Tube container and method for manufacturing the same

Abstract

The objective is to provide a tube container having a coating layer that requires less energy during the manufacturing process, exhibits excellent conformability and flexibility to the tube container body, and has superior film-forming strength, as well as a method for manufacturing the same. [Solution] A tube container made of a metal substrate, having a coating layer on the inner surface of the tube container, wherein the coating layer is a layer obtained using a fluorine-containing two-component curable urethane resin composition.

Description

[Technical Field]

[0001] The present invention relates to a tube container and a method for manufacturing the same. [Background technology]

[0002] Metal tube containers, such as aluminum tubes, are used as packaging containers for cosmetics, pharmaceuticals, and quasi-drugs because they can completely protect the contents from light (ultraviolet rays), air (gas), and water (water vapor), and offer excellent non-airbag properties, portability, and ease of use.

[0003] A metal tube container typically comprises a metal body that is easily plastically deformable, and a metal main body (hereinafter also referred to as the "tube container body") which is formed by one end of the body and continuously ending at a shoulder and neck. The other end of the body of this tube container is folded and closed, and the neck is closed with a cap that can be opened and closed.

[0004] Metal tube containers are typically used by squeezing them to push out the contents of pharmaceuticals, quasi-drugs, and cosmetics, such as liquids or creams; therefore, they are required to have excellent flexibility.

[0005] Furthermore, in addition to preventing the contents from deteriorating, tube containers often have a coating layer on their inner surface to prevent the contents from corroding the container itself. This coating layer requires not only conformability and flexibility to the tube container but also high film strength.

[0006] For example, Patent Document 1 discloses a method for coating the inside surface of a metal tube container to obtain high chemical resistance. Specifically, the method discloses a method for coating the inside surface of a metal tube container by coating the inside surface of the base material of the metal tube container with a first corrosion-resistant paint, and then further coating it with a second corrosion-resistant paint, characterized in that the viscosity of the first corrosion-resistant paint before curing is greater than the viscosity of the second corrosion-resistant paint before curing. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Japanese Patent Publication No. 2006-160289 [Overview of the project] [Problems that the invention aims to solve]

[0008] As disclosed in Patent Document 1, a known method for forming a coating layer on the inner surface of a metal tube container involves spray-coating a paint made from a chemical-resistant resin composition using a spray gun. However, since the resin composition is diluted to a viscosity that allows it to be spray-coated using a spray gun, it is common to heat the metal tube container coated with the coating layer to promote the curing reaction of the coating layer after painting. Therefore, the manufacturing process of metal tube containers with a coating layer requires a heating step, which has the problem of increasing energy consumption. Furthermore, in recent years, due to environmental concerns, there has been a greater demand than ever before to reduce energy consumption in the manufacturing processes of various products. Therefore, there was a need for tube containers that required less energy to manufacture, had a coating layer with excellent conformability and flexibility to the tube container body, and possessed superior film-forming strength.

[0009] Therefore, the object of the present invention is to provide a tube container having a coating layer that requires less energy in the manufacturing process, has excellent conformability and flexibility to the tube container body, and has excellent film formation strength, as well as a method for manufacturing the same. [Means for solving the problem]

[0010] The inventors of this invention conducted diligent research to solve the aforementioned problems and, as a result, found that the problems can be solved according to the following configuration example, and thus completed the present invention. An example of the configuration of the present invention is as follows.

[0011] [1] A tube container made of a metal substrate, wherein the tube container has a coating layer on its inner surface, and the coating layer is a layer obtained using a fluorine-containing two-component curable urethane resin composition. [2] The tube container described in [1] above, wherein the fluorine-containing two-component curable urethane resin composition contains a hydroxyl polymer as the main component and an isocyanate compound as the curing agent, and the mixing ratio of the main component and the curing agent (main component:curing agent) is 3:1 to 9:1. [3] The tube container according to [1] or [2] above, wherein the curing reaction rate of the coating layer after storing the tube container at room temperature for one week is 70% or more. [4] A tube container according to any one of [1] to [3] above, wherein the solvent resistance of the coating layer is 5 to 350 times in MEK rubbing cycles. [5] The tube container according to any of [1] to [4] above, wherein the cylindrical body member obtained by cutting off the top of the tube container does not exhibit peeling of the coating layer after a crusher test under the following condition (1). Condition (1) A stand on which the rod was fixed was prepared, and the cylindrical body member was placed on the stand with its open end facing upwards and downwards, while the open end of the rod was positioned on the stand. If the outer diameter of the opening of the cylindrical body member is 19.05 mm or more, a cylindrical weight (2 kg) with the rod passing through the center of its base was repeatedly dropped from a height of 100 cm above the upper opening end of the cylindrical body member. If the outer diameter of the opening of the cylindrical body member is less than 19.05 mm, the weight was repeatedly dropped from a height of 50 cm above the upper opening end of the cylindrical body member until the height of the cylindrical body member was 10 mm or less. The flattened cylindrical body member was stretched out, cut with scissors, and unfolded into a rectangle. The delamination of the coating layer on the unfolded body member was then evaluated. The evaluation of coating layer delamination was performed over an area of ​​more than 80% of the total area of ​​the unfolded rectangular body member, including the center. [6] A tube container according to any of [1] to [5] above, wherein the thickness of the coating layer is 3 to 25 μm. [7] A tube container according to any one of [1] to [6] above, wherein the metal substrate is an aluminum substrate. [8] A method for manufacturing a tube container according to any one of [1] to [7] above, comprising a coating film forming step of applying a paint containing a fluorine-containing two-component curable urethane resin composition to the inner surface of a tube container made of a metal substrate to form a coating layer, and a room temperature curing step of curing the coating layer at room temperature. [9] The manufacturing method according to [8] above, further comprising a heat curing step in which the coating layer is heated at 150°C or below for 5 minutes or more to cause a curing reaction, wherein the heat curing step is performed before and / or after the room temperature curing step. [Effects of the Invention]

[0012] According to the present invention, it is possible to provide a metal tube container having a coating layer that requires less energy in the manufacturing process, exhibits excellent conformability and flexibility to the tube container body, and has superior film formation strength, as well as a method for manufacturing the same. [Brief explanation of the drawing]

[0013] [Figure 1] Figure 1 is a schematic diagram showing an example of a side view of a tube container (or tube container body) according to the present invention.

Best Mode for Carrying Out the Invention

[0014] The present invention is a tube container made of a metal base material, having a coating layer on the inner surface of the tube container, and the coating layer is a layer obtained by using a fluorine-containing two-component curable urethane resin composition.

[0015] <Tube Container> An embodiment of the tube container of the present invention is shown in FIG. 1, and the present invention will be described below based on an embodiment of the tube container of the present invention shown in FIG. 1. However, the tube container of the present invention is not limited to the form shown in FIG. 1. The tube container 10 of an embodiment of the present invention shown in FIG. 1 is formed in a cylindrical shape and is provided to accommodate contents (such as cosmetics, pharmaceuticals, quasi-drugs, etc.) inside. Specifically, the tube container 10 includes a metal base material 4 (tube container body) having a body portion 2, a shoulder portion 3 continuous with one end of the body portion 2, and a mouth portion 1, and a coating layer 5 formed on the inner surface of the mouth portion 1, the shoulder portion 3, and the body portion 2, and is a container suitable for accommodating a high-viscosity liquid or a viscous substance. In the present disclosure, the portion including the mouth portion 1 and the shoulder portion 3 of the tube container 10, that is, the portion other than the body portion 2 of the tube container 10, is also referred to as the "head portion".

[0016] Male threads are engraved on the outer circumference of the mouth portion 1 of the metal base material 4, and these male threads engage detachably with female threads on the inner wall of a cap (not shown) fitted onto the tube container 10. In the metal base material 4 of this type of tube container 10, the body portion 2 is made of a plastically deformable material and wall thickness. Examples of materials for forming such a body portion 2 include a thin-film tubular body obtained by plastically deforming a metal ingot selected from aluminum, aluminum alloys, tin, tin alloys, and lead into a thin-layer tubular shape by backward extrusion. In this embodiment, the shoulder portion 3 and mouth portion 1 continuous with one end of the body portion 2 are formed from the same material as the body portion 2, but in the present invention, the material of the shoulder portion 3 and mouth portion 1 is not particularly limited, and it is also possible to fix a plastic mouth portion 1 and shoulder portion 3 to a separately molded metal body portion 2. Among the materials for forming such a body portion 2, aluminum and its alloys are preferred in many applications, and metallic aluminum is more preferred.

[0017] The metal base material of the tube container of the present invention is preferably at least one base material selected from aluminum, aluminum alloy, tin, and tin alloy, and more preferably an aluminum base material.

[0018] The thickness of the metal base material 4 of the body of the tube container of the present invention can be appropriately selected depending on the desired application and the properties of the contents. However, when using the container by squeezing it to push out the contents, it is preferable to have a thickness of 130 μm or less, more preferably 90 to 120 μm, and even more preferably 95 to 110 μm, as this allows for easy squeezing and makes it easy to obtain a container with excellent flexibility. A tube container made of a metal base material is preferable because it is easy to make the body of the tube container body to have such a thickness, and even with such a thickness, the tube container body is excellent in flexibility and stress cracking resistance.

[0019] The length of the body of the tube container of the present invention can be appropriately selected depending on the desired application. For example, the lower limit of the body length can be selected from 50 mm, 55 mm, 65 mm, 70 mm, 80 mm, 90 mm, 110 mm, 130 mm, 140 mm, and 150 mm, and the upper limit can be selected from 200 mm, 190 mm, 180 mm, 170 mm, 150 mm, 125 mm, 110 mm, 105 mm, 90 mm, and 70 mm.

[0020] In one embodiment of the present invention, the coating layer 5 in the tube container 10 is formed on the inner surface of the metal substrate 4. The coating layer 5 is preferably formed by a spray coating method, for example, in which a paint containing a fluorine-containing two-component curable urethane resin composition is sprayed from a rod-shaped nozzle inserted into the interior from the opening end (bottom portion 10a) toward the inside of the body. The coating layer 5 may be a single layer formed by one spray coat application or a multi-layered layer formed by multiple spray coat applications, and the required film thickness can be achieved depending on the contents. The coating layer 5 may also be formed by a method other than the spray coat method; for example, it can be formed by applying a paint that forms the coating film using a brush.

[0021] The thickness of the coating layer on the body of the tube container of the present invention can be appropriately selected depending on the desired application and the properties of the contents. However, from the viewpoint of enabling easy squeezing when using the container to push out the contents, having excellent conformability and flexibility to a metal substrate, and achieving high film formation strength, the thickness is preferably 3 to 25 μm, more preferably 5 to 20 μm, and even more preferably 5 to 15 μm.

[0022] The coating layer of the tube container of the present invention is a layer obtained using a fluorine-containing two-component curable urethane resin composition, and more specifically, it is a layer obtained by curing a coating film formed by applying a paint obtained by diluting a fluorine-containing two-component curable urethane resin composition. The tube container of the present invention has a coating layer obtained using a fluorine-containing two-component curable urethane resin composition, which allows the coating layer to cure at room temperature (10-35°C), eliminating the need for heating equipment (such as long furnaces) required when using conventional thermosetting resin compositions. Therefore, energy consumption and equipment costs can be reduced, and the tube container of the present invention can be manufactured efficiently while reducing the environmental impact.

[0023] The two-component curable urethane resin composition used in the above-mentioned fluorine-containing two-component curable urethane resin composition is a urethane resin that uses a hydroxyl polymer (polyol) as the main component and an isocyanate compound as the curing agent. The hydroxyl polymer (polyol) is one which has two or more hydroxyl groups in its molecule, and examples of which include polyethylene glycol, polypropylene glycol, acrylic polyol, polyester polyol, polyether polyol, polycarbonate polyol, and polyurethane polyol. The isocyanate compound is a polyvalent isocyanate that has two or more isocyanate groups in its molecule. For example, aromatic isocyanates such as 2,4-tolylene diisocyanate, xylene diisocyanate, and 4,4-diphenylmethane diisocyanate, or aliphatic (or alicyclic) isocyanates such as 1,6-hexamethylene diisocyanate, isophorone diisocyanate, hydrogenated tolylene diisocyanate, and hydrogenated diphenylmethane diisocyanate are used. Alternatively, adducts or polymers of the above-mentioned isocyanates can also be used. For example, adducts of tolylene diisocyanate, trimers of tolylene diisocyanate, etc.

[0024] The fluorine-containing two-component curable urethane resin composition used in the coating layer of the present invention is a two-component curable urethane resin composition containing the above-mentioned fluorine additive. Furthermore, the fluorine additive contained in the fluorine-containing two-component curable urethane resin composition hardens by forming a chemical bond between the two-component curable urethane resin and the fluorine additive through the reaction curing of the resin. A commercially available fluorine additive can be used; for example, NeoFluoriPer, a fluorine resin additive manufactured by Noda Screen Co., Ltd., can be used.

[0025] A preferred embodiment of the two-component curable urethane resin is one in which the mixing ratio (main component:curing agent) of the main component, a hydroxyl polymer (polyol), and the curing agent, an isocyanate compound, is 3:1 to 9:1, and more preferably, the mixing ratio of the polyol to the isocyanate compound is 5:1 to 9:1.

[0026] In the tube container of the present invention, it is preferable that the curing reaction rate of the coating layer after applying a coating containing the above-mentioned fluorine-containing two-component curable urethane resin composition to the inner surface of the tube container and storing it at room temperature (e.g., 23°C) for one week (7 days) is 70% or more. The coating layer formed on the tube container of the present invention has curing reactivity at room temperature (e.g., 23°C), and if the curing reaction rate is 70% or more under the above conditions, the coating layer formed on the inner surface of the tube container will have better film strength. It is more preferable that the curing reaction rate of the coating layer after storing the tube container of the present invention at room temperature (e.g., 23°C) for one week (7 days) is 72% or more, and even more preferable that it is 74% or more.

[0027] Furthermore, in the tube container of the present invention, it is preferable that the curing reaction rate of the coating layer after applying a coating film containing the above-mentioned fluorine-containing two-component curable urethane resin composition to the inner surface of the tube container and storing it at room temperature (e.g., 23°C) for two weeks (14 days) is 80% or more, more preferably 85% or more, and even more preferably 90% or more.

[0028] The curing reaction rate of the coating layer is defined as the curing reaction rate of the coating film formed by applying a paint containing a fluorine-containing two-component curing urethane resin composition to the inner surface of a tube container, which is considered to be 0%. The FT-IR spectrum is then used to determine the 2255 cm² value, which originates from the stretching vibration of the isocyanate group. -1 This refers to the percentage decrease in peak intensity due to the curing reaction, compared to the peak intensity when the curing reaction rate is 0%, assuming that the curing reaction rate of the coating layer in a state where no peak intensity is observed is 100%. Specifically, the FT-IR spectrum was measured using the FT-IR (ATR method), and from the FT-IR spectrum of the coating film, the 2255 cm² vibration originating from the stretching vibration of the isocyanate group was determined. -1 The ratio of peak intensity A to reference peak intensity B (A / B) was determined, and from the FT-IR spectrum of the coating layer (after curing reaction), the 2255 cm² peak intensity, which originates from the stretching vibration of the isocyanate group, was calculated. -1 The ratio of the peak intensity A' to the reference peak intensity B' (A' / B') can be determined, and the curing reaction rate can be calculated using the following formula. Curing reaction rate [%] = {1 - ((A' / B') / (A / B))} × 100 Note that the above standard peak intensity B is 1720 cm. -1 The peak intensity of the nearby C=O is preferable.

[0029] The tube container of the present invention preferably has a solvent resistance of 5 to 350 MEK rubbing cycles after the coating layer is formed by coating the inner surface of the tube container with a paint containing the above-mentioned fluorine-containing two-component curable urethane resin composition and storing it at room temperature (e.g., 23°C) for one week (7 days). If the number of MEK rubbing cycles is less than 5, the abrasion resistance and slipperiness of the coating layer on the inner surface of the tube container cannot be obtained, and the film strength is not practical. If it exceeds 350 cycles, the coating layer itself becomes too hard, which may impair its ability to conform to metal substrates and its flexibility. The MEK rubbing test involves rubbing the coating film with a cotton swab impregnated with MEK (methyl ethyl ketone) at a load of 2 pounds (908 g) and a movement speed of 40 mm / sec, and measuring the number of cycles until the coating film peels off. The MEK rubbing test is a solvent resistance test, and the more MEK rubbing cycles there are, the less the solvent swells, indicating high solvent resistance and high curability. Therefore, it can be said that the more MEK rubbing cycles there are, the better the film strength.

[0030] Furthermore, the paint containing the above-mentioned fluorine-containing two-component curable urethane resin composition is obtained by diluting the fluorine-containing two-component curable urethane resin composition with various organic solvents depending on the painting conditions. Examples of such organic solvents include aromatic solvents such as toluene, xylene, and ethylbenzene; ester solvents such as ethyl acetate, ethyl lactate, butyl acetate, isobutyl acetate, propylene glycol methyl ether acetate, and propylene glycol methyl ether propionate; ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, diisobutyl ketone, and cyclohexanone; ether solvents such as diethylene glycol dimethyl ether, diethylene glycol diethyl ether, and dipropylene glycol dimethyl ether; alicyclic hydrocarbon solvents such as cyclohexane, methylcyclohexane, and ethylcyclohexane; and petroleum hydrocarbon solvents such as mineral spirits. Furthermore, known paint formulation components may be added to the above-mentioned paint as needed.

[0031] For example, when a fluorine-containing two-component curable urethane resin composition is applied by a spray coating method, the viscosity (mPa·s) of the paint containing the fluorine-containing two-component curable urethane resin composition is preferably 20 to 200, more preferably 20 to 100, and even more preferably 20 to 70.

[0032] Furthermore, the paint containing the above-mentioned fluorine-containing two-component curable urethane resin composition is acceptable as long as it can be dried at room temperature until the coating film becomes tack-free after being applied to a metal substrate. The drying time of the coating film can be appropriately adjusted depending on the thickness of the formed coating film, the type of solvent, and the drying temperature, but is usually 5 to 15 minutes, preferably 5 to 10 minutes. In addition, the tube container on which the coating layer is formed should have an airflow of 15 to 40 m³ as the drying conditions for the solvent. 3 / h, preferably 25-30m 3 It may be placed in an environment with a fan speed of / h.

[0033] In the tube container of the present invention, it is preferable that the cylindrical body member obtained by cutting off the top of the tube container does not exhibit peeling of the coating layer in a crusher test under the following condition (1). Condition (1) A stand on which the rod was fixed was prepared, and the cylindrical body member was placed on the stand with its open end facing upwards and downwards, while the open end of the rod was positioned on the stand. If the outer diameter of the opening of the cylindrical body member is 19.05 mm or more, a cylindrical weight (2 kg) with the rod passing through the center of its base was repeatedly dropped from a height of 100 cm above the upper opening end of the cylindrical body member. If the outer diameter of the opening of the cylindrical body member is less than 19.05 mm, the weight was repeatedly dropped from a height of 50 cm above the upper opening end of the cylindrical body member until the height of the cylindrical body member was 10 mm or less. The flattened cylindrical body member was stretched out, cut with scissors, and unfolded into a rectangle. The delamination of the coating layer on the unfolded body member was then evaluated. The evaluation of coating layer delamination was performed over an area of ​​more than 80% of the total area of ​​the unfolded rectangular body member, including the center. In the crusher test conditions (1) described above, the evaluation of the peeling of the coating layer is preferably performed over an area of ​​90% or more that includes the center of the entire area of ​​the unfolded rectangular body member, and most preferably over the entire area of ​​the unfolded rectangular body member.

[0034] The crusher test is a test to evaluate the conformability and flexibility of various layers laminated on the metal substrate of the tube container body to the metal substrate. A tube container in which the coating layer does not peel off in the crusher test under the above test condition (1) is particularly excellent in terms of the conformability and flexibility of the coating layer to the metal substrate and is therefore suitable.

[0035] The cylindrical body obtained by cutting off the top of the tube container used in the crusher test should have a lateral length of 50 to 100 mm. For example, when performing a crusher test on a tube container whose body length is greater than 100 mm, the lateral length of the cylindrical body obtained by cutting off the top should be adjusted to 100 mm before performing the crusher test.

[0036] The cylindrical body member obtained by cutting off the top of the tube container used in the crusher test may have an outer diameter of the opening (i.e., the outer diameter of the body of the bottom portion 10a of the tube container) of 10 to 35 mm, preferably 10 to 30 mm, more preferably 10 to 25 mm, and even more preferably 10 to 20 mm.

[0037] The tube container of the present invention preferably further has a printed layer on the outer surface of the tube container body. Furthermore, an adhesive layer may be provided between the metal substrate and the printed layer for the purpose of ensuring adhesion of the printed layer to the metal substrate.

[0038] The above-mentioned printing layer is not particularly limited as long as it is a layer that has been conventionally provided for purposes such as displaying the contents or for design purposes, and may be, for example, an acrylic, epoxy, polyester, or polyurethane printing ink layer.

[0039] <Manufacturing method for tube containers> The method for manufacturing the tube container of the present invention is not particularly limited, but it is preferable to include a coating film forming step of applying a coating containing a fluorine-containing two-component curable urethane resin composition to the inner surface of a tube container made of a metal substrate to form a coating layer, and a room temperature curing step of curing the coating layer at room temperature.

[0040] The coating film formation step in the manufacturing method of the present invention may be any step of forming a coating layer by applying a paint containing a fluorine-containing two-component curable urethane resin composition using a known method. The painting method of the above paint can be any commonly used painting method such as spray coating using an airless spray or air spray; brush application; trowel application; roller application; dipping; lifting; pouring; or piling, but spray coating is preferred. Furthermore, the paint containing the fluorine-containing two-component curable urethane resin composition used in the coating film formation step may be diluted to a viscosity appropriately required depending on the painting method. For example, the preferred viscosity of the paint when the painting method is spray coating is the same as described in the description of the tube container of the present invention above, and the same applies to the diluent used. Furthermore, the suitable tack-free time for the paint used in the above-mentioned coating film formation process is the same as the suitable tack-free time for the paint described in the above-mentioned description of the tube container of the present invention.

[0041] The method for manufacturing a tube container of the present invention includes the above-mentioned coating film formation step and the above-mentioned room-temperature curing step. Since the curing reaction of the coating layer proceeds at room temperature (10-35°C) during the room-temperature curing step, heating equipment (such as a long furnace) required when using conventional thermosetting paints containing thermosetting resin compositions becomes unnecessary. Therefore, energy consumption and equipment costs can be reduced, and the tube container of the present invention can be manufactured efficiently while reducing the environmental impact. The above room-temperature curing process may be carried out in a humidified environment. In this disclosure, a humidified environment is an environment with a relative humidity of 20-75%.

[0042] The manufacturing method of the present invention further includes a heat curing step in which the coating layer is heated at 150°C or below for 5 minutes or more to induce a curing reaction, and it is preferable that the heat curing step is performed before and / or after the room temperature curing step. That is, the heat curing step may be performed before the room temperature curing step, or after it, or it may be performed twice, before and after the room temperature curing step. By having the above heat curing step, the curing reaction rate of the coating layer on the inner surface of the tube container can be greatly improved in a short time. The temperature required for curing a coating layer using conventional thermosetting paints is generally 180°C or higher, but the above heat curing step can promote the curing reaction of the coating layer formed from a fluorine-containing two-component curable urethane resin composition at a temperature of 150°C or lower, so that the curing reaction of the coating layer can be promoted at a lower temperature range than conventional thermosetting paints, and energy consumption can be reduced. Examples of conventional thermosetting paints include epoxy-phenol resins, and the temperature range required for the curing reaction is 230 to 280°C.

[0043] The above heat curing step is preferably a step of heating the coating film of the coating layer formed by applying a paint containing a fluorine-containing two-component curable urethane resin composition to the inner surface of a tube container made of a metal substrate at a temperature of room temperature (10 to 35°C) or higher and 150°C or lower. For example, the above heat curing step may be a step of curing the coating film of the coating layer formed on the inner surface of the tube container in a low-temperature heating environment of 35°C or higher and 65°C or lower, a step of curing the coating film of the coating layer formed on the inner surface of the tube container in a medium-temperature heating environment of 65°C or higher and 100°C or lower, or a step of curing the coating film of the coating layer formed on the inner surface of the tube container in a high-temperature heating environment of 100°C or higher and 150°C or lower.

[0044] The upper limit of the heating time in the above heat curing process can be appropriately determined by the temperature applied in the heat curing process, and is not particularly limited. For example, if the above heat curing process cures the coating film formed on the inner surface of the tube container in a high-temperature heating environment exceeding 100°C but not exceeding 150°C, the heating time is preferably 15 minutes or less, and more preferably 10 minutes or less. Furthermore, for example, if the above heat curing process cures the coating film formed on the inner surface of the tube container in a medium-temperature heating environment between 65°C and 100°C, the heating time is preferably 15 minutes or less, and more preferably 10 minutes or less. Furthermore, for example, when the above heat curing process is performed in a low-temperature heating environment between 35°C and 65°C to cure the coating film formed on the inner surface of the tube container, it is preferable that the heating time be one week or longer. Furthermore, the above heat curing process may be carried out in a humidified environment. In this disclosure, a humidified environment is an environment with a relative humidity of 20 to 75%.

[0045] If the manufacturing method of the present invention includes a heat curing step, the heat curing step may be performed at any time after the coating layer has been applied to the tube container of the present invention. For example, if a printed layer is to be formed on the outer surface of the tube container, a heat treatment necessary for forming the printed layer is performed. If the conditions for the heat treatment of the printed layer overlap with the conditions for the heat curing step, the heat curing step may be performed simultaneously with the heat treatment of the printed layer.

[0046] The above room temperature curing process and / or the above heat curing process may be performed with an airflow of 15-40 m³ in part or in whole. 3 The airflow process may include a blowing step of 25-30 m³ / h. 3 It is preferable that the process is performed at / h, and if the blowing process is included as part of each process, the blowing process is preferably performed for 5 to 20 minutes, and more preferably for 5 to 15 minutes. [Examples]

[0047] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0048] The resin compositions used in the coating layers in the examples and reference examples are as follows: • Fluorine-containing two-component curable urethane resin composition (Fluorine-based clear coat agent Shields, manufactured by Noda Screen Co., Ltd.) • Modified epoxy-phenol resin composition (Tanaka Chemical Co., Ltd. AON302T-100)

[0049] [Example 1] A coating layer was formed on the inner surface of an aluminum tube (tube container body) with a wall thickness of approximately 0.1 mm by spray coating using a two-component curing urethane resin composition containing fluorine (viscosity 50 mPa·s) to a film thickness of 12 μm (tack-free time 5-10 minutes). Subsequently, the tube container (outer diameter (φ13.8 mm), length (75 mm)) with the coating layer was prepared by storing it at room temperature (23°C) for one week.

[0050] [Example 2] The tube container according to Example 2 was prepared in the same manner as in Example 1, except that the curing conditions for the coating layer and the storage period of the tube container at room temperature (23°C) were changed from one week to three weeks.

[0051] [Example 3] The tube container according to Example 3 was prepared in the same manner as in Example 1, except that the curing conditions for the coating layer were the same as in Example 1, with the tube container being stored at room temperature (23°C) for one week and then heated at 150°C for 10 minutes.

[0052] [Reference example 1] An aluminum tube with a wall thickness of approximately 0.1 mm (tube container body) was coated with a paint containing a modified epoxy-phenol resin composition to a film thickness of 8 μm using a spray coating method, forming a coating layer. Subsequently, a tube container with a coating layer on the inside (outer diameter (φ13.8 mm), body length (75 mm)) was fabricated by heating at 280°C for 5 minutes.

[0053] [Reference example 2] A tube container according to Reference Example 2 was produced in the same manner as in Reference Example 1, except that the curing conditions of the coating film of the coating layer were changed from heating at 280°C for 5 minutes to storage in a tube container at room temperature (23°C) for 1 week.

[0054] <Curing reaction rate> The curing reaction rate was measured by the following method. The coating layers formed from the resin compositions used in the examples and reference examples were measured by FT-IR (ATR method), respectively. The curing rate was calculated based on the amount (peak intensity) of the structure that disappeared in the curing reaction before and after curing. Specifically, it was calculated by the following method.

[0055] From the FT-IR spectrum of the coating film of the coating layer formed by coating the inner surface of the tube container with the paint containing the resin composition used, 2255 cm -1 derived from the stretching vibration of the isocyanate group, the ratio (A / B) of the peak intensity A to the reference peak intensity B of 1720 cm -1 derived from the C=O bond was determined. Next, from the FT-IR spectrum of the formed coating layer, the ratio (A' / B') of the peak intensity A' of 2255 cm -1 derived from the stretching vibration of the isocyanate group to the reference peak intensity B' of 1720 cm -1 derived from the C=O bond was determined, and the curing reaction rate was calculated by the following formula. Curing reaction rate [%] = {1 - ((A' / B') / (A / B))} × 100 The results are shown in Table 1.

[0056] <MEK rubbing test> The MEK rubbing test was performed on the surface of the coating layer after the following curing reaction time described in Table 1 had elapsed, after coating the inner surface of an aluminum tube (tube container body) with the above fluorine-containing two-component curable urethane resin composition to form a coating layer. In the test, a cotton swab impregnated with MEK was used to reciprocally rub the UV-cured film at a load of 2 pounds (908 g) and a moving speed of 4 mm / sec, and the number of reciprocations of the cotton swab when the coating layer was damaged was counted. The results are shown in Table 1.

[0057] <Crusher Test> The crusher test was conducted as follows: The tops of the tube containers obtained in each embodiment and reference example were cut off to form a cylindrical shape, thereby obtaining cylindrical body members according to each embodiment and reference example. The length (body length) of the obtained cylindrical body member was 75 mm, and the outer diameter (φ) of the opening was 13.8 mm. The cylindrical body members according to each embodiment and reference example were placed on a stand to which a rod was fixed, with the rod passing through them so that the openings were facing upwards and downwards. A cylindrical weight (2 kg) with the rod passing through its center was dropped from a height of 100 cm above the upper opening end of the cylindrical body member, and the weight was dropped repeatedly until the height of the cylindrical body member was 10 mm or less. The flattened cylindrical body member was straightened, cut with scissors, and unfolded into a rectangle. The presence or absence of peeling of the coating layer formed on the inner surface of the unfolded rectangular body member was then checked. The presence or absence of peeling of the coating layer was checked over the entire area of ​​the unfolded rectangular body member (approximately 4.33 × 7.5 = 32.475 cm). 2 This was confirmed over the area of ​​[the specified region]. (Evaluation method) A "○" was used if no peeling of the coating layer was observed. If peeling of the coating layer was observed, it was marked with "×". The results are shown in Table 1.

[0058] [Table 1]

[0059] From the results of Example 1 in Table 1 above, the coating layer formed with a paint containing a fluorine-containing two-component curable urethane resin composition showed a curing reaction rate of 74.8% and required 10 rubbing cycles, even when the curing conditions were storage at room temperature for one week, confirming practical coating film strength. Furthermore, no peeling occurred in the crusher test, and a coating layer with excellent conformability to metal substrates and flexibility was obtained. Furthermore, the tube container according to Example 2, which was stored at room temperature for 3 weeks under curing conditions, showed a curing reaction rate of 93.5% for the coating layer and 56 rubbing cycles, achieving high coating film strength comparable to that of the tube container according to Reference Example 1, which has a coating layer formed with a conventional thermosetting resin-containing paint. Moreover, no peeling occurred in the crusher test, and a coating layer with excellent conformability to metal substrates and flexibility was obtained. Furthermore, the tube container according to Example 3, which was heated at 150°C for 10 minutes after being stored at room temperature for one week as curing conditions, showed a curing reaction rate of 97.5% for the coating layer and 318 rubbing cycles. Compared to the tube container according to Reference Example 1, which had a coating layer formed with a paint containing a conventional thermosetting resin, significantly superior coating film strength was obtained. Moreover, there was no peeling in the crusher test, and a coating layer with excellent conformability to metal substrates and flexibility was obtained. On the other hand, in Reference Example 2, the curing conditions for the coating film formed with conventional paint containing thermosetting resin were changed from the conventional heating at 280°C for 5 minutes to a storage period of 1 week in the tube container at room temperature (23°C). However, the curing reaction rate of the coating film was low at 25%, and the number of MEK rubbing cycles was only 2, so practical coating film strength could not be confirmed. Furthermore, peeling was observed in the crusher test, and the conformability and flexibility of the coating layer to the metal substrate could not be confirmed.

[0060] [Examples 4 and 5] Except for the storage period and storage conditions after the formation of the coating layer, as described in Table 2 below, a tube container (outer diameter (φ13.8 mm), length (75 mm)) was manufactured in the same manner as the tube container manufacturing method for Example 1. In the low-temperature humidification curing process, humidification was performed to achieve a relative humidity of 75%. The coating layer of the obtained tube container was subjected to curing rate measurement, crusher test, and MEK rubbing test using the above method. The results obtained are shown in Table 2 below.

[0061] [Reference example 3] The curing reaction rate of the coating layer immediately after its formation was considered to be "0" for the tube containers in which the coating layer was formed, using the same method as for manufacturing the tube containers according to Example 1, and is shown in Table 2 below.

[0062] [Table 2]

[0063] From the results in Table 2 above, the tube container of Example 4, which was stored at room temperature for two weeks, showed a hardening rate exceeding 90%, required 50 MEK rubbing cycles, and demonstrated high coating strength. Furthermore, there was no peeling in the crusher test, and a coating layer with excellent conformability to metal substrates and flexibility was obtained. Furthermore, the tube container according to Example 5, which was stored at room temperature for one week and then in a low-temperature, humidified environment at 40°C for one week, showed a hardening rate exceeding 95%, with 90 rubbing cycles, demonstrating remarkably excellent coating strength. In addition, there was no peeling in the crusher test, and a coating layer with excellent conformability and flexibility to metal substrates was obtained. [Explanation of Symbols]

[0064] 1: Mouth 2: Torso 3:Shoulder 4: Metal base material 5: Coating layer 10: Tube container 10a: Hem

Claims

1. It is a tube container made of a metal base material, The tube container has a coating layer on its inner surface, The aforementioned coating layer is a layer obtained using a fluorine-containing two-component curable urethane resin composition, in a tube container.

2. The aforementioned fluorine-containing two-component curable urethane resin composition contains a hydroxyl polymer as the main component and an isocyanate compound as the curing agent. The tube container according to claim 1, wherein the mixing ratio of the main component and the hardener (main component: hardener) is 3:1 to 9:

1.

3. The tube container according to claim 1 or 2, wherein the curing reaction rate of the coating layer after storing the tube container at room temperature for one week is 70% or more.

4. The tube container according to claim 3, wherein the solvent resistance of the coating layer is 5 to 350 MEK rubbing cycles.

5. The tube container according to claim 1 or 2, wherein the cylindrical body member obtained by cutting off the top of the tube container does not exhibit peeling of the coating layer in a crusher test under the following condition (1). Condition (1) A stand on which the rod was fixed was prepared, and the cylindrical body member was placed on the stand with its open end facing upwards and downwards. If the outer diameter of the opening of the cylindrical body member is 19.05 mm or more, a cylindrical weight (2 kg) with the rod passing through the center of its base was repeatedly dropped from a height of 100 cm above the upper opening end of the cylindrical body member. If the outer diameter of the opening of the cylindrical body member is less than 19.05 mm, the weight was repeatedly dropped from a height of 50 cm above the upper opening end of the cylindrical body member until the height of the cylindrical body member was 10 mm or less. The flattened cylindrical body member was stretched out, cut with scissors, and unfolded into a rectangle. The peeling of the coating layer on the unfolded body member was then evaluated. The evaluation of coating layer delamination was performed over an area of ​​more than 80% of the total surface area of ​​the unfolded rectangular body member, including the center.

6. The tube container according to claim 1 or 2, wherein the thickness of the coating layer is 3 to 25 μm.

7. The tube container according to claim 1 or 2, wherein the metal substrate is an aluminum substrate.

8. A method for manufacturing a tube container according to claim 1 or 2, comprising: a coating film forming step of applying a paint containing a fluorine-containing two-component curable urethane resin composition to the inner surface of a tube container made of a metal substrate to form a coating layer; and a room temperature curing step of curing the coating layer at room temperature.

9. Furthermore, the manufacturing method according to claim 8, comprising a heat curing step of heating the coating layer at 150°C or below for 5 minutes or more to cause a curing reaction, wherein the heat curing step is performed before and / or after the room temperature curing step.

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