Adhesive protective film, battery and manufacturing method thereof

Abstract

To provide an adhesive protective film that can be positioned at a predetermined position with high precision. The adhesive protective film of the present invention has a transmittance of T, which is the average value of the transmittance of light having wavelengths that differ by 1 nm in the range of 400 nm to 800 nm, measured using a spectrophotometer. 400-800 However, it is between 25% and 91%.

Description

[Technical field]

[0001] The present invention relates to an adhesive protective film, a battery, and a method for producing the same. [Background technology]

[0002] Various types of batteries have been developed, but in all batteries, packaging materials are essential components for sealing battery elements such as electrodes and electrolytes. For example, in metal can batteries, which are used in a wide range of fields, the battery elements are sealed in a metallic packaging material (metal can).

[0003] In recent years, batteries are being required to have a variety of shapes and to be thin and lightweight in line with the increasing performance of electric vehicles, hybrid electric vehicles, personal computers, cameras, mobile phones, etc. In response to this, a film-like laminate in which a base layer / adhesive layer / barrier layer / thermally adhesive resin layer are laminated in this order has been proposed as a packaging material that can be easily processed into a variety of shapes and can achieve a thin and lightweight structure.

[0004] When such a film-like packaging material is used, the battery element is sealed by heat-sealing the periphery of the packaging material with the heat-sealed resin layers located in the innermost layers of the packaging material facing each other. Metal terminals protrude from the heat-sealed portion of the packaging material, and the battery element sealed by the packaging material is electrically connected to the outside by the metal terminals electrically connected to the electrodes of the battery element. That is, the heat-sealed portion of the packaging material is formed so that the metal terminals protrude outside the packaging material while being sandwiched between the heat-sealed resin layers.

[0005] In the heat-sealed portion of the packaging material where the metal terminal is located, the high temperature and pressure during heat sealing may cause the heat-sealing resin layer to become thinner, and the metal terminal may penetrate the heat-sealing resin layer and electrically connect to the barrier layer, resulting in a short circuit. For this reason, in the heat-sealed portion of the packaging material where the metal terminal is located, an adhesive protective film (adhesive protective film for metal terminals) is generally disposed between the metal terminal and the packaging material (heat-sealing resin layer) (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2014-132538 A Summary of the Invention [Problem to be solved by the invention]

[0007] The adhesive protective film disposed between the metal terminal and the packaging material covers the periphery of the metal terminal by, for example, sandwiching the metal terminal between the adhesive protective films and heat-sealing the packaging material, as shown in FIG. 4. However, if the two adhesive protective films are misaligned when they are disposed, the overlapping portions of the two adhesive protective films around the metal terminal are heat-sealed in a misaligned state, as shown in FIG. 5. In such a case, there is a problem that the sealing of the heat-sealed portion becomes unstable, which easily induces a short circuit between the metal terminal and the barrier layer in the packaging material. For this reason, the adhesive protective film disposed between the metal terminal and the packaging material needs to be disposed with extremely high positional accuracy.

[0008] However, the inventors' investigations revealed that slight misalignment of the adhesive protective film, such as when two adhesive protective films are arranged or when one adhesive protective film is wrapped around a metal terminal, may not be detectable by a camera-equipped sensor or by visual inspection, and the film may be heat-sealed without correcting the misalignment.

[0009] Under these circumstances, a main object of the present invention is to provide an adhesive protective film that can be positioned with high positional accuracy, a battery using the adhesive protective film, and a manufacturing method thereof. [Means for solving the problem]

[0010] The present inventors have conducted extensive research to solve the above problems. As a result, the inventors have discovered that T 400-800 However, they found that by using an adhesive protective film having a film thickness of 25% or more and 91% or less, the adhesive protective film can be positioned at a predetermined position with high accuracy during battery production.

[0011] The present inventors have also found that the adhesive protective film can be positioned at a predetermined position with high precision during battery manufacturing by using an adhesive protective film having a haze in the range of 50 to 89. The present inventors have also found that a colored adhesive protective film can be accurately positioned at a predetermined position during battery manufacturing by using a T 400-800 and T(II) is the average value of the transmittance percentage of light having wavelengths differing by 1 nm in the range of 400 nm to 800 nm measured by a spectrophotometer with two sheets of the adhesive protective film stacked together. 400-800The inventors have found that the adhesive protective film can be positioned at a predetermined position with high precision during battery manufacturing by using an adhesive protective film in which the absolute value of the difference between the transmittance and transmittance is 13 or more. The inventors have also found that the adhesive protective film can be positioned at a predetermined position with high precision during battery manufacturing by using a colored adhesive protective film in which two sheets of the adhesive protective film are stacked and the transmittance is the average transmittance percentage T(II) of light having wavelengths that differ by 1 nm in increments in the range of 400 nm to 800 nm, measured with a spectrophotometer. 400-800 The inventors have found that by using an adhesive protective film in which the haze of the adhesive protective film is 5% or more and 50% or less, the adhesive protective film can be positioned at a predetermined position with high precision during battery production. Furthermore, the inventors have found that by using an adhesive protective film in which the absolute value of the difference between the haze measured for the adhesive protective film and the haze measured for two sheets of the adhesive protective film stacked on top of each other is 8.5 or more, the adhesive protective film can be positioned at a predetermined position with high precision during battery production.

[0012] The present invention was completed through further investigation based on these findings.

[0013] That is, the present invention provides the following aspects. Item 1. T is the average transmittance percentage of light with wavelengths that differ by 1 nm increments in the range of 400 nm to 800 nm measured by a spectrophotometer. 400-800 An adhesive protective film, wherein the adhesiveness is 25% or more and 91% or less. Item 2. T is the average transmittance percentage of light with wavelengths that differ by 1 nm increments in the range of wavelengths from 800 nm to 1200 nm, measured using a spectrophotometer. 800-1200 Item 2. The adhesive protective film according to item 1, wherein the adhesive protective film has a viscosity of 30% or more. Item 3. T is the average transmittance percentage of light with wavelengths that differ by 1 nm increments in the range of 300 nm to 400 nm measured using a spectrophotometer. 300-400 Item 3. The adhesive protective film according to item 1 or 2, wherein the adhesive protective film has a refractive index of 89.00% or less. Section 4. Said T 400-800is the average transmittance percentage of light with wavelengths that differ by 1 nm increments in the range of 300 nm to 400 nm measured by a spectrophotometer. 300-400 4. The adhesive protective film according to any one of items 1 to 3, wherein the value obtained by dividing by 1 is in the range of 0.90 or more and 8.00 or less. Item 5. Percentage transmittance T of light with a wavelength of 500 nm measured using a spectrophotometer 500 is the percent transmittance T of light with a wavelength of 700 nm measured by a spectrophotometer. 700 5. The adhesive protective film according to any one of items 1 to 4, wherein the value obtained by dividing the ratio by 1 is in the range of 0.75 to 0.99. Item 6. Percentage transmittance T of light with a wavelength of 550 nm measured by a spectrophotometer 550 is the percent transmittance T of light with a wavelength of 350 nm measured by a spectrophotometer. 350 6. The adhesive protective film according to any one of items 1 to 5, wherein the value obtained by dividing the ratio by 1 is in the range of 1.00 or more and 35.00 or less. Item 7. The adhesive protective film according to any one of items 1 to 6, having a haze of 50 or more and 89 or less. Item 8. T(II) is the average value of the transmittance percentage of light having wavelengths differing by 1 nm in the range of 400 nm to 800 nm measured by a spectrophotometer with two sheets of the adhesive protective film stacked together. 400-800 And the above T 400-800 8. The adhesive protective film according to any one of items 1 to 7, wherein the absolute value of the difference between the above is 13 or more. Item 9. T(II) is the average value of the transmittance percentage of light having wavelengths differing by 1 nm in the range of 400 nm to 800 nm measured by a spectrophotometer with two sheets of the adhesive protective film stacked together. 400-800 9. The adhesive protective film according to any one of items 1 to 8, wherein the ratio is 5% or more and 50% or less. Item 10. The adhesive protective film according to any one of Items 1 to 9, wherein the absolute value of the difference between the haze (II) measured by stacking two sheets of the adhesive protective film and the haze is 8.5 or more. Item 11. The adhesive protective film according to any one of Items 1 to 10, comprising at least a substrate and a first polyolefin layer formed from an acid-modified polyolefin or a polyolefin, the first polyolefin layer being located on one side of the substrate. Item 12. The adhesive protective film according to item 11, further comprising at least a second polyolefin layer formed from an acid-modified polyolefin or a polyolefin, located on the other side of the substrate. Item 13. The adhesive protective film according to item 12, wherein at least one of the first polyolefin layer and the second polyolefin layer is composed of two or more layers. Item 14. The adhesive protective film according to any one of Items 11 to 13, further comprising an adhesion promoter layer between the substrate and the first polyolefin layer, or between the substrate and the second polyolefin layer, or both. Item 15. The adhesive protective film according to any one of Items 1 to 14, which is an adhesive protective film interposed between a metal terminal electrically connected to an electrode of a battery element and a packaging material that seals the battery element. Item 16. The packaging material is composed of a laminate having at least a base layer, a barrier layer, and a heat-sealable resin layer in this order, Item 16. The adhesive protective film according to item 15, wherein the adhesive protective film is interposed between the heat-sealable resin layer and the metal terminal. Item 17. A battery comprising at least a battery element having a positive electrode, a negative electrode, and an electrolyte, a packaging material for sealing the battery element, and metal terminals electrically connected to the positive electrode and the negative electrode, respectively, and protruding outside the packaging material, Item 17. A battery comprising the adhesive protective film according to any one of items 1 to 16 interposed between the metal terminal and the packaging material. Item 18. A method for manufacturing a battery comprising: a battery element including at least a positive electrode, a negative electrode, and an electrolyte; a packaging material for sealing the battery element; and metal terminals electrically connected to the positive electrode and the negative electrode, respectively, and protruding outside the packaging material, comprising: 17. A method for producing a battery, comprising a step of interposing the adhesive protective film according to any one of items 1 to 16 between the metal terminal and the packaging material. Item 19. An adhesive protective film having a haze in the range of 50 or more and 89 or less. Item 20. A colored adhesive protective film, The adhesive protective film is measured using a spectrophotometer to determine the average transmittance of light having wavelengths that differ by 1 nm increments in the range of 400 nm to 800 nm. 400-800 and, Two sheets of the adhesive protective film are stacked together and the average transmittance percentage of light having wavelengths that differ by 1 nm in the range of 400 nm to 800 nm measured with a spectrophotometer is T(II). 400-800 and the absolute value of the difference is 13 or more. Item 21. A colored adhesive protective film, Two sheets of the adhesive protective film are stacked together and the average transmittance percentage of light having wavelengths that differ by 1 nm in the range of 400 nm to 800 nm measured with a spectrophotometer is T(II). 400-800 An adhesive protective film, wherein the adhesiveness is 5% or more and 50% or less. Item 22. An adhesive protective film, An adhesive protective film, wherein the absolute value of the difference between the haze measured for the adhesive protective film and the haze (II) measured for two sheets of the adhesive protective film stacked together is 8.5 or more. Effect of the Invention

[0014] According to the present invention, it is possible to provide an adhesive protective film that can be positioned at a predetermined position with high precision.

[0015] A battery using the film-like packaging material of the present invention includes at least a battery element including a positive electrode, a negative electrode, and an electrolyte, a packaging material for sealing the battery element, and metal terminals electrically connected to the positive electrode and the negative electrode, respectively, and protruding outside the packaging material, with the adhesive protective film of the present invention interposed between the metal terminals and the packaging material. Therefore, in a battery using the film-like packaging material of the present invention, the adhesive protective film is precisely positioned around the metal terminals. [Brief description of the drawings]

[0016] [Figure 1] 1 is a schematic plan view of a battery using the film-like packaging material of the present invention. [Diagram 2] 2 is a schematic cross-sectional view taken along line AA' in FIG. 1. [Diagram 3] 2 is a schematic cross-sectional view taken along line BB' in FIG. 1. [Figure 4] 4 is a schematic cross-sectional view of a portion where a metal terminal is located among the heat-sealed portions of a film-like packaging material. FIG. [Diagram 5] 4 is a schematic cross-sectional view of a portion where a metal terminal is located among the heat-sealed portions of a film-like packaging material. FIG. [Figure 6] FIG. 1 is a schematic cross-sectional view of an example of an adhesive protective film of the present invention. [Figure 7] FIG. 1 is a schematic cross-sectional view of an example of an adhesive protective film of the present invention. [Figure 8] FIG. 1 is a schematic cross-sectional view of an example of an adhesive protective film of the present invention. [Figure 9] FIG. 1 is a schematic cross-sectional view of an example of an adhesive protective film of the present invention. [Figure 10] FIG. 1 is a schematic cross-sectional view of an example of an adhesive protective film of the present invention. [Figure 11] FIG. 1 is a schematic cross-sectional view of an example of an adhesive protective film of the present invention. [Figure 12] FIG. 1 is a schematic cross-sectional view of an example of an adhesive protective film of the present invention. [Figure 13]FIG. 2 is a schematic cross-sectional view of a packaging material used for a battery using the film-like packaging material of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] 1. Adhesive protective film The first adhesive protective film of the present invention has a transmittance of 1 nm increments in the range of 400 nm to 800 nm, which is measured by a spectrophotometer. 400-800 is 25% or more and 91% or less.

[0018] The second adhesive protective film of the present invention is characterized in that it has a haze in the range of 50-89.

[0019] The third adhesive protective film of the present invention is a colored adhesive protective film, and the adhesive protective film has a transmittance T, which is an average value of the transmittance percentage of light having wavelengths that differ by 1 nm in the range of 400 nm to 800 nm, measured by a spectrophotometer. 400-800 and T(II) is the average value of the transmittance percentage of light having wavelengths differing by 1 nm in the range of 400 nm to 800 nm measured by a spectrophotometer with two sheets of the adhesive protective film stacked together. 400-800 The absolute value of the difference between the two is 13 or more.

[0020] The fourth adhesive protective film of the present invention is a colored adhesive protective film, and has a transmittance T(II) of 1 nm increments in a wavelength range of 400 nm to 800 nm measured by a spectrophotometer using two overlapping adhesive protective films. 400-800 is 5% or more and 50% or less.

[0021] The fifth adhesive protective film of the present invention is an adhesive protective film characterized in that the absolute value of the difference between the haze measured for the adhesive protective film and the haze (II) measured by stacking two of the adhesive protective films is 8.5 or more.

[0022] The first to fifth adhesive protective films of the present invention and the battery of the present invention using these will be described in detail below. In the following description, the first adhesive protective film will be described in detail as a representative of the present invention. Matters common to the first adhesive protective film and the second to fifth adhesive protective films will be described as an explanation of the present invention, and individual explanations of the first to fifth adhesive protective films will be omitted.

[0023] In this specification, the numerical range indicated by "to" means "greater than or equal to" or "less than or equal to." For example, the expression "2 to 15 mm" means greater than or equal to 2 mm and less than or equal to 15 mm.

[0024] In addition, in this specification, "T A-B " is the sum of the transmittance percentages for each wavelength that differs by 1 nm in the range of wavelengths from Anm to Bnm measured by a spectrophotometer, and divided by (B-A+1). For example, T 400-800 is the sum of the transmittance percentages for each wavelength that differs by 1 nm in the range of 400 nm to 800 nm measured by a spectrophotometer, and then divided by (800-400+1). A " is the percent transmission of the wavelength A m measured by a spectrophotometer. For example, T 400 is the transmittance percentage at a wavelength of 400 nm measured by a spectrophotometer. A-B " means the value measured for one adhesive protective film, and "T(II) 400-800 The notation "T" means the value measured with two adhesive protective films stacked on top of each other. 300-400 ","T 800-1200 ","T 500 ","T 700 ","T 550 ","T350 ","T 800-1200 Although there is no specific mention of ", these are values ​​measured for one adhesive protective film.

[0025] Optical properties of adhesive protective films In the first adhesive protective film of the present invention, T 400-800 The thickness may be 25 to 91%, but from the viewpoint of further improving the distinguishability of the adhesive protective film and arranging it at a predetermined position with high accuracy, the lower limit is preferably about 40% or more, about 50% or more, or about 60% or more, and the upper limit is preferably about 88% or less, or about 60% or less. 400-800 The range of is preferably about 25 to 88%, about 25 to 60%, about 40 to 91%, about 40 to 88%, about 40 to 60%, about 50 to 91%, about 50 to 88%, about 50 to 60%, about 60 to 91%, and about 60 to 88%. 400-800 Since the adhesive protective film 1 has such a value, if a positional deviation occurs when the adhesive protective film 1 is arranged (for example, a state in which the overlapping portions of two adhesive protective films are misaligned around a metal terminal as shown in FIG. 5), it can be suitably detected by a camera-equipped sensor, visual inspection, etc. Conventional adhesive protective films have high transparency and T 400-800 The color is dark and T is more than 91%. 400-800 was less than 25%, it was difficult to detect with high accuracy any misalignment that occurred when the adhesive protective film 1 was placed. In addition, the current situation is that the misalignment of the adhesive protective film is not detected with high accuracy in the first place.

[0026] In the present invention, the percentage of light transmittance at each wavelength of the adhesive protective film is a value measured by the following method.

[0027] <Measurement of the percentage of light transmission> Using a spectrophotometer, one side of the adhesive protective film is irradiated with light of a predetermined wavelength, and the percentage of light transmittance is measured under the following measurement conditions: Data interval: 1 nm Measurement range: 190nm to 1500nm UV-Visible Bandwidth: 5.0nm Near infrared bandwidth: 20.0 nm Response: Fast Scanning speed: 1000nm / min Light source: Deuterium discharge tube, halogen lamp Light source switching: 340 nm Diffraction grating switching: 800nm

[0028] First, a baseline is obtained using a sample folder with a measurement area of ​​φ3 mm without a sample placed in it. Next, an adhesive protective film with a size of φ3 mm or more is placed in the sample folder as a sample, and the light transmittance percentage is measured. The light transmittance percentage for a given wavelength range is the average value of the light transmittance percentage at wavelength intervals of 1 nm in that range. For example, the light transmittance percentage for light with a wavelength of 400 nm to 800 nm is the average value of the light transmittance percentage obtained by measuring the light transmittance percentage for light with wavelengths that differ by 1 nm increments in the range of 400 nm to 800 nm.

[0029] The spectrophotometer used is an ultraviolet-visible-near infrared spectrophotometer. The light transmittance percentage may be measured from either the top or bottom surface of the adhesive protective film, but the values ​​of the light transmittance percentage described above and below only need to be satisfied when measured from at least one of the top and bottom surfaces.

[0030] From the viewpoint of further enhancing the distinguishability of the adhesive protective film and arranging it in a specified position with high accuracy, T is the average value of the transmittance percentage of light with wavelengths that differ by 1 nm in the range of wavelengths from 300 nm to 400 nm measured by a spectrophotometer. 300-400 is preferably about 89.00% or less. 300-400 The lower limit of is preferably about 5.05% or more, more preferably 10.00% or more, and even more preferably about 20.00% or more, and the upper limit is preferably about 87.00% or less, more preferably about 70.00% or less. 300-400More preferred ranges of are about 5.05 to 89.00%, about 5.05 to 87.00%, about 5.05 to 70.00%, about 10.00 to 89.00%, about 10.00 to 87.00%, about 10.00 to 70.00%, about 20.00 to 89.00%, about 20.00 to 87.00%, and about 20.00 to 70.00%. 300-400 Since the adhesive protective film has such a value, it can be positioned at a predetermined position with high accuracy when detecting the position of the adhesive protective film using a light source that mainly contains light with a wavelength of 300 nm to 400 nm.

[0031] In addition, from the viewpoint of further enhancing the distinguishability of the adhesive protective film of the present invention and arranging it at a predetermined position with high accuracy, the T(II) measured by stacking two adhesive protective films was 400-800 And the above T 400-800 Absolute value of difference with |T 400-800 -T(II) 400-800 is preferably 13 or more, and more preferably 14 or more. 400-800 -T(II) 400-800 Preferred ranges of |T are, for example, about 13 to 30, about 13 to 25, about 14 to 30, and about 14 to 25. 400-800 -T(II) 400-800 From the viewpoint of suitably setting | to 13 or more, it is preferable that the adhesive protective film is colored. Examples of colorants include general colorants such as carbon black and titanium oxide, and these may be used alone or in combination. Preferred colorants are carbon black, titanium oxide, etc. The color of the adhesive protective film is preferably black, gray, etc. Furthermore, the T 400-800 is preferably 25 to 90%, and more preferably about 25 to 60%. As described above, the adhesive protective film of the third aspect of the present invention is colored, and |T 400-800 -T(II) 400-800 It is characterized by the fact that | is 13 or more.

[0032] The absolute value |T 400-800 -T(II) 400-800Examples of methods for setting | to 13 or more include a method of coloring at least one of the layers constituting the adhesive protective film 1 with a coloring agent. Another example is a method of adjusting the light transmittance percentage by using a nonwoven fabric or the like as the substrate. Still another example is a method of selecting a resin with low transparency and using it for the layers constituting the adhesive protective film 1. Still another example is a method of adjusting the thickness of the adhesive protective film 1.

[0033] In order to further improve the distinguishability of the adhesive protective film of the present invention and to place it at a predetermined position with high accuracy, T(II) was measured by stacking two adhesive protective films. 400-800 The T(II) is preferably about 5 to 50%, more preferably about 5 to 40%, and even more preferably about 8 to 35%. 400-800 From the viewpoint of suitably setting the T to about 5 to 50%, it is preferable that the adhesive protective film is colored. Examples of colorants include general colorants such as carbon black and titanium oxide, and these may be used alone or in combination. Preferred colorants are carbon black, titanium oxide, etc. The color of the adhesive protective film is preferably black, gray, etc. Furthermore, the T 400-800 The content of T(II) is preferably 25 to 90%, and more preferably about 25 to 60%. As described above, the fourth adhesive protective film of the present invention is a colored adhesive protective film, and the content of T(II) is preferably about 25 to 90%, and more preferably about 25 to 60%. 400-800 However, it is characterized by being 5 to 50%.

[0034] Said T(II) 400-800 As a method for suitably setting the absolute value |T 400-800 -T(II) 400-800 The same method as setting | to 13 or more can be used.

[0035] From the viewpoint of further enhancing the distinguishability of the adhesive protective film and arranging it in a specified position with high accuracy, T is the average value of the transmittance percentage of light with wavelengths that differ by 1 nm in the range of wavelengths from 800 nm to 1200 nm measured by a spectrophotometer. 800-1200is preferably about 30% or more, more preferably about 35% or more, and even more preferably about 40% or more. 800-1200 When T is equal to or greater than the above-mentioned lower limit, the adhesive protective film has excellent heat dissipation properties, and can effectively dissipate heat generated inside the battery to the outside. 800-1200 The upper limit of T is preferably about 92% or less. 800-1200 By being about 92% or less, when detecting the position of the adhesive protective film using a light source that mainly contains light having a wavelength of 800 nm to 1200 nm, the adhesive protective film can be positioned at a predetermined position with high accuracy. 800-1200 A preferred range of is about 30 to 92%, about 35 to 92%, or about 40 to 92%.

[0036] In order to further enhance the distinguishability of the adhesive protective film and to place it at a predetermined position with high accuracy, the adhesive protective film of the present invention is 400-800 , T 300-400 The value obtained by dividing by (T 400-800 / T 300-400 ) is preferably in the range of 0.90 to 8.00. 400-800 / T 300-400 The lower limit of T is preferably about 1.02 or more, more preferably about 1.32 or more, and the upper limit of T is preferably about 7.50 or less, more preferably about 7.00 or less. 400-800 / T 300-400 Preferred ranges of are about 0.90 to 7.50, about 0.90 to 7.00, about 1.02 to 8.00, about 1.02 to 7.50, about 1.02 to 7.00, about 1.32 to 8.00, about 1.32 to 7.50, and about 1.32 to 7.00. 400-800 / T 300-400When the adhesive protective film has such a value, the identification of the adhesive protective film is further improved. That is, when detecting the position of the adhesive protective film, a plurality of light sources may be used. For example, when detecting the position of the adhesive protective film using two light sources, one containing light having a wavelength of 400 nm to 800 nm and the other containing light having a wavelength of 300 nm to 400 nm, the T 400-800 / T 300-400 By using the above range, it becomes possible to detect differences due to contrast in optical characteristics that are difficult to detect with a single light source, enabling more reliable position detection. Furthermore, by using these two light sources, it is possible to effectively detect the presence of foreign matter on the surface or inside of the adhesive protective film, the presence of wrinkles, internal defects, etc.

[0037] From the same viewpoint, in the adhesive protective film of the present invention, the transmittance percentage T of light having a wavelength of 500 nm is 500 is the percent transmittance T of light with a wavelength of 700 nm. 700 Divided by (T 500 / T 700 ) is preferably in the range of 0.75 to 0.99. 500 / T 700 The lower limit of T is more preferably about 0.76 or more, and the upper limit of T is more preferably about 0.90 or less. 500 / T 700 The preferred range of is preferably about 0.75 to 0.90, about 0.76 to 0.99, or about 0.76 to 0.90. 500 / T 700 When the T of the adhesive protective film is in this range, the discriminability of the adhesive protective film is further improved. That is, when detecting the position of the adhesive protective film using two light sources, one containing mainly light with a wavelength of 500 nm and the other containing mainly light with a wavelength of 700 nm, 500 / T 700By using the above range, it becomes possible to detect differences due to contrast in optical characteristics that are difficult to detect with a single light source, enabling more reliable position detection. Furthermore, by using these two light sources, it is possible to effectively detect the presence of foreign matter on the surface or inside of the adhesive protective film, the presence of wrinkles, internal defects, etc.

[0038] From the same viewpoint, in the adhesive protective film of the present invention, the transmittance percentage T of light having a wavelength of 550 nm is 550 is the percent transmittance T of light with a wavelength of 350 nm. 350 Divided by (T 550 / T 350 ) is preferably in the range of 1.00 to 35.00. 550 / T 350 The lower limit of T is preferably about 1.10 or more, more preferably about 2.70 or more, and the upper limit of T is preferably about 30.00 or less, more preferably about 29.50 or less. 550 / T 350 Preferred ranges of are preferably about 1.00 to 30.00, about 1.00 to 29.50, about 1.10 to 35.00, about 1.10 to 30.00, about 1.10 to 29.50, about 2.70 to 35.00, about 2.70 to 30.00, and about 2.70 to 29.50. 550 / T 350 By having such a value, the discriminability of the adhesive protective film is further improved. That is, when detecting the position of the adhesive protective film using two types of light sources, that is, a light source mainly including light with a wavelength of 550 nm and a light source mainly including light with a wavelength of 350 nm, the T 550 / T 350 By using the above range, it becomes possible to detect differences due to contrast in optical characteristics that are difficult to detect with a single light source, enabling more reliable position detection. Furthermore, by using these two light sources, it is possible to effectively detect the presence of foreign matter on the surface or inside of the adhesive protective film, the presence of wrinkles, internal defects, etc.

[0039] Further, from the same viewpoint, in the adhesive protective film of the present invention, the haze is preferably in the range of 50 to 89. The lower limit of the haze is more preferably about 55 or more, and even more preferably about 60 or more, and the upper limit is more preferably about 88 or less, and even more preferably about 85 or less. In addition, the preferred ranges of the haze include about 50 to 88, about 50 to 85, about 55 to 89, about 55 to 88, about 55 to 85, about 60 to 89, about 60 to 88, and about 60 to 85. When the haze has such a value, the distinguishability of the adhesive protective film is further improved. As described above, the second adhesive protective film of the present invention is characterized in that the haze is in the range of 50 or more and 89 or less. Note that these haze values ​​are values ​​measured for one adhesive protective film.

[0040] From the same viewpoint, the absolute value of the difference between the haze measured for one adhesive protective film and the haze (II) measured by stacking two adhesive protective films (the haze measured by stacking two adhesive protective films is referred to as "haze (II)"), |haze-haze (II)|, is preferably about 8.5 or more, more preferably about 9 or more, and even more preferably about 15 or more, and is preferably about 30 or less, more preferably about 25 or less, and even more preferably about 23 or less. In addition, preferred ranges of |haze-haze (II)| include about 8.5 to 30, about 8.5 to 25, about 8.5 to 23, about 9 to 30, about 9 to 25, about 9 to 23, about 15 to 30, about 15 to 25, and about 15 to 23. As described above, the fifth adhesive protective film of the present invention is characterized in that the absolute value of the difference between the haze measured for one sheet of the adhesive protective film and the haze measured for two sheets of the adhesive protective film stacked together, |Haze-Haze (II)|, is 8.5 or more.

[0041] From the same viewpoint, the lower limit of the haze (II) is preferably 80 or more, more preferably 85 or more, and the upper limit is preferably 98 or less, more preferably 95 or less. Preferred ranges of the haze (II) include about 80 to 98, about 80 to 95, about 85 to 98, and about 85 to 95.

[0042] In the present invention, the haze of the adhesive protective film is a value measured by the following method.

[0043] <Haze measurement> The haze is measured using a haze meter. The haze may be measured from either the upper surface or the lower surface of the adhesive protective film, but the above-mentioned haze value only needs to be satisfied when measured from at least one of the upper surface and the lower surface.

[0044] The method for adjusting the optical properties of the adhesive protective film 1 of the present invention is not particularly limited, and examples thereof include a method of coloring at least one of the layers constituting the adhesive protective film 1 with a colorant. Another example includes a method of adjusting the optical properties by using a nonwoven fabric or the like as a substrate. Another example includes a method of selecting a resin with low transparency and using it for the layers constituting the adhesive protective film 1. Another example includes a method of adjusting the thickness of the adhesive protective film 1.

[0045] The colorant is not particularly limited, and known pigments, dyes, etc. can be used. Specific examples of the colorant include carbon black, titanium oxide, etc.

[0046] Layer structure of adhesive protective film As described above, the adhesive protective film of the present invention includes all of the first to fifth adhesive protective films. The layer structure of the adhesive protective film of the present invention is not particularly limited. Hereinafter, the layer structure of the adhesive protective film 1 of the present invention will be described with reference to Figs. 6 to 12.

[0047] For example, as shown in FIG. 6, the adhesive protective film 1 may be configured as a single layer.

[0048] Also, as shown in FIG. 7, the adhesive protective film 1 may have a two-layer structure of a substrate 11 and a first polyolefin layer 12a, or as shown in FIG. 8, the adhesive protective film 1 may have a three-layer structure in which a first polyolefin layer 12a and a second polyolefin layer 12b are laminated via a substrate 11. At least one of the first polyolefin layer 12a and the second polyolefin layer 12b may be composed of two or more layers. FIG. 9 illustrates a case in which the first polyolefin layer 12a has a two-layer structure of a first polyolefin layer 12aa and a first polyolefin layer 12ab, and the second polyolefin layer 12b has a two-layer structure of a second polyolefin layer 12ba and a second polyolefin layer 12bb. As shown in FIG. 7 to FIG. 9, by providing the substrate 11, the shape retention of the adhesive protective film 1 can be improved. Furthermore, as shown in Figures 8 and 9, by providing a substrate 11, a first polyolefin layer 12a formed from an acid-modified polyolefin or polyolefin located on one side of the substrate 11, and a second polyolefin layer 12b formed from an acid-modified polyolefin or polyolefin located on the other side of the substrate 11, the adhesion on both sides of the adhesive protective film 1 can be increased.

[0049] 10 to 12, from the viewpoint of enhancing adhesion between the substrate 11 and the first polyolefin layer 12a and / or between the substrate 11 and the second polyolefin layer 12b, it is preferable to provide an adhesion promoter layer 13 between these layers. In particular, when the substrate 11 is made of a film such as polyester and the first polyolefin layer 12a and the second polyolefin layer 12b are made of acid-modified polyolefin or polyolefin, it is preferable to provide the adhesion promoter layer 13 in order to enhance the adhesion between these layers.

[0050] On the other hand, when the substrate 11 is made of, for example, a nonwoven fabric, the substrate 11 may have an adhesion promoter layer 13, but the substrate 11 may be impregnated with the first polyolefin layer 12a and the second polyolefin layer 12b to increase the adhesion between these layers, so that it is possible to ensure high adhesion between these layers even without the adhesion promoter layer 13, as shown in Figures 7 to 9. Also, when the substrate 11 is made of polyolefin and the first polyolefin layer 12a or the second polyolefin layer 12b is also made of polyolefin or acid-modified polyolefin, the substrate 11 may have an adhesion promoter layer 13, but since the layers are laminated with the same type of resin, it is possible to ensure high adhesion between these layers even without the adhesion promoter layer 13.

[0051] The thickness (total thickness) of the adhesive protective film 1 is not particularly limited, but is preferably about 50 to 150 μm, and more preferably about 70 to 150 μm.

[0052] 6, when the adhesive protective film 1 of the present invention is constructed as a single layer, the adhesive protective film 1 can be formed of a polyolefin or an acid-modified polyolefin exemplified in the section [First polyolefin layer 12a] described later, and may contain an adhesive component described later, as in the first polyolefin layer 12a. The adhesive protective film 1 can also be formed of a curable acid-modified polyolefin.

[0053] The curable acid-modified polyolefin may be a resin composition containing an acid-modified polyolefin and a curing agent. The acid-modified polyolefin may be the same as those exemplified in the section of [First polyolefin layer 12a] described later. For example, as shown in Figs. 1 to 3, in the portion where the metal terminal 2 is sandwiched by the packaging material 3, two adhesive protective films 1 formed of a resin composition containing an acid-modified polyolefin and a curing agent are arranged on both sides of the metal terminal 2 so as to sandwich the metal terminal 2, and the battery element 20 is sealed by heat sealing from both sides of the packaging material 3, and then the adhesive protective films 1 are irradiated with ionizing radiation to cure the adhesive protective films 1. That is, when the adhesive protective film 1 is arranged at a predetermined position, it is preferable that the curable acid-modified polyolefin is thermoplastic and has ionizing radiation curability.

[0054] The curing agent is not particularly limited as long as it can cure the acid-modified polyolefin by irradiation with ionizing radiation such as electron beams or gamma rays, and examples thereof include acrylic acid or methacrylic acid esters. Specifically, examples include acrylic acid or methacrylic acid esters such as ethylene glycol diacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, trimethylolpropane triacrylate, ethylene glycol dimethacrylate, and trimethylolpropane trimethacrylate; divinyl compounds such as divinylbenzene and divinylpyridine; esters of allyl alcohol and acrylic acid or methacrylic acid such as diaryl fumarate; triallyl cyanurate, triallyl isocyanurate, and the like. The higher the amount added, the higher the degree of crosslinking, but the more likely the material becomes brittle, so it is necessary to select an optimal value. The amount of curing agent added should be 23% by mass or less.

[0055] As a commercially available product of the curing agent, for example, triallyl isocyanurate (for example, TAIC (registered trademark) manufactured by Nippon Kasei Kasei Co., Ltd.) can be used, and the amount added is preferably 0.5 to 10 mass %. Moreover, the irradiation with ionizing radiation is preferably about 50 to 200 kGy, more preferably about 70 to 130 kGy.

[0056] By blending a colorant into the single-layer adhesive protective film 1, it is possible to color the adhesive protective film 1 and adjust the light transmittance. In addition, it is possible to adjust the light transmittance of the adhesive protective film 1 by selecting a resin with low transparency.

[0057] The adhesive protective film 1 can be a laminate in which at least two layers selected from the substrate 11, the first polyolefin layer 12a, the second polyolefin layer 12b, the adhesion promoter layer 13, and the like are laminated.

[0058] [Base material 11] In the adhesive protective film 1 , the substrate 11 is a layer that functions as a support for the adhesive protective film 1 .

[0059] There is no particular limitation on the material forming the base material 11. Examples of the material forming the base material 11 include polyolefin, polyamide, polyester, epoxy resin, acrylic resin, fluororesin, silicone resin, phenol resin, polyetherimide, polyimide, polycarbonate, and mixtures and copolymers thereof.

[0060] Specific examples of polyolefins include polyethylenes such as low-density polyethylene, medium-density polyethylene, high-density polyethylene, and linear low-density polyethylene; crystalline or amorphous polypropylenes such as homopolypropylene, block copolymers of polypropylene (e.g., block copolymers of propylene and ethylene), and random copolymers of polypropylene (e.g., random copolymers of propylene and ethylene); and ethylene-butene-propylene terpolymers. Among these polyolefins, polyethylene and polypropylene are preferred, and polypropylene is more preferred.

[0061] Specific examples of polyamides include aliphatic polyamides such as nylon 6, nylon 66, nylon 610, nylon 12, nylon 46, and copolymers of nylon 6 and nylon 66; hexamethylenediamine-isophthalic acid-terephthalic acid copolymer polyamides such as nylon 6I, nylon 6T, nylon 6IT, and nylon 6I6T (I represents isophthalic acid, and T represents terephthalic acid) containing structural units derived from terephthalic acid and / or isophthalic acid, and aromatic polyamides such as polymetaxylylene adipamide (MXD6); alicyclic polyamides such as polybis(4-aminocyclohexyl)methane adipamide; polyamides copolymerized with lactam components and isocyanate components such as 4,4'-diphenylmethane diisocyanate; polyesteramide copolymers and polyetheresteramide copolymers, which are copolymers of copolymerized polyamides with polyesters or polyalkylene ether glycols; and copolymers thereof. These polyamides may be used alone or in combination of two or more.

[0062] Specific examples of polyesters include polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polyethylene isophthalate, copolymerized polyesters mainly composed of ethylene terephthalate as repeating units, copolymerized polyesters mainly composed of butylene terephthalate as repeating units, etc. Specific examples of copolymerized polyesters mainly composed of ethylene terephthalate as repeating units include copolymer polyesters in which ethylene terephthalate as a main repeating unit is polymerized with ethylene isophthalate (hereinafter abbreviated as polyethylene (terephthalate / isophthalate)), polyethylene (terephthalate / isophthalate), polyethylene (terephthalate / adipate), polyethylene (terephthalate / sodium sulfoisophthalate), polyethylene (terephthalate / sodium isophthalate), polyethylene (terephthalate / phenyl-dicarboxylate), polyethylene (terephthalate / decane dicarboxylate), etc. Specific examples of copolymer polyesters containing butylene terephthalate as the main repeating unit include copolymer polyesters in which butylene terephthalate is the main repeating unit and is polymerized with butylene isophthalate (hereinafter abbreviated as polybutylene (terephthalate / isophthalate)), polybutylene (terephthalate / adipate), polybutylene (terephthalate / sebacate), polybutylene (terephthalate / decanedicarboxylate), polybutylene naphthalate, etc. These polyesters may be used alone or in combination of two or more.

[0063] The substrate 11 may be composed of a uniaxially or biaxially stretched resin film, or may be composed of an unstretched resin film. Among these, a uniaxially or biaxially stretched resin film, particularly a biaxially stretched resin film, is preferably used as the substrate 11 because its heat resistance is improved by oriented crystallization.

[0064] Examples of the resin film forming the substrate 11 include a polyester film, and more preferably, a polyethylene naphthalate film, which has high water vapor barrier properties and excellent heat resistance. The polyethylene naphthalate film is a film formed from polyethylene naphthalate (hereinafter, sometimes referred to as "PEN").

[0065] PEN film has a higher melting point and glass transition point and is superior in mechanical strength in a high-temperature environment compared to polyethylene terephthalate (PET) film, polyolefin film, acid-modified polyolefin film, etc. Therefore, even when the adhesive protective film 1 is heat-sealed while being sandwiched between the metal terminal 2 and the packaging material 3, the PEN film is less likely to become thin, and can effectively prevent a short circuit between the metal terminal 2 and the barrier layer 33 of the packaging material 3.

[0066] In addition, PEN film has a lower water vapor permeability and superior water vapor barrier properties compared to PET film, so it can effectively prevent water vapor from penetrating the PEN film and entering the battery, allowing the battery life to be extended as designed.

[0067] The substrate 11 may be made of a nonwoven fabric made of the above-mentioned resin. When the substrate 11 is a nonwoven fabric, the substrate 11 is preferably made of the above-mentioned polyolefin, polyamide, or the like.

[0068] As described above, the substrate 11 can be made into a layer containing a colorant by blending a colorant in the substrate 11. Also, the light transmittance can be adjusted by selecting a resin with low transparency. When the substrate 11 is a film, a colored film or a film with low transparency can be used. When the substrate 11 is a nonwoven fabric, a nonwoven fabric using a fiber or binder containing a colorant or a nonwoven fabric with low transparency can be used.

[0069] When the substrate 11 is made of a resin film, the surface of the substrate 11 may be subjected to a known adhesion enhancing treatment such as corona discharge treatment, ozone treatment, or plasma treatment, if necessary.

[0070] The thickness of the substrate 11 is not particularly limited, and is preferably about 5 to 100 μm, more preferably about 8 to 80 μm, from the viewpoint of preventing short circuits.

[0071] [First polyolefin layer 12a] The adhesive protective film 1 may include a first polyolefin layer 12a formed of an acid-modified polyolefin or a polyolefin. The first polyolefin layer 12a is located on one side of the substrate 11.

[0072] The first polyolefin layer 12a contains a polyolefin skeleton. The fact that the first polyolefin layer 12a contains a polyolefin skeleton can be determined by, for example, infrared spectroscopy, gas chromatography mass spectrometry, or the like, and the analysis method is not particularly limited. For example, when maleic anhydride-modified polyolefin is measured by infrared spectroscopy, a polyolefin skeleton is detected at a wave number of 1760 cm. -1 Nearby and wave number 1780cm -1 A peak derived from maleic anhydride is detected around the peak. The polyolefin contained in the first polyolefin layer 12a is not particularly limited, but from the viewpoint of suitable adhesion not only to resin members but also to inorganic members such as metals and ceramics, preferred examples include acid-modified polyolefins.

[0073] Acid-modified polyolefin has a high affinity with metals and heat-sealing resins such as polyolefins. Therefore, for example, when the adhesive protective film 1 is applied to a battery using a film-like packaging material, the adhesion at the interface between the first polyolefin layer 12a and the metal terminal 2 can be improved by disposing the first polyolefin layer 12a formed from the acid-modified polyolefin on the metal terminal 2 side.

[0074] Specific examples of polyolefins forming the first polyolefin layer 12a include polyethylenes such as low-density polyethylene, medium-density polyethylene, high-density polyethylene, and linear low-density polyethylene; crystalline or amorphous polypropylenes such as homopolypropylene, block copolymers of polypropylene (e.g., block copolymers of propylene and ethylene), and random copolymers of polypropylene (e.g., random copolymers of propylene and ethylene); and ethylene-butene-propylene terpolymers. Among these polyolefins, polyethylene and polypropylene are preferable.

[0075] The polyolefin may be a cyclic polyolefin. For example, a carboxylic acid-modified cyclic polyolefin is a polymer obtained by copolymerizing a part of the monomers constituting the cyclic polyolefin with an α,β-unsaturated carboxylic acid or its anhydride, or by block-polymerizing or graft-polymerizing an α,β-unsaturated carboxylic acid or its anhydride to the cyclic polyolefin. The cyclic polyolefin is a copolymer of an olefin and a cyclic monomer, and examples of the olefins constituting the cyclic polyolefin include ethylene, propylene, 4-methyl-1-pentene, butadiene, and isoprene. Examples of the cyclic monomers constituting the cyclic polyolefin include cyclic alkenes such as norbornene; specifically, cyclic dienes such as cyclopentadiene, dicyclopentadiene, cyclohexadiene, and norbornadiene. Among these polyolefins, cyclic alkenes are preferred, and norbornene is more preferred.

[0076] The acid-modified polyolefin forming the first polyolefin layer 12a is not particularly limited as long as it is an acid-modified polyolefin, but is preferably a polyolefin graft-modified with an unsaturated carboxylic acid or an anhydride thereof.

[0077] Examples of the polyolefin to be acid-modified include the same polyolefins as those exemplified as the polyolefin forming the first polyolefin layer 12a.

[0078] Examples of the carboxylic acid or anhydride thereof used for the acid modification include maleic acid, acrylic acid, itaconic acid, crotonic acid, maleic anhydride, and itaconic anhydride.

[0079] From the viewpoint of achieving favorable adhesion to inorganic members such as metals and ceramics, among the polyolefins contained in the first polyolefin layer 12a, modified polyolefins such as maleic anhydride modified polypropylene are particularly preferred.

[0080] The first polyolefin layer 12a may be formed of one type of resin component alone, or may be formed of a blend polymer of two or more types of resin components. Furthermore, the first polyolefin layer 12a may be formed of only one layer, or may be formed of two or more layers of the same or different resin components. As described above, FIG. 9 shows an example in which the first polyolefin layer 12a has a two-layer structure of a first polyolefin layer 12aa and a first polyolefin layer 12ab.

[0081] The proportion of polyolefin or acid-modified polyolefin contained in the first polyolefin layer 12a is not particularly limited, but the lower limit is preferably about 70% by mass or more, more preferably about 80% by mass or more, and the upper limit is preferably about 100% by mass or less, more preferably about 95% by mass or less, and even more preferably about 90% by mass or less. The range of the proportion of polyolefin is preferably about 70 to 100% by mass, about 70 to 95% by mass, about 70 to 90% by mass, about 80 to 100% by mass, about 80 to 95% by mass, and about 80 to 90% by mass. When the proportion of polyolefin or acid-modified polyolefin contained in the first polyolefin layer 12a has such a value, the adhesive protective film 1 of the present invention can suitably exhibit excellent adhesion.

[0082] The first polyolefin layer 12a preferably further contains an adhesive component. More specifically, the first polyolefin layer 12a is preferably composed of a polyolefin or an acid-modified polyolefin containing an adhesive component. By including an adhesive component in the first polyolefin layer 12a, the first polyolefin layer of the adhesive protective film 1 can be suitably temporarily attached to a metal terminal or the like, and it is possible to suppress positional deviation during heat fusion. In the present invention, temporary attachment means a temporary adhesion, and is a state in which it can be peeled off even after it has been temporarily attached.

[0083] The adhesive component is not particularly limited as long as it can impart adhesiveness to the first polyolefin layer 12a, and examples thereof include rosin or its derivatives such as rosin, hydrogenated rosin, polymerized rosin, and rosin ester; terpene resins such as α-pinene, β-pinene, and limonene; terpene-phenol resins, coumarone-indene resins, styrene-based resins, xylene-based resins, phenol-based resins, petroleum resins, and hydrogenated petroleum resins. Hydrogenated terpene resins, rosin resins, and petroleum resins are compatible with the elastomer phase of styrene-based block copolymers, and are highly effective in improving adhesion to non-polar members such as polyolefins, while xylene-based resins, phenol-based resins, and styrene-based resins are compatible with the styrene phase and have the effect of increasing cohesive force. For this reason, hydrogenated terpene resins, rosin resins, and petroleum resins can be combined with xylene-based resins, phenol-based resins, and styrene-based resins to form adhesive components.

[0084] In addition, amorphous polyolefins can also be used as the adhesive component. Examples of amorphous polyolefins include amorphous polypropylene, or copolymers of amorphous propylene and other α-olefins, and specific examples include propylene-ethylene copolymers, propylene-butene-1 copolymers, propylene-butene-1-ethylene terpolymers, propylene-hexene-1-octene-1 terpolymers, propylene-hexene-1-4-methylpentene-1-terpolymers, propylene-hexene-1-4-methylpentene-1-terpolymers, and polybutene-1. Among the target amorphous alpha polyolefins, those with a high content of low molecular weight components, a number average molecular weight of 20,000 or less, and a glass transition point of -20°C or less are preferred.

[0085] The adhesive component is preferably an amorphous polyolefin. Commercially available amorphous polyolefin products include, for example, REXtac2280 (manufactured by REXtac. LLC). In the first polyolefin layer 12a, when REXtac2280 is used as the adhesive component and an acid-modified polyolefin is used, the content of REXtac2280 is preferably about 10 parts by mass or about 20 parts by mass relative to 100 parts by mass of the acid-modified polyolefin.

[0086] The adhesive component may be used alone or in combination of two or more kinds.

[0087] The ratio of the adhesive component contained in the first polyolefin layer 12a is not particularly limited, but the lower limit is preferably about 1% by mass or more, more preferably about 5% by mass or more, and the upper limit is preferably about 30% by mass or less, more preferably about 25% by mass or less. The range of the ratio of the adhesive component is preferably about 1 to 30% by mass, about 1 to 25% by mass, about 5 to 30% by mass, or about 5 to 25% by mass. Since the ratio of the adhesive component contained in the first polyolefin layer 12a has such a value, the adhesive protective film 1 of the present invention can suitably exhibit excellent adhesion and excellent heat fusion properties, and can be more suitably heat fused to metal terminals, etc. In particular, the adhesive protective film 1 can be suitably temporarily attached to metal terminals, etc., and the adhesive protective film 1 can be heat fused to metal terminals, etc. by suppressing positional deviation during heat fusion.

[0088] When the first polyolefin layer 12a is composed of multiple layers, at least one of the layers can contain an adhesive, and the adhesive may be contained in only one layer or in multiple layers.

[0089] The first polyolefin layer 12a may contain an additive functioning as a spacer as necessary. When the first polyolefin layer 12a contains an additive, it becomes possible to more effectively suppress short-circuiting between the metal terminal 2 and the barrier layer 33 of the packaging material 3. The particle size of the additive may be in the range of about 0.1 to 35 μm, preferably about 5.0 to 30 μm, and more preferably about 10 to 25 μm. The content of the additive may be about 5 to 30 parts by mass, and more preferably about 10 to 20 parts by mass, relative to 100 parts by mass of the resin component forming the first polyolefin layer 12a.

[0090] As the additive, either inorganic or organic additives can be used. Examples of inorganic additives include carbon (carbon, graphite), silica, aluminum oxide, barium titanate, iron oxide, silicon carbide, zirconium oxide, zirconium silicate, magnesium oxide, titanium oxide, calcium aluminate, calcium hydroxide, aluminum hydroxide, magnesium hydroxide, calcium carbonate, etc. Examples of organic additives include fluororesin, phenolic resin, urea resin, epoxy resin, acrylic resin, benzoguanamine-formaldehyde condensate, melamine-formaldehyde condensate, polymethyl methacrylate crosslinked product, polyethylene crosslinked product, etc. From the viewpoints of shape stability, rigidity, and content resistance, aluminum oxide, silica, fluororesin, acrylic resin, and benzoguanamine-formaldehyde condensate are preferred, and among these, spherical aluminum oxide and silica are more preferred. As a method for mixing the additive into the resin component forming the first polyolefin layer 12a, a method in which the two are melt-blended in advance using a Banbury mixer or the like to prepare a master batch and then adjusted to a predetermined mixing ratio, or a method in which the additive is directly mixed with the resin component can be used.

[0091] As described above, the first polyolefin layer 12a can be made into a layer containing a colorant by blending the first polyolefin layer 12a with a colorant. Also, the light transmittance can be adjusted by selecting a resin with low transparency.

[0092] When the first polyolefin layer 12a is composed of multiple layers, at least one of the layers may be colored or have low transparency, only one layer may be colored or have low transparency, or multiple layers may be colored or have low transparency.

[0093] The thickness of the first polyolefin layer 12a can be appropriately selected depending on the layer structure of the adhesive protective film 1. When applied to a battery using a film-like packaging material, the thickness is preferably about 10 to 100 μm, more preferably about 12 to 90 μm, taking into consideration the embedding of resin after heat sealing and pinholes.

[0094] [Second polyolefin layer 12b] The adhesive protective film 1 may include a second polyolefin layer 12b formed from an acid-modified polyolefin or a polyolefin. The second polyolefin layer 12b is located on the surface of the substrate 11 opposite to the first polyolefin layer 12a.

[0095] Specific examples of the polyolefin, acid-modified polyolefin, adhesive component, etc. that form the second polyolefin layer 12b include those exemplified in the above-mentioned section [First polyolefin layer 12a]. In addition, when the second polyolefin layer 12b is composed of multiple layers, at least one layer can contain an adhesive, and the adhesive may be contained in only one layer or in multiple layers.

[0096] The second polyolefin layer 12b may be formed of one type of resin component alone, or may be formed of a blend polymer of two or more types of resin components. Furthermore, the second polyolefin layer 12b may be formed of only one layer, or may be formed of two or more layers of the same or different resin components. As described above, Fig. 9 and Fig. 12 show an example in which the second polyolefin layer 12b has a two-layer structure of the second polyolefin layer 12ba and the second polyolefin layer 12bb.

[0097] Furthermore, the second polyolefin layer 12b may contain an additive, if necessary. When the second polyolefin layer 12b contains an additive, the content, type, etc. of the additive may be the same as those of the first polyolefin layer 12a described above.

[0098] As described above, the second polyolefin layer 12b can be made into a layer containing a colorant by blending a colorant in the second polyolefin layer 12b. Also, the light transmittance can be adjusted by selecting a resin with low transparency. When the second polyolefin layer 12b is composed of multiple layers, at least one layer can be colored or made less transparent, only one layer can be colored or made less transparent, or multiple layers can be colored or made less transparent.

[0099] The thickness of the second polyolefin layer 12b can be appropriately selected depending on the layer structure of the adhesive protective film 1. When applied to a battery using a film-like packaging material, the thickness is preferably about 10 to 100 μm, more preferably about 12 to 90 μm, taking into consideration the embedding of resin after heat sealing and pinholes.

[0100] [Adhesion promoter layer 13] The adhesion promoter layer 13 is a layer provided as necessary for the purpose of firmly adhering between the substrate 11 and the first polyolefin layer 12a and / or between the substrate 11 and the second polyolefin layer 12b. The adhesion promoter layer 13 may be provided on only one side between the substrate 11 and the first and second polyolefin layers 12a, 12b, or on both sides.

[0101] As described above, in particular in the adhesive protective film of the present invention, when the substrate 11 is composed of a film such as polyethylene terephthalate (PET) or polyethylene naphthalate (PEN) and the first polyolefin layer 12a and the second polyolefin layer 12b are composed of an acid-modified polyolefin or a polyolefin, it is preferable to provide an adhesion promoter layer 13 in order to enhance the adhesion between these layers.

[0102] The adhesion promoter layer 13 can be formed using known adhesion promoters such as isocyanate-based, polyethyleneimine-based, polyester-based, polyurethane-based, and polybutadiene-based. It can also be formed using known adhesives such as two-component curing adhesives and one-component curing adhesives. From the viewpoint of further improving electrolyte resistance, it is preferable to form the adhesion promoter using an isocyanate-based adhesion promoter. As the isocyanate-based adhesion promoter, one made of an isocyanate component selected from triisocyanate monomer and polymeric MDI has excellent laminate strength and shows little decrease in laminate strength after immersion in electrolyte. It is particularly preferable to form the adhesive using an adhesion promoter made of triphenylmethane-4,4',4"-triisocyanate, which is a triisocyanate monomer, or polymethylene polyphenyl polyisocyanate, which is a polymeric MDI (NCO content of approximately 30%, viscosity of 200 to 700 mPa s). It is also preferable to form the adhesive using a two-component curing adhesion promoter that uses tris(p-isocyanatephenyl)thiophosphate, which is a triisocyanate monomer, or a polyethyleneimine-based agent as the main agent and polycarbodiimide as the crosslinking agent.

[0103] The adhesion promoter layer 13 can be formed by coating and drying using a known coating method such as bar coating, roll coating, gravure coating, etc. The coating amount of the adhesion promoter is 20 to 100 mg / m in the case of an adhesion promoter made of triisocyanate. 2 , preferably 40 to 60 mg / m 2 In the case of adhesion promoters made of polymeric MDI, the range is 40 to 150 mg / m 2 , preferably 60 to 100 mg / m 2 In the case of a two-component curing type adhesion promoter that uses polyethyleneimine as the base agent and polycarbodiimide as the crosslinking agent, the adhesive strength is 5 to 50 mg / m 2 , preferably 10 to 30 mg / m 2 When using a known adhesive as an adhesion promoter, the upper limit of the coating amount is about 10 g / m 2 Below, the lower limit is about 1g / m 2It is also preferable that the triisocyanate monomer is a monomer having three isocyanate groups in one molecule, and the polymeric MDI is a mixture of MDI and MDI oligomers formed by polymerization of MDI, and is represented by the following formula (1).

[0104] [ka]

[0105] When the adhesive protective film 1 of the present invention has a layer structure as shown in Fig. 8, for example, it can be produced by laminating a first polyolefin layer 12a on one side of a substrate 11. When the adhesive protective film 1 has a layer structure as shown in Fig. 9, for example, it can be produced by laminating a first and a second polyolefin layer 12a, 12b on both sides of the substrate 11, respectively.

[0106] The substrate 11 and the first and second polyolefin layers 12a and 12b can be laminated by known methods such as extrusion lamination and thermal lamination. The same applies to the case where the first polyolefin layer 12a and the second polyolefin layer 12b each have two or more layers. When the substrate 11 and the first and second polyolefin layers 12a and 12b are laminated via the adhesion promoter layer 13, for example, the adhesion promoter constituting the adhesion promoter layer 13 may be applied and dried on the substrate 11 by the above-mentioned method, and the first and second polyolefin layers 12a and 12b may be laminated on the adhesion promoter layer 13.

[0107] The adhesive protective film 1 of the present invention may further have another layer laminated thereon that is different from the substrate 11, the first polyolefin layer 12a, the second polyolefin layer 12b, and the adhesion promoter layer 13.

[0108] Furthermore, the adhesive protective film 1 of the present invention may contain other additives such as lubricants, antioxidants, UV absorbers, light stabilizers, etc. Depending on the type and content of the additives, the adhesive protective film 1 may discolor.

[0109] When the adhesive protective film 1 of the present invention is configured as a single layer, a resin film manufactured by extrusion molding or the like can be used as the adhesive protective film 1. When the adhesive protective film 1 is a laminate having a substrate 11, a first polyolefin layer 12a, a second polyolefin layer 12b, an adhesion promoter layer 13, and the like, it can be manufactured by laminating these layers. As described above, the lamination method of these layers is not particularly limited, and can be performed using, for example, a thermal lamination method, a sandwich lamination method, an extrusion lamination method, or the like.

[0110] 2. Applications of adhesive protective films The adhesive protective film 1 of the present invention is useful, for example, in the manufacture of a battery using a film-like packaging material, as being interposed between a metal terminal 2 electrically connected to an electrode of a battery element 20 and a packaging material 3 that seals the battery element 20. Specifically, as shown in Figs. 1 to 3, for example, the adhesive protective film 1 of the present invention can be interposed between a metal terminal 2 electrically connected to an electrode of the battery element 20 and a packaging material 3 that seals the battery element 20. The adhesive protective film 1 of the present invention is T 400-800 is set in the range of 25 to 91%, it is easy to distinguish the color between the overlapping and non-overlapping parts of the adhesive protective film 1 when, for example, two sheets of the adhesive protective film 1 are sandwiched from both sides of the metal terminal 2 or one sheet of the adhesive protective film 1 is wrapped around the metal terminal 2 before heat sealing. That is, the overlapping parts are darker in color than the non-overlapping parts. Therefore, it is easy to detect whether the adhesive protective film 1 is misaligned by a camera-equipped sensor or visually.

[0111] As described below, the adhesive protective film 1 of the present invention can be used in a wide range of applications other than being interposed between a metal terminal and a packaging material that seals a battery element.

[0112] The metal terminal 2 protrudes outside the packaging material 3, and is sandwiched by the packaging material 3 via the adhesive protective film 1 at the peripheral edge 3a of the heat-sealed packaging material 3. In the present invention, the heat applied when heat-sealing the packaging material is usually in the range of about 160 to 190°C, and the pressure is usually in the range of about 1.0 to 2.0 MPa.

[0113] The method for interposing the adhesive protective film 1 between the metal terminal 2 and the packaging material 3 is not particularly limited, and for example, as shown in Figures 1 to 3, the adhesive protective film 1 can be arranged on both sides of the metal terminal 2 so as to sandwich the metal terminal 2 in the portion where the metal terminal 2 is sandwiched by the packaging material 3.

[0114] The metal terminal 2 and the packaging material 3 used in the manufacture of a battery using a film-like packaging material will be described in detail below.

[0115] [Metal terminal 2] The adhesive protective film 1 of the present invention can be used by being interposed between a metal terminal 2 and a packaging material 3. The metal terminal 2 (tab) is a member electrically connected to an electrode (positive electrode or negative electrode) of the battery element 20, and is made of a metal material. The metal material constituting the metal terminal 2 is not particularly limited, and examples thereof include aluminum, nickel, copper, etc. For example, the metal terminal 2 connected to the positive electrode of a lithium ion battery is usually made of aluminum, etc. Furthermore, the metal terminal connected to the negative electrode of a lithium ion battery is usually made of copper, nickel, etc.

[0116] From the viewpoint of enhancing resistance to electrolyte, it is preferable that the surface of the metal terminal 2 is subjected to a chemical conversion treatment. For example, when the metal terminal 2 is made of aluminum, specific examples of the chemical conversion treatment include known methods for forming an acid-resistant film using phosphates, chromates, fluorides, triazine thiol compounds, etc. Among the methods for forming an acid-resistant film, a phosphate chromate treatment using a compound consisting of three components: a phenolic resin, a chromium (III) fluoride compound, and phosphoric acid is preferable.

[0117] The size of the metal terminal 2 may be appropriately set depending on the size of the battery to be used, etc. The thickness of the metal terminal 2 is preferably about 50 to 1000 μm, more preferably about 70 to 800 μm. The length of the metal terminal 2 is preferably about 1 to 200 mm, more preferably about 3 to 150 mm. The width of the metal terminal 2 is preferably about 1 to 200 mm, more preferably about 3 to 150 mm.

[0118] [Packaging material 3] The packaging material 3 may have a laminated structure including at least a base material layer 31, a barrier layer 33, and a heat-sealable resin layer 34 in this order. FIG. 13 shows an example of a cross-sectional structure of the packaging material 3, in which the base material layer 31, the adhesive layer 32, the barrier layer 33, the adhesive layer 35, and the heat-sealable resin layer 34 are laminated in this order. In the packaging material 3, the base material layer 31 is the outermost layer, and the heat-sealable resin layer 34 is the innermost layer. When assembling the battery, the heat-sealable resin layers 34 located on the periphery of the battery element 20 are brought into contact with each other and heat-sealed to seal the battery element 20, thereby sealing the battery element 20. Note that FIGS. 1 to 3 show the battery 10 using an embossed type packaging material 3 formed by embossing or the like, but the packaging material 3 may be an unformed pouch type. Note that the pouch type includes three-sided seal, four-sided seal, pillow type, and the like, and any type may be used.

[0119] [Base material layer 31] In the packaging material 3, the base material layer 31 is a layer that functions as a base material for the packaging material and forms the outermost layer side.

[0120] The material forming the base material layer 31 is not particularly limited as long as it has insulating properties. Examples of materials forming the base material layer 31 include polyester, polyamide, epoxy, acrylic, fluororesin, polyurethane, silicone resin, phenol, polyetherimide, polyimide, polycarbonate, and mixtures and copolymers thereof.

[0121] The thickness of the base layer 31 is, for example, about 3 to 50 μm, and preferably about 10 to 35 μm.

[0122] [Adhesive layer 32] In the packaging material 3, the adhesive layer 32 is a layer that is disposed on the base material layer 31 as necessary in order to impart adhesion to the base material layer 31. That is, the adhesive layer 32 is provided between the base material layer 31 and the barrier layer 33 as necessary.

[0123] The adhesive layer 32 is formed of an adhesive capable of bonding the base material layer 31 and the barrier layer 33. The adhesive used to form the adhesive layer 32 may be a two-component curing adhesive or a one-component curing adhesive. The adhesion mechanism of the adhesive used to form the adhesive layer 32 is not particularly limited, and may be any of a chemical reaction type, a solvent volatilization type, a thermal melting type, a thermal pressure type, and the like.

[0124] The thickness of the adhesive layer 32 is, for example, about 1 to 10 μm, and preferably about 2 to 5 μm.

[0125] [Barrier layer 33] In the packaging material, the barrier layer 33 is a layer that has the function of preventing water vapor, oxygen, light, and the like from penetrating into the inside of the battery, in addition to improving the strength of the packaging material for the battery. Specific examples of metals constituting the barrier layer 33 include aluminum, stainless steel, titanium, and the like, and aluminum is preferred. The barrier layer 33 can be formed, for example, from a metal foil, a metal vapor deposition film, an inorganic oxide vapor deposition film, a carbon-containing inorganic oxide vapor deposition film, a film provided with these vapor deposition films, and the like, and is preferably formed from a metal foil, and more preferably from an aluminum foil. From the viewpoint of preventing the occurrence of wrinkles or pinholes in the barrier layer 33 during the production of the battery packaging material, it is more preferable that the barrier layer be formed from a soft aluminum foil such as annealed aluminum (JIS H4160:1994 A8021H-O, JIS H4160:1994 A8079H-O, JIS H4000:2014 A8021P-O, JIS H4000:2014 A8079P-O).

[0126] The thickness of the barrier layer 33 is not particularly limited as long as it functions as a barrier layer against water vapor and the like, but it can be, for example, about 10 to 100 μm, and preferably about 10 to 80 μm.

[0127] [Adhesive layer 35] In the packaging material 3, the adhesive layer 35 is a layer that is provided, if necessary, between the barrier layer 33 and the heat-sealable resin layer 34 in order to firmly bond the heat-sealable resin layer 34.

[0128] The adhesive layer 35 is formed of an adhesive capable of bonding the barrier layer 33 and the heat-fusible resin layer 34. The composition of the adhesive used to form the adhesive layer is not particularly limited, and examples thereof include a resin composition containing an acid-modified polyolefin. Examples of acid-modified polyolefins include those exemplified for the first polyolefin layer 12a. Other examples include polyethylenes such as low-density polyethylene, medium-density polyethylene, high-density polyethylene, and linear low-density polyethylene that have been acid-modified with an unsaturated carboxylic acid or an anhydride thereof (for example, those exemplified for the first polyolefin layer 12a).

[0129] The thickness of the adhesive layer 35 is, for example, about 1 to 50 μm, and preferably about 2 to 40 μm.

[0130] [Thermal adhesive resin layer 34] In the packaging material 3, the heat-sealable resin layer 34 corresponds to the innermost layer, and is a layer that seals the battery element by heat-sealing the heat-sealable resin layers together when the battery is assembled.

[0131] The resin component used in the heat-fusible resin layer 34 is not particularly limited as long as it is heat-fusible, and examples thereof include polyolefin and acid-modified polyolefin.

[0132] Examples of the polyolefin include the same ones as those exemplified for the first polyolefin layer 12a, and polyethylenes such as low-density polyethylene, medium-density polyethylene, high-density polyethylene, linear low-density polyethylene, etc. Examples of the acid-modified polyolefin include the same ones as those exemplified for the first polyolefin layer 12a.

[0133] The thickness of the heat-fusible resin layer 34 is not particularly limited, but is preferably 100 μm or less, more preferably about 15 to 60 μm, and even more preferably about 15 to 40 μm.

[0134] 3.Battery In the present invention, a battery 10 using a film-like packaging material includes at least a battery element 20 including a positive electrode, a negative electrode, and an electrolyte, a packaging material 3 that seals the battery element 20, and metal terminals 2 that are electrically connected to the positive electrode and the negative electrode, respectively, and protrude outside the packaging material 3. The battery 10 of the present invention is characterized in that the adhesive protective film 1 of the present invention is interposed between the metal terminals 2 and the packaging material 3.

[0135] Specifically, a battery element including at least a positive electrode, a negative electrode, and an electrolyte is packaged in a packaging material 3. With the metal terminals 2 connected to the positive and negative electrodes protruding outward, the adhesive protective film 1 of the present invention is interposed between the metal terminals 2 and the heat-sealing resin layer 34, and the battery element 20 is covered so that a flange portion of the packaging material (a region where the heat-sealing resin layers 34 come into contact with each other, the peripheral portion 3a of the packaging material) can be formed around the periphery of the battery element 20, and the heat-sealing resin layers 34 of the flange portion are heat-sealed to provide a battery 10 using the packaging material 3. When the battery element 20 is housed using the packaging material 3, the packaging material 3 is used so that the heat-sealing resin layer 34 of the packaging material 3 faces inside (the surface in contact with the battery element 20).

[0136] The batteries of the present invention may be either primary batteries or secondary batteries, but are preferably secondary batteries. The type of secondary battery is not particularly limited, and examples thereof include lithium ion batteries, lithium ion polymer batteries, lead acid batteries, nickel-hydrogen batteries, nickel-cadmium batteries, nickel-iron batteries, nickel-zinc batteries, silver oxide-zinc batteries, metal-air batteries, polyvalent cation batteries, condensers, and capacitors. Among these secondary batteries, lithium ion batteries and lithium ion polymer batteries are preferred.

[0137] The adhesive protective film 1 of the present invention can be used for purposes other than being interposed between a metal terminal and a packaging material that seals a battery element, and can be widely used for purposes in which a resin member, a metal member, a ceramic member, etc. are sandwiched and bonded from both sides using the adhesive protective film. Furthermore, the adhesive protective film 1 of the present invention can be bonded to a resin member, a metal member, a ceramic member, etc., and can be widely used for purposes requiring positional accuracy. EXAMPLES

[0138] The present invention will be described in detail below with reference to examples and comparative examples, but the present invention is not limited to these examples.

[0139] <Production of adhesive protective film> Example 1 A polyethylene naphthalate (PEN, 12 μm thick) substrate was treated with corona discharge on both sides. One side of the substrate was coated with 50 mg / m2 of triphenylmethane-4,4',4"-triisocyanate adhesion promoter in solid form. 2 At the same time, maleic anhydride modified polypropylene (PPa) as the first polyolefin layer was extruded and coated to a thickness of 44 μm using a T-die extruder. Next, the same adhesion promoter was applied to the other side of the substrate at a solid content of 50 mg / m 2 At the same time, PPa as the second polyolefin layer was extruded and coated to a thickness of 44 μm using a T-die extruder. After that, aging treatment was performed to obtain an adhesive protective film having a laminate of PPa (44 μm) / adhesion promoter layer / PEN (12 μm) / adhesion promoter layer / PPa (44 μm). The PPa as the first polyolefin layer and the second polyolefin layer was colored with carbon black.

[0140] Example 2 A polyethylene naphthalate (PEN, 12 μm thick) substrate was treated with corona discharge on both sides. One side of the substrate was coated with 50 mg / m2 of triphenylmethane-4,4',4"-triisocyanate adhesion promoter in solid form. 2At the same time, maleic anhydride modified polypropylene (PPa) as the first polyolefin layer was extruded and coated to a thickness of 30 μm using a T-die extruder. Next, the same adhesion promoter was applied to the other side of the substrate at a solid content of 50 mg / m 2 At the same time, PPa (thickness 30 μm) and maleic anhydride modified polyethylene (PEa, thickness 33 μm) were co-extruded and coated in two layers using a T-die extruder so that the PPa side was laminated on the adhesion promoter layer to form a second polyolefin layer. After that, an aging treatment was performed to obtain an adhesive protective film in which PPa (30 μm) / adhesion promoter layer / PEN (12 μm) / adhesion promoter layer / PPa (30 μm) / PEa (33 μm) were laminated. The PPa in the first polyolefin layer and the PPa contained in the second polyolefin layer were each colored with carbon black.

[0141] Example 3 On one side of a polyethylene nonwoven fabric (thickness 16 μm) as a substrate, maleic anhydride modified polypropylene (PPa) as a first polyolefin layer was extrusion coated to a thickness of 67 μm using a T-die extruder. Next, the same PPa as the first polyolefin layer was extrusion coated to a thickness of 67 μm using a T-die extruder on the other side of the nonwoven fabric to form a second polyolefin layer. After that, an aging treatment was performed to obtain an adhesive protective film in which PPa (67 μm) / nonwoven fabric (16 μm) / PPa (67 μm) were laminated. A white adhesive protective film was obtained.

[0142] Example 4 On one side of a polyamide nonwoven fabric (thickness 12 μm) as a substrate, maleic anhydride modified polypropylene (PPa) as a first polyolefin layer was extrusion coated to a thickness of 44 μm using a T-die extruder. Next, the same PPa as the first polyolefin layer was extrusion coated to a thickness of 44 μm using a T-die extruder on the other side of the nonwoven fabric to form a second polyolefin layer. After that, an aging treatment was performed to obtain an adhesive protective film in which PPa (44 μm) / nonwoven fabric (12 μm) / PPa (44 μm) were laminated. A pale yellow adhesive protective film was obtained.

[0143] Example 5 On one side of the unstretched polypropylene film (CPP, thickness 60 μm) as the substrate, maleic anhydride modified polypropylene (PPa) was extrusion coated to a thickness of 20 μm using a T-die extruder as the first polyolefin layer. Next, the same PPa as the first polyolefin layer was extrusion coated to a thickness of 20 μm using a T-die extruder on the other side of the substrate to form a second polyolefin layer. After that, an aging treatment was performed to obtain an adhesive protective film in which PPa (20 μm) / CPP (60 μm) / PPa (20 μm) were laminated.

[0144] Example 6 A mixed resin of polypropylene and polyethylene (PP+PE) was extruded and coated to a thickness of 20 μm on one side of a polypropylene film (PP, thickness 70 μm) as a first polyolefin layer using a T-die extruder. Next, the same mixed resin (PP+PE) as the first polyolefin layer was extruded and coated to a thickness of 20 μm on the other side of the substrate using a T-die extruder to form a second polyolefin layer. After that, an aging treatment was performed to obtain an adhesive protective film in which PP+PE (20 μm) / PP (70 μm) / PP+PE (20 μm) were laminated.

[0145] Example 7 A first polyolefin layer was formed by applying two layers of polypropylene (PP, thickness 15 μm) and a mixed resin of polypropylene and polyethylene (PP+PE, 35 μm) by coextrusion coating using a T-die extruder on one side of a polypropylene film (PP, thickness 10 μm) as a substrate. Next, a second polyolefin layer was formed by applying two layers of polypropylene (PP, thickness 15 μm) and a mixed resin of polypropylene and polyethylene (PP+PE, 25 μm) by coextrusion coating using a T-die extruder on the other side of the substrate. After that, an aging treatment was performed to obtain an adhesive protective film in which PP+PE (35 μm) / PP (15 μm) / PP (10 μm) / PP (15 μm) / PP+PE (25 μm) were laminated. Both PP (15 μm) were colored gray.

[0146] Example 8 A mixed resin of polypropylene and polyethylene (PP+PE) was extruded and coated to a thickness of 30 μm using a T-die extruder on one side of a polypropylene film (PP, thickness 40 μm) as a substrate to form a first polyolefin layer. Next, the same mixed resin (PP+PE) as the first polyolefin layer was extruded and coated to a thickness of 30 μm using a T-die extruder on the other side of the substrate to form a second polyolefin layer. After that, an aging treatment was performed to obtain an adhesive protective film in which PP+PE (30 μm) / PP (40 μm) / PP+PE (30 μm) were laminated.

[0147] Comparative Example 1 A 12 μm thick polyethylene naphthalate (PEN) film was used as the adhesive protective film.

[0148] Comparative Example 2 A film in which carbon black was kneaded into polyethylene terephthalate (PET) was used as an adhesive protective film (thickness 12 μm).

[0149] Comparative Example 3 A film in which carbon black was kneaded into polyethylene terephthalate (PET) so as to have a lighter color than that of Comparative Example 2 was used as an adhesive protective film (thickness 12 μm).

[0150] <Measurement of the percentage of light transmission> Using a spectrophotometer (V670, manufactured by JASCO Corporation), the adhesive protective film obtained above was irradiated with light of a predetermined wavelength from one side of the adhesive protective film to measure the light transmittance percentage. The measurement conditions were as follows. The results are shown in Table 1. Data interval: 1 nm Measurement range: 190nm to 1500nm UV-Visible Bandwidth: 5.0nm Near infrared bandwidth: 20.0 nm Response: Fast Scanning speed: 1000nm / min Light source: Deuterium discharge tube, halogen lamp Light source switching: 340 nm Diffraction grating switching: 800nm

[0151] First, a baseline is obtained using a sample folder with a measurement area of ​​φ3 mm without a sample placed in it. Next, an adhesive protective film with a size of φ3 mm or more is placed in the sample folder as a sample, and the light transmittance percentage is measured. The light transmittance percentage for a wavelength range is the average value of the light transmittance percentage at wavelength intervals of 1 nm in that range. For example, the light transmittance percentage for a wavelength range of 400 nm to 800 nm is the average value of the light transmittance percentage obtained by measuring the light transmittance percentage for wavelengths that differ by 1 nm in increments in the range of 400 nm to 800 nm.

[0152] <Haze measurement> For each of the adhesive protective films obtained above, the haze was measured in accordance with JIS K7136:2000 using a haze meter (Murakami Color Research Laboratory Co., Ltd., device name HM-150). The sample size was about 30 mm x 30 mm, the light source was a halogen lamp with a dichroic mirror, the filter was A light, D65 light filter switching type, and the light receiving element was a planar type silicon photocell. Note that JIS K7136:2000 is a single beam, but HM-150 is a double beam. Also, JIS K7136:2000 is applicable to materials with a haze value of 40% or less, but in the present invention, measurements were made in accordance with this. The results are shown in Table 1.

[0153] <Evaluation of position accuracy> Two pieces of each of the adhesive protective films obtained above were prepared by cutting them into rectangles of 60 mm (length) × 4 mm (width). In addition, one aluminum metal terminal (50 mm (length) × 3 mm (width)) with a thickness of 100 μm was prepared. Next, the metal terminal was sandwiched between two adhesive protective films while aligning the length and width so that the horizontal center of the metal terminal and the horizontal center of the adhesive protective film were aligned, and the two adhesive protective films were heat-sealed from both sides with a hot plate (heat sealing conditions: temperature 190 ° C, surface pressure 1.0 MPa, time 3 seconds) to produce a joint of the metal terminal and the adhesive protective film. The joint obtained was observed, and when the length of the parts of the two adhesive protective films that did not overlap each other was within 0.1 mm, it was determined that the positional deviation was easily detected and corrected, and the adhesive protective film was positioned with high positional accuracy. On the other hand, if the length of the non-overlapping parts exceeds 0.1 mm, it is deemed that the misalignment is difficult to detect, the positional accuracy of the adhesive protective film placement is low, and misalignment has occurred. The positional accuracy of each adhesive protective film was measured 10 times and evaluated according to the following criteria. The results are shown in Table 1. A: No misalignment occurred B: Only one misalignment occurred C: Position misalignment occurred more than twice

[0154] [Table 1]

[0155] T 400-800 However, when the adhesive protective films of Examples 1 to 8, which have a color difference of 25% or more and 91% or less, were used, the color difference between the overlapping and non-overlapping parts of the two adhesive protective films was large, and it was easy to correct the positional deviation, so that it was possible to position the adhesive protective films with high positional accuracy, as shown in Table 1. 400-800 However, in Comparative Example 1, which exceeded 91%, the color difference between the overlapping and non-overlapping parts of the two adhesive protective films was small, making it difficult to detect the misalignment, resulting in low positional accuracy in the placement of the adhesive protective films. 400-800However, in comparison example 2, where the difference in color was less than 25%, the color difference between the overlapping and non-overlapping areas of the two adhesive protective films was small, making it difficult to detect misalignment, resulting in low positional accuracy in the placement of the adhesive protective films.

[0156] <Measurement of the percentage of light transmission when two adhesive protective films are stacked> For each of the adhesive protective films of Examples 1, 2, and 7 and Comparative Example 3, the light transmittance percentage T(II) was measured in the same manner as in the above <Measurement of the light transmittance percentage>, except that two identical adhesive protective films were stacked together to perform the measurement. 400-800 The method for overlapping two adhesive protective films involved attaching double-sided tape of about 100 μm thickness to the top and bottom edges of one adhesive protective film, and then attaching the other adhesive protective film to the two films while taking care not to wrinkle them. Measurements were carried out on this sample. The parts of the sample that were not attached with the double-sided tape were used as the measurement points. Table 2 below shows the light transmittance percentage T measured for each adhesive protective film. 400-800 and the percent light transmission T(II) measured with two sheets of each adhesive protective film stacked together. 400-800 and the percent light transmission T 400-800 and percent light transmission T(II) 400-800 The absolute value of the difference between 400-800 -T(II) 400-800 |) and the position accuracy results mentioned above.

[0157] [Table 2]

[0158] From the results shown in Table 2, the colored adhesive protective film has a light transmittance percentage T 400-800 and percent light transmission T(II) 400-800 The absolute value of the difference between 400-800 -T(II) 400-800 It can be seen that in Examples 1, 2, and 7, where |) is large, the adhesive protective film can be positioned with high positional accuracy.

[0159] <Haze measurement when two adhesive protective films are stacked> For each adhesive protective film of Examples 1, 2, 4, 5 and Comparative Example 1, the haze (II) was measured in the same manner as in <Haze Measurement>, except that the same adhesive protective film was stacked two times and the measurement was performed. In addition, as a method of stacking two films, a double-sided tape of about 100 μm was attached to the upper and lower ends of one adhesive protective film, and the other adhesive protective film was attached to the film so as not to cause wrinkles, and the measurement was performed on this sample. The part of the sample that was not attached with the double-sided tape was used as the measurement point. Table 3 below shows the haze measured for one adhesive protective film, the haze (II) measured by stacking two adhesive protective films, the absolute value of the difference between the haze and the haze (II) (|Haze-Haze (II)|), and the positional accuracy results.

[0160] [Table 3]

[0161] The results shown in Table 3 show that in Examples 1, 2, 4, and 5, in which the absolute value of the difference between haze and haze (II) (|Haze-Haze (II)|) is large, the adhesive protective film can be positioned with high positional accuracy. [Explanation of symbols]

[0162] 1 Adhesive protective film 2 metal terminals 3 Packaging materials 10 batteries 11 Base material 12a First polyolefin layer 12aa First Polyolefin Layer 12ab First Polyolefin Layer 12b Second polyolefin layer 12ba Second Polyolefin Layer 12bb Second Polyolefin Layer 13 Adhesion promoter layer 20 Battery element 31 Base material layer 32 Adhesive layer 33 Barrier Layer 34 Heat-fusible resin layer 35 Adhesive layer

Claims

1. T is the average value of the transmittance percentage of light with wavelengths that differ by 1 nm in the range of 400 nm to 800 nm measured by a spectrophotometer. 400-800 is 30.52% or more and 60% or less, The adhesive protective film includes at least a substrate, a first polyolefin layer located on one side of the substrate, and a second polyolefin layer located on the other side of the substrate, At least one of the first polyolefin layer and the second polyolefin layer is formed of an acid-modified polyolefin, Two sheets of the adhesive protective film are stacked together and the average transmittance percentage of light having wavelengths that differ by 1 nm in the range of 400 nm to 800 nm is measured using a spectrophotometer. T(II) 400-800 And the T 400-800 The absolute value of the difference between the above and the above is 13 or more.

2. T is the average value of the transmittance of light with wavelengths that differ by 1 nm in the range of 800 nm to 1200 nm measured by a spectrophotometer. 800-1200 The adhesive protective film according to claim 1 , wherein the thickness of the adhesive protective film is 30% or more.

3. T is the average value of the transmittance of light with wavelengths that differ by 1 nm in the range of 300 nm to 400 nm measured by a spectrophotometer. 300-400 The adhesive protective film according to claim 1 or 2, wherein the elastic modulus is 89.00% or less.

4. Said T 400-800 is the average transmittance percentage of light whose wavelengths differ by 1 nm in the range of 300 nm to 400 nm measured by a spectrophotometer. 300-400 The adhesive protective film according to any one of claims 1 to 3, wherein the value obtained by dividing by is in the range of 0.90 or more and 8.00 or less.

5. Percentage transmittance T of light with a wavelength of 500 nm measured by a spectrophotometer 500 is the percent transmittance T of light with a wavelength of 700 nm measured by a spectrophotometer. 700 The adhesive protective film according to any one of claims 1 to 4, wherein the value obtained by dividing by is in the range of 0.75 or more and 0.99 or less.

6. Percent transmittance T of light with a wavelength of 550 nm measured by a spectrophotometer 550 is the percent transmittance T of light with a wavelength of 350 nm measured by a spectrophotometer. 350 The adhesive protective film according to any one of claims 1 to 5, wherein the value obtained by dividing by (a) is in the range of 1.00 or more and 35.00 or less.

7. The adhesive protective film according to any one of claims 1 to 6, which has a haze in the range of 50 or more and 89 or less.

8. Two sheets of the adhesive protective film are stacked together and the average transmittance percentage of light having wavelengths that differ by 1 nm in the range of 400 nm to 800 nm is measured using a spectrophotometer. T(II) 400-800 And the T 400-800 The adhesive protective film according to any one of claims 1 to 7, wherein the absolute value of the difference between the above and is 14 or more.

9. Two sheets of the adhesive protective film are stacked together and the average transmittance percentage of light having wavelengths that differ by 1 nm in the range of 400 nm to 800 nm is measured using a spectrophotometer. T(II) 400-800 The adhesive protective film according to any one of claims 1 to 8, wherein the adhesion ratio is 5% or more and 50% or less.

10. The adhesive protective film according to any one of claims 1 to 9, wherein the absolute value of the difference between the haze (II) measured by stacking two sheets of the adhesive protective film and the haze is 8.5 or more.

11. The adhesive protective film according to any one of claims 1 to 10, wherein at least one of the first polyolefin layer and the second polyolefin layer is composed of two or more layers.

12. The adhesive protective film according to any one of claims 1 to 11, comprising an adhesion promoter layer between the substrate and the first polyolefin layer, or between the substrate and the second polyolefin layer, or both.

13. The adhesive protective film according to any one of claims 1 to 12, which is an adhesive protective film interposed between a metal terminal electrically connected to an electrode of a battery element and a packaging material that seals the battery element.

14. the packaging material is composed of a laminate having at least a base layer, a barrier layer, and a heat-sealable resin layer in this order; The adhesive protective film according to claim 13 , wherein the adhesive protective film is interposed between the heat-sealable resin layer and the metal terminal.

15. A battery comprising at least a battery element having a positive electrode, a negative electrode, and an electrolyte, a packaging material for sealing the battery element, and metal terminals electrically connected to the positive electrode and the negative electrode, respectively, and protruding outside the packaging material, A battery comprising the adhesive protective film according to any one of claims 1 to 14 interposed between the metal terminal and the packaging material.

16. A method for manufacturing a battery including at least a battery element including a positive electrode, a negative electrode, and an electrolyte, a packaging material for sealing the battery element, and metal terminals electrically connected to the positive electrode and the negative electrode, respectively, and protruding outside the packaging material, comprising: A method for manufacturing a battery, comprising the step of interposing the adhesive protective film according to any one of claims 1 to 14 between the metal terminal and the packaging material.

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