass pool can be stretched after insertion.

[0031] Furthermore, when the stem portion forming process involves heating the glass pool into which colored glass has been inserted and then stretching the glass pool to form the stem portion, even if the colored glass inserted in the glass pool is not sufficiently melted, the clear glass and colored glass can both be heated and maintained at appropriate temperatures during the process, so that the clear glass and colored glass can be easily stretched.

[0032] In addition, in order to achieve the above-mentioned object, the stemware of the present invention comprises a ball portion made of transparent glass, a stem portion supporting the ball portion and having a central portion made of colored glass and a peripheral portion made of transparent glass arranged around the central portion, and a plate portion on which the stem portion is erected and made of transparent glass, wherein the colored glass is white glass containing sodium silicofluoride in a ratio of 1.3 wt% to 3.5 wt% relative to the weight of the transparent glass.

[0033] Here, due to the "center part made of white glass containing sodium silicofluoride at a ratio of 1.3 wt% to 3.5 wt% relative to the weight (total weight) of the transparent glass, and the stem part arranged around the center part and having a peripheral part made of transparent glass," when light is shone on it from above, the stem part appears to glow (specifically, the white glass itself appears to emit light).

[0034] In addition, when a beverage (e.g., wine) is poured into the bowl and light is shone on it from above, light reflecting the color of the beverage enters the stem, but because the center is "white glass," the stem appears to glow in the color of the beverage (specifically, the white glass itself appears to glow in the color of the beverage).

[0035] Furthermore, the "stem portion having a center portion made of white glass and a peripheral portion made of transparent glass arranged around the center portion" gives the stem portion a special aesthetic look and creates a gorgeous appearance even when no light is shining on it.

[0036] Here, if the proportion of sodium silicofluoride relative to the weight (total weight) of the transparent glass is less than 1.3 wt %, the white glass becomes too close to colorless transparency (too little whiteness) and the transmittance of the white glass becomes too high, making it difficult for diffuse reflection of incident light to occur within the white glass and making the stem shiny and difficult to see.

[0037] On the other hand, if the proportion of sodium silicofluoride exceeds 3.5 wt% relative to the weight (total weight) of the transparent glass, the white glass becomes too close to white (too white) and the transmittance of the white glass becomes too low, making it difficult for incident light to enter the white glass and making the stem shiny and difficult to see. Effect of the Invention

[0038] The method for manufacturing stemware according to the present invention allows for optical presentation, can be easily manufactured, and can provide stemware that is not easily broken despite being made of glass. Furthermore, the stemware according to the present invention is capable of producing optical effects, is easy to manufacture, and is not easily broken despite being made of glass. [Brief description of the drawings]

[0039] [Figure 1] 1 is a schematic diagram for explaining an example of stemware to which the present invention is applied. [Diagram 2] 1 is a process diagram of an example of a method for manufacturing stemware to which the present invention is applied. [Diagram 3] FIG. 11 is a schematic diagram for explaining a ball portion forming step. [Figure 4] FIG. 13 is a schematic diagram for explaining an insertion process. [Diagram 5] FIG. 11 is a schematic diagram for explaining a stem portion forming step. [Figure 6] FIG. 11 is a schematic diagram for explaining a plate portion forming step. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0040] Hereinafter, modes for carrying out the invention (hereinafter, referred to as "embodiments") will be described. The description will be made in the following order. 1. First embodiment 2. Second embodiment 3. Variations

[0041] <1. First embodiment> [Configuration Description] FIG. 1 is a schematic diagram for explaining an example of stemware to which the present invention is applied. The stemware A shown here is composed of a bowl portion 1 into which the beverage is poured, a stem portion 2 which extends continuously from the bottom 10 of the bowl portion 1 to support the bowl portion 1 and serve as a handle when the stemware A is in use, and a disc-shaped plate portion 3 on which the stem portion 2 is erected and which supports the bowl portion 1 and the stem portion 2.

[0042] The ball portion 1 is made of transparent glass G, has a height of about 110 mm, a diameter of the lower protruding portion of about 80 mm, an aperture of about 55 mm, and is formed in a shape that tapers gradually toward the top.

[0043] The stem portion 2 is composed of a central portion 20 made of white glass C and a peripheral portion 21 made of transparent glass G over almost its entire length, with the peripheral portion 21 covering the outside of the central portion 20, and is formed in an approximately cylindrical shape with a length of approximately 100 mm and a diameter of approximately 4.5 mm (of which the diameter of the central portion 20 is 1.5 mm to 2.5 mm).

[0044] The plate portion 3 is made of transparent glass G, and is formed in a disk shape with a height of about 10 mm and a diameter of about 80 mm.

[0045] Here, the transparent glass G constituting the ball portion 1, the peripheral portion 21 of the stem portion 2, and the plate portion 3 contains the components shown in Table 1.

[0046] [Table 1]

[0047] The white glass C constituting the central portion 20 of the stem portion 2 contains the components of the transparent glass G described above, as well as the white pigment "sodium silicofluoride." Specifically, sodium silicofluoride is contained at a ratio of 3.0 wt % with respect to the weight (total weight) of the transparent glass G.

[0048] [effect] In the stemware A to which the present invention is applied described above, when a translucent beverage W (e.g., red wine) is poured into the bowl portion 1 and light L is irradiated from above, the color of the beverage W (red in the case of red wine) is reflected in the light L' transmitted through the bowl portion 1. Then, the light L' (light reflecting the color of the beverage W) transmitted through the bowl portion 1 enters the center portion 20 of the stem portion 2, and the center portion 20 appears to emit the color of the beverage W, making it possible to create an optical effect.

[0049] Specifically, "light L' reflecting the color of beverage W" incident on center portion 20 is diffusely reflected within center portion 20, causing center portion 20 to exhibit the color of beverage W. In addition, peripheral portion 21 acts as a lens, making the color of center portion 20 easier to see, and as described above, center portion 20 appears to exhibit the color of beverage W.

[0050] For convenience, Figure 1 only shows light L coming from vertically above; however, when light L coming from an oblique direction (a direction having a predetermined angle with the vertical axis) passes through the bowl portion 1 and light L' coming from an oblique direction is incident on the center portion 20, the center portion 20 will similarly appear to emit the color of the beverage W.

[0051] Furthermore, the stemware A to which the present invention is applied has a solid stem portion 2, which makes it easier to ensure strength compared to a hollow stem portion (for example, the stem portion of the luminous glass described in Patent Document 1).As a result, a thin diameter of approximately 4.5 mm can be achieved, which, combined with the optical effects described above, gives the stem portion a special aesthetic appearance.

[0052] [Variation 1] In the above-mentioned first embodiment, the transparent glass G contains the components shown in Table 1, but the components are not limited to these.

[0053] [Variation 2] In addition, in the above-mentioned first embodiment, an explanation is given using an example of white glass C containing sodium silicofluoride at a ratio of "3.0 wt%" relative to the weight (total weight) of transparent glass G, but this is not necessarily limited to "3.0 wt%."

[0054] Table 2 shows the relationship between the "proportion of sodium silicofluoride relative to the weight (total weight) of transparent glass G" and the "transmittance."

[0055] [Table 2]

[0056] From Table 2, it can be seen that when the ratio of sodium silicofluoride to the weight (total weight) of transparent glass G is "1.0 wt% or less" or "1.2 wt%", the transmittance of center portion 20 exceeds 90%. And, when the transmittance exceeds 90%, diffuse reflection of incident light in center portion 20 is difficult to occur, and the color development of center portion 20 is poor.

[0057] Furthermore, it can be seen from Table 2 that when the ratio of sodium silicofluoride to the weight (total weight) of transparent glass G is "4.0 wt% or more," the transmittance of center portion 20 is 0%. And, when the transmittance is 0%, incident light cannot enter center portion 20, and the color development of center portion 20 is poor.

[0058] Therefore, the proportion of sodium silicofluoride relative to the weight (total weight) of the transparent glass G does not necessarily have to be "3.0 wt%", but in order to achieve good color development in the center portion 20, it is preferable that it be "1.3 wt% to 3.5 wt%".

[0059] <2. Second embodiment> A method for producing the above-mentioned stemware A will be described below. That is, an example of a method for producing stemware to which the present invention is applied will be described.

[0060] [Production method description] FIG. 2 is a process diagram of an example of a method for producing stemware to which the present invention is applied, and stemware A is produced through steps (1) to (7). (1) Melting process (2) Ball part forming process (3) Insertion process (4) Stem part formation process (5) Plate part forming process (6) Annealing process (7) Finishing and inspection process

[0061] Each of the above steps (1) to (7) will now be described in detail.

[0062] (1) Melting process In one example of a method for manufacturing stemware to which the present invention is applied, first, sodium oxide, etc. is added to silica to obtain the component ratio of transparent glass G shown in Table 1, and the mixture is heated to 1250°C in a glass melting furnace (not shown) to melt it (see symbol ST1 in Figure 2).

[0063] After the transparent glass G is melted, an appropriate amount of the molten transparent glass G is removed from the glass melting furnace using a blowpipe (hollow rod-shaped body) B. Specifically, the transparent glass G is wound around one end of the blowpipe B, and an appropriate amount of seed glass is removed from the glass melting furnace.

[0064] (2) Ball part forming process The 1250°C high-temperature glass (seed glass) removed from the glass melting furnace is cooled to approximately 800°C in approximately 90 seconds, and the wound-up transparent glass G is shaped into a hollow sphere by blowing air into it from the other end of the blowpipe B (the end opposite to the end where the transparent glass G is wound up).

[0065] Next, as shown in Figure 3, a hollow spherical piece of transparent glass G is placed into a form M, and air is blown into it from the other end of a blowpipe B (the symbol Br in Figure 3 indicates "blow in") to inflate the sphere and form a ball portion 1, and a glass reservoir portion 11 is formed at the bottom of the ball portion 1 (see symbol ST2 in Figure 2).

[0066] (3) Insertion process After forming the ball portion 1 and the glass pool portion 11, the glass pool portion 11 is heated to a temperature of approximately 800°C using a gas burner, and 20 mm to 30 mm of the tip portion of a rod-shaped white glass C is inserted along the longitudinal direction of the white glass C near the center of the glass pool portion 11, as shown in Figures 4(a) and (b).

[0067] Next, a gas burner is used to heat the boundary between the "inserted portion of the white glass C" and the "exposed portion (non-inserted portion) of the white glass C" to melt the white glass C, forming a state in which a length of the white glass C of approximately 20 mm to 30 mm is inserted in the glass reservoir portion 11, as shown in FIG. 4(c) (see symbol ST3 in FIG. 2).

[0068] (4) Stem part formation process From the state in which the white glass C is inserted into the glass reservoir portion 11 (the white glass C is surrounded by the transparent glass G), as shown in Figure 5, the glass reservoir portion 11 is gradually stretched using a tool such as pincers D to form the stem portion 2 (see symbol ST4 in Figure 2).

[0069] Here, when the glass pool portion 11 is stretched, the white glass C inserted therein is also stretched, and a stem portion 2 is formed over almost its entire length, which is composed of a central portion 20 made of white glass C and a peripheral portion 21 made of transparent glass G.

[0070] It should be noted that by stretching the glass pool portion 11 while paying attention so that the white glass C is stretched in a straight line, a straight stem portion 2 can be formed relatively easily.

[0071] (5) Plate part forming process After forming the stem portion 2, as shown in FIG. 6(a), molten transparent glass G (seed glass) is attached to the end of the stem portion 2 (the end opposite the ball portion 1), and as shown in FIG. 6(b)(c), the shape is adjusted using wet wooden trowels E1, E2, etc. to form a disk-shaped plate portion 3 (see symbol ST5 in FIG. 2).

[0072] Since the central portion 20 made of the white glass C extends to the end of the stem portion 2 (the end opposite to the ball portion 1), the position where the seed glass is to be attached can be easily grasped.

[0073] (6) Annealing process After the plate portion 3 is formed, the stemware A is placed in an annealing furnace at about 230° C., and the temperature of the furnace is lowered to about 80° C. to 90° C. over about three hours, after which the stemware A is taken out (see symbol ST6 in FIG. 2). Such an annealing treatment can remove the internal stress of the stemware A and improve the performance of the glass.

[0074] (7) Finishing and inspection process The finishing process involves cutting off excess transparent glass G, polishing the mouth of ball portion 1 to make it flat, and heating the mouth of ball portion 1 to approximately 300°C to smooth the edges (see symbol ST7 in Figure 2).

[0075] The inspection process checks for overall scratches and distortions (see ST7 in Figure 2). Since the stem portion 2 has the central portion 20 made of the white glass C, it is easy to inspect whether the stem portion 2 is formed straight or not.

[0076] [effect] In the manufacturing method of stemware to which the present invention is applied as described above, the glass pool portion 11 formed in the ball portion forming process ST2 is stretched in the stem portion forming process ST4 to form the stem portion 2, thereby eliminating the joint (seam) between the ball portion 1 and the stem portion 2 and forming the ball portion 1 and the stem portion 2 as a single unit.

[0077] Furthermore, by forming the bowl portion 1 and the stem portion 2 integrally, light L' (see Figure 1) that passes through the bowl portion 1 can easily enter the stem portion 2, so that the center portion 20 appears to be colored the color of the beverage W.

[0078] [Variation 3] In the second embodiment described above, the ball portion forming process ST2 is explained using as an example a method in which spherically shaped transparent glass G is poured into a mold M to form the ball portion 1 (a molding method using the so-called "mold blowing" method). However, it is sufficient to be able to form the ball portion 1 and the glass reservoir portion 11, and it is not necessarily necessary to use the mold M. For example, a method may be used in which, without using a formwork M, a blowpipe B is rotated in the air while blowing air into the air to form the ball portion 1 and the glass pool portion 11 (a molding method using so-called "air blowing").

[0079] [Variation 4] In addition, in the above-mentioned second embodiment, in the insertion process, an example has been given of a method in which "only the tip" of a rod-shaped white glass C is inserted into the glass pool 11, and then the tip (20 mm to 30 mm) is left in the glass pool 11 and the white glass C is melted. However, it is sufficient if a state in which 20 mm to 30 mm of white glass C is inserted can be formed, and other methods may also be used. For example, a white glass C having a total length of about 20 mm to 30 mm may be inserted into the glass reservoir 11.

[0080] [Variation 5] Furthermore, as in the above-mentioned modified example 2, the ratio of sodium silicofluoride to the weight (total weight) of the transparent glass G is not necessarily limited to "3.0 wt %."

[0081] Here, the relationship between the "ratio of sodium silicofluoride to the weight (total weight) of transparent glass G" and the "degree of deviation of center portion 20" is shown in Table 3. Table 3 also shows the "transmittance" and "degree of color development of center portion 20" (the same contents as Table 2).

[0082] [Table 3]

[0083] From Table 3, it can be seen that when the ratio of sodium silicofluoride to the weight (total weight) of transparent glass G is "1.0 wt% or less," "1.2 wt%," "1.3 wt%," or "1.5 wt%," deflection occurs in the center 20 (white glass C) in the stem portion forming process ST4.

[0084] Therefore, the proportion of sodium silicofluoride relative to the weight (total weight) of the transparent glass G does not necessarily have to be "3.0 wt%", but in order to prevent distortion of the center portion 20 (white glass C) and form it neatly and straight, it is preferable that it be "2.0 wt% or more". As described in the second modification, in order to allow the central portion 20 to exhibit a good color, the content is preferably "1.3 wt % to 3.5 wt %." Therefore, in order to form the central portion 20 (white glass C) neatly and straight and to achieve good color development, the content is preferably "2.0 wt % to 3.5 wt %."

[0085] <3. Modifications> In the above-described first and second embodiments, the central portion 20 is described as being made of white glass C as an example, but the central portion 20 does not necessarily have to be white and may be other than white. However, in order to make the color of the beverage W easier to see when the "light L' reflecting the color of the beverage W" incident on the stem portion 2 is diffusely reflected within the center portion 20 to give the appearance of a colored center portion 20, it is preferable that the glass be white (i.e., it is preferable that the glass be white glass C, which is transparent glass G containing a white pigment). [Explanation of symbols]

[0086] A Stemware B. Blowstick C White glass G Transparent glass 1 Ball part 10 bottom 11 Glass Reservoir 2 Stem 20 Center 21 Periphery 3 Plate section

Claims

1. a ball portion forming step of forming a ball portion of a predetermined shape having a glass reservoir portion made of molten transparent glass at a bottom thereof; an insertion step of inserting colored glass into the glass pool; a stem portion forming step of melting the colored glass inserted in the glass pool portion and then stretching the glass pool portion while containing the colored glass to form a stem portion; and a plate portion forming step of attaching molten transparent glass to an end of the stem portion to form a plate portion of a predetermined shape. How stemware is made.

2. The inserting step inserts the white glass, which is the colored glass containing sodium silicofluoride at a ratio of 1.3 wt % to 3.5 wt % with respect to the weight of the transparent glass. A method for producing the stemware of claim 1.

3. The inserting step inserts the white glass, which is the colored glass containing sodium silicofluoride at a ratio of 2.0 wt % to 3.5 wt % with respect to the weight of the transparent glass. A method for producing the stemware according to claim 2.

4. The inserting step includes inserting the rod-shaped colored glass into the glass pool, The stem portion forming step includes stretching the glass pool portion in the longitudinal direction of the rod-shaped colored glass to form the stem portion. A method for producing stemware according to claim 1 or 2.

5. In the inserting step, the rod-shaped colored glass is heated to a degree that allows the shape of the rod to be maintained, and then the colored glass is inserted into the glass pool. A method for producing stemware according to claim 1 or 2.

6. The stem portion forming step includes heating the glass pool portion into which the colored glass is inserted, and then stretching the glass pool portion to form the stem portion. A method for producing stemware according to claim 1 or 2.

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