Heat-shrinkable film, method for producing heat-shrinkable film, and method for determining heat-shrinkage of heat-shrinkable film

Abstract

This invention provides a heat-shrinkable film or the like with a predetermined heat-shrinkage speed to achieve uniform heat-shrinkage characteristics. It is a heat-shrinkable film or the like with its long side or width direction as the main shrinkage direction. A predetermined interval is set along the main shrinkage direction, and heat shrinkage is performed at a predetermined temperature T and a predetermined time t1. The maximum value of the heat-shrinkage speed V1, calculated based on the change in distance between the predetermined interval before heat shrinkage (PL0) and the predetermined interval at the predetermined time t2, and based on the following formula (1), is set to 3 mm / s or more. [Mathematical Formula 1] Heat-shrinkage speed V1 (mm / s) = (PL0 - PL1) / t2 (1) PL0 - PL1: Change in distance between the predetermined intervals (mm) t2: Predetermined time (seconds)

Description

Technical Field

[0001] This invention relates to heat shrink film, a method for manufacturing heat shrink film, and a method for determining the heat shrinkage rate of heat shrink film. More specifically, it relates to a heat-shrinkable film having a specified heat-shrinkage rate in order to achieve uniform heat-shrinkage properties, an effective manufacturing method for the heat-shrinkable film, and a method for rapidly and accurately determining the heat-shrinkage rate of the heat-shrinkable film. Background Technology

[0002] Previously, heat-shrinkable films were known to be formed from various heat-shrinkable resins, such as heat-shrinkable polyester films, heat-shrinkable polyvinyl chloride films, and heat-shrinkable polystyrene films. Furthermore, heat shrink film is widely used, for example, as a substrate film for labels on PET bottles. However, the aforementioned shrink film undergoes heat shrinkage and is packaged on a container by passing through a tunnel that generates hot air or steam. However, uneven shrinkage can sometimes occur during heat shrinkage, resulting in wrinkles and uneven color. Therefore, in order to prevent uneven shrinkage during heat shrinkage, which in turn leads to wrinkles and uneven color, various heat shrink films have been proposed.

[0003] For example, a heat-shrinkable polyester film has been proposed that controls the proportion of alcohol components other than ethylene glycol, or strictly controls the amount of naphthalic acid and the amount of alkali metal salt of sulfophthalic acid in the overall acid composition (see Patent Document 1). More specifically, the membrane is characterized in that, regarding the polyester resin, the proportion of acid components other than terephthalic acid in the overall acid component (A mol%) and the proportion of alcohol components other than ethylene glycol in the overall alcohol component (B mol%) are in the range of 5 mol% ≤ A + B ≤ 40 mol%, and the overall acid component contains naphthalic acid in a proportion of 1 to 30 mol% and alkali metal salt of sulfophthalic acid in a proportion of 0.3 to 3 mol%. Furthermore, regarding the heat shrinkage rate of the polyester film, it is preferably 5% or more when immersed in warm water at a temperature of 60°C for 60 seconds along the long side of the film, and preferably 30% or more when immersed in warm water at a temperature of 80°C for 60 seconds.

[0004] In addition, a heat-shrinkable polyester film was proposed that strictly controls the amount of amorphous components in the overall polyester resin composition and simultaneously limits the hot water thermal shrinkage rate at 80°C and 90°C in the long side direction of the film and the hot water thermal shrinkage rate at 90°C in the width direction of the film (see Patent Document 2). More specifically, the film is a heat-shrinkable polyester film that uses polyethylene terephthalate as the main component and contains one or more monomeric components that can be amorphous components in the overall polyester resin composition, and their total amount is more than 15 mol%. Furthermore, the heat-shrinkable polyester film is characterized in that, in the long side direction of the film, the hot water heat shrinkage rate of the polyester film is more than 30% when the treatment temperature is 80°C and the treatment time is 10 seconds, and more than 40% when the treatment temperature is 90°C and the treatment time is 10 seconds; and in the width direction of the film, the hot water shrinkage rate is less than 10% when the treatment temperature is 90°C and the treatment time is 10 seconds.

[0005] In addition, a heat-shrinkable polyester film is proposed that defines a shrinkage rate in one direction and a heat shrinkage rate in a direction orthogonal to that direction, while setting the average heat shrinkage rate coefficient within a temperature range of 70~120°C within a specified range (see Patent Document 3). More specifically, the film is a heat-shrinkable polyester film, which is a homopolymer of polyethylene terephthalate, or a copolymer containing dicarboxylic acid components other than terephthalic acid and / or diol components other than ethylene glycol and / or hydroxycarboxylic acid components. Furthermore, the heat-shrinkable polyester film is characterized in that the heat shrinkage rate in at least one direction is 30% or more, and the average heat shrinkage rate coefficient in the temperature range of 70 to 120°C in at least that direction is in the range of 0.1 to 0.5% / second·°C.

[0006] In addition, a shrinkage label that limits the maximum heat shrinkage rate measured under specified conditions has been proposed (see Patent Document 4). More specifically, the shrink label is a heat-shrinkable shrink label having at least one film layer and a printing layer with polylactic acid polymer as an essential component. Furthermore, the shrink label is characterized in that the thermal shrinkage rate in the main orientation direction after 1 second of thermal shrinkage in 75°C warm water is 3~23%, and the thermal shrinkage rate in the main orientation direction under the conditions of 90°C and 10 seconds is 40~84%. Alternatively, the shrink label is characterized in that the maximum thermal shrinkage rate in the main orientation direction in 75°C warm water is 7~40% / second, and the thermal shrinkage rate in the main orientation direction under the conditions of 90°C and 10 seconds is 40~84%. Existing technical documents Patent documents

[0007] Patent Document 1: Japanese Patent Application Publication No. 08-027259 (claims, etc.) Patent Document 2: Japanese Patent Application Publication No. 2007-016120 (claims, etc.) Patent Document 3: Japanese Patent Application Publication No. 8-323859 (claims, etc.) Patent Document 4: Japanese Patent Application Publication No. 2008-1098 (claims, etc.) Summary of the Invention (a) Technical problems to be solved

[0008] However, although the heat shrink film described in Patent Documents 1 and 2 limits the heat shrinkage rate to a specified range at a specified temperature and time, it does not take into account the heat shrinkage speed at all. Therefore, it is easy to produce uneven heat distribution, which leads to a larger deviation in the measured value. That is, for heat shrink films with heat shrinkage rates measured in the above manner, there are cases where the heat shrinkage rate characteristics cannot be managed with good accuracy. Therefore, in cases such as PET bottles with inconsistent bottle diameters and complex, non-circular horizontal cross-sectional shapes depending on the location, heat shrinkage can easily become uneven, making it difficult to suppress the formation of fine wrinkles.

[0009] Furthermore, although the heat shrink film described in Patent Document 3 specifies the amount of change in heat shrinkage rate relative to time, it only specifies the averaged heat shrinkage rate coefficient (% / (second·℃)) before and after heat shrinkage, and does not take into account the measurement of the heat shrinkage rate (mm / second) from before heat shrinkage to the specified time and its maximum value. Therefore, for heat shrink film, it is impossible to accurately measure the heat shrinkage rate (mm / second) during the rapid changes that occur in a short period of time during heat shrinkage.

[0010] Furthermore, although the shrink label described in Patent Document 4 specifies the heat shrinkage rate (%) one second after the start of heat shrinkage, it is a heat shrinkage rate that is time-limited and does not take into account shrink labels with different heat shrinkage times. In addition, although the maximum heat shrinkage rate (% / second) is mentioned, it measures the actual instantaneous heat shrinkage rate when measured at 0.1-second intervals, and does not take into account the measurement of the maximum value of the heat shrinkage rate (mm / second) from before heat shrinkage to the specified time. Therefore, when converting to the maximum value of the heat shrinkage rate from before heat shrinkage to the specified time, it limits the range to a very small range.

[0011] In response, the inventors of this application discovered that by using a motion capture device to measure the heat shrinkage speed of the heat shrinkage film and limiting it within a specified range, a heat shrinkage film that consistently exhibits excellent heat shrinkage properties can be obtained, thus completing this invention. That is, the object of the present invention is to provide a heat shrink film with uniform heat shrinkage characteristics, an effective manufacturing method for the heat shrink film, and a method for rapidly and accurately determining the heat shrinkage rate of the heat shrink film. (II) Technical Solution

[0012] The present invention is a heat shrink film, which is a heat shrink film with the long side direction or the width direction as the main shrink direction. The feature is that a specified interval is set along the main shrink direction of the heat shrink film that can shrink in at least one of the long side direction or the width direction. When heat shrinking is performed at a specified temperature T and a specified time t1, the maximum value of the heat shrinking speed V1 calculated based on the following formula (1) is a value of 3 mm / second or more, according to the change in distance between the specified interval before heat shrinking PL0 and the specified interval at a specified time t2 which is shorter than the specified time t1.

[0013] [Mathematical Expression 1] Heat shrinkage rate V1 (mm / s) = (PL0 - PL1) / t2 (1) PL0-PL1: Distance variation (mm) within the specified interval t2: Specified time (seconds)

[0014] That is, by constructing it in the above manner, it is possible to adjust the balance between the amount of change and time when the heat shrink film undergoes its maximum change with good precision, and to effectively prevent wrinkles and other defects when the heat shrink film is used on an object.

[0015] Furthermore, when constructing the heat shrink film of the present invention, it is preferable to set the specified time t1 to be greater than 5 seconds and the specified time t2 to be less than 5 seconds. By constructing it in the above manner, even during the period of large shrinkage at the beginning of heat shrinkage, the distance of the specified interval can be accurately measured, the heat shrinkage speed can be adjusted, and the uniform heat shrinkage characteristics can be achieved with better precision. Furthermore, it can be used on objects that use heat-shrinkable film in the desired state.

[0016] Furthermore, when constructing the heat shrink film of the present invention, it is preferable to set the maximum value of the heat shrinkage rate V2 calculated based on the following formula (2) to be 30% / second or more.

[0017] [Mathematical Expression 2] The rate of thermal shrinkage, V2 (% / second), is calculated as follows: (PL0 - PL1) / (PL0 × t2) × 100 (2)

[0018] By constructing it in the above manner, it is possible to adjust the balance between the amount of change and time when the heat shrink film undergoes its maximum change with good precision, and to effectively prevent wrinkles and other defects when the heat shrink film is used on objects. Furthermore, by measuring the change in heat shrinkage rate, the heat shrink film can be evaluated without relying on the distance of a specified range.

[0019] Furthermore, when constituting the heat shrink film of the present invention, it is preferable that the heat shrink film is composed of at least one resin selected from the group consisting of polyester resin, styrene resin (including styrene-butadiene resin), polyolefin resin and polyvinyl chloride resin. By constructing it in the above manner, it can be applied to heat shrink films derived from a wide variety of resins, making it easy to measure the heat shrinkage rate of various heat shrink films, and enabling faster and more accurate adjustment of the heat shrinkage rate.

[0020] Furthermore, when constructing the heat-shrinkable film of the present invention, it is preferable to set the specified temperature T to 70~98°C and the heat shrinkage rate along the main shrinkage direction to a value within the range of 10~80%. By constructing it in the manner described above, the heat shrinkage rate can be adjusted with greater precision by limiting the heat shrinkage rate.

[0021] Furthermore, when constructing the heat-shrinkable film of the present invention, it is preferable that the distance variation within the specified interval is a value calculated using a motion capture device based on the distance information of the specified interval. By constructing it in the above manner, a motion capture device that can be easily and accurately measured can be used to continuously monitor distance changes within a specified range over a very short period of time, and the heat shrinkage rate can be measured and controlled.

[0022] Furthermore, another aspect of the present invention is a method for manufacturing a heat-shrinkable film, which is a method for manufacturing a heat-shrinkable film with the long side direction or the width direction as the main shrinkage direction, characterized in that it includes the following steps (1) to (3): (1) The process of preparing raw material resin; (2) A process of forming a resin film from molten raw material resin and stretching it to produce a heat shrink film with the long side or width direction as the main shrinkage direction. (3) When heat shrinking is performed at a specified temperature T and a specified time t1, a heat shrinking speed adjustment process is set at the maximum value of the heat shrinking speed V1 calculated based on the distance PL0 of the specified interval before heat shrinking and the distance PL1 of the specified interval at a specified time t2 which is shorter than the specified time t1, based on the distance change between the specified interval before heat shrinking and the specified interval at a specified time t2 which is shorter than the specified time t1. The process is set at 3 mm / s or more.

[0023] [Mathematical Expression 3] Heat shrinkage rate V1 (mm / s) = (PL0 - PL1) / t2 (1) PL0-PL1: Distance variation (mm) within the specified interval t2: Specified time (seconds)

[0024] That is, by implementing it in the above manner, it is possible to adjust the balance between the amount of change and time when the heat shrink film undergoes its maximum change with good precision, and to effectively prevent wrinkles and other defects when the heat shrink film is used on an object.

[0025] Furthermore, when implementing the manufacturing method of the heat-shrinkable film of the present invention, it is preferable to use a motion capture device and perform calculations based on distance information within a specified interval. By implementing the above method, a motion capture device that can be easily and accurately measured can be used to continuously monitor distance changes within a specified range over a very short period of time, and the heat shrinkage rate can be measured and controlled.

[0026] Furthermore, when implementing the manufacturing method of the heat shrinkable film of the present invention, it is preferable to place the heat shrinkable film on a measuring fixture composed of a frame member, and to heat shrink the heat shrinkable film along the main shrinkage direction while it is pressed down by a limiting part arranged in a direction perpendicular to the main shrinkage direction. By implementing the above method, not only will the operation of the heat shrink film during heat shrinking be easier, but the heat shrinking behavior will also become extremely smooth, enabling the heat shrinking speed to be measured with better accuracy.

[0027] Furthermore, another aspect of the present invention is a method for determining the heat shrinkage rate of a heat shrink film, which is the method for determining the heat shrinkage rate of the aforementioned heat shrink film, characterized by comprising the following steps (1) to (3): (1) A preparation process for heat shrink film in which the main shrinkage direction of the heat shrink film is clearly marked and a specified range is set along the state that the heat shrink film can shrink along at least one of the long side direction or the width direction; (2) The heat shrink film is heated under a specified temperature T and a specified time t1, and the heat shrink film is heated in such a way that the maximum value of the heat shrink speed V1 calculated based on formula (1) is more than 3 mm / second, and the heat shrink process is carried out. (3) A process for estimating the heat shrinkage rate of the heat shrink film based on a characteristic curve pre-made based on the heat shrinkage rate, which shows the relationship between the heat shrinkage rate and the heat shrinkage rate of the heat shrink film. Based on the characteristic curves pre-produced in the manner described above, which show the relationship between the heat shrinkage rate V1 and the heat shrinkage rate (A2 and / or B1) of the heat shrink film, the heat shrinkage rate (A2 and / or B1) of the heat shrink film can be estimated and determined. Therefore, the estimated heat shrinkage rate of the heat shrinkage film can be obtained quickly and with good accuracy in the form of a value equivalent to the actual heat shrinkage rate measured under specified conditions. Attached Figure Description

[0028] Figure 1 Figures (a) to (c) are used to illustrate the morphology of the heat shrink film. Figure 2 Figures (a) to (b) are used to illustrate the rate of thermal shrinkage and the rate of thermal shrinkage. Figure 3 (a) is a diagram illustrating multiple measurement samples (W, C, E) collected by a roller-shaped heat-shrinkable film along the main shrinkage direction. Figure 3 Figures (b) to (d) are diagrams illustrating the method for measuring the heat shrinkage speed of heat shrink film using motion capture devices, etc. Figure 4 This is a graph illustrating the relationship between the distance change (mm) of the heat shrink film in a specified range in Examples 1-2 and Comparative Examples 1-2 and the time (second). Figure 5 Figures (a) to (b) are graphs illustrating the relationship between the heat shrinkage rate (mm / s) and time (second) of the heat shrink film in Examples 1 to 2. Figure 5 (c) is a graph used to illustrate the relationship between the rate of thermal shrinkage (% / second) and time. Figure 6 Figures (a) to (b) are graphs illustrating the relationship between the heat shrinkage rate (mm / s) of the heat shrink film in Comparative Examples 1 to 2 and time (seconds). Figure 6 (c) is a graph used to illustrate the relationship between the rate of thermal shrinkage (% / second) and time. Figure 7 Figures (a) to (c) are examples illustrating the configuration of a device for measuring the thermal shrinkage speed using a motion capture instrument. Figure 8 Figures (a) to (c) are examples of the configuration of the fixture used in measuring the thermal shrinkage speed of a motion capture device. Figure 9 (a) is a graph illustrating the relationship between the intermediate heat shrinkage rate V3 (mm / s) of the heat shrink film in Example 1 and time (seconds). Figure 9 (b) is a graph used to illustrate the relationship between the intermediate heat shrinkage rate V4 (% / second) and time. Figure 10 (a) is a graph illustrating the relationship between the intermediate heat shrinkage rate V3 (mm / s) of the heat shrink film in Example 2 and time (seconds). Figure 10 (b) is a graph used to illustrate the relationship between the intermediate heat shrinkage rate V4 (% / second) and time. Figure 11(a) is a graph illustrating the relationship between the intermediate heat shrinkage rate V3 (mm / s) of the heat shrink film in Comparative Example 1 and time (seconds). Figure 11 (b) is a graph used to illustrate the relationship between the intermediate heat shrinkage rate V4 (% / second) and time. Figure 12 (a) is a graph illustrating the relationship between the intermediate heat shrinkage rate V3 (mm / s) of the heat shrink film in Comparative Example 2 and time (seconds). Figure 12 (b) is a graph used to illustrate the relationship between the intermediate heat shrinkage rate V4 (% / second) and time. Figure 13 This is a graph illustrating the relationship between the thermal shrinkage rate A2 (%) in the main shrinkage direction and the thermal shrinkage rate (mm / s) at time point 5 seconds. Figure 14 This is a graph illustrating the relationship between the thermal shrinkage rate B1 (%) in the main shrinkage direction based on existing methods and the thermal shrinkage rate A2 (%) in the main shrinkage direction obtained using a motion capture device. Figure 15 (a) is a diagram (photograph) showing the appearance of the cylindrical label, equivalent to Example 1, without wrinkles. Figure 15 (b) to (d) respectively will Figure 15 (a) is an enlarged view of the appearance of regions P, Q, and R. Figure 16 (a) is a diagram (photograph) showing the appearance of the cylindrical label when wrinkles have formed, corresponding to Comparative Example 1. Figure 16 (b) to (d) respectively will Figure 16 (a) is an enlarged view of the appearance of regions S, T, and U. Detailed Implementation

[0029] The embodiments of the present invention will now be described with appropriate reference to the accompanying drawings. In addition, in the figures used for illustration, the same reference numerals are used to label the same components, and sometimes their descriptions are omitted. Furthermore, the figures used in this description are schematic diagrams to enable those skilled in the art to understand the invention described above, and the usage devices, shapes, sizes, materials, etc., described in the description are merely preferred examples within the scope of this invention. Therefore, unless otherwise specified, this invention is not limited to the following embodiments.

[0030] [First Implementation Plan] like Figure 1As exemplified, the first embodiment is a heat shrink film, which is a heat shrink film 10 with the long side direction or the width direction as the main shrink direction. The characteristic is that a predetermined interval is set along the main shrink direction of the heat shrink film that can shrink in at least one of the long side direction or the width direction. When heat shrinking is performed at a predetermined temperature T and a predetermined time t1, the maximum value of the heat shrinking speed V1 calculated based on the following formula (1) is a value of 3 mm / second or more, according to the change in distance between the predetermined interval before heat shrinking PL0 and the predetermined interval at a predetermined time t2 which is shorter than the predetermined time t1.

[0031] [Mathematical Expression 4] Heat shrinkage rate V1 (mm / s) = (PL0 - PL1) / t2 (1) PL0-PL1: Distance variation (mm) within the specified interval t2: Specified time (seconds)

[0032] 1. Basic Components (1) Heat shrink film The basic structure of the present invention is a heat shrinkable film that maintains a specified shape under specified stretching conditions and stably shrinks along the long side or short side direction, which is the main shrinkage direction, under specified shrinkage conditions. That is, there is no particular limitation on the type of resin, but it is generally preferred to be at least one resin selected from the group consisting of polyester resin, polystyrene resin (including styrene-butadiene resin), polyolefin resin and polyvinyl chloride resin. In particular, if it is a polyester resin, its mechanical strength, heat resistance, transparency, versatility, gas barrier properties, and economy are even better, so it can be said to be a better constituent resin.

[0033] For example, if it is a polyester resin, it is generally preferred to be: a polyester resin formed from diol and dicarboxylic acid as reactants, a polyester resin formed from diol and hydroxycarboxylic acid as reactants, or a crystalline polyester resin formed from diol, dicarboxylic acid and hydroxycarboxylic acid as reactants. In addition, it is also preferable to use at least one of ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, pentaethylene glycol, hexaethylene glycol, heptaethylene glycol, octaethylene glycol, 2,2-dimethyl-1,3-propanediol, 1,4-cyclohexanediol, neopentyl glycol, etc., in a specified amount as a reaction component of the above-mentioned crystalline polyester resin to prepare a non-crystalline polyester resin. Furthermore, by using a mixture of crystalline and non-crystalline polyester resins, the mechanical strength, heat resistance, transparency, versatility, gas barrier properties, and economy are all better adjusted, making it arguably a superior resin.

[0034] Furthermore, if polystyrene resin is used, commonly used polystyrene resins can be widely adopted, preferably homopolymers of styrene monomers, and copolymers of styrene monomers and other monomers that can be copolymerized with them (e.g., styrene-butadiene copolymers). That is, as styrene monomers, styrene, 2-methylstyrene, 3-methylstyrene, 4-methylstyrene, 4-ethylstyrene, chlorostyrene, bromostyrene and other halogenated styrene, halogenated alkylstyrene, polyalkoxystyrene, polycarboxyalkylstyrene, polyalkyl etherstyrene, polyalkylsilylstyrene and so on are usually preferred. Furthermore, as other monomers that can be copolymerized with styrene monomers, at least one of the following is generally preferred: butadiene, butyl acrylate, acrylic acid or methacrylic acid, methyl acrylate or methyl methacrylate, ethyl acrylate or ethyl methacrylate, butyl acrylate or butyl methacrylate, 2-ethylhexyl acrylate or 2-ethylhexyl methacrylate. Especially when copolymerizing other monomers such as butadiene or butyl acrylate, it is preferable to set the amount of such other monomers to 20% by weight or less relative to the total amount of monomers (100% by weight). The reason is that if the amount of the comonomer is excessive or too large, the transparency of the resulting heat-shrinkable film will be significantly reduced or it will be difficult to obtain uniform heat-shrinkable properties.

[0035] In addition, if it is a polyolefin resin, high-density polyethylene (HDPE), low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), polypropylene, ethylene-vinyl acetate copolymer (EVA) and the like are generally preferred.

[0036] Furthermore, if the resin is polyvinyl chloride, homopolymers or copolymers of vinyl chloride or vinylidene chloride are generally preferred. That is, monomers that can be copolymerized as vinyl chloride resins are preferably ethylene, propylene, acrylonitrile, vinyl acetate, maleic acid or its esters, acrylic acid or its esters, methacrylic acid or its esters, etc. Furthermore, polymer blends of polyvinyl chloride resin are also preferred, such as polymer blends composed of polyvinyl chloride resin and polyvinylidene chloride.

[0037] (2) Determination of thermal shrinkage rate When thermally shrinking along the main shrinkage direction at a specified temperature T and a specified time t1, the thermal shrinkage rate V1 can be calculated based on Equation (1) using the specified correlation between the distance information of the specified interval obtained by the motion capture device and the measurement time. More specifically, such as Figure 2As shown, the distance of a specified interval from the point when heat shrinking begins (e.g., t0=0) can be set as PL0. At any time during the period up to a specified time t1, the distance of the specified interval of the heat shrink film after a specified time t2 from the point when heat shrinking begins can be set as PL1, thereby measuring the change in distance of the specified interval (PL0-PL1) at the specified time t2. That is, by measuring the distance of a specified interval after a specified time t2 from t0 using a motion capture device, the heat shrinkage rate V1 is calculated in the form of the change in distance of the specified interval per unit time. Here, the time point t0 at which heat shrinkage begins can be basically defined as: the time point at which the start of heat shrinkage behavior can be confirmed based on images captured by a motion capture device or the like. However, when there is a time lag between immersion in warm water and the actual start of heat shrinkage, the time t0 before the start of heat shrinkage is short (e.g., 0.01 to 0.1 seconds) before and after the start of the shrinkage action, the results may not be completely consistent and may vary. It is known that for the time point t0 at which heat shrinkage begins, a short deviation will not have a substantial impact on the calculation of the heat shrinkage rate and the heat shrinkage ratio based on that heat shrinkage rate.

[0038] 2. Specific Composition (1) Specified interval The specified interval is the area clearly marked on the heat shrink film for the purpose of measuring the behavior of the heat shrink film during heat shrinkage. That is, such as Figure 3 As shown in (b) to (d), the specified interval M is clearly marked in the form of a straight line using the prescribed markings 14' such as dots, lines, cross marks, circular marks, arrows, L-shaped marks, T-shaped marks, and check marks. The reason is that by setting it as described above, it is easy to identify the situation where the heat shrink film shrinks from its surroundings. Therefore, the specified interval is preferably configured such that virtual coordinates are set in a plane containing the sample to measure the coordinate values ​​at both ends of the specified interval, and calculations are performed based on these coordinate values. Specifically, regarding the specified range, such as Figure 3 As shown in (b), when a measurement point P0 is set on the measurement sample 11 of the heat shrink film 10 before heat shrinkage or at the time point t0 when heat shrinkage begins, and a measurement point P0' different from P0 is set, the distance between the measurement point P0 and the measurement point P0' along the main shrinkage direction can be defined as the distance PL0 of a specified interval. In addition, such as Figure 3As shown in (c), when the points corresponding to measurement points P0 and P0' after a specified time t2 from the start of heat shrinkage are respectively set as measurement points P1 and P1', the distance between measurement points P1 and P1' along the main shrinkage direction can be defined as the distance PL1 of the specified interval. And, as Figure 3 As shown in (d), when the points corresponding to measurement points P0 and P0' after a specified time t3 from the start of heat shrinkage are respectively set as measurement points P2 and P2', the distance between measurement points P2 and P2' along the main shrinkage direction can be defined as the distance PL2 of the specified interval. Therefore, the distance change PL2-PL1 within the specified interval during the measurement period t3-t2 can be calculated as the difference between the specified interval distance PL2 and the specified interval distance PL1.

[0039] Furthermore, the position of the specified interval is preferably set as the coordinate value of the axis along the main shrinkage direction in a coordinate system that includes the plane of the heat shrink film being measured. That is, for example, in a coordinate system of a plane containing the heat-shrinkable film, it is preferable to determine the coordinate values ​​of the two ends of a specified interval, and calculate the distance of the specified interval based on the respective coordinate values. Furthermore, it is preferable to set the distance of the specified interval before heat shrinkage to a value within the range of 8 to 50 mm. The reason is that by setting the specified range in the above manner, the heat shrinkage rate can be calculated without depending on the shape of the heat shrink film, which is more versatile and can be measured with good accuracy. Therefore, it is more preferable to set the distance of the specified interval before heat shrinkage to a value in the range of 9 to 30 mm, and even more preferably to a value in the range of 10 to 20 mm.

[0040] In addition, in heat shrink film, it is generally preferable to clearly mark the specified range and set it at a position more than 5 mm away from the outer edge when viewed along the main shrinkage direction. The reason is that during heat shrinking, the measurement error based on the distance change within a specified range can be effectively prevented from increasing due to the curling of the heat shrink film. Therefore, it is more preferable to clearly mark the specified interval and set it at a position within 8 to 300 mm from the end of the main contraction direction, and even more preferable to clearly mark it and set it at a position within 10 to 200 mm from the end of the main contraction direction.

[0041] The heat shrink film preferably has clearly marked graduations indicating the position and length of a specified interval, which is a component that enables the measurement of distance changes within the specified interval. The reason is that by more accurately capturing distance changes (PL1-PL2) within a specified range using motion capture devices, heat shrink films with adjusted heat shrink speeds can be produced with greater precision.

[0042] Furthermore, since the graduations on the heat shrink film are easily identifiable by optical cameras, it is preferable that they be formed from printed materials made of oil-based ink coatings, carbon black coatings, inkjet printer coatings, laser printer coatings, ultraviolet luminescent coatings, or other special coatings. Furthermore, as other components, as long as the distance change can be measured, the scale is preferably formed by a cut, laser marking, or the like. The reason is that by constructing the scale in the above manner, the position of each specified interval can be captured more easily and accurately by a motion capture device or the like, and deviations in the heat shrinking speed can be suppressed throughout the heat shrink film. This is because, for example, by marking the scale using methods such as inkjet printing, the shrinkage rate of the heat shrink film can be measured in-line during the manufacturing process, allowing for quality control during manufacturing.

[0043] In addition, the specified intervals are preferably clearly marked along the main contraction direction and set in multiple locations. The reason is that by setting the above configuration, the heat shrinkage rate of each specified interval of the heat shrink film can be calculated, and a heat shrink film with a better precision adjustment of the heat shrinkage rate throughout the entire heat shrink film can be produced. Therefore, when the number of specified intervals is set to n, it is preferable to set the distances of the specified intervals at specified time t2 to PL11~PL1n, and the distances of the specified intervals at specified time t3 to PL21~PL2n for measurement. Furthermore, regarding the number n of the specified interval, it is preferable to set 2 to 100 positions, more preferably 3 to 30 positions, and even more preferably 5 to 20 positions.

[0044] Furthermore, when the specified intervals are set in multiple locations, it is preferable to continuously configure the specified intervals along the main contraction direction without interruption. The reason is that by configuring it in the above manner, the heat shrink film can be divided without bias, and deviations in the heat shrinkage rate of each specified interval can be suppressed. Therefore, it is preferable to set the distance of the specified interval to be equal. On the other hand, from the perspective of measuring the overall deviation of the heat shrink film, it is also preferable to configure the specified intervals discontinuously.

[0045] (2) Correlation Furthermore, for heat-shrinkable films, it is assumed that the distance change (PL0-PL1) of a specified interval during the measurement period from the start of heat shrinkage time t0 to a specified time t2 is proportional to time (e.g., less than 5 seconds), and the heat shrinkage rate is calculated in the form of the heat shrinkage rate during the measurement period.

[0046] (3) Thermal shrinkage rate Furthermore, the heat shrink film is characterized by a maximum heat shrinkage rate V1 calculated using equation (1) of 3 mm / s or more. The reason is that by setting the heat shrinkage speed to its maximum value, the balance between the amount of change and time when the heat shrink film undergoes its maximum change can be adjusted with good precision, which can effectively prevent wrinkles from occurring when the heat shrink film is used on the object. Therefore, it is more preferable to set the maximum value of the heat shrinkage rate to 3.5 mm / second or more, and even more preferably to set it to 4 mm / second or more.

[0047] Here, refer to Figure 4 The relationship between time (seconds) and the change in distance (mm) within a specified interval is explained. That is, for Examples 1-2 and Comparative Examples 1-2 described later, time (seconds) was set as the horizontal axis, and the maximum value of the distance change (mm) in a specified interval set at 6 positions at a distance of 10mm along the main contraction direction was set as the vertical axis. The measurements were taken at intervals of 0.1 seconds and a graph was generated. As can be seen from the chart, Example 1 and Example 2 both increased in the same way during the time period of 0 to 2 seconds, and then continued to increase slowly thereafter. Furthermore, it can be seen that in Comparative Example 1, there is a portion of the distance change that decreases within a specified interval during the time period of 0 to 1 second. On the other hand, it can be seen that the distance change in the specified interval of Comparative Example 2 increases slowly in the time period of 0 to 1 second, rises sharply in the time period of 1 to 2 seconds, and then decreases slightly. Furthermore, it can be seen that in Comparative Example 2, the time point at which the self-heating shrinkage begins after 1 second is approximately 1 / 3 to 1 / 2 of the other relationship curves.

[0048] In addition, refer to Figure 5 (a)~(c) and Figure 6 Sections (a) to (c) explain the relationship between time (seconds) and heat shrinkage rate (mm / second) and heat shrinkage percentage (% / second). Specifically, for Examples 1-2 and Comparative Examples 1-2 described later, time (seconds) was set as the horizontal axis, and the heat shrinkage speed of the interval with the smallest maximum value of heat shrinkage speed (mm / second) in the specified intervals set at 10mm intervals along the main shrinkage direction in 6 positions was set as the vertical axis, and a graph was made at 0.1-second intervals. According to this Figure 5 As can be seen from (a) to (b), the heat shrinkage rate of Examples 1 and 2 increases relatively steadily shortly after the start of heat shrinkage, and exceeds 3 mm / s after 1 second, and decreases to below 3 mm / s within a period of 1 to 2 seconds. On the other hand, according to Figure 6 As can be seen from (a) to (b), the heat shrinkage rate of Comparative Example 1 and Comparative Example 2 did not increase much shortly after the start of heat shrinkage, and even after 1 second from the start of heat shrinkage, it did not exceed 3 mm / s. In addition, in Figure 5 (c) and Figure 6 In case (c), a heat shrinkage rate of 1 mm / s is equivalent to a heat shrinkage rate of 10% / s.

[0049] (4) Thermal shrinkage rate In addition, preferred will be as follows Figure 2 The maximum value of the heat shrinkage rate V2 of the heat shrink film shown in (a) based on the following formula (2) is set to 30% / second or more.

[0050] [Mathematical Expression 5] The rate of thermal shrinkage, V2 (% / second), is calculated as follows: (PL0 - PL1) / (PL0 × t2) × 100 (2)

[0051] The reason is that by setting the heat shrinkage rate to the above-mentioned speed, the balance between the amount of change and time when the heat shrink film undergoes maximum change can be adjusted with good precision, which can effectively prevent wrinkles from occurring when the heat shrink film is used on the object. Furthermore, the reason is that by measuring the change in the heat shrinkage rate, the heat shrink film can be evaluated without relying on the distance of a specified range. Therefore, it is more preferable to set the maximum value of the heat shrinkage rate to 3.5% / second or more, and even more preferably to set it to 4% / second or more.

[0052] (5) Thermal shrinkage conditions Furthermore, for heat shrink film, it is preferable to set the specified time t1 to be greater than 5 seconds. The reason is that by setting the time as specified above, the heat shrink film can be fully shrunk when the heat shrinkage rate is measured during heat shrinkage. Therefore, it is more preferable to set the specified time t1 to 10 seconds or more, and even more preferable to set it to 20 seconds or more. On the other hand, from the perspective of preventing defects caused by overheating of the heat shrink film, it is preferable to set the specified time t1 to 180 seconds or less, more preferably to 120 seconds or less, and even more preferably to 60 seconds or less.

[0053] Furthermore, for heat shrink film, it is preferable to set the specified time t2 to within 5 seconds. The reason is that by setting the heat shrinkage period as described above, the position of the specified interval after a specified time elapsed from the start of heat shrinkage can be accurately measured before the heat shrinkage ends completely, and a heat shrink film with a heat shrinkage speed adjusted with better precision can be produced. Therefore, it is more preferable to set the specified time t2 to within 4 seconds, and even more preferably to within 3 seconds.

[0054] Furthermore, for heat-shrinkable films, it is preferable to set the specified temperature T, which is the heat-shrinking temperature, to a value within the range of 70 to 98°C. The reason is that by setting the heat shrink temperature as described above, the heat shrink film can be made more stable during shrinkage, and the heat shrinkage rate can be measured with better accuracy. Therefore, it is more preferable to set the specified temperature T to 78~95°C, and even more preferably to set it to 80~90°C.

[0055] (6) Measuring fixture Furthermore, when heat shrinking the heat shrink film, it is preferable to use a measuring fixture that does not hinder the shrinkage of the heat shrink film and maintains the posture of the heat shrink film. That is, preferably, the heat shrink film is placed on a measuring fixture made of a frame member, and the heat shrink film is heat-shrinked along the main shrink direction while being pressed by a limiting part arranged in a direction perpendicular to the main shrink direction. More specifically, preferred options include Figure 8 As exemplified in (a) to (c), the measuring fixture 13 is composed of a frame member and has at least a mounting portion 13a for mounting and holding the heat shrink film, a guide portion 13b for controlling the shrinkage direction of the heat shrink film, and a limiting portion 13c for preventing deviation during heat shrinkage. Furthermore, from the perspective of further improving operability, the measuring clamp 13 preferably has at least a handle portion 13d that is disposed at the end of the main contraction direction of the mounting portion 13a and protrudes obliquely upward. Specifically, the measuring fixture is preferably made of metal wires such as stainless steel, iron, aluminum, and copper, or frame components such as resin. The reason is that by constructing it in the above manner, the heat shrink film can be stably placed, and at the same time, the shaking during heat shrinking can be reduced, and the heat shrinking speed can be measured with better accuracy.

[0056] Furthermore, from the perspective of ease of operation and uniform heating of the heat shrink film, the mounting portion is preferably a frame-like part that is actually flat, and preferably a part with at least two track-like sections parallel to the main shrinkage direction when viewed from a vertical top. Furthermore, the guide portion is preferably arranged parallel to the mounting portion when viewed from a vertically upward position, and is wavy in the vertical direction. In addition, the limiting part is a portion that is arranged to bridge the guide part in a direction perpendicular to the main shrinkage direction and is provided in a way that can be installed upward and downward along the frame of the guide part. It is a portion in which the heat shrink film placed on the mounting part is clamped by the mounting part and the limiting part. The reason is that by constructing it in the above manner, the position of the heat-shrink film can be prevented from shifting during heat shrinkage, and the center position of shrinkage can be stabilized at the same time, so that the heat shrinkage speed can be measured with good accuracy by a motion capture device. Furthermore, the reason is that by making the guide part wavy, for example, when using a warm water tank as a heat shrinking device during heat shrinking, it can fall onto the water surface without producing ripples. By making the height of the guide part consistent with the water level, it is possible to measure at the bottom of the water tank.

[0057] (7) Determine the sample Furthermore, regarding the determination of the heat shrink film, it is preferable to measure a sample obtained in the following manner: a portion of the heat shrink film, which is cut into strips (rectangles) or squares in the main shrinkage direction, from the heat shrink film formed into sheets or rolls. As an example, such as Figure 3 As shown in (a), it is preferable to prepare measurement samples 11 of the same size, which are cut from three positions (W, C, E) along the main shrinkage direction. Furthermore, when preparing multiple samples in the manner described above, it is preferable to set a predetermined scale at at least the same position on each of the measured samples. Furthermore, as the size of the sample to be measured, it is preferable to set the width orthogonal to the main contraction direction to a value in the range of 20 to 150 mm, more preferably to a value in the range of 30 to 120 mm, and even more preferably to a value in the range of 40 to 100 mm. Furthermore, as the size of the sample to be measured, it is preferable to set the length along the main contraction direction to a value in the range of 100 to 300 mm, more preferably to a value in the range of 110 to 250 mm, and even more preferably to a value in the range of 120 to 200 mm.

[0058] (8) Heat shrink device Furthermore, the heat shrinking device of the present invention is not particularly limited, but is preferably at least one of a constant temperature bath (oven), a steam bath, a warm water bath, a hot air heater, a liquid bath containing fluorine compounds, a steam bath containing fluorine compounds, and an infrared irradiation device. The reason is that when using a motion capture device, the various heat shrinking devices mentioned above can be used depending on the application of the heat shrink film, and the heat shrinkage rate can be measured more easily and with good accuracy.

[0059] Furthermore, as an example, it is preferable to use a warm water bath as the heat shrinking device. The reason is that by using the heat shrinking device described above, it is easy to keep the temperature of the warm water constant, and the heat shrinking temperature can be controlled more precisely. Furthermore, the reason is that by setting it as a warm water tank, the heat shrink film can float and be heated evenly on a flat surface, and the behavior of the heat shrink film during heat shrinkage can be captured more easily from above using optical cameras or the like.

[0060] Specifically, preferred options include Figure 7 As shown in (a) to (c), a warm water bath 20 is prepared, for example, containing hot water 22 maintained at a specified temperature by a heater 22a. The hot water is immersed in the warm water under the conditions of heat shrinking temperature: 70~98°C and shrinking time: 1~60 seconds, so that the heat shrink film is heat-shrinked along the main shrinking direction. At this point, the preferred option is, for example, Figure 7 As shown in (a), a frame-shaped measuring fixture 13 with a handle portion 13d is used in a manner in which heat-shrinkable film is uniformly impregnated and heated. In addition, preferred options include Figure 7 As shown in (b), a measuring fixture 12 made of stainless steel wire or the like is prepared, and a heat shrink film 10 is housed in a portion of its interior.

[0061] Furthermore, as another example, it is preferable to configure the heat shrink device as a hot air heater. That is, as a hot air heater, it is preferable to use a device that blows air supplied by a compressed air pump or fan to the object via a heat source such as an electric heating wire or an oil heater. Specifically, for example, the heat shrinking device is preferably configured to heat shrink the heat shrinking film by blowing hot air from above the heat shrinking film onto the heat shrinking film which is placed flat on a conveyor belt or a platform. The reason is that by using the above-mentioned heat shrinking device, the device has greater freedom of placement. It can be placed above the heat shrink film manufacturing device and hot air can be blown onto the cut-off ends, making it easier to measure the heat shrinking speed online. Therefore, when using a hot air heater in the manner described above, from the perspective of effectively transferring the heat of the hot air to the heat shrink film, it is preferable to configure the heat shrink film to receive the hot air within a tunnel-shaped housing made of stainless steel, aluminum, glass, or the like.

[0062] (9) Motion capture device Furthermore, the distance variation of the specified interval on the heat-shrinkable film is preferably calculated, for example, based on the distance information of the specified interval obtained using a motion capture device. Here, motion capture is a technology that converts the movements of a target into digital data. It mainly tracks the position of a specified marker on the target and records it as coordinate data. The reason is that by using such a motion capture device, the distance of the measurement area on the membrane can be obtained quickly and with good accuracy in the form of digital data.

[0063] Specifically, there is no particular limitation on the type of motion capture device, but image-based motion capture devices, inertial motion capture devices, optical motion capture devices, or combinations thereof are preferred. However, in the case of heat-shrinkable film, since it is heated by immersion in warm water or the like, it is more preferable to use an image-based motion capture device because it is easier to make into a miniaturized or simplified device under conditions with more space constraints.

[0064] Furthermore, when using a single motion capture device, the heat shrinkage rate can be measured and calculated based on a two-dimensional specified range. However, when using multiple motion capture devices, there is an advantage in being able to measure the positional relationship of a three-dimensional specified range and calculate the heat shrinkage rate based on that positional relationship. For example, when a flat heating plate is used as a heat shrinking device, the heat shrinkage rate can be easily and quickly measured in three dimensions, even when it is tilted not only in the horizontal direction but also in the direction of gravity, or when it is arranged in a vertical direction in a manner parallel to the direction of gravity. Therefore, when using a single or multiple motion capture devices, various heat shrinkage devices can be used, thus enabling more rapid and easier determination of the heat shrinkage rate with good accuracy, depending on the application of the heat shrink film.

[0065] Furthermore, as an example of the distance within a specified interval in this invention, it is preferable to calculate the distance change within the specified interval based on the distance information of the specified interval obtained using an image-based motion capture device. That is, preferred as Figure 7 As shown in (a), an optical camera 14a is used in an image-based motion capture device to capture an animation of the heat shrink film 10, which is the object being measured, during heat shrinkage, and the acquired data is analyzed to determine the position of a specified interval. The reason is that an image-based motion capture device, which is a simple and highly accurate optical measuring instrument, can be used to continuously monitor the distance change of the heat shrink film within a specified range in the very short time before the heat shrink ends, and the heat shrink speed can be measured and controlled. Therefore, it is preferable to have a configuration in which a predetermined range is pre-marked on the heat shrink film using a pre-defined oil-based coating or similar material. Furthermore, it is preferable to place the heat-shrinkable film on a flat surface and use an optical camera to capture an animation before and after a specified time from a vertical position.

[0066] That is, when using an image-based motion capture device, it is preferable to include the following steps: using a measuring device such as an optical camera to capture an image or animation of a plane containing a heat-shrinkable film within a specified time, and recording it on a recording medium such as an HDD (hard disk drive) or SSD (solid-state drive). Next, an image analysis is preferably performed on the image recorded on the recording medium using a computing processing device (PC, etc.) to convert the position of the specified range into coordinates. At this point, the coordinates are not specifically limited, but it is preferable to set them to rectangular coordinates, polar coordinates, etc. The reason is that by converting to coordinates in the above manner, the position of the specified range can be obtained quickly and with good accuracy.

[0067] Furthermore, optical motion capture devices are preferred as motion capture devices. That is, preferably, it is an optical position measuring device in which a motion capture device irradiates an optical marker (reflective marker, etc.) with infrared or other radiation and detects the reflected light. Furthermore, this motion capture device is a measuring device that can determine the position (center of gravity, etc.) of a marker in two dimensions by performing prescribed image processing based on the obtained reflected light, and can determine the three-dimensional position by using multiple motion capture devices simultaneously.

[0068] On the other hand, the motion capture device is preferably configured as an inertial position measuring device that can acquire information on acceleration, angular velocity, and orientation from an inertial sensor such as an IMU installed on the heat-shrink film, and can accurately determine the position (center of gravity, etc.) of the marker based on the acquired information. That is, preferably, an inertial motion capture device consisting of a combination of an accelerometer and an angular velocity meter (gyroscope sensor) and a 9-axis inertial sensor consisting of an accelerometer, an angular velocity meter and a magnetometer.

[0069] 3. Other characteristics (1) Thermal shrinkage rate When a specified range is set along the main shrinkage direction of the heat shrink film, and the heat shrink film is heat-shrinked along the main shrinkage direction at a specified temperature T and a specified time t1, the heat shrinkage rate is calculated based on the change in distance between the specified range before heat shrinkage PL0 and the specified range at the specified time t1, and based on the following formula (3). Under specified conditions (specified temperature T: 70~98℃, specified time t1: 60 seconds or more), it is usually preferably set to a value of 30% or more and less than 95%. In addition, when the heat shrink film is extended in the opposite direction to the main shrinkage direction under specified conditions including shrinkage temperature and shrinkage time, the heat shrinkage rate is recorded as a negative value. [Mathematical Expression 6] Thermal shrinkage rate (%) in the main shrinkage direction = (PL0 - PLN) / PL0 × 100 (3)

[0070] The reason is that by setting the heat shrinkage rate as described above, a good heat shrinkage rate can be obtained in the heat shrink film during heat shrinkage, and it is also easy to obtain the maximum shrinkage stress. Therefore, it is more preferable to set the heat shrinkage rate to a value in the range of 40% or more and less than 90%, and even more preferably to set it to a value in the range of 50% or more and less than 85%.

[0071] (2) Standard deviation of the maximum heat shrinkage rate Furthermore, for heat shrink film, when multiple specified intervals are set, and the heat shrinkage rate from the start of heat shrinkage to the specified time t1 is calculated for each specified interval every 0.1 seconds, it is preferable to set the standard deviation of the maximum value of the heat shrinkage rate of each specified interval to less than 3.5 mm / s. The reason is that by setting the standard deviation as described above, the shrinkage ratio at each time point during heat shrinkage can be adjusted with good accuracy, resulting in more stable behavior during heat shrinkage. Therefore, it is more preferable to set the standard deviation of the maximum value of the heat shrinkage rate to less than 1 mm / s, and even more preferably to set it to less than 0.3 mm / s. In addition, the standard deviation is the square root of the sum of the squares of the deviations divided by the number of data points minus 1.

[0072] (3) Heat shrinkage rate during the specified period (intermediate heat shrinkage rate V3) In addition, such as Figure 2 As shown in (b), for a heat shrinkable film, a specified interval is set along the main shrinkage direction of the heat shrinkable film in a state that can shrink in at least one of the long side direction or the width direction, and when heat shrinking is performed at a specified temperature T and a specified time t1, the heat shrinkage speed (hereinafter, sometimes referred to as the intermediate heat shrinkage speed V3) of the main shrinkage direction during the specified period is preferably set to 20 mm / second or less, based on the distance variation between the specified interval before heat shrinkage PL0, the specified interval at a specified time t2 which is shorter than the specified time t1, and the specified interval at a specified time t3 which is shorter than the specified time t1 and longer than the specified time t2.

[0073] [Mathematical Expression 7] Intermediate heat shrinkage rate V3 (mm / s) = (PL1-PL2) / (t3-t2) (4) PL1-PL2: Distance variation (mm) within the specified interval t3-t2: Measurement period (seconds)

[0074] The reason is that by setting the aforementioned intermediate heat shrinkage speed V3, a predetermined correlation can be established between the distance change of the heat shrink film within a specified range during heat shrinkage and the position information obtained using a motion capture device. Furthermore, the heat shrinkage speed of the heat shrink film can be adjusted to a value within a specified range, and excellent heat shrinkability can be stably maintained. Therefore, it is more preferable to set the heat shrinkage rate during the measurement period to 18 mm / second or less, and even more preferably to 15 mm / second or less. In addition, the intermediate heat shrinkage rate V3 is positive when the heat shrinkage film shrinks in the direction of shrinkage, and negative when the heat shrinkage film stretches due to the reaction of shrinkage or when the film undergoes three-dimensional deformation due to rapid heat shrinkage and then recovers to a planar shape.

[0075] Furthermore, for heat-shrinkable films, it is preferable to set the measurement period t3-t2 to a value within 3 seconds. The reason is that by setting the measurement period as described above, the behavior during heat shrinkage can be measured with better accuracy. Therefore, it is more preferable to set the measurement period t3-t2 to a value of less than 2 seconds, and even more preferably to a value of less than 1 second. On the other hand, from the perspective of preventing measurement errors from increasing due to excessively increasing time resolution, it is preferable to set the measurement period t3-t2 to a value of 0.1 seconds or more.

[0076] Furthermore, it is preferred that the intermediate heat shrinkage rate V3 is always positive during heat shrinkage, but it is known that even when it is negative, there is no problem with the intended use of the heat shrink film when its value is small. Therefore, it is preferable to suppress the minimum value of the intermediate heat shrinkage rate V3 of the heat shrink film during the specified period to be above -2.5 mm / s. This is because by suppressing the behavior of the intermediate heat shrinkage rate V3 of the heat shrink film to become negative in the manner described above, wrinkles and other issues can be prevented more effectively when it is used as a heat shrink film. Therefore, it is more preferable to set the minimum value of the intermediate heat shrinkage rate V3 to -1.5 mm / s or more, and even more preferably to set it to 0 mm / s or more.

[0077] Here, refer to Figures 9-12 The relationship between time (seconds) and intermediate heat shrinkage rate V3 (mm / second) is explained. Specifically, for Examples 1-2 and Comparative Examples 1-2 described later, time (seconds) was set as the horizontal axis, and the intermediate heat shrinkage speed V3 (mm / second) of the interval with the largest maximum value among the specified intervals set at 10mm intervals along the main shrinkage direction at 6 positions was set as the vertical axis, and a graph was made at 0.1-second intervals. According to this Figures 9-10 It can be seen that the intermediate heat shrinkage rate V3 in Examples 1 and 2 reaches its maximum value in the time period of 0 to 1 second, and decreases to about 0 mm / second after 1 second from the time point when heat shrinkage begins. On the other hand, according to Figure 11 It can be seen that although the intermediate heat shrinkage rate V3 of Comparative Example 1 reaches its maximum value in the time period of 0 to 1 second, it deviates significantly in the subsequent time period of 1 to 2 seconds, with 0 mm / s as the boundary. Furthermore, according to Figure 12 It can be seen that the intermediate heat shrinkage rate V3 of Comparative Example 2 is less than 5 mm / s in the time period of 0 to 1 second, and after about 1 second, the intermediate heat shrinkage rate V3 increases to more than 20 mm / s, and then decreases to less than 5 mm / s in the time period of 1.1 to 1.5 seconds. In addition, in Figure 9 (b)~ Figure 12 In case (b), a heat shrinkage rate of 1 mm / s is equivalent to a heat shrinkage rate of 10% / s.

[0078] (4) Standard deviation of the maximum value of intermediate heat shrinkage rate V3 Furthermore, for heat shrink film, when multiple specified intervals are set, and the heat shrinkage rate from the start of heat shrinkage to the specified time t1 is calculated for each specified interval every 0.1 seconds, it is preferable to set the standard deviation of the maximum value of the intermediate heat shrinkage rate V3 of each specified interval to be less than 4.5 mm / s. The reason is that by setting the standard deviation as described above, the shrinkage ratio within a specified time during heat shrinkage can be adjusted with good accuracy, resulting in more stable behavior during heat shrinkage. Therefore, it is more preferable to set the standard deviation of the maximum value of the intermediate heat shrinkage rate V3 to 3.5 mm / s or less, and even more preferably to set it to 3 mm / s or less. In addition, the standard deviation is the square root of the sum of the squares of the deviations divided by the number of data points minus 1.

[0079] (5) The rate of heat shrinkage during the specified period (intermediate rate of heat shrinkage V4) In addition, such as Figure 2As shown in (b), for heat-shrinkable film, when heat shrinking is performed at a specified temperature T and a specified time t1, the intermediate heat shrinkage rate speed V4 (hereinafter sometimes referred to as intermediate heat shrinkage rate speed V4) in the main shrinkage direction is preferably set to 200% / second or less, based on the distance changes between the specified interval before heat shrinkage PL0, the specified interval at a specified time t2 which is shorter than the specified time t1, and the specified interval at a specified time t3 which is shorter than the specified time t1 and longer than the specified time t2.

[0080] [Mathematical Expression 8] Intermediate heat shrinkage rate V4 (% / second) =(PL1-PL2) / (PL0×(t3-t2))×100 (5)

[0081] The reason is that by setting the intermediate heat shrinkage rate speed V4 as described above, the heat shrinkage speed of the heat shrink film can be adjusted with better precision without depending on the size of the heat shrink film. Therefore, it is more preferable to set the intermediate heat shrinkage rate V4 to 180% / second or less, and even more preferably to 150% / second or less.

[0082] On the other hand, from the perspective of preventing defects caused by excessive shrinkage in a short period of time, it is preferable to set the intermediate heat shrinkage rate V4 to 60% / second or more, more preferably 80% / second or more, and even more preferably 90% / second or more. In addition, similar to the intermediate heat shrinkage rate V3, it is preferred that the intermediate heat shrinkage rate V4 is always positive, but it is known that even when it is negative, there is no problem with the purpose of using the heat shrink film when its value is small.

[0083] Therefore, it is preferable to suppress the minimum value of the intermediate heat shrinkage rate of the heat shrink film to above -2.5% / second. This is because by suppressing the behavior of the intermediate heat shrinkage rate V4 of the heat shrink film to become negative in the manner described above, wrinkles and other issues can be prevented more effectively when it is used as a heat shrink film. Therefore, it is more preferable to set the minimum value of the intermediate heat shrinkage rate V4 to -1.5% / second, and even more preferably to set it to 0% / second or higher.

[0084] In addition, when calculating the rate of thermal shrinkage, it is preferable to set the specified times t2 and t3 to within 5 seconds. The reason is that by setting the specified time as described above, the behavior of the heat-shrinkable film during heat shrinkage can be measured in more detail. Therefore, it is more preferable to set the specified times t2 and t3 to within 4 seconds, and even more preferably to within 3 seconds.

[0085] In addition, it is preferable that the time for the intermediate heat shrinkage rate V3 to reach its maximum is less than 1 second. The reason is that by constructing it in the above manner, it is possible to control the timing of the significant shrinkage of the heat shrink film, and to adjust the heat shrinkage characteristics with better precision. Therefore, it is more preferable to set the time when the intermediate heat shrinkage rate V3 reaches its maximum to be less than 0.8 seconds, and even more preferably to be less than 0.6 seconds.

[0086] (6) Difference in thermal shrinkage rate per second Furthermore, for heat shrink film, when a specified interval is set along the main shrinkage direction of the heat shrink film, and heat shrinkage is performed along the main shrinkage direction at a specified temperature T and a specified time t1, the distance of the specified interval before heat shrinkage is set as PL0, the distance of the specified interval at a specified time t2 that is shorter than the specified time t1 is set as PL1, the distance of the specified interval at a specified time t3 that is shorter than the specified time t1 and longer than the specified time t2 is set as PL2, the measurement period t3-t2 is set as 1 second, and the difference in heat shrinkage rate per second calculated based on the following formula (6) is usually preferably set to less than 100% / second under specified conditions (specified temperature T: 70~98℃, specified time t1: greater than 5 seconds).

[0087] [Mathematical Expression 9] Difference in thermal shrinkage rate per second (% / second) =(PL0-PL1) / (PL0×t2)×100 -(PL0-PL2) / (PL0×t3)×100 (6)

[0088] The reason is that by setting the difference in heat shrinkage rate as described above, the heat shrink film can be shrunk more stably. Therefore, it is more preferable to set the difference in heat shrinkage rate rate to 80% / second or less, and even more preferably to set it to 50% / second or less.

[0089] (7) Thickness In addition, the thickness of the heat shrink film only needs to be such that it is not easy to break or be damaged during use, but it is usually preferred to be a value in the range of 10 to 200 μm. The reason is that if the thickness is as described above, it is less likely to cause thickness deviation in the whole membrane, and the shrinkage rate can be controlled more quickly and with good precision. Therefore, it is more preferable to set the thickness of the heat shrink film to a value in the range of 20 to 100 μm, and even more preferably to a value in the range of 30 to 60 μm.

[0090] Furthermore, when measuring the thickness of the heat-shrinkable film along the main shrinkage direction, it is preferable to set the difference between the maximum value and the average value of the thickness within 10 μm. The reason is that by controlling the deviation in the thickness of the heat shrink film, it is also easy to control the heat shrinkage rate in the main shrinkage direction, and the heat shrinkage rate in the main shrinkage direction can be controlled more quickly and with good precision. Therefore, when measuring the thickness of the heat-shrinkable film along the main shrinkage direction, it is more preferable to set the difference between the maximum value of the thickness and the average value of the thickness to a value in the range of 0.01 to 5 μm, and even more preferably to set it to a value in the range of 0.1 to 3 μm.

[0091] (8) Transparency In addition, when using a motion capture device to measure the heat shrinkage rate, the haze value of the heat shrink film can sometimes affect the image reading accuracy. That is, when measuring the heat shrinkage rate, it is preferable to adjust the film so that the haze value measured according to JIS K 7136:2000 is 7% or less. On the other hand, this is because if the haze value of the film before heat shrinkage becomes excessively small, it will be difficult to maintain stable control and the yield during production will be significantly reduced. Therefore, it is more preferable to adjust the haze value of the film before heat shrinking to a value in the range of 0.1% to 5%, and even more preferably to a value in the range of 0.5% to 3%.

[0092] (9) Mechanical strength Furthermore, for heat-shrinkable films, it is preferable to set the right-angle tear strength per unit thickness in the direction orthogonal to the main shrinkage direction to a value in the range of 180~350 N / mm after shrinking by 10% in warm water at 80°C along the main shrinkage direction. The reason is that by setting the tear strength as described above, it is possible to produce a heat shrink film that exhibits uniform heat shrinkage characteristics, is less prone to breakage, has good perforation and opening properties, and has superior shrinkage finishing properties. Therefore, it is more preferable to set the tear strength to a value in the range of 200~320N / mm, and even more preferably to set it to a value in the range of 230~300N / mm.

[0093] Furthermore, for heat-shrinkable films, it is preferable to set the tensile strength in the main shrinkage direction to a value in the range of 5 to 60 MPa. The reason is that by setting the tensile strength as described above, it is possible to produce a heat shrink film that exhibits uniform heat shrinkage characteristics, while also having higher stretchability and superior shrinkage finish even when used on objects with large concavities and convexities. Therefore, it is more preferable to set the tensile strength to a value in the range of 8 to 55 MPa, and even more preferably to set it to a value in the range of 10 to 50 MPa.

[0094] 4. Additives Preferably, various additives are incorporated into the heat shrink film of the first embodiment, or various additives are attached to one or both sides of the heat shrink film of the first embodiment. More specifically, generally, relative to the total amount of heat shrink film, at least one of the following is preferably incorporated in the range of 0.01 to 10% by weight, more preferably in the range of 0.1 to 1% by weight: anti-hydrolysis agent, antistatic agent, ultraviolet absorber, infrared absorber, colorant, organic filler, inorganic filler, organic fiber, inorganic fiber, etc.

[0095] 5. Layer Composition In addition, such as Figure 1 As shown in (b), it is also preferable to laminate other resin layers 10a, 10b containing at least one of the above-mentioned additives onto one or both sides of the heat shrink film 10. At this point, when the thickness of the heat shrink film is set to 100%, it is generally preferable to set the single-layer thickness or total thickness of the additional resin layers to a value in the range of 0.1% to 10%. Furthermore, the resin that forms the main component of the other resin layers can be the same polyester resin as the heat shrink film, or preferably at least one of acrylic resin, olefin resin, polyurethane resin, rubber resin, etc., which are different from the heat shrink film.

[0096] Furthermore, it is also preferable to fabricate the heat shrink film into a multi-layered structure to further enhance its hydrolysis resistance and mechanical protection, or as... Figure 1 As shown in (c), a shrinkage adjustment layer 10c is provided on the surface of the heat shrink film 10 to make the shrinkage rate of the heat shrink film uniform in the plane. This shrinkage adjustment layer can be laminated according to the shrinkage characteristics of the heat shrink film through adhesives, coating methods, or heat treatment.

[0097] More specifically, the thickness of the shrinkage adjustment layer is in the range of 0.1~3μm. When the shrinkage rate of the heat shrinkage film at a specified temperature is too large, it is preferable to laminate a shrinkage adjustment layer of the type that suppresses it. Furthermore, when the shrinkage rate of the heat-shrinkable film at a specified temperature is too low, it is preferable to laminate a shrinkage rate adjustment layer of the type that increases its shrinkage rate. Therefore, heat shrink film is not produced by creating various heat shrink films with different shrinkage rates, but rather by using a shrinkage rate adjustment layer to obtain a film with the desired shrinkage rate.

[0098] [Second Implementation Plan] The second embodiment is a method for manufacturing a heat shrink film, which is a method for manufacturing a heat shrink film with the long side direction or the width direction as the main shrinkage direction, characterized by comprising the following steps (1) to (3): (1) The process of preparing raw material resin; (2) A process of forming a resin film from molten raw material resin and stretching it to produce a heat shrink film with the long side or width direction as the main shrinkage direction. (3) When heat shrinking is performed at a specified temperature T and a specified time t1, a heat shrinking speed adjustment process is set at the maximum value of the heat shrinking speed V1 calculated based on the distance PL0 of the specified interval before heat shrinking and the distance PL1 of the specified interval at a specified time t2 which is shorter than the specified time t1, based on the distance change between the specified interval before heat shrinking and the specified interval at a specified time t2 which is shorter than the specified time t1. The process is set at 3 mm / s or more.

[0099] [Mathematical Expression 10] Heat shrinkage rate V1 (mm / s) = (PL0 - PL1) / t2 (1) PL0-PL1: Distance variation (mm) within the specified interval t2: Specified time (seconds)

[0100] 1. Process (1) First, process (1) is the process of preparing the main agent and additives of the heat shrink film as raw materials. That is, the resin shown in the first embodiment can be used appropriately. For example, as the main agent, at least one resin selected from the group consisting of polyester resins, polystyrene resins, polyolefin resins and polyvinyl chloride resins is preferred. Furthermore, step (1) includes: weighing and adding the raw material resin, etc., which is the main agent to the mixer, and mixing and stirring it until uniform using a stirring device.

[0101] 2. Process (2) Next, step (2) is to form a resin film from the molten raw material resin and stretch it to produce a heat shrink film with the long side or width direction as the main shrinkage direction. That is, it is preferable to dry the uniformly mixed raw material resin to a completely dry state. Furthermore, typically, extrusion molding is preferred to produce raw material sheets of a specified thickness. More specifically, for example, extrusion molding can be performed using an extruder (manufactured by TANABE PLASTICS MACHINERY CO.,LTD.) with an L / D of 24 and an extrusion screw diameter of 50 mm at an extrusion temperature of 260°C, thereby obtaining raw material sheets of a specified thickness (typically 10~100μm).

[0102] Next, for the obtained raw material sheet, a heat shrink film manufacturing device is preferably used to move it on or between rollers while heating and extruding it, thereby producing a heat shrink film. That is, preferably, the film width is substantially increased by using a specified stretching temperature and stretching ratio, while heating and extrusion are performed and stretching is carried out in a specified direction, thereby enabling the raw material resin constituting the heat shrink film to crystallize into a specified shape. In addition, it is preferable to measure the haze, glass transition temperature, or various thermal properties of the heat-shrinkable film in advance at this stage.

[0103] 3. Process (3) (1) Basic procedures Next, step (3) is to measure the heat shrinkage rate V1 at a specified time t2 calculated based on equation (1), and to make adjustments when the heat shrinkage rate is outside the specified range. That is, the present invention preferably includes the steps described below in step (3).

[0104] (2) Process (a) As step (a), the present invention preferably includes a step of setting at least one predetermined interval M in the heat-shrinkable film before heat shrinking. That is, it is preferred to basically set the configuration of the specified interval as described in the first embodiment. For example, as the specified interval, it is preferred to record specified marks such as dots, lines, cross marks, circular marks, arrows, L-shaped marks, T-shaped marks, and check marks on the heat shrink film. The reason is that by setting it to the above configuration, it is easy to identify the situation where the heat shrink film shrinks from its surroundings.

[0105] In addition, in order to measure the distance change within a specified interval, it is preferable to clearly mark the scale indicating the specified interval and length. The reason is that by more accurately capturing the distance change (PL0-PL1) within a specified range using motion capture devices in the subsequent processes, heat shrink film with a heat shrinking speed that is adjusted with better precision can be produced.

[0106] Furthermore, since the graduations are easily identifiable by optical cameras, they are preferably formed by printing with oil-based inks, carbon black coatings, inkjet printer coatings, laser printer coatings, ultraviolet luminescent coatings, or other special coatings. Furthermore, as other components, the scale is preferably formed by engraving such as cutting or laser marking. The reason is that by constructing the scale in the above manner, the position of each specified interval can be captured more easily and accurately using motion capture devices, and deviations in the heat shrinking speed can be suppressed throughout the heat shrink film.

[0107] (3) Process (b) Next, as step (b), the present invention preferably includes a step of determining the position of a predetermined interval before heat shrinking using a motion capture device. That is, preferably, virtual coordinates are set in the plane containing the heat shrink film, and the coordinates of the position of the specified interval before heat shrinking are determined and set as PL1. The reason is that by constructing it in the above manner, the position can be calculated effectively, and the thermal shrinkage rate can be measured quickly and with good accuracy.

[0108] Furthermore, the preferred specified interval has a configuration that is substantially the same as that of the first embodiment, and is preferably located at multiple positions along the main contraction direction. The reason is that by setting the above configuration, the heat shrinkage rate of each specified interval of the heat shrink film can be precisely calculated, and a heat shrink film with a better precision adjustment of the heat shrinkage rate throughout the entire heat shrink film can be produced. Therefore, the specified interval is preferably set at 2 to 100 positions, more preferably at 3 to 30 positions, and even more preferably at 5 to 20 positions.

[0109] In addition, preferred options include Figure 7 As shown in (b) to (c), the specified inertial motion capture device 14 and the specified optical cameras 14a and 14b are used simultaneously to capture the heat shrinkage state of the heat shrink film 10, convert it into image data, thereby measuring the heat shrinkage rate and using it as a reference. The reason is that, by simultaneously using an optical camera and an inertial sensor and continuously recording the thermal contraction state as described above, the reliability of the thermal contraction state and images in the main contraction direction can be confirmed. Furthermore, the thermal contraction rate in the main contraction direction can be measured more effectively and with better accuracy. More specifically, it is preferable to prepare one or more optical cameras to capture image data of the heat shrinkage state of the heat shrink film from the front, side, top, back, or oblique direction of the heat shrink film as the object being measured.

[0110] (4) Process (c) Next, the present invention preferably includes in step (3) a step of using a heat shrinking device, setting heat shrinking conditions, and heating the heat shrink film of the test object to a specified temperature and a specified time, thereby heat shrinking it, as step (c). Here, the heat shrinking device can be basically the same as the heat shrinking device described in the first embodiment, preferably at least one of a constant temperature bath (oven), a steam bath, a warm water bath, a hot air heater, a liquid bath containing fluorine compounds, a steam bath containing fluorine compounds, and an infrared irradiation device. The reason is that when using a motion capture device, the various heat shrinking devices mentioned above can be used depending on the purpose of the heat shrink film, and the heat shrinking speed can be measured more easily and with good accuracy.

[0111] Furthermore, the heat shrinking device described in the first embodiment can be used as a heat shrinking film heat shrinking device. Specifically, preferred options include Figure 3 As shown in (a) to (c), a warm water bath 20 is prepared, for example, containing hot water 22 maintained at a specified temperature by a heater 22a. The heat shrink film is immersed in the warm water under the conditions of heat shrinking temperature of 70 to 98°C and shrinking time of 10 seconds or more, so that the heat shrink film is heat-shrinked. At this time, it is preferable to prepare a measuring fixture, such as one made of stainless steel wire, by uniformly impregnating and heating the heat shrink film, and then place the heat shrink film on the measuring fixture.

[0112] More specifically, from the perspective of using optical cameras or the like for stable shooting, it is preferable to float the heat-shrinkable film in warm water in a warm water tank, which is one of the heat-shrinkable devices, so that it can be heat-shrinked. That is, preferably, the heat shrink film is supported in a way that makes the water surface of the warm water tank horizontal, and the heat shrink film is in contact with the water surface of the warm water tank while maintaining this horizontal state.

[0113] In addition, preferably, at least two wires are installed at both ends of the heat shrink film by means of further uniformly impregnating the heat shrink film and heating it for a specified time. That is, it is preferably configured such that the filaments or the like of the aforementioned linear material are further connected to a lifting mechanism, which winds or unwinds the linear material so that the heat shrink film can be moved up and down at a constant speed while maintaining the horizontal direction of the heat shrink film.

[0114] Furthermore, when using the measuring fixture, it is preferable to place the heat shrink film on the horizontal track-like frame of the measuring fixture, while using a limiting member that is arranged to span the horizontal track-like frame to clamp the heat shrink film. The reason is that it can effectively prevent the heat shrink film from moving during heat shrinking.

[0115] (5) Process (d) As step (d), the present invention preferably includes the step of measuring the distance PL1 of a specified interval at a specified time t2 using a motion capture device. That is, it is preferable to use a motion capture device to measure the coordinate values ​​of the two ends of the specified interval, and calculate PL1 based on the coordinate values.

[0116] (6) Process (e) As step (e), the present invention preferably includes the following steps: calculating the distance change PL0-PL1 of a specified interval based on the measured PL0 and PL1, and adjusting the heat shrinkage speed V1 calculated based on formula (1) to 3 mm / second or more.

[0117] (7) Adjusting the process Furthermore, as a prescribed adjustment process, the present invention preferably includes a process of adjusting the standard deviation of the heat shrinkage speed (temperature: 70~98°C, time: 0.1~5 seconds).

[0118] Furthermore, it was clarified that the heat shrinkage rate measured using a motion capture device can sometimes be affected by the thickness of the heat shrink film. That is, it is preferable to set the thickness of the heat shrink film in the range of 10~200μm, and at the same time adjust the difference between the maximum value of the thickness and the average value of the thickness (hereinafter, sometimes referred to as the thickness deviation) to a value within 10μm. The reason is that by controlling the thickness of the heat-shrinkable film and its thickness deviation, it is also easy to control the heat shrinkage speed in the main shrinkage direction, and the heat shrinkage rate in the main shrinkage direction can be controlled more quickly and with good precision. However, if the thickness deviation becomes excessively small, the yield rate during manufacturing becomes extremely low, which may result in economic losses. Therefore, it is more preferable to adjust the thickness deviation to a value in the range of 0.01 to 5 μm, and even more preferably to a value in the range of 0.1 to 3 μm.

[0119] (8) Other processes In addition, as other steps, the present invention preferably includes: using a motion capture device to calculate the heat shrinkage rate, the standard deviation of the heat shrinkage speed, the intermediate heat shrinkage speed V3, the intermediate heat shrinkage rate speed V4, the difference between the heat shrinkage rate speeds per second, etc., as other heat shrinkage characteristics in the first embodiment. Furthermore, it is preferable to include a process of adjusting each measured value to a specified range.

[0120] Furthermore, the present invention preferably includes a prescribed inspection process that measures the following characteristics, etc., continuously or intermittently. That is, by measuring the following characteristics through a prescribed inspection process and confirming that the values ​​fall within a prescribed range, it is possible to produce a heat shrink film with more uniform shrinkage characteristics. 1) Visually inspect the appearance of the heat shrink film. 2) Deviation in thickness measurement 3) Determine the tensile modulus of elasticity 4) Determine tear strength 5) Determining viscoelastic properties based on SS curves 6) Thermal properties (TD direction, MD direction) 7) Thermal shrinkage stress 8) Stretch ratio

[0121] [Third Implementation Plan] The third embodiment is a method for determining the heat shrinkage rate of a heat shrink film, characterized by comprising the following steps (1) to (3): (1) A preparation process for heat shrink film in which the main shrinkage direction of the heat shrink film is clearly marked and a specified range is set along the state that the heat shrink film can shrink along at least one of the long side direction or the width direction; (2) Heating the heat shrink film under specified temperature T and specified time t1, so that the heat shrink film is heated in such a way that the maximum value of the heat shrinkage speed V1 calculated based on the above formula (1) is 3 mm / second or more, and performing a heat shrinkage process; (3) The process of estimating the heat shrinkage rate of the heat shrinkage film based on the characteristic curve showing the relationship between the heat shrinkage rate and the heat shrinkage rate of the heat shrinkage film, which is prepared in advance based on the heat shrinkage rate V1. The method for determining the heat shrinkage rate of the heat shrink film in the third embodiment will be specifically explained below, without repeating the content described in the first and second embodiments.

[0122] 1. Heat shrink film and its preparation process (Process 1) Step 1 is the specified heat shrink film and its preparation process, the outline of which is basically the same as that described in the first embodiment, etc. Therefore, it is generally preferred to first use a known manufacturing apparatus to produce a roll of heat shrink film of a specified length (e.g., 50m or more) from polyester resin, polystyrene resin (including styrene-butadiene resin) or the like. Next, preferably by using a known printing method, the specified heat shrink film is clearly marked and a scale showing the specified range is formed along the surface (front or back) or a portion (the lateral end of the long strip roller, etc.) of the specified heat shrink film, and the roller-shaped heat shrink film is prepared in an easy-to-operate manner.

[0123] 2. Heat shrinking process of heat shrink film (process 2) As described in the first embodiment, step 2 is a heat shrinking process in which the heat shrink film obtained in step 1 is heated under the conditions of a specified temperature T and a specified time t1, so that the maximum value of the heat shrinking speed defined based on formula (1) is more than 3 mm / second. Therefore, it is preferable to place the heat shrink film on Figure 8On the measuring fixture consisting of frame members as exemplified in (a) to (c), the heat shrink film is heat-shrinked along the main shrink direction while being pressed by a limiting part arranged in a direction perpendicular to the main shrink direction. That is, by measuring the heat shrinkage rate and controlling its maximum value in the manner described above, it is possible to adjust the balance between the amount of change and time when the heat shrink film undergoes its maximum change with good precision, and to effectively prevent wrinkles from occurring when the heat shrink film is used on objects. In addition, the heat shrinkage rate is defined, for example, as the heat shrinkage rate of the heat shrink film in the main shrinkage direction calculated based on Equation (1) according to the change in distance of a specified mark before and after a specified time obtained using an image-based motion capture device.

[0124] 3. Determining the heat shrinkage rate of heat shrink film (Step 3) Step 3 is a process of estimating the heat shrinkage rate (A2 and / or B1) of the heat shrinkage film and determining the heat shrinkage rate (A2 and / or B1) of the heat shrinkage film based on the characteristic curve of the relationship between the heat shrinkage speed V1 defined by the pre-made formula (1). That is, the actual heat shrinkage rate of the heat shrink film can be estimated based on the characteristic curve of the heat shrinkage rate V1, which is pre-made based on the heat shrinkage rate V1 and shows the relationship between the heat shrinkage rate V1 and the heat shrink film. Therefore, the estimated heat shrinkage rate of the heat shrinkage film can be obtained quickly and with good accuracy in a form that is equivalent to the actual heat shrinkage rate measured under specified conditions. Furthermore, various properties of the heat shrinkage film can be controlled. Furthermore, the characteristic curve showing the relationship between the heat shrinkage rate and the heat shrinkage ratio of the heat shrink film is not limited to one; multiple characteristic curves can also be used.

[0125] More specifically, the heat shrinkage rate (%) in the main shrinkage direction, which was actually measured by the conventional method for measuring heat shrinkage rate by immersion in warm water at a specified temperature and time (hereinafter, the existing method), can be estimated based on the heat shrinkage rate V1 (mm / s) measured over a specified time. Therefore, as an example, in process 3, the heat shrinkage rate V1 is measured 5 seconds after the heat shrinkage time point. Next, as Figure 13 As shown, based on the pre-set characteristic curve (characteristic curve 1) showing the relationship between the heat shrinkage rate V1 after 5 seconds and the heat shrinkage rate A2 in the main shrinkage direction obtained by the motion capture device, the heat shrinkage rate A2 corresponding to the heat shrinkage rate V1 at the measured time point of 5 seconds is calculated. Next, as Figure 14As shown, based on the pre-set characteristic curve (characteristic curve 2) showing the relationship between the thermal shrinkage rate A2 obtained by the motion capture device and the thermal shrinkage rate B1 of the main shrinkage direction based on the existing method, the thermal shrinkage rate B1 corresponding to the calculated thermal shrinkage rate A2 is determined. Therefore, by estimating the actual heat shrinkage rate B1 measured under specified conditions based on the heat shrinkage rate V1 in the manner described above, the heat shrinkage behavior of the heat shrink film can be controlled quickly and with good accuracy. In addition, here, the heat shrinkage rate B1 is estimated and determined using the specified characteristic curves 1 and 2, but it is also preferable to use AI, which has been learned to relate heat shrinkage rate V1 to heat shrinkage rate B1, formulas composed of approximate curves, correspondence tables, etc., to comprehensively estimate the heat shrinkage rate B1. Example

[0126] The present invention will now be described in detail based on embodiments. However, unless otherwise specified, the scope of the present invention is not limited by the description of the embodiments. Furthermore, the resins used in Examples 1, etc., are as follows.

[0127] 1) Non-crystalline polyester resin (PETG1) An amorphous polyester (glass transition temperature: 69°C) formed from 100 mol% dicarboxylic acid: terephthalic acid, 69 mol% glycol: ethylene glycol, 20 mol% 1,4-cyclohexanediethanol, and 11 mol% diethylene glycol.

[0128] 2) Non-crystalline polyester resin (PETG2) An amorphous polyester (glass transition temperature: 69°C) formed from 100 mol% dicarboxylic acid: terephthalic acid, 63 mol% glycol: ethylene glycol, 24 mol% 1,4-cyclohexanediethanol, and 13 mol% diethylene glycol.

[0129] 3) Non-crystalline polyester resin (PETG3) An amorphous polyester (glass transition temperature: 75°C) formed from 100 mol% dicarboxylic acid: terephthalic acid, 68 mol% glycol: ethylene glycol, 30 mol% neopentyl glycol, and 2 mol% diethylene glycol.

[0130] 4) Non-crystalline polyester resin (PETG4) An amorphous polyester (glass transition temperature: 69°C) formed from 100 mol% dicarboxylic acid: terephthalic acid, 70 mol% glycol: ethylene glycol, 28 mol% 1,4-cyclohexanediethanol, and 2 mol% diethylene glycol.

[0131] 5) Styrene-butadiene copolymer (SBC1) Styrene-butadiene copolymer (styrene / butadiene weight ratio of 85 / 15)

[0132] 6) Styrene-butadiene copolymer (SBC2) Styrene-butadiene copolymer (styrene / butadiene weight ratio of 82 / 18)

[0133] 7) Hydrogenated elastomers (SEBS) A mixture of styrene-butadiene block copolymer and polystyrene resin (weight ratio: 50:50)

[0134] 8) Anti-blocking agent (HIPS) Impact-resistant polystyrene resin

[0135] 9) Polyolefin copolymer (PE) Ethylene-1-hexene copolymer (density: 0.900 g / cm³) prepared using Ziegler-Natta catalyst 3 MFR (190℃, 2.16kgf): 0.8g / 10min, enthalpy of melting (ΔH): 92mJ / mg

[0136] 10) Petroleum resin C5 series fully hydrogenated petroleum resin (I-MARV P140, manufactured by Idemitsu Kosan Co., Ltd.)

[0137] [Example 1] 1. Preparation of heat shrink film Use non-crystalline polyester resin (PETG1) at a ratio of 100 parts by weight in a mixing vessel. Next, the raw material is dried completely, and then extruded at an extruder (manufactured by TANABE PLASTICS MACHINERY CO.,LTD.) with an L / D of 24 and an extrusion screw diameter of 50 mm at an extrusion temperature of 260°C to obtain a raw material sheet with a thickness of 200 μm.

[0138] Next, using a heat shrink film manufacturing apparatus, a heat shrink film with a thickness of 40μm is produced from the raw material sheet under the conditions of a preheating temperature of 75°C, a stretching temperature of 75°C, a stretching ratio (MD direction: 105%, TD direction: 500%), and a heat setting temperature of 60°C.

[0139] 2. Evaluation of heat shrink film (1) Evaluation 1: Thickness deviation The thickness of the heat shrink film obtained (n=6) was measured using a micrometer (based on a target value of 40 μm) and evaluated according to the following criteria. ◎: Thickness deviation is within 3μm. 〇: The thickness deviation is within 5μm. △: Thickness deviation within 10μm. ×: The thickness deviation is greater than 10μm.

[0140] (2) Evaluation 2: Thermal shrinkage rate in the main contraction direction (A1) Use a warm water bath to float the obtained heat shrink film on 80°C warm water for 10 seconds to allow it to heat shrink. Next, as Figure 3 As shown in (b) to (c), while capturing image data using an optical camera, the thermal shrinkage rate (A1) in the main shrinkage direction at time point 1 second is calculated according to Equation (3) based on the change in distance of the markers before and after the heat treatment obtained using an image-based motion capture device, and evaluated according to the following criteria. ◎: The heat shrinkage rate (A1) is a value in the range of 20~35%. 〇: The heat shrinkage rate (A1) is 10% or more but less than 20% or greater than 35% but less than 40%. △: The heat shrinkage rate (A1) is 5% or more but less than 10% or greater than 40% but less than 45%. ×: The heat shrinkage rate (A1) is less than 5% or greater than 45%.

[0141] (3) Evaluation 3: Thermal shrinkage rate in the main shrinkage direction (A2) Use a warm water bath to float the obtained heat shrink film on 80°C warm water for 10 seconds to allow it to heat shrink. Next, as Figure 3 As shown in (b) to (c), while capturing image data using an optical camera, the thermal shrinkage rate (A2) in the main shrinkage direction at time 10 seconds is calculated according to Equation (3) based on the change in distance of the markers before and after the heat treatment obtained using an image-based motion capture device, and evaluated according to the following criteria. ◎: The heat shrinkage rate (A2) is a value in the range of 30% to 60%. 〇: The heat shrinkage rate (A2) is 10% or more but less than 30% or greater than 60% but less than 65%. △: The heat shrinkage rate (A2) is 5% or more but less than 10% or greater than 65% but less than 70%. ×: The heat shrinkage rate (A2) is less than 5% or greater than 70%.

[0142] (4) Evaluation 4: Thermal shrinkage rate in the main shrinkage direction Using a warm water bath, the obtained heat shrink film is floated on 80°C warm water for 10 seconds, and the heat shrinking is simultaneously measured for more than 10 seconds using an image-based motion capture device. That is, such as Figure 3 As shown in (b) to (c), while capturing image data using an optical camera, the thermal shrinkage rate in the main shrinkage direction is calculated according to Equation (1) based on the distance change of the specified mark 14' before and after a specified time obtained using an image-type motion capture device, and evaluated according to the following criteria. At this point, when calculating the heat shrinkage rate, the distance PL0 of the specified interval before heat shrinkage is set to 10mm, and the measurement is performed at intervals of 0.1 seconds. ◎: The heat shrinkage rate is 4 mm / second or higher. 〇: The heat shrinkage rate is 3 mm / s or more and less than 4 mm / s. △: The heat shrinkage rate is above 2 mm / s and less than 3 mm / s. ×: The heat shrinkage rate is less than 2 mm / second.

[0143] (5) Evaluation 5: Minimum value of intermediate heat shrinkage rate V3 Use a warm water bath to float the obtained heat shrink film on 80°C warm water for 10 seconds to allow it to heat shrink. Next, as Figure 3 As shown in (b) to (c), while using an optical camera to capture image data, the intermediate thermal shrinkage rate V3 is calculated according to Equation (4) based on the thermal shrinkage rate of the main shrinkage direction obtained by the image-type motion capture device (the number of specified intervals n = 6), and evaluated according to the following criteria based on the minimum value of the intermediate thermal shrinkage rate V3 in the interval with the largest maximum value of the intermediate thermal shrinkage rate V3 in the specified interval. At this point, when calculating the intermediate heat shrinkage rate V3, the distance PL0 of the specified interval before heat shrinkage is set to 10mm, and the measurement period t3-t2 is set to 0.1 seconds for measurement. ◎: The minimum value of the intermediate heat shrinkage speed V3 is 0 mm / second or higher. 〇: The minimum value of the intermediate heat shrinkage speed V3 is above -1.5mm / second. △: The minimum value of the intermediate heat shrinkage speed V3 is above -2.5mm / second. ×: The minimum value of the intermediate heat shrinkage rate V3 is less than -2.5 mm / second.

[0144] (6) Evaluation 6: Standard deviation of the maximum value of intermediate heat shrinkage rate V3 Use a warm water bath to float the obtained heat shrink film on 80°C warm water for 10 seconds to allow it to heat shrink. Next, as Figure 3As shown in (b) to (c), while using an optical camera to capture image data, the maximum value of the intermediate thermal shrinkage rate V3 is calculated according to Equation (4) based on the thermal shrinkage rate of the main shrinkage direction obtained by the image-type motion capture device (the number of specified intervals n = 6). Next, the standard deviation of the maximum value of the intermediate heat shrinkage rate V3 is calculated and evaluated according to the following criteria. At this point, when calculating the intermediate heat shrinkage rate V3, the distance PL0 of the specified interval before heat shrinkage is set to 10mm, and the measurement period t3-t2 is set to 0.1 seconds for measurement. ◎: The standard deviation of the maximum value of the intermediate heat shrinkage rate V3 is less than 3 mm / second. 〇: The standard deviation of the maximum value of the intermediate heat shrinkage rate V3 is greater than 3 mm / s and less than 3.5 mm / s. △: The standard deviation of the maximum value of the intermediate heat shrinkage rate V3 is greater than 3.5 mm / s and less than 4.5 mm / s. ×: The standard deviation of the maximum value of the intermediate heat shrinkage rate V3 is greater than 4.5 mm / s.

[0145] (7) Evaluation 7: Thermal shrinkage rate in the main shrinkage direction based on existing methods (B1) Using a warm water bath, immerse the obtained heat shrink film in 80°C warm water for 10 seconds to allow it to heat shrink. Next, as an existing method, the specified marks before and after a specified time are measured using calipers, and the thermal shrinkage rate (B1) in the main shrinkage direction is calculated based on the dimensional changes, and evaluated according to the following criteria. ◎: Values ​​with a heat shrinkage rate in the range of 35% to 70%. 〇: The heat shrinkage rate is 25% or more but less than 35% or greater than 70% but less than 75%. △: The heat shrinkage rate is 15% or more but less than 25% or greater than 75% but less than 80%. ×: Values ​​with a heat shrinkage rate of less than 15% or greater than 80%.

[0146] (8) Rating 8: Haze The haze value of the obtained heat shrink film was determined according to JIS K 7136:2000 and evaluated according to the following standards. ◎: Value for fog level below 3%. 〇: Value for haze below 5%. △: Value for haze below 7%. ×: Haze is a value greater than 7%.

[0147] [Example 2] 1. Preparation of heat shrink film In Example 2, except that a non-crystalline polyester resin (PETG2) was used in a stirring vessel at a ratio of 100 parts by weight as shown in Table 1, a raw material sheet with a thickness of 200 μm was obtained in the same manner as in Example 1. Next, using a heat shrink film manufacturing apparatus, a heat shrink film with a thickness of 40μm is produced from the raw material sheet under the conditions of a preheating temperature of 75°C, a stretching temperature of 75°C, a stretching ratio (MD direction: 105%, TD direction: 500%), and a heat setting temperature of 60°C.

[0148] 2. Evaluation of heat shrink film In Example 2, the thickness deviation of the obtained heat-shrinkable film (Evaluation 1), the average heat shrinkage rate at 80°C for 1 second in the main shrinkage direction obtained using an image-based motion capture device (Evaluation 2), and the average heat shrinkage rate at 80°C for 10 seconds in the main shrinkage direction obtained using an image-based motion capture device (Evaluation 3) were measured and evaluated in the same manner as in Example 1. The results are shown in Table 2.

[0149] [Comparative Example 1] 1. Preparation of heat shrink film In Comparative Example 1, except that a non-crystalline polyester resin (PETG4) was used in a stirring vessel at a ratio of 100 parts by weight as shown in Table 1, a raw material sheet with a thickness of 200 μm was obtained in the same manner as in Example 1. Next, using a heat shrink film manufacturing apparatus, a heat shrink film with a thickness of 40μm is produced from the raw material sheet under the conditions of a preheating temperature of 90°C, a stretching temperature of 90°C, a stretching ratio (MD direction: 105%, TD direction: 500%), and a heat setting temperature of 60°C.

[0150] 2. Evaluation of heat shrink film In Comparative Example 1, the thickness deviation of the obtained heat-shrinkable film (Evaluation 1), the average heat shrinkage rate at 80°C for 1 second in the main shrinkage direction obtained using an image-based motion capture device (Evaluation 2), and the average heat shrinkage rate at 80°C for 10 seconds in the main shrinkage direction obtained using an image-based motion capture device (Evaluation 3) were evaluated in the same manner as in Example 1. The results are shown in Table 2.

[0151] [Comparative Example 2] 1. Preparation of heat shrink film In Comparative Example 2, except that a non-crystalline polyester resin (PETG3) was used in a stirring vessel at a ratio of 100 parts by weight as shown in Table 1, a raw material sheet with a thickness of 200 μm was obtained in the same manner as in Example 1. Next, using a heat shrink film manufacturing apparatus, a heat shrink film with a thickness of 40μm is produced from the raw material sheet under the conditions of extrusion temperature of 260°C, preheating temperature of 90°C, stretching temperature of 90°C, stretching ratio (MD direction: 105%, TD direction: 500%), and heat setting temperature of 60°C.

[0152] 2. Evaluation of heat shrink film In Comparative Example 2, the thickness deviation of the obtained heat-shrinkable film (Evaluation 1), the average heat shrinkage rate at 80°C for 1 second in the main shrinkage direction obtained using an image-based motion capture device (Evaluation 2), and the average heat shrinkage rate at 80°C for 10 seconds in the main shrinkage direction obtained using an image-based motion capture device (Evaluation 3) were evaluated in the same manner as in Example 1. The results are shown in Table 2.

[0153] [Table 1]

[0154] [Table 2]

[0155] [Example 3] 1. Preparation of heat shrink film In Example 3, except that styrene-butadiene copolymer (SBC1) was used in a stirred container at a ratio of 100 parts by weight as shown in Table 1, a raw material sheet with a thickness of 200 μm was obtained in the same manner as in Example 1. Next, using a heat shrink film manufacturing apparatus, a heat shrink film with a thickness of 40μm is produced from the raw material sheet under the conditions of a preheating temperature of 95°C, a stretching temperature of 85°C, a stretching ratio (MD direction: 100%, TD direction: 500%), and a heat setting temperature of 85°C.

[0156] 2. Evaluation of heat shrink film In Example 3, except that the measurement was performed using a motion capture device and existing methods with hot water at 90°C, the deviation of the thickness of the obtained heat shrink film (evaluation 1) and the heat shrinkage speed obtained using the image-type motion capture device (evaluation 4') were evaluated in the same manner as in Example 1. That is, except for utilizing the difference in measurement temperature (90°C and 80°C) using the motion capture device, evaluations 2' to 7' in Example 3 and evaluations 2 to 7 in Example 1, etc., were evaluated using the same method as in Example 1, etc. The results obtained are shown in Table 3.

[0157] [Example 4] 1. Fabrication of heat shrink film (SBC-PE-SBC) In Example 4, as the composition constituting the first layer (intermediate layer) of the film, an olefin resin composition comprising 10% by weight of petroleum resin and 90% by weight of polyolefin copolymer (PE) was prepared. In addition, as a composition constituting the second layer (surface layer) of the membrane, a styrene-butadiene copolymer (SBC2) is prepared. In addition, as the composition constituting the second layer (surface layer) of the film, a styrene block copolymer resin composition having a composition of 87.7% by weight of styrene block copolymer (SBC), 10% by weight of hydrogenated elastomer (SEBS) and 2.3% by weight of antiblocking agent (HIPS) is prepared. Next, using an olefin resin composition and a styrene block copolymer resin composition, the mixture was fed into an extruder (manufactured by LABOTEC) with an L / D of 30 and an extrusion screw diameter of 25 mm at an extrusion temperature of 210°C, and extruded in two three-layer forms to obtain a raw material sheet with a thickness of 160 μm.

[0158] That is, in this extrusion molding, an olefin resin composition is added to the raw material supply port for forming a substrate layer (first layer), and a styrene block copolymer resin composition is added to the two raw material supply ports for forming two surface layers (second layers) that are respectively stacked on the two surfaces of the substrate layer, so as to form a raw material sheet with two three-layer structures. Therefore, a raw material sheet with a three-layer structure is formed, comprising a substrate layer formed of an olefin resin composition, a styrene-based block copolymer resin composition surface layer laminated on one side of the substrate layer, and a styrene-based block copolymer resin composition surface layer laminated on the other side of the substrate layer.

[0159] Next, the raw material sheet is stretched using a heat shrink film manufacturing device with a preheating temperature of 90°C, a stretching temperature of 90°C, and a stretching ratio of (MD direction: 100%, TD direction: 500%). Next, at a heat-fixing temperature of 90°C, a relaxation operation is immediately performed using a heat-shrinkable film manufacturing apparatus to change the stretch ratio in the MD direction to 100% and the stretch ratio in the TD direction to 450%, ultimately producing a heat-shrinkable film with a thickness of 40 μm (layer ratio: surface layer on both sides 30 (=15+15) / intermediate layer 70).

[0160] 2. Evaluation of heat shrink film In Example 4, except that the measurement was performed using a motion capture device and existing methods with hot water at 90°C, the deviation of the thickness of the obtained heat shrink film (evaluation 1) and the heat shrinkage speed obtained using the image-type motion capture device (evaluation 4') were evaluated in the same manner as in Example 1. That is, except for utilizing the difference in measurement temperature (90°C and 80°C) using the motion capture device, evaluations 2' to 7' in Example 4 and evaluations 2 to 7 in Example 1, etc., were evaluated using the same method as in Example 1, etc. The results obtained are shown in Table 3.

[0161] [Table 3] Industrial applicability

[0162] According to the present invention, by limiting the heat shrinkage rate and other properties measured under specified conditions to a specified range, it is possible to quickly and accurately evaluate and provide heat shrink films and the like that exhibit uniform and excellent stability in terms of heat shrinkage properties. Therefore, the heat shrink film of the present invention can be applied to various PET bottles, etc., which can significantly broaden its versatility and has extremely high industrial applicability. Explanation of reference numerals in the attached figures

[0163] 10: Heat shrink film; 10a: Other resin layers; 10b: Other resin layers; 10c: Shrinkage adjustment layer; 13: Measuring fixture; 14: Motion capture device; 14': Specified mark; 14a, 14b: Optical camera; 20: Warm water bath; 22: Hot water; 24: Elevator; 26: Thread.

Claims

1. A heat-shrinkable film, wherein the long side direction or the width direction is the main shrinkage direction, characterized in that, A predetermined interval is set along the main shrinkage direction of the heat-shrinkable film, which is capable of shrinking in at least one of the long side direction or the width direction. When heat shrinking is performed at a predetermined temperature T and a predetermined time t1, the maximum value of the heat shrinkage speed V1, calculated based on the distance PL0 of the predetermined interval before heat shrinking and the distance PL1 of the predetermined interval at a predetermined time t2 shorter than the predetermined time t1, is a value of 3 mm / s or more. [Mathematical Expression 1] Heat shrinkage rate V1 (mm / s) = (PL0-PL1) / t2 (1), PL0-PL1: Distance variation (mm) within the specified interval. t2: Specified time (seconds).

2. The heat-shrinkable film according to claim 1, characterized in that, Set the specified time t1 to be greater than 5 seconds, and set the specified time t2 to be less than 5 seconds.

3. The heat-shrinkable film according to claim 1 or 2, characterized in that, The maximum value of the thermal shrinkage rate V2 calculated based on the following formula (2) is more than 30% / second. [Mathematical Expression 2] The rate of thermal shrinkage V2 (% / second) = (PL0-PL1) / (PL0×t2)×100 (2).

4. The heat-shrinkable film according to claim 1 or 2, characterized in that, The heat-shrinkable film is composed of at least one resin selected from the group consisting of polyester resin, styrene resin, polyolefin resin and polyvinyl chloride resin.

5. The heat-shrinkable film according to claim 1 or 2, characterized in that, The specified temperature T is set to 70~98℃, and the thermal shrinkage rate along the main shrinkage direction is set to a value in the range of 10~80%.

6. The heat-shrinkable film according to claim 1 or 2, characterized in that, The distance change within the specified interval is a value calculated using a motion capture device based on the distance information within the specified interval.

7. A method for manufacturing a heat-shrinkable film, characterized in that the long side direction or the width direction is the main shrinkage direction of the heat-shrinkable film, wherein... Includes the following processes (1) to (3): (1) The process of preparing raw material resin; (2) A process of forming a resin film from the molten raw material resin and stretching it to produce a heat-shrinkable film with the long side direction or the width direction as the main shrinkage direction. (3) When heat shrinking is performed at a specified temperature T and a specified time t1, a heat shrinking speed adjustment process is performed, which sets a specified interval along the main shrinking direction of the heat shrink film that is capable of shrinking in at least one of the long side direction or the width direction, and sets the specified interval as PL0 before heat shrinking and the specified interval as PL1 at a specified time t2 which is shorter than the specified time t1, and sets the maximum value of the heat shrinking speed V1 calculated based on the following formula (1) as 3 mm / s or more. [Mathematical Expression 3] Heat shrinkage rate V1 (mm / s) = (PL0-PL1) / t2 (1), PL0-PL1: Distance variation (mm) within the specified interval. t2: Specified time (seconds).

8. The method for manufacturing a heat-shrinkable film according to claim 7, characterized in that, The distance change is calculated using a motion capture device based on the distance information within the specified interval.

9. The method for manufacturing a heat-shrinkable film according to claim 7 or 8, characterized in that, The heat-shrinkable film is placed on a measuring fixture consisting of a frame member, and the heat-shrinkable film is heat-shrinked along the main shrinkage direction while being pressed by a limiting part arranged in a direction perpendicular to the main shrinkage direction.

10. A method for determining the heat shrinkage rate of a heat shrink film, characterized in that, Includes the following processes (1) to (3): (1) A preparation process for heat shrink film in which the main shrinkage direction of the heat shrink film is clearly marked and a specified range is provided, which is in a state that can shrink along at least one of the long side direction or the width direction. (2) The heat shrink film is heated under a specified temperature T and a specified time t1, and the heat shrink film is heat-shrinked in such a way that the maximum value of the heat shrinkage speed V1 calculated based on the following formula (1) is 3 mm / second or more. (3) A process for estimating the heat shrinkage rate of the heat shrinkage film based on a characteristic curve pre-made based on the heat shrinkage rate V1, which shows the relationship between the heat shrinkage rate V1 and the heat shrinkage rate of the heat shrinkage film. [Mathematical Expression 4] Heat shrinkage rate V1 (mm / s) = (PL0-PL1) / t2 (1), PL0-PL1: Distance variation (mm) within the specified interval. t2: Specified time (seconds).

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