Thermally insulated container

Abstract

To provide a heat insulating container capable of suppressing welding failure between an inner container and an outer container.SOLUTION: According to the present invention, there is provided a heat-insulating container including a container body, in which the container body includes an inner container and an outer container disposed so as to cover the inner container, a sealed space is provided between the inner container and the outer container, the inner container includes a mouth portion and a body portion having an outer diameter larger than that of the mouth portion, and the body portion includes a shoulder portion having an outer diameter that increases as a distance from the mouth portion increases, and a reduced diameter portion that is continuous with an outer edge of the shoulder portion and has an outer diameter that decreases as a distance from the mouth portion increases, D1 / R1 is 0.10 or more, where R1 is an outer diameter of the inner vessel at the outer edge, and D1 is a curvature radius of a portion of the shoulder portion adjacent to the outer edge.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an insulated container. [Background technology]

[0002] Patent Document 1 discloses a heat-insulating container in which an inner container and an outer container are integrally joined together with a gap therebetween. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2002-68324 Summary of the Invention [Problem to be solved by the invention]

[0004]

[0003] In one example, a thermally insulated container is formed by enhancing design by making the outer diameter of the outer edge of the shoulder of the inner container approximately the same as the outer diameter of the open end of the outer container, then providing a portion below the shoulder of the inner container that is smaller in diameter than the outer edge of the shoulder, and welding the inner and outer containers at this portion. When welding the inner and outer containers, the mouth of the inner container is pressed downward to tightly seal the inner and outer containers together, but during this process, the inner container deforms so that the shoulder rotates around the outer edge of the shoulder as a fulcrum, making it difficult for the pressure applied to the mouth to be transmitted to the portion where the inner and outer containers are tightly sealed together, making the inner and outer containers more susceptible to poor welding.

[0005] The present invention has been made in view of the above circumstances, and aims to provide an insulated container that can prevent poor welding between the inner container and the outer container. [Means for solving the problem]

[0006] According to the present invention, the following inventions are provided. [1] An insulated container comprising a container body, the container body comprising an inner container and an outer container arranged to cover the inner container, with a sealed space provided between the inner container and the outer container, the inner container comprising a mouth and a body having an outer diameter larger than that of the mouth, the body comprising a shoulder whose outer diameter increases with increasing distance from the mouth, and a tapered portion connected to the outer edge of the shoulder and whose outer diameter decreases with increasing distance from the mouth, wherein R1 / D1 is 0.10 or greater, where D1 is the outer diameter of the inner container at the outer edge and R1 is the radius of curvature of the shoulder adjacent to the outer edge. [2] The insulated container according to [1], wherein the shoulder portion has a minimum inclination angle of 10 to 60 degrees relative to a plane perpendicular to the central axis of the mouth portion. [3] The insulated container according to [1] or [2], wherein the shoulder portion and the reduced diameter portion are connected in a curved manner. [4] The insulated container according to any one of [1] to [3], wherein the reduced diameter portion is curved so as to be convex outward. [Effects of the Invention]

[0007] According to the present invention, the radius of curvature of the area adjacent to the outer edge of the shoulder is relatively large, so that when a force is applied to press the mouth downward, the inner container is less likely to deform so that the position of the mouth is displaced downward, thereby suppressing poor welding between the inner container and the outer container. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a front view of a container body 1 of a heat-insulating container 10 according to one embodiment of the present invention. [Figure 2] 2 is a vertical cross-sectional view taken along the central axis C of the container body 1 in FIG. [Figure 3] FIG. 3 is an enlarged view of an area A in FIG. [Figure 4] FIG. 4 is a diagram corresponding to FIG. 3 in Reference Example 1. [Figure 5] 10 is an explanatory diagram of a grinding step for grinding the portion 2i of the inner container 2 to be laser welded. FIG. [Figure 6] Fig. 6A is an enlarged view of region A in Fig. 5. Fig. 6B shows a state in which the grinding tool 5 is pressed against the regions 2i to be laser welded to grind the protruding portions 2i1 that make up the regions 2i to be laser welded. Fig. 6C shows a state after the grinding tool 5 has been released from the regions 2i to be laser welded after grinding is completed. DETAILED DESCRIPTION OF THE INVENTION

[0009] The following describes embodiments of the present invention. The various features shown in the following embodiments can be combined with each other. Furthermore, each feature can be an invention independently. Furthermore, in the following embodiments, elements not specified in the claims are optional elements and can be omitted. Any number of "0"s (for example, one or two) may be added to the end of numerical values ​​disclosed in the following description. For example, one or two "0"s may be added after "1.4" to make it "1.40" or "1.400."

[0010] An insulated container 10 according to one embodiment of the present invention and a method for manufacturing the same will be described with reference to Figures 1 to 6. The embodiment shown below includes at least the inventions of the following aspects.

[0011] The invention of the first aspect is as follows: A heat-insulating container 10 including a container body 1, The container body 1 includes an inner container 2 and an outer container 3 arranged to cover the inner container 2. A sealed space 4 is provided between the inner container 2 and the outer container 3, The inner container 2 is made of a resin containing 60% by mass or more of a propylene homopolymer, The outer container 3 is made of a resin containing 60% by mass or more of a random copolymer of propylene and another olefin, The gas in the sealed space 4 includes a gas having a thermal conductivity lower than that of air, The air pressure in the sealed space 4 is 0.5 to 1.5 atmospheres, and the sealed space 4 is a heat-insulating container 10.

[0012] The invention of the second aspect is as follows: A method for manufacturing a container body 1 of a thermally insulated container 10, The method comprises a molding process, a grinding process, and a laser welding process, In the molding step, the inner container 2 and the outer container 3 are molded separately, In the grinding step, a laser welding target portion 2i, which is a portion to be laser welded, is ground in at least one of the inner container 2 and the outer container 3, The laser welding step is a method of laser welding the inner container 2 and the outer container 3 together at the intended laser welding portion 2i.

[0013] The invention of the third aspect is as follows: A heat-insulating container 10 including a container body 1, The container body 1 includes an inner container 2 and an outer container 3 arranged to cover the inner container 2. A sealed space 4 is provided between the inner container 2 and the outer container 3, The inner container 2 has a mouth 2a and a body 2g having an outer diameter larger than that of the mouth 2a, The body portion 2g includes a shoulder portion 2g1 whose outer diameter increases with increasing distance from the mouth portion 2a, and a tapered portion 2g5 that is continuous with an outer edge 2g4 of the shoulder portion 2g1 and whose outer diameter decreases with increasing distance from the mouth portion 2a, If the outer diameter of the inner container 2 at the outer edge 2g4 is D1 and the radius of curvature of a portion 2g8 of the shoulder 2g adjacent to the outer edge 2g4 is R1, then: An insulated container with R1 / D1 of 0.10 or more.

[0014] 1. Configuration of the insulated container 10 The insulated container 10 is preferably a refillable bottle that can be repeatedly filled with contents, such as water, tea, soft drinks, and carbonated drinks.

[0015] The insulated container 10 comprises a container body 1. The container body 1 comprises a mouth 1a, a body 1b, and a bottom 1c. The container body 1 is preferably bottle-shaped. Unless otherwise specified, "upper" or "lower" in the following description refers to "upper" or "lower" when the container body 1 is held upright with the bottom 1c facing downwards.

[0016] As shown in FIGS. 2 and 3, the container body 1 includes an inner container 2 and an outer container 3 disposed so as to cover the inner container 2.

[0017] The inner container 2 is cylindrical with a bottom, and contains the contents. The inner container 2 has a mouth 2a, a body 2g, and a bottom 2f. The mouth 2a becomes the mouth 1a of the container body 1. The mouth 2a is provided with an engagement portion 2c to which a cap (not shown) can be attached. The cap may be a screw-type or a stopper-type. The outer diameter of the open end of the mouth 2a is, for example, 20 to 50 mm (33 mm in this embodiment), preferably 25 to 45 mm, and more preferably 30 to 40 mm.

[0018] The body 2g has a larger outer diameter (in this specification, "outer diameter" refers to the diameter equivalent to a circle when the cross section is not circular) than the mouth 2a. The body 2g is cylindrical, and the bottom 2f is provided at the lower end of the body 2g and closes the lower end of the body 2g. The body 2g has a shoulder 2g1 whose outer diameter increases with increasing distance from the mouth 2a, and a tapered portion 2g5 that is continuous with the outer edge 2g4 of the shoulder 2g1 and whose outer diameter decreases with increasing distance from the mouth 2a. If the outer diameter of the inner container 2 at the outer edge 2g4 of the shoulder 2g1 is D1 and the radius of curvature of a portion 2g8 of the shoulder 2g1 adjacent to the outer edge 2g4 is R1, then it is preferable that R1 / D1 be 0.10 or more (0.15 in this embodiment). In the embodiment of Reference Example 1, R1 / D1 is 0.06.

[0019] In Reference Example 1 shown in Figure 4, when an attempt is made to weld the inner container 2 and the outer container 3 together by pressing the mouth 2a of the inner container 2 downward to bring the inner container 2 and the outer container 3 into close contact, the inner container 2 deforms so that the shoulder 2g1 rotates around the outer edge 2g4 of the shoulder 2g1 as a fulcrum, as shown by arrow X, making it difficult for the pressing force applied to the mouth 2a to be transmitted to the region 2l that brings the inner container 2 and the outer container 3 into close contact, making it more likely that defects will occur in the welding of the inner container 2 and the outer container 3.

[0020] In this embodiment, as shown in Fig. 3, D1 is the same as in Reference Example 1, but R1 is larger than in Reference Example 1, resulting in a larger R1 / D1 than in Reference Example 1. The larger R1 / D1, the less likely deformation occurs in the shoulder portion 2g1 due to rotation around the outer edge 2g4. In this embodiment, R1 / D1 is a relatively large value of 0.10 or greater, which suppresses rotation of the shoulder portion 2g1 around the outer edge 2g4, thereby suppressing poor welding between the inner container 2 and the outer container 3. R1 / D1 is, for example, 0.10 to 0.50, and specifically may be, for example, 0.10, 0.15, 0.20, 0.25, 0.30, 0.35, 0.40, 0.45, or 0.50, or may be in a range between any two of the values ​​exemplified here or greater than any one of them.

[0021] D1 is, for example, 50 to 80 mm (66.5 mm in this embodiment), and preferably 60 to 70 mm. Specific examples of D1 include 50, 55, 60, 65, 70, 75, and 80 mm, and may be within a range between any two of the values ​​exemplified here. R1 is, for example, 5 to 30 mm (10 mm in this embodiment), and preferably 8 to 15 mm. Specific examples of R1 include 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, and 30 mm, and may be within a range between any two of the values ​​exemplified here.

[0022] The inclination angle α of the shoulder 2g1 at a portion 2g6 where the inclination angle with respect to a plane P1 perpendicular to the central axis C of the mouth 2a is minimum is 10 to 60 degrees (30 degrees in this embodiment). In this case, rotation of the shoulder 2g1 around the outer edge 2g4 as a fulcrum is suppressed compared to Reference Example 1, in which the inclination angle α is 4 degrees. The inclination angle α is preferably 20 to 45 degrees, specifically, for example, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, or 60 degrees, or may be in a range between any two of the values ​​exemplified here. As shown in FIG. 3, if the radial length from the base 2d of the mouth 2a to the outer edge 2g4 is D2 and the radial length of the portion of the shoulder 2g1 where the inclination angle is constant is D3, then D3 / D2 is, for example, 0.30 to 0.90 (0.63 in this embodiment), and preferably 0.45 to 0.75. Specifically, D3 / D2 is, for example, 0.30, 0.35, 0.40, 0.45, 0.50, 0.55, 0.60, 0.65, 0.70, 0.75, 0.80, 0.85, or 0.90, or may be in a range between any two of the numerical values ​​exemplified here.

[0023] The shoulder portion 2g1 and the reduced diameter portion 2g5 are preferably connected in a curved shape. In this case, thinning and damage to the outer edge 2g4 are suppressed compared to Reference Example 1, in which the outer edge 2g4 has a pointed shape. The reduced diameter portion 2g5 is preferably curved so as to be convex outward. In this case, thinning and damage to the outer edge 2g4 are suppressed compared to Reference Example 1, in which the reduced diameter portion 2g5 is flat. The reduced diameter portion 2g5 has an inclination angle β with respect to the central axis C of, for example, 15 to 75 degrees (45 degrees in this embodiment), preferably 30 to 60 degrees. Specific examples of the inclination angle β are 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, and 75 degrees, and may be in a range between any two of the values ​​exemplified here. The reduced diameter portion 2g5 faces the open end 3a of the outer container 3. The reduced diameter portion 2g5 may or may not abut the open end 3a. The outer diameter at the outer edge 2g4 is preferably the same as the outer diameter at the open end 3a. In this case, the appearance of the insulated container 10 is particularly excellent. In FIG. 3, a gap is provided between the reduced diameter portion 2g5 and the open end 3a. The gap between the reduced diameter portion 2g5 and the open end 3a at the center in the thickness direction of the open end 3a is preferably 10 mm or less (1.4 mm in this embodiment), and more preferably 5 mm or less. Specific examples of this gap are 0, 0.5, 1, 1.5, 2, 2.5, 3, 4, 5, 6, 7, 8, 9, and 10 mm, and may be within a range between any two of the numerical values ​​exemplified here.

[0024] In addition, in this embodiment, the curve of the inner container 2 near the outer edge 2g4 is gentler than in Reference Example 1, making it easier to clean the inside of the inner container 2. In addition, in this embodiment, the inclination angle β of the portion 2g6 is larger than in Reference Example 1, making it less likely that the contents will remain in the insulated container 10 when the insulated container 10 is tilted to dispense the contents.

[0025] The body 2g includes a body main body 2g2 closer to the bottom 2f than the shoulder 2g1. The body main body 2g2 has, for example, a shape in which the outer diameter is substantially constant toward the bottom 2f, or a shape in which the diameter decreases toward the bottom 2f. The bottom 2f is provided with a pair of grooves 2f1 extending parallel to each other. Both ends of each groove 2f1 face toward the mouth 2a. A ridge 2f2 is formed between the pair of grooves 2f1. Both ends of the ridge 2f2 face toward the mouth 2a. With this configuration, the bottom 2f is reinforced by the grooves 2f1 and the ridge 2f2, suppressing deformation of the bottom 2f.

[0026] 2, the outer container 3 is cylindrical with a bottom, and the portion of the body main body 2g2 other than the reduced diameter portion 2g5 and the bottom 2f are housed within the outer container 3. The outer container 3 has a cylindrical body 3d and a bottom 3e that closes the lower end of the body 3d. The shoulder 2g1, the reduced diameter portion 2g5, and the body 3d form the body 1b of the container body 1, and the bottom 3e forms the bottom 1c of the container body 1.

[0027] The body 3d of the outer container 3 comprises, in order from the opening end 3a side, an upper body 3d1, a central body 3d2, and a lower body 3d3. The upper body 3d1 and the lower body 3d3 are each curved so as to convex inward, and the central body 3d2 is curved so as to convex outward. A step 3d4 is provided between the central body 3d2 and the upper body 3d1, where the central body 3d2 faces inward (i.e., the side closer to the central axis C of the container body 1; the same applies below). A step 3d5 is provided between the central body 3d2 and the lower body 3d3, where the central body 3d2 faces inward. These curved shapes and steps increase the rigidity of the body 3d.

[0028] 3, the barrel body 2g2 of the inner container 2 is provided with a reduced diameter section 2g7 that is continuous with the reduced diameter section 2g5 and that reduces in diameter as it moves away from the shoulder 2g1. Furthermore, the barrel 3d of the outer container 3 is provided with an expanded diameter section 3d6 that expands in diameter toward the open end 3a, at a position adjacent to the open end 3a. When the inner container 2 is inserted into the outer container 3, the outer surface of the reduced diameter section 2g7 abuts against the inner surface of the expanded diameter section 3d6, and it is preferable to join this section to form a joint 3b.

[0029] When the inner container 2 and the outer container 3 are made of a thermoplastic resin, the joining at the joint 3b is preferably by welding, and examples of the welding method include ultrasonic welding and laser welding.

[0030] By joining the inner container 2 and the outer container 3 at the joint 3b, a sealed space 4 is formed between the inner container 2 and the outer container 3. If the sealed space 4 is a reduced-pressure space or if the sealed space 4 contains a gas with a lower thermal conductivity than air (hereinafter referred to as "low thermal conductivity gas", e.g., krypton gas (Kr), argon gas (Ar), or xenon gas (Xe)), the thermal conductivity of the sealed space 4 will be low, and the thermal insulation of the insulated container 10 will be improved.

[0031] Preferably, the gas in the sealed space 4 contains a low-thermal-conductivity gas, and the air pressure in the sealed space 4 is 0.5 to 1.5 atmospheres. In this case, the difference in air pressure between the sealed space 4 and the external space is relatively small, making it possible to suppress deformation of the outer container 3 due to the difference in air pressure. The air pressure in the sealed space 4 is preferably 0.8 to 1.2 atmospheres, and specifically, for example, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, or 1.5 atmospheres, or may be in a range between any two of the values ​​exemplified here. The total proportion of argon gas, krypton gas, and xenon gas in the gas in the sealed space 4 is preferably 50% by volume or more. In this case, the thermal conductivity of the sealed space 4 is likely to be particularly low. This ratio is, for example, 50 to 100% by volume, specifically, for example, 50, 60, 70, 80, 90, 95, 99, 99.9, or 100% by volume, and may be in a range between any two of the values ​​exemplified here.

[0032] The inner container 2 and the outer container 3 are preferably made of a thermoplastic resin such as PET or polyolefin. The inner container 2 and the outer container 3 can be formed by blow molding. The blow molding may be direct blow molding or injection blow molding. In direct blow molding, a molten cylindrical parison extruded from an extruder is sandwiched between a pair of split molds and air is blown into the parison. In this case, a long and narrow cut-off portion (not shown) is formed in the bottom portion 3e when the parison is sandwiched between the pair of molds and cut off. In injection blow molding, a test-tube-shaped, bottomed parison called a preform is formed by injection molding, and this parison is used for blow molding.

[0033] The inner container 2 preferably has a higher rigidity (higher tensile modulus) than the outer container 3. In this case, the inner container 2 is less likely to break due to its own rigidity, and the outer container 3 acts as a cushion when the insulated container 10 is dropped, thereby preventing leakage of the contents due to breakage of the inner container 2. The tensile modulus of the inner container 2 is, for example, 1500 to 2500 MPa. Specific examples of this value are 1500, 1600, 1700, 1800, 1900, 2000, 2100, 2200, 2300, 2400, and 2500 MPa, and may be in a range between any two of the values ​​exemplified here. The tensile modulus of the outer container 3 is, for example, 200 to 1000 MPa. Specific examples of this value include 200, 300, 400, 500, 600, 700, 800, 900, and 1000 MPa, and may be within a range between any two of the values ​​exemplified herein. The difference in tensile modulus between the inner container 2 and the outer container 3 is preferably 1000 MPa or more, and more preferably 1000 to 2300 MPa. Specific examples of this difference include 1000, 1100, 1200, 1300, 1400, 1500, 1600, 1700, 1800, 1900, 2000, 2100, 2200, and 2300 MPa, and may be within a range between any two of the values ​​exemplified herein. Note that, in this specification, tensile modulus refers to a value measured at 25°C. Tensile modulus can be measured in accordance with JIS K 7161-1:2014.

[0034] Incidentally, polyolefins such as polypropylene have superior moldability in direct blow molding compared to PET, so when forming the inner container 2 and outer container 3 by direct blow molding, it is preferable to construct the inner container 2 and outer container 3 from a resin mainly composed of polyolefin. On the other hand, polyolefins have lower transparency and heat resistance compared to PET, so an insulated container 10 in which the inner container 2 and outer container 3 are formed from polyolefin has problems such as poor visibility of the contents and being prone to deformation in high-temperature environments.

[0035] To solve this problem, the inner container 2 is preferably made of a resin (hereinafter referred to as "hPP-based resin") containing 60% by mass or more of a homopolymer of propylene (hereinafter referred to as "hPP"), and the outer container 3 is preferably made of a resin (hereinafter referred to as "rPP-based resin") containing 60% by mass or more of a random copolymer of propylene and another olefin (e.g., ethylene) (hereinafter referred to as "rPP-based resin"). If the outer container 3 is made of an hPP-based resin, the visibility of the contents of the inner container 2 is significantly impaired. If both the inner container 2 and the outer container 3 are made of rPP-based resin, the outer container 3 will deform in a high-temperature environment if the air pressure in the sealed space 4 is too low, and if the sealed space 4 is filled with a low-thermal-conductivity gas, the inner container 2 will likely deform due to gas expansion in a high-temperature environment. On the other hand, by filling the sealed space 4 with a low thermal conductivity gas so that the air pressure in the sealed space 4 is 0.5 to 1.5 atmospheres, and then constructing the inner container 2 from an hPP-based resin and the outer container 3 from an rPP-based resin, it is possible to ensure thermal insulation and visibility of the contents while suppressing deformation of the inner container 2 and outer container 3 in a high-temperature environment.

[0036] The proportion of hPP contained in the hPP resin and the proportion of rPP contained in the rPP resin are, for example, 60 to 100% by mass, preferably 70 to 100% by mass, and specifically, for example, 60, 65, 70, 75, 80, 85, 90, 95, or 100% by mass. They may be between any two of the values ​​exemplified here or any value greater than or equal to these. The hPP resin may contain other resins other than hPP in the form of layers or in the form of a mixed resin with hPP. The rPP resin may contain other resins other than rPP in the form of layers or in the form of a mixed resin with rPP. Examples of other resins include gas barrier resins such as EVOH and adhesive resins.

[0037] The inner container 2 preferably comprises an hPP layer made of hPP and a gas barrier layer made of a gas barrier resin, with the gas barrier layer preferably being sandwiched between a pair of hPP layers. The outer container 3 preferably comprises an rPP layer made of rPP and a gas barrier layer made of a gas barrier resin, with the gas barrier layer preferably being sandwiched between a pair of rPP layers. The provision of a gas barrier layer inhibits gas permeation through the wall surface, thereby suppressing a decrease in insulation performance due to gas permeation. Furthermore, the proportion of resins other than polypropylene contained in the hPP or rPP resin is preferably less than 6% by mass. This is because the hPP or rPP resin can be considered a single material (monomaterial), improving recyclability.

[0038] At the center of the height of the container body 1, the wall thickness of the inner container 2 is preferably 0.5 to 1.5 mm, and the wall thickness of the outer container 3 is preferably 1.0 to 2.0 mm. With such wall thicknesses, it is possible to prevent an increase in the weight of the container body 1 while achieving particularly good insulation, visibility, and heat resistance. Specific examples of the wall thickness of the inner container 2 are 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, and 1.5 mm, and may be within a range between any two of the values ​​exemplified here. Specific examples of the wall thickness of the outer container 3 are 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, and 2.0 mm, and may be within a range between any two of the values ​​exemplified here.

[0039] 2. Manufacturing method of the insulated container 10 The insulated container 10 can be manufactured by attaching a cap to the opening 2a of the container body 1. The container body 1 can be manufactured by separately molding the inner container 2 and the outer container 3, and joining the inner container 2 and the outer container 3 to form the joint 3b.

[0040] 5 and 6, the container body 1 is preferably manufactured by a method including a molding step, a grinding step, and a laser welding step. Each step will be described below.

[0041] <Forming process> In the molding step, the inner container 2 and the outer container 3 are molded. The molding methods for the inner container 2 and the outer container 3 are as described above.

[0042] <Grinding process> In the grinding process, as shown in FIGS. 5 and 6 , the planned laser welding areas 2i are ground on at least one of the inner container 2 and the outer container 3. In this embodiment, the planned laser welding areas 2i on the inner container 2 side are ground. However, grinding may be performed on the outer container 3 side, or on both the inner container 2 and the outer container 3 side. This grinding makes the planned laser welding areas 2i suitable for laser welding, thereby reducing the occurrence of defective laser welding. The planned laser welding areas 2i are preferably provided around the entire circumference of the inner container 2. This grinding is preferably performed by rotating the inner container 2 around the central axis C of the mouth 2a of the inner container 2 while bringing a grinding tool 5 into contact with the planned laser welding areas 2i. This facilitates stable grinding. In one example, rotation of the inner container 2 can be performed by attaching the head 7 of a rotation device to the mouth portion 2a with the bottom portion 2f bearing on the bearing member 6, and rotating the mouth portion 2a together with the head 7.

[0043] Examples of the grinding tool 5 include a grindstone and a cutting tool. Furthermore, it is preferable that the regions 2i to be laser welded are roughened by grinding. When laser welding is performed with a laser-absorbing agent applied to the regions 2i to be laser welded, roughening the regions 2i to be laser welded can prevent the laser-absorbing agent from dripping if the laser-absorbing agent is in liquid form. The thickness removed by this cutting is, for example, 0.05 to 0.30 mm, specifically, for example, 0.05, 0.10, 0.15, 0.20, 0.25, or 0.30 mm, and may be within a range between any two of the numerical values ​​exemplified here.

[0044] 5, in one example, the grinding tool 5 is driven by a cylinder mechanism 8. The cylinder mechanism 8 includes a cylinder 8a and a rod 8b whose protruding amount from the cylinder 8a is variable. The grinding tool 5 is fixed to the rod 8b, and the grinding tool 5 can be displaced by changing the protruding amount of the rod 8b.

[0045] As shown in FIG. 6A, before grinding, the region to be laser welded 2i preferably has a protruding portion 2i1 that protrudes in an annular shape from a reference plane P2 connecting a region 2j above the region 2i and a region 2k below the region 2i. This grinding is preferably performed so as to remove at least a portion of the protruding portion 2i1, as shown in FIG. 6B. Furthermore, as shown in FIG. 6C, it is preferable that the protruding portion 2i1 remains partially even after grinding. In this case, the ground region is prevented from being recessed below the reference plane P2, thereby preventing defects in laser welding. Before grinding, the protruding portion 2i1 protrudes from the reference plane P2 by a height of, for example, 0.10 to 0.50 mm, preferably 0.20 to 0.40 mm. Specifically, the protrusion height is, for example, 0.10, 0.15, 0.20, 0.25, 0.30, 0.35, 0.40, 0.45, or 0.50 mm, and may be in a range between any two of the values ​​exemplified here.

[0046] When the inner container 2 has a parting line at the intended laser welding location 2i, the convex shape caused by the parting line is likely to cause defects in laser welding. However, by removing the convex shape caused by the parting line through the grinding process, the occurrence of defects in laser welding can be suppressed.

[0047] <Laser welding process> In the laser welding process, the inner container 2 and the outer container 3 are laser welded together at the intended laser welding area 2i. This forms a joint 3b between the inner container 2 and the outer container 3, forming a sealed space 4 between the inner container 2 and the outer container 3. Laser welding can be performed by irradiating the intended laser welding area 2i with a laser while rotating the inner container 2 and the outer container 3 around the central axis C of the opening 2a of the inner container 2, with the inner container 2 and the outer container 3 in contact with each other at the intended laser welding area 2i. Laser welding is preferably performed with a laser-absorbing agent applied to the intended laser welding area 2i. This increases the laser absorption efficiency and enables more efficient laser welding. [Example]

[0048] Test examples related to the first aspect of the invention will be described below.

[0049] 1. Manufacturing a sample of the insulated container 10 <Sample 1> The insulated container 10 of Sample 1 has the structure shown in the above embodiment and a capacity of 390 mL. The container body 1 of the insulated container 10 has an inner container 2 composed of a 1 mm-thick hPP-based resin layer (specifically, from the outside, hPP layer (70%) / adhesive resin layer (3.5%) / EVOH layer (4%) / adhesive resin layer (3.5%) / hPP layer (19%); the numbers in parentheses indicate the layer thickness ratios). The outer container 3 has a 1.5 mm-thick rPP-based resin layer (specifically, from the outside, rPP layer (70%) / adhesive resin layer (3.5%) / EVOH layer (4%) / adhesive resin layer (3.5%) / rPP layer (19%); the numbers in parentheses indicate the layer thickness ratios). The sealed space 4 was produced by reducing the pressure to 0.01 atmospheres and then filling it with argon gas to 1 atmosphere. The adhesive resin layer was composed of a polypropylene-based adhesive resin.

[0050] <Samples 2-6> The insulated container 10 was manufactured in the same manner as Sample 1, except that the configuration of the insulated container 10 was changed as shown in Table 1. In Table 1, hPP-based and rPP-based refer to an hPP-based resin layer and an rPP-based resin layer, respectively.

[0051] 2. Exam The following tests were carried out on samples 1 to 6 of the heat-insulating container 10.

[0052] <Heat resistance test> In the heat resistance test, the container body 1 of the empty insulated container 10 was left in an environment of 70°C for one hour, and then it was confirmed whether the inner container 2 or the outer container 3 changed shape. If neither the inner container 2 nor the outer container 3 changed shape, it was judged as OK, and if at least one of the inner container 2 or the outer container 3 changed shape, it was judged as NG. The test results are shown in Table 1.

[0053] In Samples 1 to 3, neither the inner container 2 nor the outer container 3 was deformed. In Samples 4 and 5, the inner container 2 was deformed. In Sample 6, the outer container 3 was deformed.

[0054] <Visibility test> The visibility test involved filling 200 mL of water into the inner container 2 of the container body 1 of the insulated container 10, and checking whether the water level was visible from the outside of the outer container 3. Tests in which the water level was clearly visible were rated as OK, and tests in which the water level was unclear were rated as NG. The test results are shown in Table 1.

[0055] <Insulation test> The heat insulation test was conducted by filling the insulated container 10 with water at 4°C and leaving it to stand for three hours in an environment at 20°C, and then measuring the water temperature. The water temperatures after three hours of standing were 16.3°C, 15.3°C, and 14.1°C for the single-walled PET container, the single-walled polypropylene container, and the double-walled container having the same configuration as Sample 1 except that the gas in the sealed space 4 was air, respectively. On the other hand, the water temperatures for Samples 1 and 2 were 12.2°C and 11.2°C, respectively. This result indicates that the insulated containers 10 of Samples 1 and 2 have excellent heat insulation properties.

[0056] [Table 1] [Explanation of symbols]

[0057] 1: Container body 1a: Mouth 1b: Body 1c: bottom 2: Inner container 2a: Mouth 2c: Engagement part 2f: Bottom 2f1 : Groove 2f2: Convex strip 2g: Body 2g1:Shoulder 2g2: Body 2g4: outer edge 2g5: Reduced diameter part 2g6 : Part 2g7: Reduced diameter part 2g8 : Part 2i: Area to be laser welded 2i1:Protruding part 2j :part 2k: part 2l: part 3: Outer container 3a: Open end 3b:Joint part 3d: Body 3d1: Upper torso 3d2: Central body 3d3: lower torso 3d4: Step 3d5: Step 3d6: Expanded diameter part 3e: bottom 4: Closed space 5: Grinding tools 6: Bearing material 7: Head 8: Cylinder mechanism 8a: Cylinder 8b: Rod 10: Insulated container C: Central axis P1: Surface P2: Reference plane α: Inclination angle

Claims

1. A thermally insulated container comprising a container body, The container body includes an inner container and an outer container arranged to cover the inner container, A sealed space is provided between the inner container and the outer container, The inner container has a mouth and a body having an outer diameter larger than that of the mouth, the body portion includes a shoulder portion whose outer diameter increases with increasing distance from the mouth portion, and a tapered portion that is continuous with the outer edge of the shoulder portion and whose outer diameter decreases with increasing distance from the mouth portion, If the outer diameter of the inner container at the outer edge is D1 and the radius of curvature of the shoulder portion adjacent to the outer edge is R1, An insulated container having R1 / D1 of 0.10 or more.

2. The insulated container according to claim 1, The insulated container has a minimum inclination angle of the shoulder portion relative to a plane perpendicular to the central axis of the mouth portion of 10 to 60 degrees.

3. The insulated container according to claim 1, The shoulder portion and the reduced diameter portion are connected in a curved shape.

4. The heat-insulating container according to any one of claims 1 to 3, The reduced diameter portion is curved so as to be convex outward.

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