JP2011098850A - Method for manufacturing returnable glass bottle and returnable glass bottle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a returnable glass bottle having a sufficient film thickness even at a lateral embossed part of the glass bottle, relating to a method for manufacturing a returnable glass bottle by forming a resin coating film on the outer surface of a glass bottle. <P>SOLUTION: The method for manufacturing a returnable glass bottle uses a glass bottle 100 which satisfies expression: θ1+θ2=35-40°, wherein θ1 represents the maximum shoulder inclination angle between a main axis O of the glass bottle and a tangent S of a shoulder part passing through the main axis, and θ2 represents the angle between the main axis of the glass bottle and a generatrix D obtained by connecting an upper end N of a neck part and a lower end H of a hem part 50 on a longitudinal section passing along the main axis, and which has an embossed part 5 in a region 30a corresponding to the upper half of the shoulder part. The method for manufacturing a returnable glass bottle includes a dipping step in which the glass bottle 100 is dipped in a resin coating liquid in a dipping tank in such a way that the generatrix coincides with the liquid surface in the tank, and the glass bottle is turned on the main axis to apply the resin coating liquid to the glass bottle. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a method for producing a returnable glass bottle capable of forming a uniform resin coating film on the outer surface of a glass bottle having an embossed portion, and a returnable glass bottle obtained thereby.

  Returnable glass bottles are filled with beer, milk, etc., collected and washed after use, then filled again with the contents and used repeatedly tens of times. The outer surface of such a returnable glass bottle is provided with a resin coating for the purpose of preventing scratches, ensuring strength, maintaining appearance quality, preventing scattering when broken, and coloring.

  In the method of manufacturing a returnable glass bottle with such a resin coating, as a method of applying a resin coating to the outer surface of the glass bottle, a so-called spray coating method in which a coating liquid is sprayed from the nozzle of a spray gun toward the glass bottle. (For example, refer to Patent Document 1), so-called dipping method (for example, refer to Patent Document 2 or 3) in which a glass bottle is immersed in a dipping tank filled with a coating solution, brush coating method, flow coating (For example, see Patent Document 4).

  In addition, a concavo-convex pattern (so-called emboss) for expressing a company name, a logo, a mark, a design, and the like on a glass bottle base may be provided on the side surface of the returnable glass bottle. As a method of forming the embossed part on the surface of the glass bottle, for example, a concave part is provided on the surface of the glass bottle forming mold, and a convex part is formed on the surface of the glass bottle by the concave part. A method to form a concavo-convex pattern on a glass bottle by molding a parison with a rough mold and then forming a concavo-convex pattern on the inner surface by finishing the bottle using a finishing mold having a smooth inner surface. (For example, refer to Patent Document 5).

  On the other hand, lightweight returnable glass bottles are being developed from the viewpoints of energy saving during production and transportation, resource saving, reduction of carbon dioxide emissions, and universal design. For example, when used as a container for beer, carbonated drinks, etc., it is necessary to have strength that can withstand the internal pressure of carbon dioxide gas and can withstand repeated use. In lightweight returnable bottles, there is a demand for durability of the coating film that provides strength and can withstand repeated use several tens of times.

JP 2002-36396 A, paragraph 0047 JP 2000-335582 A JP 2000-281385 A JP-A-9-239311, paragraph 0061 JP-A-8-175824

  The coating film of a returnable glass bottle is required to have durability against washing with high-temperature alkaline water that is performed every time it is reused and wear resistance against rubbing between bottles. The present inventors have found that in order to obtain durability after several tens of uses, it is necessary to secure a coating film thickness on the outer periphery of the glass bottle at a predetermined thickness or more. In particular, in the embossed portion, it is difficult to ensure a target coating film thickness, and the coating film is easily peeled off. As a result, alkali resistance and wear resistance are lowered, which is a fatal defect.

  Therefore, an object of the present invention is to provide a returnable glass bottle manufacturing method in which a coating film made of a resin coating liquid is formed on the outer surface of the glass bottle, and is provided on the outer surface of the glass bottle, particularly on the side surface of the glass bottle. It is to provide a method for producing a returnable glass bottle having a coating film made of a resin coating solution having a uniform and sufficient film thickness at an embossed portion and capable of withstanding several tens of uses.

  As a result of intensive investigations to solve the above problems, the present inventors paid attention to the behavior of the resin coating solution when the glass bottle is immersed in the dip bath and the behavior of the resin coating solution after being detached from the dip bath. In particular, the glass bottle is designed to have a shape that prevents liquid accumulation or liquid drop from occurring in the shoulder, and the glass bottle is provided with an embossed part at a position where a large amount of resin coating liquid flows. In particular, the inventors have found that a coating film having a uniform film thickness can be formed on an embossed portion provided on the side surface of a glass bottle, and completed the present invention. That is, the returnable glass bottle manufacturing method according to the present invention includes a mouth portion, a neck portion connected to the lower portion of the mouth portion, a barrel portion connected to the neck portion via a shoulder portion, and a hem to the barrel portion. In the method of manufacturing a returnable glass bottle in which a coating film made of a resin coating liquid is formed on the outer surface of a glass bottle having a bottom part connected via a part, the shoulder part is a lower end part of the neck part as the glass bottle And a shoulder slope formed by a main axis of the glass bottle and a tangent line of a shoulder part on a longitudinal section passing through the main axis. The maximum angle of the angle is θ1, the angle between the main axis of the glass bottle and the generatrix obtained by connecting the upper end of the neck and the lower end of the hem on the longitudinal section passing through the main axis is θ2, and θ1 The sum (θ1 + θ2) with θ2 is 3 And a glass bottle provided with an embossed part in the upper half region of the shoulder part, and the glass bottle is filled with the bus bar and a liquid surface of a dip tank filled with a resin coating solution. Are immersed so that they coincide with each other, rotate the glass bottle around the main axis, and apply the resin coating liquid to the outer surface of the glass bottle; and a curing process for curing the resin coating liquid; It is characterized by having.

  In the method for producing a returnable glass bottle according to the present invention, the outer surface of the glass bottle coated with the resin coating liquid while rotating the glass bottle around the main shaft in a posture in which the main shaft of the glass bottle is kept horizontal. It is preferable to have a preliminary drying step of drying by applying hot air. By this process, the film thickness of the resin coating solution adhered to the outer surface of the glass bottle in the dipping process can be made uniform.

  In the method for producing a returnable glass bottle according to the present invention, it is preferable to use a glass bottle having a shoulder inclination angle θ1 of 30 to 35 °. Even in the embossed portion provided in the upper half region of the shoulder portion, a sufficient coating film thickness can be ensured. Further, even after the glass bottle is removed from the dip tank, the resin coating liquid adhering to the outer surface of the shoulder portion of the glass bottle is difficult to hang down, so that the coating film thickness can be secured at the shoulder portion.

  The method for producing a returnable glass bottle according to the present invention includes a form in which a glass bottle having an angle θ2 formed by the main axis of the glass bottle and the bus bar of 4 to 10 ° is used.

  In the method for producing a returnable glass bottle according to the present invention, it is preferable to use a glass bottle in which the outline of the longitudinal section passing through the main axis of the glass bottle is outside the bus bar. Since all the neck part, shoulder part, trunk part and hem part of the glass bottle are all immersed in the dip tank, the resin coating liquid can be adhered to the outer surface of the glass bottle without any leakage.

  The returnable glass bottle according to the present invention is manufactured by the method for manufacturing a returnable glass bottle according to the present invention. The returnable glass bottle according to the present invention can form a coating film with a resin coating solution having a uniform and sufficient film thickness on the outer surface of the glass bottle, particularly on the embossed portion provided on the side surface of the glass bottle. The durability of the coating film at the embossed portion is improved and it can withstand several tens of uses.

  In the present invention, in the returnable glass bottle manufacturing method in which a coating film formed of a resin coating liquid is formed on the outer surface of the glass bottle, the outer surface of the glass bottle, in particular, the embossed portion provided on the side surface of the glass bottle, It is possible to provide a method for producing a returnable glass bottle which has a coating film made of a resin coating solution having a uniform and sufficient film thickness and can withstand tens of uses.

It is a front view which shows one form of the returnable glass bottle used with the manufacturing method which concerns on this embodiment. It is a figure for demonstrating the state where the glass bottle is immersed in the dip tank. It is a figure for demonstrating the process of forming the coating film by a resin coating liquid. It is a figure for demonstrating a dipping process, and the figure seen from the front. It is a figure for demonstrating a dipping process, and is the figure seen from upper direction. It is the figure which showed the shape of the glass bottle used by the Example and the comparative example, and the state of the glass bottle in a dipping process, (a) is Example 1, (b) is Example 2, (c) is implementation. Example 3, (d) is Example 4, (e) is Comparative Example 1, and (f) is Comparative Example 2.

  Hereinafter, although an embodiment is shown and explained in detail about the present invention, the present invention is limited to these descriptions and is not interpreted. As long as the effect of the present invention is exhibited, the embodiment may be variously modified.

  The method for manufacturing a returnable glass bottle according to the present embodiment uses a glass bottle having a specific shape, and includes a dipping process and a curing process. First, the shape of the glass bottle used for the manufacturing method of the returnable glass bottle which concerns on this embodiment is demonstrated using FIG. FIG. 1 is a front view showing an embodiment of a returnable glass bottle used in the manufacturing method according to the present embodiment.

  A glass bottle 100 used in the method for manufacturing a returnable glass bottle according to the present embodiment includes a mouth portion 10, a neck portion 20 connected to the lower portion of the mouth portion 10, and a barrel connected to the neck portion 20 via a shoulder portion 30. A narrow mouth bottle having a portion 40 and a bottom portion 60 connected to the body portion 40 through a skirt portion 50. The mouth portion 10 is a place where the contents are filled and poured out, and a glass bottle is sealed by attaching a stopper (not shown) such as a crown stopper, a screw stopper, or a cork stopper. The neck portion 20 has a shape that gradually increases in diameter downward, and further expands in diameter at the shoulder portion 30 and is connected to the trunk portion 40. The trunk | drum 40 is a location mainly hold | gripped by a consumer. The skirt 50 is connected with a body diameter substantially the same as the body 40 and is connected to the bottom 60. A coating film made of a resin coating solution is used on the outer surface in order to impart durability after repeated use several tens of times. Since the coating film suppresses the generation of scratches on the outer surface of the glass bottle, it is difficult for the pressure resistance of the bottle to decrease. Therefore, the thickness of the glass bottle can be reduced and the weight of the glass bottle can be reduced.

  The glass bottle used for the manufacturing method of the returnable glass bottle according to the present embodiment is provided with an embossed portion 5 in which patterns such as a company name, a brand name, a logo mark, and a product name are expressed by unevenness. The embossed portion 5 is convex if the surface of the glass bottle is used as a reference. For this reason, in the embossed part 5, compared with the location without the embossed part 5, the resin coating liquid flows down, and it is difficult to ensure a sufficient coating film thickness. Therefore, the glass bottle used in the method for manufacturing the returnable glass bottle according to the present embodiment is designed so that the coating liquid flows in a concentrated manner on the embossed portion 5. That is, in the glass bottle 100, the maximum angle of the shoulder inclination angle formed by the main axis O of the glass bottle 100 and the tangent S of the shoulder portion 30 on the longitudinal section passing through the main axis O is θ1, and the main axis O of the glass bottle 100 is The angle formed by the generatrix D obtained by connecting the upper end N of the neck 20 and the lower end H of the skirt 50 on the longitudinal section passing through the main axis O is θ2, and the total of θ1 and θ2 (θ1 + θ2) is 35 to 35 The glass bottle has a shape of 40 ° and the embossed portion 5 provided in the upper half region 30a of the shoulder portion.

  The shape in which the embossed portion 5 is provided in the upper half region 30a of the shoulder is sufficient if 50% or more of the area of the embossed portion is in the upper half region 30a of the shoulder. For example, when the embossed part 5 is large, a part of the embossed part may be provided so as to hang over the neck part 20, or a part of the embossed part may be laid over the lower half region 30b of the shoulder part. May be provided. Alternatively, a part of the embossed part may be provided so as to hang over the trunk part 40. However, it is preferable that the height of the convex portion of the embossed portion 5 be lower than the portion provided in the upper half region 30a of the shoulder portion outside the upper half region 30a of the shoulder portion. By doing in this way, it becomes easy to ensure the coating film thickness in the embossed part 5. And it is more preferable that the embossed part 5 whole is settled in the area | region 30a of the upper half of a shoulder part.

  The relationship between the shape of the glass bottle 100 and the behavior of the coating liquid will be described with reference to FIG. In this embodiment, the coating film by the resin coating liquid is formed by a dipping method. Since the ground contact portion of the bottom portion 60 is easily damaged, the bottom portion 60 of the glass bottle 100 may be easily peeled off by cleaning when reused and may deteriorate in appearance. It is preferable not to apply a coating film with a liquid. Therefore, the glass bottle 100 includes a bus bar D obtained by connecting the upper end N of the neck 20 and the lower end H of the skirt 50 on the longitudinal section passing through the main axis O of the glass bottle 100, and the liquid level D ′ of the dip tank 1. Immerse to match. That is, the angle θ2 formed between the main axis O of the glass bottle 100 and the generatrix D and the dip elevation angle θ3 that is the angle formed between the main axis O of the glass bottle 100 and the liquid level D ′ of the dip tank are the same angle. In the manufacturing method of the returnable glass bottle according to the present embodiment, a glass bottle having an angle θ2 (θ2 is equal to the dip elevation angle θ3) between the main axis O and the bus D of the glass bottle 100 is 4 to 10 °. Forms to be included. If it is less than 4 °, it will not be in the shape of a narrow bottle. If the angle exceeds 10 °, the diameter of the bottom portion becomes large, and the diameter of the trunk portion connected to the upper portion of the bottom portion also becomes large, which may make it difficult to grip. In the dip process, the dip elevation angle θ3 is preferably small. When the dip elevation angle θ3 exceeds 10 °, the film thickness may be nonuniform over the entire region of the neck portion 20, the shoulder portion 30, the trunk portion 40, and the skirt portion 50. In particular, the degree of non-uniform film thickness at the body 40 and the skirt 50 may increase.

  In the dip tank 1, the glass bottle 100 is rotated (rotated) about the main axis O, and the resin coating liquid 2 is applied to the outer surface of the glass bottle 100. At this time, the resin coating liquid 2 adhering to the outer surface of the glass bottle 100 flows down the inclination of the shoulder 30 toward the neck 20 from the body 40 side. The behavior 105 of the resin coating liquid is influenced by θ1 as the maximum angle of the shoulder inclination angle formed between the main axis O of the glass bottle 100 and the tangent S of the shoulder 30 on the longitudinal section passing through the main axis O. However, since the glass bottle 100 is immersed in the dip tank 1 with an inclination of an angle θ2 (dip elevation angle θ3) formed by the main axis O of the glass bottle and the bus D as described above, in practice, It is influenced by the sum of θ1 and θ2.

  In this embodiment, the glass bottle 100 whose total (θ1 + θ2) of θ1 and θ2 is 35 to 40 ° is used. More preferably, it is 36-38 degrees, Most preferably, it is 36.5-37.5 degrees. By setting this range, a large amount of the resin coating liquid 2 flows and the coating liquid concentrates and adheres to the embossed portion 5 provided in the upper half region 30a of the shoulder portion. Thickness can be ensured. If the angle is less than 35 °, the effect of providing the embossed portion 5 in the upper half region 30a of the shoulder is weakened. If the angle exceeds 40 °, the coating liquid flows down in the shoulder 30 and the resin coating liquid does not stay. Since it flows toward the neck portion 20, a sufficient coating film thickness cannot be ensured in the embossed portion 5 provided in the upper half region 30a of the shoulder portion. Further, the position of the embossed portion 5 is particularly preferably a region of ¼ to ３ from the upper end portion of the shoulder portion 30.

  In the method of manufacturing a returnable glass bottle according to the present embodiment, it is preferable to use a glass bottle whose contour line in the longitudinal section passing through the main axis O of the glass bottle 100 is outside the bus bar D. Since all the neck part, shoulder part, trunk part and hem part of the glass bottle are all immersed in the dip tank, the resin coating liquid can be adhered to the outer surface of the glass bottle without any leakage.

  The manufacturing process of the returnable glass bottle according to the present embodiment will be described with reference to FIG. In this embodiment, for example, a known coating method (Patent Document 3) can be applied. As shown in FIG. 3, a group of returnable glass bottles 100 carried in by the carry-in conveyor 72 is chucked by a chuck mechanism (not shown) of the load unit 80 and is raised in the direction a, and the glass bottles provided on the endless conveyor 71 Transfer to gripping tool (not shown). The endless transfer conveyor 71 moves in the b direction, and the glass bottle 100 is also transferred accordingly. The glass bottle 100 is washed in the washing part 81 and dried in the drying part 82. Subsequently, it is sent to the dip tank 1 and a dip process is performed. After drying in the drying furnace 86, the unloading unit 88 moves from a glass bottle gripping tool (not shown) to a chuck mechanism (not shown) and descends in the direction c. To move to the curing furnace 89. The glass bottle 100 that has passed through the curing furnace 89 is carried out to the next process (not shown). In the returnable glass bottle manufacturing method according to the present embodiment, the primer treatment unit 83 can modify the surface state between the drying unit 82 and the dip tank 1. Further, it is preferable to provide a step of preliminary drying with hot air in the preliminary drying step 3 between the dip tank 1 and the drying furnace 86.

  The dipping process will be described with reference to FIGS. FIG. 4 is a diagram for explaining the dipping process, as viewed from the front. FIG. 5 is a diagram for explaining the dipping process, as viewed from above. The dip tank 1 is installed along the transport direction of the endless transport conveyor 71. As described above, the dip tank 1 is filled with the resin coating liquid 2, and the glass bottle 100 is immersed with the bus bar D aligned with the dip liquid surface D '. Is done. A glass bottle gripping tool 75 (75a, 75b) is attached to the entire length of the endless transport conveyor 71 via a joint portion 76 at a predetermined interval. The glass bottle 100 is gripped by the glass bottle gripping tool 75 when the tip 75 a of the glass bottle gripping tool is fitted into the mouth 10 of the glass bottle 100. The joint portion 76 is a universal joint, and the glass bottle 100 can be changed in posture (gripping angle) and is rotatably held. As the endless conveyor 71 moves, the glass bottle 100 moves while the roller 75b of the glass bottle gripping tool 75 rolls on the cam plate 78. In the present embodiment, the rotation mechanism is not limited. In the dipping process, the glass bottle may be rotated about the main axis O, and may be rotated by, for example, power fitted to a gear provided between the glass bottle gripping tool 75 and the endless transport conveyor 71.

  The glass bottle 100 with the resin coating solution attached to the outer surface by the dipping process is dried by applying hot air to the outer surface of the glass bottle 100 in the preliminary drying process 3 before entering the drying furnace 86. In the preliminary drying step 3, it is preferable that the glass bottle 100 is rotated around the main axis O in a posture in which the main axis O of the glass bottle 100 is kept horizontal. By this process, the resin coating liquid adhered to the outer surface of the glass bottle in the dipping process is stabilized, and the film thickness can be made uniform.

  In the method for manufacturing a returnable glass bottle according to the present embodiment, θ1 which is the maximum angle of the shoulder inclination angle formed by the main axis O of the glass bottle 100 and the tangent S of the shoulder portion 30 on the longitudinal section passing through the main axis O is: It is preferred to use a glass bottle that is 30-35 °. More preferably, it is 31 to 34 °. If it is less than 30 °, the regions of the shoulder portion 30 and the neck portion 20 are unclear, and the effect of providing the embossed portion 5 in the upper half region 30a of the shoulder portion is weakened. When the angle exceeds 35 °, the resin coating solution adhering to the outer surface of the glass bottle hangs down in the predrying step 3 when the main axis O of the glass bottle 100 is kept horizontal, and the upper half of the shoulder portion In the embossed portion 5 provided in the region 30a, the coating film thickness may not be ensured.

  In FIG. 3, the dip tank 1, the preliminary drying step 3, and the drying furnace 86 are provided one by one, but the present embodiment is not limited to this. For example, as in the coating method described in Patent Document 3, a second dip tank, a second preliminary drying step, and a second drying step may be provided downstream of the drying furnace 86. In the second dip tank, a coating film thickness may be secured by applying the same type of resin coating liquid as that of the dip tank 1, or a different kind of coating liquid may be applied to the dip tank 1. Good.

  The coating liquid can be a color coating liquid for the purpose of coloring glass bottles. By applying a color coating to the outer surface of the colorless glass bottle, it is possible to obtain a glass bottle with high design and content protection. Coloring by coating is not only easy to produce and inexpensive to produce, but also suitable for recycling, compared to a method of coloring by mixing a colorant into a glass substrate.

  By being manufactured by the returnable glass bottle manufacturing method according to this embodiment, the returnable glass bottle according to this embodiment is formed on the outer surface of the glass bottle, in particular, on the embossed portion 5 provided on the side surface of the glass bottle 100. Since it is possible to form a coating film with the resin coating solution 2 having a uniform and sufficient film thickness, it is possible to withstand several tens of uses.

  Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not construed as being limited to the examples.

  FIG. 6 is a diagram showing the shape of the glass bottles used in Examples 1 to 4 and Comparative Examples 1 and 2 and the dip liquid level.

Example 1
The height from the upper end side of the mouth part to the lower end side of the hem part is 255 mm, the shoulder part is a region 30 mm downward from the position of 105 mm from the upper end side of the mouth part, and the embossed part is the upper end side of the mouth part. Using a glass bottle provided in a 12 mm region from the position 107 mm to the bottom and θ1 of 31 ° and θ2 of 4.41 ° (θ1 + θ2 = 35.41 °), a resin coating solution (urethane coating solution, MX -1300, Techno Tsukisei Co., Ltd. Viscosity of 21 to 31 mPa · s (25 ° C.) was immersed in a dip tank except for the bottom, and the coating liquid was applied while rotating. Thereafter, hot air was applied and cured to produce a returnable glass bottle.

(Example 2)
A returnable glass bottle was produced in the same manner as in Example 1 except that a glass bottle having θ1 of 32 ° and θ2 of 4.38 ° (θ1 + θ2 = 36.38 °) was used.

(Example 3)
A returnable glass bottle was produced in the same manner as in Example 1 except that a glass bottle having θ1 of 33 ° and θ2 of 4.38 ° (θ1 + θ2 = 37.38 °) was used.

Example 4
The height from the upper end side of the mouth part to the lower end side of the hem part is 238 mm, the shoulder part is a region of 35.2 mm downward from the position of 78.8 mm from the upper end side of the mouth part, and the embossed part is Except that a glass bottle having a θ1 of 34 ° and a θ2 of 5.3 ° (θ1 + θ2 = 39.30 °) is used in an area of 6.0 mm downward from a position of 82.2 mm from the upper end side of the portion. A returnable glass bottle was prepared in the same manner as in Example 1.

(Comparative Example 1)
A returnable glass bottle was produced in the same manner as in Example 1 except that a glass bottle having θ1 of 36 ° and θ2 of 4.38 ° (θ1 + θ2 = 40.38 °) was used.

(Comparative Example 2)
A returnable glass bottle was prepared in the same manner as in Example 1 except that the embossed portion of the glass bottle to be used was provided in a 12 mm region downward from a position 118 mm from the upper end side of the mouth.

  About the glass bottle of the above Examples 1-4 and Comparative Examples 1-2, durability evaluation of the average film thickness measurement of the coating film and a trip test was performed.

(1) Average film thickness measurement of coating film The average film thickness measurement of the coating film was performed as follows. The thickness of the embossed part of the glass bottle and the outer surface of the glass bottle other than the embossed part was measured using a micrometer device (MDC-25MJ, manufactured by Mitutoyo Corporation). The n value = 4, and the average value of the four film thicknesses was taken as the average film thickness.

(2) Endurance evaluation of trip test The trip test was conducted as follows. Using a beer bottle washer containing a 4 wt% sodium hydroxide aqueous solution, the appearance after visual observation after 20 trips (one trip corresponds to one on the market) was visually observed to confirm the presence or absence of peeling of the coating film. If n value = 5 and 4 out of 5 were in the practical range, it was judged as acceptable. Judgment criteria are as follows.
○: No peeling (practical level)
Δ: Slight peeling (practical lower limit)
×: Complete peeling (unsuitable for practical use)

  The evaluation results are shown in Table 1.

  In each of Examples 1 to 4, θ1 + θ2 was 35 to 40 °, and the embossed part was provided in the upper half region of the shoulder, so that the coating film thickness could be secured even in the embossed part. As a result, it was durable in 40 trip tests.

  On the other hand, in Comparative Example 1, θ1 + θ2 exceeded 40 °, so that the coating liquid could not stay in the upper half region of the shoulder, and the coating film thickness became thin. In Comparative Example 2, since the embossed portion was provided in the lower half region of the shoulder portion, the coating liquid flowed down and the coating film thickness became thin. As a result, in Comparative Examples 1 and 2, peeling of the coating film occurred in 40 trip tests.

1 Dip tank 2 Resin coating liquid 3 Pre-drying process 5 Embossed portion 10 mouth portion 20 neck portion 30 shoulder portion 30a upper half region 30b lower half region 40 shoulder portion 50 bottom portion 60 bottom portion 71 endless conveyor 72 carry-in conveyor 73 transport conveyor 75 (75a, 75b) gripping tool 75a gripper tip 75b gripper roller part 76 joint part 78 cam plate 80 load part 81 bottle washing part 82 drying part 83 primer processing part 86 drying furnace 88 Unloading section 89 Curing furnace 100 Glass bottle 105 Behavior of coating liquid O Main axis S of glass bottle S Tangent line N Upper end of neck H Lower end of hem D Lower end of neck and lower end of skirt Liquid surface of dip tank θ1 Maximum angle of shoulder inclination angle θ2 Angle between main axis and generatrix θ3 Dip elevation angle

Claims (6)

An outside of a glass bottle having a mouth, a neck connected to the lower part of the mouth, a body part connected to the neck part through a shoulder, and a bottom part connected to the body part through a skirt part. In the method for producing a returnable glass bottle in which a coating film is formed by a resin coating liquid on the surface,
As the glass bottle, the shoulder portion has a shape whose diameter is expanded downward so as to connect the lower end portion of the neck portion and the upper end portion of the trunk portion, and the main shaft of the glass bottle and the main shaft The maximum angle of the shoulder inclination angle formed with the tangent to the shoulder portion on the longitudinal section passing through is θ1, and the main axis of the glass bottle, the upper end of the neck portion and the lower end of the hem portion on the longitudinal section passing through the main axis are The glass bottle in which the angle formed with the busbar obtained by tying is θ2, the total of θ1 and θ2 (θ1 + θ2) is 35 to 40 °, and an embossed portion is provided in the upper half region of the shoulder Use
The glass bottle is immersed so that the bus bar and the liquid level of the dip tank filled with the resin coating liquid coincide with each other, the glass bottle is rotated around the main axis, and the glass bottle is placed on the outer surface of the glass bottle. A dipping process for applying a resin coating solution;
And a curing step for curing the resin coating liquid. A method for producing a returnable glass bottle, comprising:   A pre-drying step of drying by applying hot air to the outer surface of the glass bottle coated with the resin coating liquid while rotating the glass bottle around the main axis in a posture in which the main axis of the glass bottle is kept horizontal The manufacturing method of the returnable glass bottle of Claim 1 characterized by the above-mentioned.   The method for producing a returnable glass bottle according to claim 1 or 2, wherein a glass bottle having a shoulder inclination angle θ1 of 30 to 35 ° is used.   The method for producing a returnable glass bottle according to claim 1, 2 or 3, wherein a glass bottle having an angle θ2 between the main axis of the glass bottle and the bus bar of 4 to 10 ° is used.   The method for producing a returnable glass bottle according to any one of claims 1 to 4, wherein a glass bottle whose contour line of a longitudinal section passing through the main axis of the glass bottle is outside the bus bar is used.   A returnable glass bottle produced by the method for producing a returnable glass bottle according to any one of claims 1 to 5.

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