Beverage can body and manufacturing method thereof, beverage can and manufacturing method thereof

Abstract

The present invention discloses a beverage can body and a manufacturing method thereof, a beverage can and a manufacturing method thereof. The beverage can body comprises a main body, and the inner surface of the peripheral wall of the main body has a coating; the coating comprises a first area, a second area and a third area which are sequentially arranged and evenly distributed along a first direction, and each area has a distribution density of 160 to 4900 pieces / mm 2 The distribution density of the second area is 28~1300 / mm greater than that of the first area. 2 The distribution density in the first zone is 25~640 / mm greater than that in the third zone. 2 The surface areas of the first to third zones are 4550 to 18500 mm 2 . The diameter of the concave part is 0.1~5.0μm. The diameter-to-depth ratio of the concave part in the first zone is 4.0~8.0, 2.5~6.0 in the second zone, and 3.0~5.5 in the third zone; the film thickness in the first zone is 3.0~4.5μm, the film thickness in the second zone is 3.5~5.0μm, and the film thickness in the third zone is 2.8~4.0μm. When filled with gas-containing liquid, after opening, the foam overflows quickly and sustainably, the appearance and taste of the foam are improved, and the consumer's experience is enhanced.

Description

Technical Field

[0001] The invention relates to the field of food packaging, and in particular to a beverage can body and a manufacturing method thereof, a beverage can and a manufacturing method thereof. Background Art

[0002] At present, there are a variety of canned products such as carbonated beverages and beer on the market. These canned products are often packaged in metals such as aluminum alloys. The function of traditional metal packaging is to isolate the contents from the external environment. On the one hand, it is convenient for logistics and transportation, and on the other hand, it isolates oxygen and microorganisms, slowing down the rate of spoilage of the contents. The inner surface of the main body of the beverage can usually has a coating. The basic function of the coating is to protect the metal substrate on the inner surface of the can, that is, to form a complete protective layer on the inner surface of the can, completely isolating the contents encapsulated in the can from the metal substrate used for canning, and avoiding a series of undesirable phenomena such as metal corrosion and beverage can leakage. For the contents, metal packaging is a good sealed container. However, with the growing demand of consumers to try new things, the call for adding functional innovation to traditional packaging is also growing.

[0003] Some liquid contents in traditional metal packaging contain a certain amount of gas, which is an indispensable element for consumers to obtain a good tasting experience and intuitive consumption experience. In order to enhance the consumer experience, there is a new type of metal packaging, which, when filled with liquid contents containing gas, can be fully left to stand, and when the package is opened, the gas contained inside can come out of the package autonomously, showing a foam form visible to the naked eye, which can give consumers a certain visual enjoyment.

[0004] However, this type of packaging has poor control over the gas overflow process. For example, after the package is opened, there will be a long waiting time for the foam to be generated and overflow, and the foam overflow is not persistent. At the same time, when drinking, the taste of the foam will also affect the consumer experience, which needs further improvement.

[0005] The Chinese patent with publication number CN116670038A discloses a beverage can, which is intended to increase the foam overflow speed and amount at a lower temperature. It unilaterally increases the foam overflow speed when the beverage is stored at a lower temperature. However, in actual use, the storage temperature range of the can is relatively large. When the storage temperature is high, the foam overflows faster and more, and violent foam overflow may occur, affecting the user experience. Summary of the invention

[0006] In order to solve the above technical problems, the embodiment of the present invention discloses a beverage can body, which includes:

[0007] The main body is used to contain beverages and comprises a peripheral wall, wherein the inner surface of the peripheral wall has a coating;

[0008] The coating includes a first area, a second area and a third area arranged in sequence along a first direction, and the first area, the second area and the third area have a distribution density of 160 to 4900 per mm 2 The distribution density of the second area is 28~1300 / mm greater than that of the first area. 2 The distribution density of the first zone is 25~640 / mm greater than that of the third zone. 2 The surface areas of the first, second and third zones are 4550~18500mm respectively. 2 , the diameter of the concave portion is 0.1~5.0μm; the diameter-to-depth ratio of the concave portion in the first zone is 4.0~8.0, the diameter-to-depth ratio of the concave portion in the second zone is 2.5~6.0, and the diameter-to-depth ratio of the concave portion in the third zone is 3.0~5.5; the film thickness in the first zone is 3.0~4.5μm, the film thickness in the second zone is 3.5~5.0μm, and the film thickness in the third zone is 2.8~4.0μm;

[0009] The first direction is the direction from the top of the main body to the bottom thereof, and the diameter-to-depth ratio is the ratio of the diameter of the recessed portion to the depth of the recessed portion.

[0010] By adopting the above technical solution, when a carbonated beverage is contained in a beverage can, after the sealed beverage can is opened, the gas in the liquid can spontaneously overflow from the can in the form of foam, and the overflow speed is fast and the sustainability is enhanced, the appearance and taste of the foam are improved, and the consumer's experience is fully enhanced. First, the rapid and full overflow of the foam at a relatively low temperature is guaranteed. In addition, even at a relatively high temperature, the gas in the can will be released evenly, and there will be no rapid foam overflow. Therefore, the drinkable amount of the liquid in the can can be guaranteed, satisfying the use and drinking experience.

[0011] Optionally, the first area, the second area and the third area are evenly distributed along the first direction, and the distribution density of the recessed parts in the second area is 282-2004 / mm 2 The distribution density of the depressions in the first zone is 227 to 1272 per mm 2 The distribution density of the depressions in the third zone is 169 to 1031 per mm 2 .

[0012] Optionally, the diameter-to-depth ratio of the recessed portion in the first zone is greater than the diameter-to-depth ratio of the recessed portions in the second zone and the third zone.

[0013] Optionally, the film thickness of the first zone is 3.2-3.8 μm, the film thickness of the second zone is 3.8-4.5 μm, the film thickness of the third zone is 2.8-3.2 μm, and the film thickness of the second zone ≥ the film thickness of the first zone ≥ the film thickness of the third zone.

[0014] Optionally, the coating is formed by applying a slurry to the inner surface of the peripheral wall, and the slurry includes, by mass percentage, 20% to 30% of epoxy acrylic resin and 0.1% to 0.2% of a defoaming agent.

[0015] According to another specific embodiment of the present invention, the embodiment of the present invention discloses a method for manufacturing a beverage can, comprising the following steps:

[0016] Slurry spraying: Use a spray gun to spray the slurry on the inner surface of the main body of the container at a preset angle of 7 to 20 degrees, where the preset angle is the angle between the center line of the spray gun and the normal line of the beverage can surface;

[0017] Drying to form a coating: Drying the sprayed slurry to form a coating.

[0018] By adopting the above technical solution, a beverage can with a faster foam overflow speed, a longer foam overflow duration, and improved foam visual appearance and taste can be easily manufactured, which is suitable for large-scale application and production.

[0019] Optionally, the preset angle is 12-20°, and the drying temperature of the slurry is 80-100°C.

[0020] Optionally, the spray pressure of the spray gun is 500-550 psi.

[0021] Optionally, in the step of drying to form a coating, the drying process includes pre-drying and post-drying, the drying temperature of the pre-drying is 80-100°C, the drying time of the pre-drying is 1-3 minutes, and the drying temperature of the post-drying is 150-280°C.

[0022] According to another specific embodiment of the present invention, the embodiment of the present invention discloses a beverage can, which includes the above-mentioned beverage can body and a top cover, wherein the top cover is sealed to the beverage can body, and the beverage can is used to contain beverages and be filled with carbon dioxide.

[0023] By adopting the above technical solution, a beverage can with a foam effect can be obtained, enriching the visual experience of consumers.

[0024] Optionally, the top cover includes an opening portion, and when the opening portion is opened, foam overflows from the beverage can within 6 to 15 seconds.

[0025] According to another specific embodiment of the present invention, the embodiment of the present invention discloses a method for manufacturing a beverage can, comprising the following steps:

[0026] Filling carbon dioxide into a liquid storage container storing a beverage;

[0027] Fill the beverage can with carbon dioxide to make the gas pressure in the beverage can equal to the gas pressure in the liquid storage container; use the beverage's own gravity to fill the beverage into the beverage can;

[0028] The top cover is sealed and connected to the beverage can body to obtain a beverage can, and the gas pressure in the beverage can is 0.18~0.40MPa.

[0029] By adopting the above technical solution, beverage cans can be easily obtained, which are suitable for industrial large-scale production. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 A schematic diagram showing the structure of a beverage can body according to an embodiment of the present invention is shown;

[0031] Figure 2 A scanning electron microscope image of a coating surface magnified 10000X according to an embodiment of the present invention is shown;

[0032] Figure 3 A 500X scanning electron microscope image of the coating surface of one embodiment of the present invention is shown;

[0033] Figure 4 Another SEM image showing the coating surface of one embodiment of the present invention at 500X magnification;

[0034] Figure 5 A photograph showing foam overflow of a beverage can at 12° C. according to an embodiment of the present invention. DETAILED DESCRIPTION

[0035] The following specific embodiments illustrate the implementation of the present invention, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. Although the description of the present invention will be introduced in conjunction with the preferred embodiment, this does not mean that the features of this invention are limited to this implementation. On the contrary, the purpose of introducing the invention in conjunction with the implementation is to cover other options or modifications that may extend based on the claims of the present invention. In order to provide a deep understanding of the present invention, the following description will include many specific details. The present invention can also be implemented without using these details. In addition, in order to avoid confusion or blurring the focus of the present invention, some specific details will be omitted in the description. It should be noted that the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict.

[0036] It should be noted that in this specification, similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not need to be further defined and explained in the subsequent drawings.

[0037] The terms “first”, “second”, etc. are only used for distinguishing descriptions and should not be understood as indicating or implying relative importance.

[0038] In the description of this embodiment, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in this embodiment can be understood according to specific circumstances.

[0039] In order to make the objectives, technical solutions and advantages of the present invention more clear, the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0040] In the embodiments of the present application, "beverage" refers to drinkable liquids, including but not limited to water (such as mineral water, soda water, sparkling water, etc.), tea, coffee, juice, milk, yogurt, carbonated drinks (such as cola, etc.), alcoholic beverages (such as beer, cocktails, sparkling wine, wine, etc.).

[0041] In the embodiments of the present application, a “depression” refers to a pit present on a coating layer, which is recessed relative to a flat surface but does not penetrate the coating layer.

[0042] In the embodiments of the present application, "film thickness" refers to the thickness of the solid coating formed on the inner surface of the tank wall after the slurry is completely cured by drying. Due to the characteristics of industrial production, the inner wall coating of the tank is not absolutely evenly distributed. When testing the film thickness in this field, according to common practice, points are averaged on the circumference at the same height in the tank, usually 3 to 4 points, and the film thickness of each point is measured using a scanning electron microscope. Usually, the film thickness is expressed as a range value; alternatively, the film thickness can also be expressed as an average value, that is, the average of the film thickness of 3 to 4 measurement points is taken. In the embodiments of the present application, the film thickness is expressed as a range value.

[0043] In the embodiments of the present application, "can" refers to metal packaging products made of metal sheets, including various forms of thin-walled packaging containers made for different purposes. Metal packaging products usually include a metal packaging can body and a cover. The metal can body includes various forms such as thinned and stretched two-piece cans, three-piece cans, and stamped two-piece cans. Typical forms of covers include SOT pull ring covers, RPT pull ring covers, and full-open covers. In the present invention, cans refer to all forms of the above-mentioned metal can bodies and covers, including but not limited to the can body and cover types listed above.

[0044] like Figure 1As shown, the first aspect of the present invention discloses a beverage can body 1, which includes a main body 10, and the main body 10 is used to contain beverages. The main body 10 has a peripheral wall 101, and the inner surface of the peripheral wall 101 has a coating (not shown in the figure). The beverage can body 1 can be open, and the main body 10 has a top and a bottom, the top is opposite to the bottom, and the bottom can be a bottom 20 integrally formed with the main body 10, for example, by integrally stamping an aluminum alloy plate to form a can body with an opening. The beverage can body can be cylindrical or rectangular, and its shape is not particularly limited. In addition, the beverage can body can be matched with various can lids, such as a fully open can lid or a half-open can lid. For example, the can lid can be one of 202SOT, 202RPT, 206SOT, 206RPT, a large opening easy-pull lid, a fully open lid, or a lid type with a sealing function that is not within the above-mentioned range. The can lid can be an opening area of ​​220~400mm 2 , the opening area accounts for 10%~29% of the total area of ​​the can cover, or the opening area is greater than 1300mm 2 For can covers whose opening area accounts for more than 50% of the total area of ​​the can cover, there is no special restriction on this.

[0045] Specifically, the coating includes a first area, a second area, and a third area arranged in sequence along a first direction, wherein the first direction is, for example, Figure 1 In the direction A shown, the first direction is the direction from the top of the main body 10 to the bottom thereof (e.g., the bottom 20). Specifically, in the first direction, based on the length of the main body 10 extending in the first direction, the three regions can be evenly distributed into three equal parts, that is, the length occupied by each region in the first direction is the same, and the shapes of the three regions are exactly the same; or, the second region extends the longest in the first direction, for example, occupies half of the main body 10, and the first region and the third region are the same size.

[0046] Furthermore, the first zone, the second zone and the third zone have a distribution density of 160 to 4900 per mm 2 Preferably, the first area, the second area and the third area have a distribution density of 160 to 2004 / mm 2 Furthermore, the distribution density of the second zone is 28 to 1300 / mm greater than the distribution density of the first zone. 2 The distribution density of the first zone is 25~640 / mm greater than that of the third zone. 2Furthermore, the distribution density of the second zone is 100 to 1500 greater than that of the third zone. That is, in the first to third zones, the distribution of the depressions is not uniform, among which the depressions in the second zone have the highest distribution density, followed by the first zone, and the third zone has the lowest distribution density. In addition, the surface areas of the first to third zones are 4550 to 18500 mm, respectively. 2 .

[0047] The distribution density reflects the sparse distribution of the depressions. In a specific embodiment of the present invention, multiple unit areas are selected from the first to third areas, the number of depressions in each unit area is measured, and the distribution density of the depressions in each unit area is obtained by dividing it by the area of ​​each unit area. Finally, the distribution density of each area is represented by a range value, or the average value can be taken to represent the distribution density of each area. In an embodiment of the present invention, a range value is selected for representation. Specifically, 4 to 6 unit areas are evenly distributed along the circumferential direction at the same height position in the middle of each area, and each unit area is a square with a side length of 1 to 2 cm. A scanning electron microscope (German ZEISS GeminiSEM300) is used to obtain a unit area microscopic image, and the number of depressions in each unit area is measured using image processing software, and then the distribution density of the depressions in each unit area is calculated based on the number of depressions and the area of ​​the unit area, and finally the distribution density range of each area is obtained. Furthermore, the difference in distribution density between different areas is calculated by an average value. For example, when it is necessary to calculate the difference in distribution density between the first zone and the second zone, the average distribution density of the unit area is first calculated based on the distribution density of each unit area in the first zone and the number of unit areas (the sum of the distribution densities of the unit areas / the number of unit areas). Then, the average distribution density of the unit area is calculated based on the distribution density of each unit area in the second zone and the number of unit areas. The difference between the average distribution densities of the unit areas represents the difference in distribution density between the first zone and the second zone. When the average distribution density of the unit areas in the second zone is greater than that of the first zone, it means that the distribution of the depressions in the second zone is denser than that in the first zone.

[0048] In a specific embodiment of the present invention, more specifically, the diameter of the bottom is 5.5~8.2cm, the total length of the peripheral wall of the main body in the first direction is 15cm, the shortest distance between the second area and the bottom is 5cm, and the shortest distance between the first area and the bottom is 10cm; or, the total length of the peripheral wall of the main body in the first direction is 20cm, the shortest distance between the second area and the bottom is 6.8cm, and the shortest distance between the first area and the bottom is 13.6cm.

[0049] In a general tank container, the coating is basically flat relative to the main body, that is, if the main body is cylindrical, the coating on its inner surface is also cylindrical with a flat surface. In an embodiment of the present invention, the coating includes a first area, a second area and a third area arranged in sequence along a first direction, and the three areas are respectively provided with a distribution density of 160 to 4900 pieces / mm 2 The concave part. Figure 2~Figure 4 As shown, the recessed parts 102 are distributed on the surface of the coating, presenting a state of pits, that is, although the recessed parts 102 are recessed toward the inner surface of the main body, they do not penetrate the coating. Due to the existence of these recessed parts 102, when the beverage can body 1 contains a carbonated beverage, such as beer filled with carbon dioxide, if the sealed state of the beverage can body 1 is eliminated and the internal beverage is in contact with the outside, foam will spontaneously overflow from the inside of the can body to the outside of the can body. For example, when the can body cooperates with the can lid, the can lid is used to seal the inside of the can body, and when the can body contains beer containing carbon dioxide, due to the existence of the recessed parts, when the consumer opens the can lid, at this time, no other operation of the consumer is required, and the beer foam will automatically flow out, giving the consumer a good visual experience. With the full effect of vision and taste, the product experience performance is better.

[0050] In particular, as mentioned above, among the first to third zones, the distribution density of the recessed parts in the second zone is the highest, followed by the first zone, and the third zone is the lowest, and the three zones have a certain distribution density gradient. At the same time, the first to third zones each have a certain surface area. Under such a setting, the effect of foam overflow is enhanced. Specifically, first of all, since the first zone is closest to the top of the can, the gas in the first zone will first flow out of the can. Therefore, ensuring the distribution density of the recessed parts in the first zone can ensure that foam will flow out of the beverage can in the first time. However, if the distribution density in the first zone is too large, it may cause more foam to gush out, affecting the consumer experience. Therefore, a higher distribution density is set in the second zone, and the difference in distribution density between the second zone and the first zone is set to 28~1300 / mm 2, through this setting, on the basis of ensuring that the gas volume in the first zone can bring a faster foam overflow speed in the first time, the larger gas volume in the second zone can quickly continue this step, so that the foam overflow process will not stop quickly. In other words, the first zone ensures "speed" and the second zone ensures "durability". Even if the gas in the first zone is almost consumed, the gas in the second zone can still make sufficient foam overflow. In addition, the larger gas in the second zone can push the gas in the first zone to fully escape, ensuring that the role of the recessed part is fully exerted. Under the setting of the distribution density gradient, this process can also be carried out more accurately. In addition, the recessed part of the third zone has the lowest distribution density, and there is a distribution density gradient with the first and second zones. This is because, considering that the third zone is farthest from the top of the tank and the gas escape speed is the slowest, its greatest role is to "make up" the overflowed foam. While the gas in the first zone rushes out quickly and the second zone continues, the gas in the third zone also moves to the top at the same time, ensuring that the foam can always fully overflow outward and improve the uniformity of the foam overflow process. In addition, since there is a certain distance between the second zone and the top, there may be a certain loss of gas in the second zone when it moves to the top, resulting in poor visual effect of the foam. At this time, due to the existence of the third zone, the foam of the second zone and the third zone can be superimposed under the supplement of the third zone to ensure the effect of foam overflow. Moreover, under the distribution density gradient design, it can be ensured that the third zone can be supplemented in time while the gas in the second zone is released. Similarly, it should be noted that the structural distribution density of the third zone should not be too high. Otherwise, after the gas in the first and second zones has been basically released, if only the third zone is still releasing gas, it will affect the visual experience and drinking experience of consumers. Therefore, the structural density gradient of the third zone and the other two zones should be controlled within a reasonable range. At the same time, through the combined design of distribution density and surface area of ​​the first to third zones, the number of recessed parts in the first to third zones can be ensured to ensure sufficient gas storage.

[0051] In the embodiments of the present invention, the structural characteristics of the tank body itself are utilized, and the differences in the internal spatial distribution of the tank body are fully utilized to design different coating partitions so that different partitions play different roles, that is, the foam release speed is increased as much as possible through the first zone, the foam release continuity is fully improved through the second zone, and the foam amount is increased through the third zone to ensure that the foam overflows quickly, sufficiently, and continuously. At the same time, combined with the distribution density of each zone and the distribution density gradient design between the zones, this process can be accurately controlled to ensure the uniformity of the effects between products and the continuity and smoothness of the entire process of foam production of a single product. In particular, the number of recessed parts in the tank body of the present invention does not need to be too many, which reduces the process difficulty. This is because under the functional coordination of the first zone to the third zone, a good foam overflow effect can also be achieved.

[0052] In a specific embodiment of the present invention, the diameter of the depression is 0.1-5.0 μm, and the diameter-to-depth ratio of the depression is 2.0-20.0, wherein the diameter-to-depth ratio is the ratio of the diameter of the depression to the depth of the depression. Since the depression is relatively small, it is necessary to use instruments and equipment such as a scanning electron microscope and a laser confocal microscope during the research process. In an embodiment of the present invention, when measuring the diameter, it is necessary to image under a scanning electron microscope (German ZEISS GeminiSEM 300), such as Figure 2~Figure 4 As shown, it can be seen that the shape of the depression located on the coating surface is roughly circular. Therefore, in the research process, multiple depressions are approximated as circles, and then the diameter of the depression can be measured. Since the depressions are of different sizes, the measured diameter is a range, or an average value can be calculated. In the embodiment of the present invention, a range is used to represent it; when measuring the depth, a laser confocal microscope (VK3000) can be used for measurement, and the distance that the depression is recessed relative to the coating surface to the inner surface of the main body is the depth of the depression. Further calculation can be used to obtain the diameter-to-depth ratio of the depression. Since the depressions are different, the measured depth is a range, or an average value can be calculated. In the embodiment of the present invention, a range is used to represent it, and then the diameter-to-depth ratio is also represented as a range.

[0053] Specifically, when measuring the diameter of the depressed part of each zone, a circle is identified on the coating surface at the middle or upper middle position of each zone. The circle is perpendicular to the height direction of the can body. A depressed part falls on this circle. 6 to 10 points are selected from the depressed part falling on this circle as the depressed part to be measured, such as Figure 2 As shown, a scanning electron microscope (German ZEISS GeminiSEM 300) was used to take pictures of the surface of each concave part, and the contour of the concave part was extracted by image processing software and approximated as a circle. The diameter of each circle was measured to obtain the diameter range of the concave part in each area. Furthermore, a laser confocal microscope (VK3000) was used to obtain the internal structure of the above 6 to 10 concave parts to be measured, and the depth of three positions was measured on average along the circumferential direction of each concave part, and the average value was taken to obtain the depth of each concave part, and then the diameter-to-depth ratio of each concave part was calculated in combination with the diameter, thereby obtaining the diameter-to-depth ratio range of the concave part in each area.

[0054] The diameter-to-depth ratio of the recessed portion also has a certain influence on the effect of gas storage in the recessed portion. If the diameter-to-depth ratio is set within an appropriate range, the recessed portion can reasonably store a certain amount of gas, and the gas escape rate is appropriate. Combined with the above-mentioned distribution density and distribution density gradient design, the speed and visual effect of foam overflow can be further guaranteed. In particular, the diameter design range of the recessed portion is 0.1~5.0μm, the size is relatively uniform, and the diameter difference between the recessed portions is not large, which can improve the fineness of the foam. Combined with the design of the diameter-to-depth ratio, it can fully guarantee the storage capacity of gas and improve the foam overflow effect.

[0055] With the comprehensive design of distribution density, diameter and diameter-to-depth ratio, it can also be ensured that when the sealed can lid is opened, the foam will not gush out instantly in large quantities, causing a "blowout" phenomenon. On the contrary, this design can ensure that the overflow of the foam is always a uniform process with appropriate speed and quantity.

[0056] In a specific embodiment of the present invention, the first area, the second area and the third area are evenly distributed along the first direction, that is, the first area to the third area are three areas that are completely identical in space. The distribution density of the depressions in the second area is 282 to 2004 per mm 2 The distribution density of the depressions in the first zone is 227~1272 / mm 2 The distribution density of the depressions in the third zone is 169~1031 / mm 2 Through the precise gradient design of the recessed parts, the functions of the three areas can be maximized to optimize the foam generation and overflow of the beverage can.

[0057] In a specific embodiment of the present invention, the diameter-to-depth ratio of the depression in the first zone is 4.0-8.0, the diameter-to-depth ratio of the depression in the second zone is 2.5-6.0, and the diameter-to-depth ratio of the depression in the third zone is 3.0-5.5. On the basis of the above-mentioned coating structure, the diameter-to-depth ratio of the depression in each zone is further designed. The combination of the distribution density of the depression in each zone and the diameter-to-depth ratio can further strengthen the functional design of each zone. Among them, the diameter-to-depth ratio of the depression in the first zone is wider, considering that the first zone is closest to the can mouth and has a certain gas escape speed advantage. Therefore, there can be some depressions with relatively small diameter-to-depth ratios in this area to ensure the storage capacity of the gas; there can also be some depressions with relatively large diameter-to-depth ratios in this area to further ensure the gas escape speed in the first zone. Under a certain range of diameter-to-depth ratio design, the foam produced by the beverage can will also have a more delicate taste, and the foam produced will also be denser, which improves the drinking taste of the foam and further improves the consumer experience.

[0058] The size design of the recessed portion is not limited to the diameter of the recessed portion or the depth of the recessed portion, because if only focusing on a single factor of the diameter or the depth, the control of the storage and state of the gas in the recessed portion is not comprehensive. For example, if the diameter is controlled alone, it seems that expanding the diameter can increase the storage capacity of the gas, but different depths at the same diameter will inevitably lead to differences in storage capacity. In addition, both the diameter and the depth will affect the state of the gas molecules. In fact, the gas diffusion and movement state in the tank are not the same as those in a normal environment. Knudsen diffusion occurs in a smaller space, especially in microscale or nanoscale systems. The diffusion phenomenon is relatively complex, and the movement of gas molecules is related to many factors. As shown in Formula 1, the Knudsen number and and related.

[0059] (Formula 1).

[0060] in, is the mean free path, It is the characteristic length scale of the fluid, which can be the diameter of a channel, the thickness of a boundary layer, or the pore size in a porous medium.

[0061] Based on the different states and dynamics of the gas in the tank, a more detailed design of the diameter-to-depth ratio is made. Since the gas in the first zone needs to have a faster escape speed than the other two zones, the diameter-to-depth ratio of the first zone recess is designed to be relatively larger. When the diameter-to-depth ratio is larger, the structure of the recess is closer to the shape of a "plate". The shallower "plate bottom" can ensure the rapid escape of the gas, and can ensure that the gas in the innermost part of the recess can also escape as soon as possible, and the gas in the first zone recess can quickly and fully play its role. However, the diameter-to-depth ratio of the first zone recess cannot be too large. If it is too large, the storage of the gas in the recess is difficult to be stable, and the number of molecules of the gas in the recess exposed to the interface is large, which makes the gas molecules more likely to change. For example, when the gas is carbon dioxide, the solubility of carbon dioxide will be affected by temperature. When carbon dioxide molecules are mostly present at the interface, they are more affected by temperature, which leads to instability of the gas in the tank, and even causes the problem of violent foam gushing out. This problem is more likely to occur at higher temperatures, and the design of the diameter-to-depth ratio of the first zone can reduce the occurrence of this problem. The concave part of the second zone plays the role of ensuring the continuity of foam overflow. Therefore, compared with the first zone, the diameter depth of the concave part of the second zone is relatively smaller. Therefore, when the diameter is in the range of 0.1~5.0μm, the concave part of the second zone can be relatively deeper. Unlike the situation in which the gas escapes as quickly as possible in the first zone, the gas in the concave part of the second zone can be relatively gently, evenly and stably dispersed, thereby improving the continuity and uniformity of the foam. The diameter-to-depth ratio of the concave part of the third zone is in a relatively moderate state, making it between the first zone and the second zone, so that the gas in this zone can escape faster, making up for the problem of the long distance of gas movement caused by the distance from the tank mouth, and ensuring the relatively uniform escape of the gas. Therefore, with the cooperation of the three zones, the foam overflow can be improved in terms of speed, continuity and uniformity.

[0062] In a specific embodiment of the present invention, the diameter-to-depth ratio of the depression in the first zone is greater than the diameter-to-depth ratio of the depressions in the second zone and the third zone. Furthermore, the diameter-to-depth ratio of the depression in the third zone is greater than the diameter-to-depth ratio of the depression in the second zone. Setting the diameter-to-depth ratio of the depression in the first zone to the maximum is to first ensure the gas escape rate in the first zone. The diameter-to-depth ratio of the depression in the third zone is second, and it is also considered that the distance to the third zone is the farthest. Therefore, the diameter-to-depth ratio of the depression in this area is set accordingly to reasonably improve the escape rate of the gas in the third zone. The diameter-to-depth ratio of the depression in the second zone can be the smallest, because the gas in the second zone does not need a particularly fast escape rate, and a smaller diameter-to-depth ratio can ensure a larger gas storage capacity.

[0063] Preferably, the diameter-depth ratio of the depressions in the first zone is 4.5-7.5, the diameter-depth ratio of the depressions in the second zone is 2.5-6.0, and the diameter-depth ratio of the depressions in the third zone is 4.0-5.5, which can achieve a better foam overflow effect with the distribution density and make the foam have a delicate and dense taste. More preferably, on this basis, the diameter-depth of the depressions in the first zone is greater than that of the other two zones.

[0064] In a specific embodiment of the present invention, the film thickness of the first zone is 3.0-4.5 μm, the film thickness of the second zone is 3.5-5.0 μm, and the film thickness of the third zone is 2.8-4.0 μm. Through the design of the film thickness of each zone, the diameter-to-depth ratio of the recessed portion, and the density of the recessed portion, it can be achieved that foam overflows in a relatively short time after the beverage can is opened, and the foam can fully cover the can mouth to achieve an excellent visual effect, and the duration of the foam is reasonable, neither too short to give consumers a full visual experience, nor too long to prevent the consumption of more beverages. At the same time, the design of the thickness of the coating can also ensure the role of the coating in protecting the internal beverage.

[0065] In a specific embodiment of the present invention, the film thickness of the first zone is 3.2-3.8 μm, the film thickness of the second zone is 3.8-4.5 μm, and the film thickness of the third zone is 2.8-3.2 μm, and the film thickness of the second zone is ≥ the film thickness of the first zone ≥ the film thickness of the third zone. Through the gradient design of the film thickness, further combined with the structure of the diameter-to-depth ratio and the distribution density, the foam effect of the beverage can can be further guaranteed, and the thickness gradient of the coating is also conducive to achieving different gradients of the diameter-to-depth ratio and the distribution density, making the structure more stable. Preferably, on the basis of the above, the film thickness of the second zone is > the film thickness of the first zone > the film thickness of the third zone. Specifically, for example, the film thickness of the first zone is 3.2-3.8 μm, the film thickness of the second zone is 3.9-4.5 μm, and the film thickness of the third zone is 2.8-3.1 μm.

[0066] Specifically, when measuring the film thickness of each zone, a circular plane is confirmed in the middle or upper middle position of each zone. The circular plane is perpendicular to the height direction of the can body. The coating forms a circular ring shape with different thicknesses on the circular plane. An average of 3 to 4 points on the circular ring shape are taken as measurement points, and the can body is cut on the circular plane. In this way, the internal section of the coating is exposed, and then a scanning electron microscope (ZEISS GeminiSEM300, Germany) is used to obtain a cross-sectional image. The width of the coating cross section at each point is measured by image processing software to obtain the film thickness at each point, and finally the film thickness range is obtained.

[0067] It was found in process production and laboratory research that there is usually a certain corresponding relationship between the film thickness and the distribution density of the depressed part. In the production process, the control of film thickness can be used as one of the factors to adjust the distribution density. The distribution density or the distribution density difference can be further adjusted in combination with some influencing factors in the process and slurry formula to obtain the preset distribution density and distribution density difference, and then the required product can be obtained.

[0068] The beverage can body design of the present invention fully considers the factors affecting the foam overflow at all levels, makes a reasonable structural layout and design, and considers the relationship and influence between various structural features, so as to bring consumers a dual enjoyment of taste and vision, and enhance the functionality of the beverage can body. In addition, the beverage can body is particularly suitable for use after storage at low temperature (for example, 4-9°C), and the foam generation and overflow effect at low temperature is better, and the foam tastes smoother. In addition, even if the can body is in a relatively high temperature environment, such as 10-14°C, the foam overflow speed is fast, the overflow amount is sufficient, and the gas stored in the recessed part will not escape violently, which can further prevent the gas from taking out a large amount of liquid stored in the can and affecting the use. At the same time, 10-14°C can meet the drinking temperature habits of consumers in some areas, and can also prevent the safety problems that may be caused by the rapid escape of gas. In particular, the beverage can body is suitable for storage and use temperatures of 12°C, has a faster overflow speed and a more stable overflow amount, a moderate overflow time, and a rich and delicate foam taste.

[0069] A second aspect of the present invention discloses a method for manufacturing a beverage can body, comprising the following steps:

[0070] Slurry spraying: Use a spray gun to spray the slurry on the inner surface of the main body of the container at a preset angle of 7 to 20 degrees, wherein the preset angle is the angle between the center line of the spray gun and the normal line of the beverage can surface;

[0071] Drying to form a coating: Drying the sprayed slurry to form a coating;

[0072] Among them, the composition of the slurry includes 20%~30% epoxy resin and 0.1%~0.2% defoaming agent by mass percentage.

[0073] The production process of beverage can bodies includes: aluminum coil uncoiling, cup punching, stretching and trimming, cleaning and drying, primer coating and drying, color printing and drying, internal spraying and drying, necking and flanging, optical inspection and photography, and stacking and packaging. Through the above process, the entire production process from aluminum material to cans is completed. Among them, the coating of the present invention is formed in the internal spraying and drying steps.

[0074] Specifically, by designing the angle of the spray gun, a slurry with 20% to 30% epoxy resin and 0.1% to 0.2% defoamer can be sprayed to obtain a structure with the first to third zones at one time after drying, and the recessed parts of the first to third zones meet a certain distribution density range. The method is simple in steps, and only requires the preparation of the slurry and the spraying angle of the spray gun to be set. It is suitable for industrial mass production, efficient and with high product uniformity. By adjusting the angle of the spray gun, the distribution and structure of the coating can also be controlled.

[0075] In an embodiment of the present invention, by setting the spray gun angle, spray gun pressure, etc., when the tank body rotates continuously and changes from horizontal to standing state, three different areas can be formed after spraying. Specifically, firstly, the tank body is placed horizontally, the tank body is rotated, and the center line of the spray gun is at a certain angle with the normal line of the surface of the beverage tank body, and a certain spray gun pressure is set. By setting the relative position of the spray gun and the tank body, the film thickness difference can be made in different areas of the tank. After the spraying is completed, the tank body changes from being placed horizontally to being placed vertically. At this time, the wet slurry will flow downward due to the influence of gravity, and then the tank body is placed in a drying oven for drying at a certain temperature. In particular, the film thickness is also related to the angle and pressure, and the flow of the slurry will also affect the film thickness to a certain extent. Therefore, the setting of the relative position of the spray gun and the tank body, the spray gun angle and the spray gun pressure also needs to take into account the flow of the slurry in advance, so that the flow of the slurry eventually leads to the film thickness within the preset range, and then the distribution density of each zone and the distribution density difference between different zones can also be within the preset range. In addition, the spray gun angle, spray gun pressure, and drying temperature will also affect the diameter and depth of the concave part. Therefore, in order to obtain a beverage can body with the target structure, the spraying process should be designed as a whole and the entire spraying process should be mastered.

[0076] In a specific embodiment of the present invention, the preset angle of the spray gun is 12-20°, and the drying temperature of the slurry is 80-100° C. Within this range, each region with an appropriate recessed portion distribution density and diameter-to-depth ratio can be formed, and the film thickness of each region after drying is also within an appropriate range.

[0077] In a specific embodiment of the present invention, the spray pressure of the spray gun is 500-550 psi. By setting the spray pressure of the spray gun, it is further ensured that three regions with corresponding diameter-to-depth ratio gradients are formed at one time. By precisely controlling the spray angle and pressure, regions with different recessed portion distribution densities and diameter-to-depth ratios can be obtained, and a suitable coating can be obtained.

[0078] In a specific embodiment of the present invention, in the step of drying to form a coating, the drying process includes pre-drying and subsequent drying, the drying temperature of the pre-drying is 80-100°C, the drying time of the pre-drying is 1-3 minutes, and the drying temperature of the subsequent drying is 150-280°C, until a stable coating is formed after solidification. That is, after the slurry is sprayed onto the inner surface of the main body, it is first dried at a temperature of 80-100°C for 1-3 minutes. At this time, the structure of the recessed part has been stably formed, and then the drying temperature can be increased to 150-280°C, and the coating is quickly solidified to form a stable coating. This staged drying method is conducive to the formation of a coating with specific physical properties, and can also ensure the basic functions of the coating.

[0079] The third aspect of the present invention discloses a slurry sprayed on the inner surface of the main body to form a coating, wherein the components of the slurry include 20% to 30% epoxy resin, 1% to 3% phenolic resin, 55% to 65% deionized water and 0.1% to 0.2% defoaming agent in terms of mass percentage.

[0080] First, epoxy resin can constitute the main structure of the coating. It has excellent bonding properties and can firmly adhere to the surface of aluminum or other metal substrates to ensure good adhesion between the coating and the can body; the epoxy resin coating has a certain hardness and flexibility, and can withstand the mechanical stress that may be generated during the transportation and stacking of the can body to prevent the coating from cracking or falling off; the epoxy resin also has good chemical stability, which can ensure the stability of the performance of the coating and the beverage in the can. In the embodiment of the present invention, since it is necessary to form a recessed portion in the coating, and it is also necessary to form a recessed portion with specific structural characteristics, therefore, compared with the ordinary coating preparation process, the coating preparation of the present invention will have additional reactions, and the epoxy resin forming the main structure has higher requirements, which needs to maintain the original performance advantages and can serve as a stable recessed portion load to ensure the functional characteristics of the recessed portion. Specifically, in the embodiment of the present invention, 20% to 30% of epoxy resin is used, and within this range, the multiple functions of the epoxy resin can be guaranteed. More specifically, in the embodiment of the present invention, the epoxy resin used is epoxy acrylic resin. Compared with other types of epoxy resins, epoxy acrylic resin has better water solubility and is more suitable as a matrix for the generation of recessed portions. Further, the epoxy equivalent of the epoxy acrylic resin is 4000-6000 g / mol. Preferably, the epoxy equivalent of the epoxy acrylic resin is 5000-6000 g / mol. Within this range, the compatibility of the epoxy acrylic resin with water is within an appropriate range, which will promote the unevenness of the surface of the coating during the subsequent curing process, further promoting the generation of recessed portions.

[0081] Specifically, in the embodiment of the present application, the epoxy equivalent is measured as follows:

[0082] Weigh a certain amount of epoxy resin (at least accurate to three decimal places) and put it into the sample conical flask; add 25 ml of butanone to the sample conical flask, and also add the same amount of butanone to the control blank flask; dissolve the resin on a magnetic stirrer (slightly heated), and add 50 ml of cyclohexanone glacial acetic acid mixed solvent to the conical flask and the blank flask; add 2.0±0.1 g CTBA to the conical flask and the blank flask respectively, and then add 4 drops of crystal violet indicator respectively, and titrate with 0.1M perchloric acid glacial acetic acid solution. The color changes from blue to blue-green to emerald green, which is the titration end point. Among them, the calculation formula of epoxy equivalent is as follows:

[0083] EEW 1000 M / (AB) N (Formula 2).

[0084] Wherein, EEW is the epoxy equivalent weight of the epoxy resin to be tested, A is the milliliters of perchloric acid solution consumed by the sample, B is the milliliters of perchloric acid solution consumed by the blank sample, N is the equivalent concentration of the perchloric acid solution, and M is the weight of the epoxy resin.

[0085] Secondly, the slurry also contains 1%~3% phenolic resin, which can fully react with 20%~30% epoxy resin. Phenolic resin can be used as a cross-linking agent, and cross-links with epoxy acrylic resin under high temperature baking to form a strong and dense coating, which covers the metal surface and isolates the metal from the contents of the can. 1%~3% phenolic resin and 20%~30% epoxy resin can ensure sufficient cross-linking and form a stable coating structure.

[0086] In addition, 55% to 65% of deionized water in the slurry is mainly used to adjust the viscosity of the slurry so that the slurry is easy to spray. The use of deionized water ensures that no additional impurities or ions are introduced during the spraying process, thereby ensuring the quality and consistency of the coating.

[0087] In addition, the slurry also has 0.1% to 0.2% defoamer. The use of defoamer can avoid excessive bubbles affecting the spraying effect during the coating spraying process. However, in the embodiment of the present invention, the defoamer also has a more important role. During the experiment, the compatibility of the defoamer with the coating body is poor. During the curing process of the resin in the coating, it can form a certain shape and dense pits and fine wrinkles on the coating surface. The dense pits and wrinkles on the coating surface can make the gas in the beverage unevenly distributed in the can, so that when the can lid is opened and the pressure in the can is released instantly, the gas can be concentrated and quickly released, generating a large amount of foam. At the same time, the defoamer can have better dispersibility in the coating, and can ensure that the pits achieve a certain distribution density on the coating surface. If other substances are used instead of the defoamer, agglomeration may occur in the slurry, resulting in the distribution density of the depressed portion being difficult to achieve. In addition, the physicochemical properties of the defoamer are relatively stable, which is conducive to obtaining a depressed portion with a certain diameter and diameter-to-depth ratio, so that a sufficient amount of gas can be stored. Defoamers are usually in liquid or soluble form and can be added directly to the slurry without the need for pretreatment steps. They are very convenient to operate and are conducive to industrial production. In addition, defoamers also have good heat resistance and maintain their chemical stability under various temperature conditions, which allows defoamers to play a stable role in high-temperature or low-temperature application scenarios, especially in the production process of slurry and tank bodies, which require certain high-temperature treatment. At this time, the defoamer can still maintain its performance and dispersibility, so that the depression can be stably generated.

[0088] Specifically, in the embodiment of the present invention, the defoamer is an acrylic defoamer and a polyester defoamer. Acrylic defoamers and polyester defoamers are not highly compatible with the resin system of the slurry of the present invention, and can ensure the full formation of the concave part.

[0089] In particular, the dosage relationship between the resin and the defoamer also affects the final structure and performance of the coating. The more defoamer is used, the more depressions are produced. However, when the amount of defoamer is too much, the mass ratio of the defoamer to the resin is too high, which will lead to poor dispersion of the defoamer and poor coverage of the coating on the metal substrate, and even make the can highly conductive. Therefore, using 20% ​​to 30% epoxy resin, 1% to 3% phenolic resin and 0.1% to 0.2% defoamer can achieve a good match between the resin and the defoamer, the defoamer can have good dispersibility, and the required depressions can be properly generated without affecting the final performance of the coating. Preferably, the mass ratio of the defoamer to the resin is less than 1:100, specifically, the mass ratio of the defoamer to the epoxy resin and the phenolic resin is less than 1:100, that is, the ratio of the mass of the defoamer to the sum of the mass of the epoxy resin and the phenolic resin is less than 1:100, which can ensure that the distribution density, diameter-to-depth ratio, coating coverage, and film thickness of the recessed portion are all within an appropriate range, and the speed, continuity, and appearance of the foam overflow are ensured. In addition, the use of the defoamer can make the generated recessed portion maintain structural stability in the resin system, whether in the subsequent production or transportation process, or in the process of storage by the consumer, the structural integrity of the recessed portion can be guaranteed, and undesirable problems such as collapse of the recessed portion will not occur.

[0090] In a specific embodiment of the present invention, the composition of the slurry also includes 2% to 5% of dimethylethanolamine, 3% to 6% of ethylene glycol butyl ether, 0.5% to 3% of n-butanol and 0.3% to 0.4% of carnauba wax. Dimethylethanolamine can improve the water solubility of the slurry. Ethylene glycol butyl ether and n-butanol are both cosolvents, which help epoxy acrylic resin to be better miscible with water. The main function of carnauba wax is to provide sufficient slippage of the coating to ensure metal deformation.

[0091] Preferably, the composition of the slurry includes 23% epoxy resin, 2% phenolic resin, 4% dimethylethanolamine, 6% ethylene glycol butyl ether, 2% n-butanol, 62.5% deionized water, 0.32% carnauba wax and 0.18% defoamer by mass percentage. The slurry of this component system is combined with a certain slurry spraying process to obtain a coating with different recessed structures in the first to third zones, and the coating has good performance stability. When the beverage can is opened, the gas in the can can escape quickly, rich foam can gush out, the visual sense is better, and the duration of the foam gush out is appropriate, which not only ensures a full visual experience, but also ensures less consumption of beverages. At the same time, the foam is more delicate, dense, and has a better taste.

[0092] Under the above slurry component system, the role of the coating in protecting the contents of the beverage can is firstly ensured, and the recessed part can also be reasonably and appropriately generated, so that the various functions of the beverage can can be realized. By matching the various components, a coating suitable for foam generation can also be produced efficiently and at low cost, and the foam generation effect can be improved. Under the multi-layer design of the recessed part structure, functional zoning design, slurry application process, and slurry formula, the foam generation performance of the beverage can is improved, which can bring consumers a multi-faceted sensory experience.

[0093] The fourth aspect of the present invention discloses a method for preparing the above slurry, comprising:

[0094] Chain extension reaction: The epoxy equivalent of the basic epoxy resin (epoxy equivalent 182-192 g / mol) is increased to 4000-6000 g / mol by reacting with bisphenol A. Specifically, add the solvent ethylene glycol butyl ether, the basic epoxy resin, and bisphenol A into the reactor, start heating, and when the temperature rises to 175-185°C, start heat preservation for 2-3 hours until the epoxy equivalent reaches 4000-6000 g / mol.

[0095] Grafting reaction: Grafting acrylic acid onto the chain-extended high molecular weight epoxy resin. Specifically, cool the chain-extended epoxy resin to 120-130°C, pre-mix n-butanol, acrylic acid, ethyl acrylate, methacrylic acid, styrene and benzoyl peroxide, and slowly drip the pre-mixed acrylic acid and other monomers at 120-130°C at a dripping speed of 1-2 kg / min. After all the acrylic acid and other monomers have been added, keep warm for 1 hour.

[0096] Emulsification: The grafted epoxy acrylic resin is emulsified in water under the action of dimethylethanolamine. Specifically, the grafted epoxy acrylic resin is pumped into a stirring kettle, dimethylethanolamine and deionized water are added, stirred for 2 hours, and the solid content of the emulsion is adjusted to 30-35%.

[0097] Dilution. Specifically, the emulsified epoxy acrylic emulsion is diluted with water to reduce the solid content, and a crosslinking agent and a defoaming agent are added, and wax can also be added. Finally, the solid content of the product is controlled at 22-26%, and the viscosity range is 18-22 seconds (25°C, Ford No. 4 cup).

[0098] The fifth aspect of the present invention discloses a beverage can, which includes the beverage can body mentioned above, and the beverage can also has a top cover, which is sealed with the beverage can body so that the beverage in the can body can be isolated from the external environment, and the top cover also has an opening portion, when the opening portion is opened, the beverage can contact the outside world. In particular, the beverage can contains a beverage and is filled with carbon dioxide.

[0099] In particular, when the opening portion is opened, foam overflows from the beverage can within 6 to 15 seconds. In addition, the amount of foam overflowing is relatively uniform, and too much foam will not overflow immediately after opening. The foam overflow is also continuous, and the foam has a delicate taste, and the taste and visual experience are good. Specifically, the beverage is beer. In particular, the beverage can is particularly suitable for opening after standing for 24 hours in an environment of 4 to 12°C, and the visual effect and taste of the foam can better meet the needs of consumers.

[0100] A sixth aspect of the present invention discloses a method for manufacturing the beverage can, comprising the following steps:

[0101] Since the unfilled beverages are stored in another liquid storage container, carbon dioxide is first charged into the liquid storage container storing the beverages;

[0102] Fill the beverage can with carbon dioxide to make the gas pressure in the beverage can equal to the gas pressure in the liquid storage container; use the beverage's own gravity to fill the beverage into the beverage can;

[0103] The top cover is sealed and connected to the beverage can body to obtain a beverage can, and the gas pressure in the beverage can is 0.18~0.40MPa. After the beverage is filled into the beverage can body, there is no need to additionally fill the interior with carbon dioxide, so that the gas pressure in the final beverage can is 0.18~0.40MPa.

[0104] In particular, ensuring the gas pressure in the can can ensure that an appropriate amount of carbon dioxide is stored in the recessed portion, ensure that the carbon dioxide is distributed evenly in the recessed portion in the can, and that the gas can fully overflow after the beverage can is opened.

[0105] The following will introduce it through a more specific implementation method.

[0106] Example 1 is a beverage can with a coating.

[0107] (1) Example 1

[0108] Example 1 is obtained by applying the slurry on the inner surface of the tank body and preparing a coating, which specifically includes the following steps:

[0109] Slurry spraying: Use a spray gun to spray the slurry on the inner surface of the main body of the container at a preset angle of 18° and a spray pressure of 550psi. The composition of the slurry includes, by mass percentage, 23% epoxy acrylic resin, 2% phenolic resin, 4% dimethylethanolamine, 6% ethylene glycol butyl ether, 2% n-butanol, 62.5% deionized water, 0.32% carnauba wax and 0.18% defoamer. The epoxy equivalent of epoxy polypropylene resin is 5500g / mol.

[0110] Drying to form a coating: Dry the sprayed slurry, first at 80°C for 3 minutes, and then at 250°C to form a coating;

[0111] The coating of Example 1 has three regions evenly distributed in the first direction, namely the first region to the third region, and the surface area of ​​each region is 7958 mm 2 The structural characteristics of the depressions in the first to third zones were statistically analyzed, and the statistical results are shown in Table 1.

[0112] Table 1:

[0113] .

[0114] Among them, the distribution density of the second zone is 764 / mm greater than that of the first zone. 2 The distribution density of the first zone is 380 / mm greater than that of the third zone. 2 The diameter of the concave portion is 0.1 to 5.0 μm. Furthermore, the film thickness of the second region ≥ the film thickness of the first region ≥ the film thickness of the third region.

[0115] The test method for the distribution density of the concave parts is as follows: 4 evenly distributed unit areas are drawn along the circumferential direction at the same height position in the middle of each area, each unit area is a square with a side length of 1 cm, and a scanning electron microscope (German ZEISS GeminiSEM 300) is used to obtain a unit area microscopic image, and the number of concave parts in each unit area is measured using image processing software, and then the distribution density of the concave parts in each unit area is calculated based on the number of concave parts and the area of ​​the unit area, and finally the distribution density range of each area is obtained. Furthermore, the difference in distribution density between different areas is represented by the difference in average distribution density of the unit area.

[0116] The measurement and calculation method of the diameter-to-depth ratio of the depressed part is as follows: first, the diameter of the depressed part is measured, and a circle is confirmed on the coating surface at the middle position of each zone. The circle is perpendicular to the height direction of the can body, and a depressed part falls on this circle. Six points are taken in the depressed part falling on this circle as the depressed parts to be measured, and the surface of each depressed part is photographed by a scanning electron microscope (ZEISSGeminiSEM 300, Germany). The contour of the depressed part is extracted and approximated to a circle by image processing software, and the diameter of each circle is measured, thereby obtaining the diameter range of the depressed part in each zone; then, the depth of the depressed part is measured, and the internal structure of the above six depressed parts to be measured is obtained by a laser confocal microscope (VK3000), and the depth of three positions along the circumferential direction of each depressed part is measured on average, and the average value is taken to obtain the depth of each depressed part; finally, the diameter-to-depth ratio is calculated, and the diameter calculation obtains the diameter-to-depth ratio of each depressed part, thereby obtaining the diameter-to-depth ratio range of the depressed part in each zone.

[0117] The film thickness is measured as follows: a circular plane is identified in the middle of each zone, the circular plane is perpendicular to the height direction of the tank body, the coating forms a circular ring shape of varying thickness on the circular plane, 3 points are taken on average as measuring points on the circular ring shape, and the tank body is cut on the circular plane, so that the internal section of the coating is exposed, and then a scanning electron microscope (German ZEISS GeminiSEM 300) is used to obtain a cross-sectional image, and the width of the coating cross section at each point is measured by image processing software to obtain the film thickness at each point, and finally the film thickness range is obtained.

[0118] The measurement methods of the following comparative examples are the same as those of Example 1.

[0119] Comparative Examples 1 to 5 are beverage cans with coatings.

[0120] (1) Comparative Example 1

[0121] The difference between Comparative Example 1 and Example 1 is that the spray gun angle is 12°, the pressure is 480 psi, the sprayed slurry is first dried at 95°C, and the mass proportion of carnauba wax in the slurry is 0.4% and the defoamer is 0.1%, and the epoxy equivalent of the epoxy polypropylene resin is 5000 g / mol. The rest is reference to Example 1.

[0122] The coating of Comparative Example 1 has three regions evenly distributed in the first direction, namely the first region to the third region, and the surface area of ​​each region is 7958 mm 2 The structural characteristics of the depressions in the first to third zones were statistically analyzed, and the statistical results are shown in Table 2.

[0123] Table 2:

[0124] .

[0125] Among them, the distribution density of the second zone is 208 / mm greater than that of the first zone. 2 The distribution density of the first zone is 183 / mm greater than that of the third zone. 2 The diameter of the depression is 0.1~5.0μm.

[0126] (2) Comparative Example 2

[0127] The difference between Comparative Example 2 and Example 1 is that the spray gun angle is 15°, the pressure is 500 psi, the sprayed slurry is first dried at 95°C, and the mass proportion of carnauba wax and defoamer in the slurry is 0.35% and 0.15%, and the epoxy equivalent of epoxy polypropylene resin is 5000 g / mol. The rest is the same as Example 1.

[0128] The coating of Comparative Example 2 has three regions evenly distributed in the first direction, namely the first region to the third region, and the surface area of ​​each region is 7958 mm 2 The structural characteristics of the depressions in the first to third zones were statistically analyzed, and the statistical results are shown in Table 3.

[0129] Table 3:

[0130] .

[0131] The distribution density of the second zone is 225 / mm greater than that of the first zone. 2 The distribution density of the first zone is 339 / mm greater than that of the third zone. 2 The diameter of the depression is 0.1~5.0μm.

[0132] (3) Comparative Example 3

[0133] The difference between Comparative Example 3 and Example 1 is that the spray gun angle is 7°, the pressure is 450psi, the sprayed slurry is first dried at 100°C, and the mass proportion of carnauba wax in the slurry is 0.42% and the defoamer is 0.08%, and the epoxy equivalent of the epoxy polypropylene resin is 5000g / mol. The rest is the same as Example 1.

[0134] The coating of Comparative Example 3 has three regions evenly distributed in the first direction, namely the first region to the third region, and the surface area of ​​each region is 7958 mm 2 The structural characteristics of the depressions in the first to third zones were statistically analyzed, and the statistical results are shown in Table 4.

[0135] Table 4:

[0136] .

[0137] Among them, the distribution density of the second zone is 52 / mm greater than that of the first zone. 2 The distribution density of the first zone is 27 / mm greater than that of the third zone. 2 The diameter of the depression is 0.1~5.0μm.

[0138] (4) Comparative Example 4

[0139] The difference between Comparative Example 4 and Example 1 is that the spray gun angle is 15°, the pressure is 450psi, the sprayed slurry is first dried at 90°C, and the mass proportion of carnauba wax in the slurry is 0.4% and the defoamer is 0.1%, and the epoxy equivalent of the epoxy polypropylene resin is 5000g / mol. The rest is the same as Example 1.

[0140] The coating of Comparative Example 4 has three regions evenly distributed in the first direction, namely the first region to the third region, and the surface area of ​​each region is 7958 mm 2 The structural characteristics of the depressions in the first to third zones were statistically analyzed, and the statistical results are shown in Table 5.

[0141] Table 5:

[0142] .

[0143] The film thicknesses of the first zone, the second zone and the third zone are the same, and the distribution density of the recessed portions is at a consistent level within an allowable error range. The diameter of the recessed portions is 0.1 to 5.0 μm.

[0144] (5) Comparative Example 5

[0145] The only difference between Comparative Example 5 and Example 1 is that the spray gun angle is 23°, and the rest is the same as Example 1.

[0146] The coating of Comparative Example 5 has three regions evenly distributed in the first direction, namely the first region to the third region, and the surface area of ​​each region is 7958 mm 2 The structural characteristics of the depressions in the first to third zones were statistically analyzed, and the statistical results are shown in Table 6.

[0147] Table 6:

[0148] .

[0149] The distribution density of the recessed parts in the first zone is greater than that in the second zone and the third zone, and the film thickness in the first zone is greater than that in the second zone and the third zone.

[0150] (6) Comparative Example 6

[0151] The only difference between Comparative Example 6 and Example 1 is that the spray gun angle is 12° and the pressure is 500 psi. The rest is the same as Example 1.

[0152] The coating of Comparative Example 6 has three regions evenly distributed in the first direction, namely the first region to the third region, and the surface area of ​​each region is 7958 mm 2 The structural characteristics of the depressions in the first to third zones were statistically analyzed, and the statistical results are shown in Table 7.

[0153] Table 7:

[0154] .

[0155] Among them, the distribution density of the second zone is 755 / mm greater than that of the first zone. 2 The distribution density of the first zone is 326 / mm greater than that of the third zone.2 The diameter of the depression is 0.1~5.0μm.

[0156] Beer filled with carbon dioxide was poured into the beverage cans of the above-mentioned Example 1 and Comparative Examples 1 to Comparative Examples 6, and the gas pressure in the beverage cans was 0.29 MPa. The above-mentioned Examples and Comparative Examples were stored at 8°C for 24 hours and then opened. The fastest foam overflow time after opening, the total foam overflow time, the foam persistence time, the average foam overflow amount were weighed and calculated, and the taste of the foam was professionally evaluated. The can lids of the beverage cans of the embodiments and comparative examples are easy-open lids, and the "fastest foam overflow time after opening" refers to the time from opening the can lid to the time when the foam overflows the can lid pull ring; the "total foam overflow time" refers to the time from the time when the foam overflows the can lid pull ring to the time when the foam stops overflowing; the "average foam overflow amount" refers to the escape amount of gas in the can, which is calculated by the difference in mass before and after opening the can; the "foam persistence (foam retention, refer to the national standard GB4927-2008)" refers to the life span of the foam from its generation to its disappearance; the "foam taste evaluation" is a taste evaluation comparison of the embodiments and comparative examples based on the fineness and density of the foam, wherein "☆☆☆☆☆" means that the foam tastes very fine and smooth, and the flavor substances in the beer can be tasted; "☆☆☆☆" means that the foam tastes relatively fine but lacks smoothness, and the flavor substances in the beer can be tasted; "☆☆☆" means that the foam is not fine and lacks smoothness, and the flavor substances in the beer can be tasted; "☆☆" means that the foam is not fine and lacks smoothness, and the flavor substances in the beer can be tasted; "☆☆" means that the foam is low in fineness and smoothness, and the flavor is poor.

[0157] The results are shown in Table 8.

[0158] Table 8:

[0159] .

[0160] As can be seen from Table 8, after Example 1 is opened, the foam overflows at a faster speed, lasts longer, the amount of foam overflow is moderate, and the foam tastes better, the flavor substances can be tasted, and the foam persistence is also improved. The overflow speed of Comparative Example 1 is slow, and the foam flavor is poor. Although the overflow speed of Comparative Example 2 is accelerated and the foam flavor is improved, the persistence of the foam is not as good as that of Example 1. The foam overflow speed of Comparative Example 3 is slow, and the amount produced is very small. Compared with Comparative Example 3, the speed of Comparative Example 4 is improved, but the amount of foam overflow is still very small, and the foam fineness of Comparative Examples 3 and 4 is not high, and the flavor substances in the beer cannot be tasted. After opening, the foam of Comparative Example 5 rushes out of the can mouth, the foam overflows violently, and the duration is very short, and a considerable part of the wine is brought out, which seriously affects the user experience. Although Comparative Example 6 has a faster overflow speed and better persistence, it is not as good as Example 1, and the foam flavor is insufficient, especially the fineness is poor.

[0161] In addition, beverage cans as in Example 1 and Comparative Example 6 were prepared, and commercially available beer products were prepared and stored at 12° C. for 24 hours. Figure 5 As shown, after the beverage can of Example 1 is opened, the foam covers the can mouth, but the foam can overflow relatively gently without the "rush" phenomenon. However, the beverage can of Comparative Example 6 and the relevant beer products on the market will produce violent foam overflow at 12°C.

[0162] Although the present invention has been illustrated and described with reference to certain preferred embodiments of the present invention, it should be understood by those skilled in the art that the above is a further detailed description of the present invention in conjunction with specific embodiments, and it cannot be determined that the specific implementation of the present invention is limited to these descriptions. Those skilled in the art may make various changes in form and details, including making several simple deductions or substitutions, without departing from the spirit and scope of the present invention.

Claims

1. A beverage can body, characterized in that: The beverage can body comprises: The main body is used to contain beverages and comprises a peripheral wall, wherein the inner surface of the peripheral wall has a coating; The coating includes a first area, a second area and a third area which are arranged in sequence and evenly distributed along a first direction, and the first area, the second area and the third area have a distribution density of 160 to 4900 per mm 2 The distribution density of the second area is 28 to 1300 / mm greater than the distribution density of the first area. 2 The distribution density of the first zone is 25-640 / mm greater than the distribution density of the third zone. 2 The surface areas of the first zone, the second zone and the third zone are 4550-18500 mm respectively. 2 , the diameter of the depressed portion is 0.1-5.0 μm; the diameter-to-depth ratio of the depressed portion in the first zone is 4.0-8.0, the diameter-to-depth ratio of the depressed portion in the second zone is 2.5-6.0, the diameter-to-depth ratio of the depressed portion in the third zone is 3.0-5.5, the diameter-to-depth ratio of the depressed portion in the first zone is greater than the diameter-to-depth ratios of the depressed portions in the second zone and the third zone; the film thickness in the first zone is 3.2-3.8 μm, the film thickness in the second zone is 3.8-4.5 μm, the film thickness in the third zone is 2.8-3.2 μm, and the film thickness in the second zone is greater than the film thickness in the first zone and greater than the film thickness in the third zone; The first direction is a direction from the top of the main body to the bottom thereof, and the diameter-to-depth ratio is a ratio of the diameter of the recessed portion to the recessed depth.

2. A beverage can body as claimed in claim 1, characterized in that: The first area, the second area and the third area are evenly distributed along the first direction, and the distribution density of the depressions in the second area is 282-2004 / mm 2 The distribution density of the depressions in the first zone is 227 to 1272 per mm 2 The distribution density of the depressions in the third zone is 169 to 1031 per mm 2 .

3. A beverage can body as claimed in claim 1, characterized in that: The coating is formed by applying a slurry to the inner surface of the peripheral wall. The slurry includes, by mass percentage, 20% to 30% of epoxy acrylic resin and 0.1% to 0.2% of a defoaming agent.

4. A method for manufacturing a beverage can body according to any one of claims 1 to 3, characterized in that: The steps include: Slurry spraying: using a spray gun, spray the slurry on the inner surface of the peripheral wall of the main body at a preset angle of 7 to 20 degrees, wherein the preset angle is the angle between the center line of the spray gun and the normal line of the surface of the beverage can body; Drying to form a coating: Drying the sprayed slurry to form a coating.

5. The manufacturing method according to claim 4, characterized in that: The preset angle is 12-20°, and the drying temperature of the slurry is 80-100°C.

6. The manufacturing method according to claim 4, characterized in that: The spray pressure of the spray gun is 500-550 psi.

7. The manufacturing method according to claim 4, characterized in that: In the step of drying to form a coating, the drying process includes pre-drying and post-drying, the pre-drying temperature is 80-100°C, the pre-drying time is 1-3 minutes, and the post-drying temperature is 150-280°C.

8. A beverage can, characterized in that: The beverage can comprises a beverage can body as claimed in any one of claims 1 to 3, and a top cover, wherein the top cover is sealedly connected to the beverage can body, and the beverage can is used to contain beverages and is filled with carbon dioxide.

9. The beverage container according to claim 8, characterized in that The top cover comprises an opening portion, and when the opening portion is opened, foam overflows from the beverage can within 6 to 15 seconds.

10. A method for manufacturing a beverage can according to claim 8 or 9, characterized in that: The steps include: Filling carbon dioxide into a liquid storage container storing a beverage; Filling the beverage can with carbon dioxide so that the gas pressure in the beverage can is equal to the gas pressure in the liquid storage container; Filling the beverage into the beverage can by utilizing the beverage's own gravity; The top cover is sealed and connected to the beverage can body to obtain the beverage can, and the gas pressure in the beverage can is 0.18-0.40 MPa.

Images