Sealant and packaging material used in transport packaging of silicon material, transport packaging of silicon material, and packaging of silicon material

Abstract

To provide a sealant used for a transporting packaging body of a silicon material and well in slidability, transparency and cleanliness and a packaging material using the sealant, a transporting packaging body of a silicon material, and a package of a silicon material.SOLUTION: A sealant used for a transporting packaging body of a silicon material comprises a first surface positioned closer to a silicon material in a transporting packaging body and a second surface opposite to the first surface. The sealant comprises a first portion including the first surface and a second portion positioned closer to the second surface than the first portion. The first portion includes low-density polyethylene (LDPE) and the second portion includes linear low-density polyethylene (LLDPE), and the first surface has a fractal dimension D falling in a range of 1.50-1.90 and the first surface has a persistent homology value N10 equal to or greater than 1.0.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to sealants and packaging materials for use in transport packages of silicone materials, transport packages of silicone materials, and packaging of silicone materials. [Background technology]

[0002] A high degree of cleanliness is required for silicon wafers used in the manufacture of semiconductor products and silicon materials such as polysilicon used as raw materials for silicon wafers. For example, when transporting silicon wafers, the silicon wafers are stored in a cleaned resin case, and the resin case in which the silicon wafers are stored is affixed with a label containing information about the silicon wafer, and then each resin case is packaged and sealed in a clean package. As such a package, for example, Patent Document 1 discloses a dust-free packaging bag for packaging electronic parts and the like, which is made of a laminate of at least two layers, a base layer including an outermost film and a sealant layer as an innermost layer, and the surface of the outermost film is formed into a rough surface with a static friction coefficient (μs) of 0.40 or less, a dynamic friction coefficient (μk) of 0.35 or less, and a surface roughness (Ra) of 0.10 to 0.40 μm between the surfaces, and at least one adhesive layer or adhesive primer layer containing an antistatic agent is provided on the inside or innermost surface of the base layer. The dust-free packaging bag has excellent suitability for automatic packaging. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2013-136405 A Summary of the Invention [Problem to be solved by the invention]

[0004] The sealant of the packaging material constituting the transport package of the silicon material is required to have good slip properties. For example, if the slip properties between the sealants are poor, it becomes difficult to open the package, and if the slip properties between the sealant and the resin case are poor, it becomes difficult to insert and remove the resin case from the package.

[0005] In addition, the sealant of the packaging material constituting the transport package for the silicon material is also required to have good transparency. For a sealant with poor transparency, for example, problems occur in which it is difficult to confirm the information on the label attached to the resin case or the state of the silicon wafer or the resin case when the package is unopened, and it is difficult to confirm the presence of foreign matter in the sealant.

[0006] However, there is a trade-off between slipperiness and transparency, and in addition, a sealant used in a package for transporting a silicon material is required to have a high degree of cleanliness as a basic required property. It is not easy to obtain a sealant that has a high degree of cleanliness sufficient for use in a package for transporting a silicon material, and also has good slipperiness and good transparency.

[0007] An object of the present disclosure is to provide a sealant that is used in transport packaging for silicon materials and has good slipperiness, transparency, and cleanability, as well as a packaging material in which the sealant is used, a transport packaging for silicon materials, and a package of silicon materials. [Means for solving the problem]

[0008] In order to solve the above problem, one embodiment of the present disclosure is a sealant used in a transport package of a silicon material, the sealant having a first surface located on the silicon material side in the transport package and a second surface opposite to the first surface, the sealant having a first portion including the first surface and a second portion located on the second surface side of the first portion, Virtually no slip agent added The second portion comprises low density polyethylene (LDPE), Virtually no slip agent added The sealant contains linear low density polyethylene (LLDPE), the thickness of the sealant is 30 μm to 60 μm, the image clarity of the sealant at an optical comb width of 2 mm is 60% or more, the fractal dimension D of the first surface is in the range of 1.74 to 1.76, and the persistent homology value N of the first surface is 10 The present invention provides a sealant having a viscosity of 3.3 or more.

[0009] One embodiment of the present disclosure provides a packaging material comprising a substrate and the above-described sealant provided on one surface side of the substrate.

[0010] The substrate may further include a gas barrier layer provided on the side opposite to the sealant, and the gas barrier layer may contain aluminum oxide or silicon oxide.

[0011] An embodiment of the present disclosure provides a transport package for a silicon material, which is configured by the above-mentioned packaging material. An embodiment of the present disclosure provides a package for a silicon material, which includes the above-mentioned transport package for a silicon material and a silicon material contained in the transport package for a silicon material. Effect of the Invention

[0012] According to the present disclosure, it is possible to provide a sealant that is used in transport packaging for silicon materials and has good slipperiness, transparency, and cleanability, as well as a packaging material in which the sealant is used, a transport packaging for silicon materials, and a packaged body for silicon materials. [Brief description of the drawings]

[0013] [Figure 1] FIG. 1 is a partially enlarged cutaway end view showing a schematic configuration of a sealant according to an embodiment of the present disclosure. [Diagram 2] FIG. 2 is a partially enlarged cutaway end view showing a schematic configuration of another aspect of the sealant according to an embodiment of the present disclosure. [Diagram 3]FIG. 3 is a partially enlarged cutaway end view showing a schematic configuration of another aspect of the sealant according to an embodiment of the present disclosure. [Figure 4] FIG. 4 is a partially enlarged cross-sectional end view showing a schematic configuration of a packaging material in one embodiment of the present disclosure. [Diagram 5] FIG. 5 is a partially enlarged end view showing a schematic configuration of another aspect of a packaging material according to an embodiment of the present disclosure. [Figure 6] FIG. 6 is a schematic diagram illustrating the configuration of an example of a manufacturing apparatus capable of manufacturing a packaging material in an embodiment of the present disclosure. [Figure 7] FIG. 7 is a perspective view showing a schematic configuration of a transport package for a silicon material in one embodiment of the present disclosure. [Figure 8] FIG. 8 is a perspective view showing a schematic configuration of a package of silicon material in one embodiment of the present disclosure. [Figure 9] FIG. 9 is a perspective view showing a schematic configuration of a package of silicon material in one embodiment of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] An embodiment of the present disclosure will be described with reference to the drawings. In the drawings, the shape, scale, aspect ratio, etc. of each part may be changed or exaggerated from the actual one in order to facilitate understanding. In this specification, the terms "film," "sheet," "plate," etc. are not distinguished from each other based on the difference in name. For example, "plate" is a concept that includes members that can be generally called "sheet" and "film."

[0015] [Sealant] A sealant for use in a transport package for a silicon material, the sealant having a first surface located on the silicon material side in the transport package and a second surface opposite the first surface, the sealant having a first portion including the first surface and a second portion located on the second surface side of the first portion, the first portion including low density polyethylene (LDPE), the second portion including linear low density polyethylene (LLDPE), a fractal dimension D of the first surface being in the range of 1.50 to 1.90, and a persistent homology value N of the first surface being in the range of 1.50 to 1.90. 10 is 1.0 or more. The sealant according to this embodiment has good slip properties, transparency, and cleanability.

[0016] The first portion may further comprise linear low density polyethylene (LLDPE), high density polyethylene (HDPE), or polypropylene (PP). For example, the fractal dimension D and persistent homology N of the first surface may be 10 The sealant may be a laminate having a first layer including the first surface and a second layer, and the first portion may be the first layer. 10 The sealant may be a laminate having a first layer including the first surface and a second layer, the first portion being the first layer, and the second portion being the second layer. 10 The sealant base material may further include a third portion including the second surface, and the third portion may include low density polyethylene (LDPE). 10 The sealant may be a laminate having a first layer including the first surface, a second layer, and a third layer in this order, the first portion being the first layer, the second portion being the second layer, and the third portion being the third layer. 10The second portion may further include low density polyethylene (LDPE). 10 This makes it easier to adjust the

[0017] Further, the sealant according to the present embodiment is a sealant used in a transport package for a silicon material, the sealant being a single layer having a first surface located on the silicon material side in the transport package and a second surface opposite to the first surface, the sealant having a first portion including the first surface, the first portion including low density polyethylene (LDPE), the sealant further having a second portion located on the second surface side of the first portion, the second portion including linear low density polyethylene (LLDPE), a content ratio of low density polyethylene (LDPE) to linear low density polyethylene (LLDPE) in the sealant being in a range of 1:1 to 7:3 on a mass basis, a fractal dimension D of the first surface being in a range of 1.50 to 1.90, and a persistent homology value N of the first surface being in a range of 1:1 to 7:3 on a mass basis. 10 is 1.0 or more. The sealant according to this embodiment has good slip properties, transparency, and cleanability.

[0018] The low density polyethylene (LDPE) may be substantially free of added slip agents. 10 This makes it easier to adjust the

[0019] The sealant 10 according to this embodiment is used in a package for transporting a silicon material, and has a first surface 11A located on the silicon material side in the transport package and a second surface 11B facing the first surface, and is equipped with a heat-sealable sealant substrate 11, and has a first portion including the first surface 11A, a second portion located closer to the second surface 11B than the first portion, and a third portion including the second surface 11B. The sealant 10 according to this embodiment may be a laminate (see FIGS. 1 and 2) or a monolayer (see FIG. 3). For example, the sealant 10 may be a laminate having a first layer 111 located on the first surface 11A side, a third layer 113 located on the second surface 11B side, and a second layer 112 sandwiched between the first layer 111 and the third layer 113, with the first portion being the first layer 111, the second portion being the second layer 112, and the third portion being the third layer 113 (see FIG. 1), or a laminate having the first layer 111 and the second layer 112, with the first portion being the first layer 111, and the second portion being the second layer 112 (see FIG. 2). Also, the sealant 10 may be a monolayer having the first surface 11A and the second surface 11B (see FIG. 3). The sealant 10 according to this embodiment may be a laminate (see FIGS. 1 and 2) or a monolayer (see FIG. 3), but a laminate of two or more layers is more preferable than a monolayer because it has more options than a monolayer in terms of adjusting the surface shape of the sealant.

[0020] The fractal dimension D of the first surface 11A of the sealant 10 according to this embodiment is in the range of 1.50 to 1.90, and the persistent homology value N 10 is 1.0 or more. When the fractal dimension D of the first surface 11A is within a predetermined range, good sliding properties can be obtained between the first surfaces 11A of the sealant 10 and between the first surface 11A and a resin case that stores a silicon wafer. Also, when the fractal dimension D of the first surface 11A is within a predetermined range, good cleanliness of the sealant 10 can be ensured. Furthermore, the persistent homology value N 10is in a predetermined range, good transparency of the sealant 10 can be ensured. This makes it possible to prevent the sealant 10 from deteriorating the visibility of the inside of the transport package 40 for the silicon material when the silicon material is packaged in the transport package 40 for the silicon material (see FIG. 7) made from the packaging material 20 (see FIGS. 4 and 5) containing the sealant 10. In addition, it is possible to easily check whether or not a foreign object is attached to the first surface 11A of the sealant 10 in the transport package 40 for the silicon material.

[0021] In general, a resin case for storing a silicon wafer is automatically packaged in a package for transporting a silicon material using an automatic packaging machine. In this automatic packaging machine, the package is automatically opened to store the resin case, and the packages before opening are stacked so that the surfaces of the sealants are in contact with each other. In order to smoothly perform packaging using the automatic packaging machine, it is required that the package can be automatically and easily opened. For this purpose, it is required that the sealants of the packaging material constituting the package have good slip properties. In addition, in order to easily insert the resin case through the opening of the package and to easily remove the resin case from the opened package, it is required that the resin case and the sealant have good slip properties.

[0022] On the other hand, it is desirable that the packaging material constituting the silicon material transport package and the sealant located in the innermost layer thereof have good transparency. For example, a label containing information about the silicon wafer may be attached to a resin case storing a silicon wafer. If the packaging material and sealant have good transparency, the information on the label can be confirmed visually or with a reading device when the package is unopened. In addition, damage or discoloration of the silicon wafer or the resin case during transportation can be confirmed when the package is unopened. In particular, the silicon material package is opened in a clean room to maintain the cleanliness (purity) of the silicon wafer. Due to the lighting in the clean room, if the packaging material and sealant are not highly transparent, there is a problem that the inside of the unopened package is difficult to see. Therefore, it is desirable that the packaging material constituting the silicon material transport package has a transparency to such an extent that the information on the label and the state of the silicon wafer and the resin case can be recognized visually or with a reading device through the packaging material in the clean room. In addition, for example, the surface of the sealant in a package for transporting a silicon material is in direct contact with the resin case that stores the silicon wafer, so if there is a foreign object on the sealant surface, there is a risk that the foreign object will adhere to the silicon wafer packaged in the package. It is desirable to remove the package or sealant to which the foreign object is attached before use, as it is unsuitable for transporting silicon wafers. If the packaging material or sealant has transparency to the extent that the foreign object can be visually recognized, the presence of the foreign object can be confirmed before packaging the resin case in the package, and contamination of the silicon wafer can be prevented in advance. The foreign object can be confirmed by visually inspecting the package, packaging material or its intermediate material, or sealant, or by using an inspection device. Since both sides of the sealant can be simultaneously inspected, it is preferable that the sealant has transparency to the extent that the foreign object present in the sealant can be recognized visually or with an inspection device through the sealant.

[0023] However, the present inventors have found that it is not easy to obtain a sealant that has both good slipperiness and transparency required for a silicon material transport package as a sealant used in a silicon material transport package. The reason is that the sealant used in a silicon material transport package is required to ensure a high degree of cleanliness as a prerequisite, and therefore there are many restrictions on the raw materials, manufacturing machines, conditions or processes, or film configuration. For example, slip agents that are generally used to adjust slipperiness are limited in use because they may themselves become foreign matter. For example, the use of a printing roll that is generally used to adjust the surface shape of a film is not preferable because there is a risk of foreign matter being transferred. Alternatively, factors that may affect slipperiness and transparency include, for example, the type and amount of resin used as a raw material, and the laminated structure and thickness of the sealant, but these factors are first selected from the perspective of obtaining a clean sealant, and then it is required to increase slipperiness and transparency within the range allowed under the selected conditions. Moreover, as described below, slipperiness and transparency may be in a trade-off relationship. Therefore, the inventors realized that the surface condition of a sealant used in a packaging for transporting silicon materials is important, and from the viewpoint of slipperiness, transparency, and cleanliness required for packaging for transporting silicon materials, the fractal dimension D and the persistent homology value N are used as indicators representing the surface condition. 10 We noticed that we should pay attention to the fractal dimension D in the range of 1.50 to 1.90 and the persistent homology value N 10 The present inventors have realized that when the viscosity is 1.0 or more, a sealant having good lubricity, transparency, and cleanability required for a silicone material transport package can be obtained, and have completed the present invention.

[0024] The fractal dimension D is an index that indicates the complexity and fractality of the surface state (surface structure) of an object (target). Generally, a sealant is formed to make its surface flat, but slight unevenness (waviness) on the order of nanometers is present on the surface of the sealant when the sealant is formed. When the fractal dimension D of the sealant surface is relatively small (for example, less than 1.50), it can be said that the sealant formed to make the surface flat has unevenness larger than the slight unevenness (waviness) that may occur when the sealant is formed. Since such unevenness is caused by additives contained in the sealant, it can be said that the smaller the fractal dimension D of the sealant surface is, the lower the cleanliness. On the other hand, when the fractal dimension D of the sealant surface is relatively large, it can be said that only slight unevenness (waviness) that occurs when the sealant is formed is present on the sealant surface. In other words, since the sealant does not substantially contain additives, it is believed that only slight unevenness (waviness) that occurs during the formation of the sealant film can be present on the sealant surface, and therefore it can be said that the larger the fractal dimension D of the sealant surface is, the cleaner it is.

[0025] The persistent homology value N 10 is an index that relatively expresses the magnitude of unevenness on the surface of an object (target). As mentioned above, a sealant is generally formed to make its surface flat, but slight unevenness (waviness) on the order of nanometers will be present on the surface of the sealant when the sealant is formed. In this way, for a sealant formed to make the surface flat, the persistent homology value N 10A relatively large value of N means that the concaves (or convex portions) of the multiple concaves and convex portions on the sealant surface are located relatively close to each other (for example, there are a relatively large number of concave-convex groups on the sealant surface, each of which is made up of multiple concaves (or convex portions) that are located close to each other to form a roughly circular shape, and one or more convex portions (or concave portions) located within the circular shape), and when the wavelength of visible light is taken into consideration, it can be said that light is less likely to be reflected by the concaves and convex portions on the sealant surface. In other words, the persistent homology value N of the sealant surface 10 The larger the value of the persistent homology of the sealant surface, the higher the transparency of the sealant. 10 A relatively small value of N means that the concave (or convex) portions of the multiple concaves and convexes on the sealant surface are located relatively far from each other (for example, the group of concaves and convexes on the sealant surface is relatively few in number or absent), and when considering the wavelength of visible light, it can be said that the sealant surface is prone to reflecting light. In other words, the persistent homology value N 10 It can be said that the smaller the value is, the lower the transparency of the sealant is.

[0026] In this embodiment, the fractal dimension D of the first surface 11A of the sealant 10 is in the range of 1.50 to 1.90, and the persistent homology N 10 When the value is 1.0 or less, good transparency of the sealant 10 can be ensured, and the slipperiness between the first surfaces 11A of the sealant 10 and between the first surface 11A and the resin case storing the silicon wafer can be obtained, and the cleanliness required for the transport package of the silicon material can be obtained. Since there are restrictions on the use of slip agents and printing rolls in sealants used in transport packages of silicon materials, the sealant of the present embodiment, which can obtain good slipperiness even with reduced use or substantial elimination of slip agents and printing rolls, is particularly suitable as a sealant used in transport packages of silicon materials.

[0027] In this embodiment, the fractal dimension D of the first surface 11A of the sealant 10 can be obtained, for example, as follows. The first surface 11A of the sealant 10 is imaged under the following conditions, for example, using a white light interference optical microscope (manufactured by Zygo, product name: NewView6300), and a grayscale image (496 pixels x 496 pixels) containing height information of the first surface 11A is obtained. [Measurement conditions] Measurement equipment: White light interference optical microscope (Zygo, product name: NewView6300) Objective lens: 50x Zoom lens: 1x Measurement pixel count: 496 pixels x 496 pixels Field of view: 216μm x 216μm [Analysis conditions] Analysis software: MetroPro ver8.3.2 Removed: Cylinder FilterType: None

[0028] For example, the grayscale image is subjected to threshold processing (select Image-Adjust-Threshold: Otsu) using image analysis software ImageJ (image analysis freeware developed by the National Institutes of Health (NIH)) to convert the grayscale image into a binary image so that the convex portions on the first surface 11A of the sealant 10 are white and the concave portions are black. The grayscale image may also be converted into a binary image so that the convex portions on the first surface 11A of the sealant 10 are black and the concave portions are white.

[0029] The binarized image is converted into a contour image (white background, contour width 2 pixels) by performing contour extraction processing (Process-Find Edges) using, for example, image analysis software ImageJ.

[0030] For example, image analysis software ImageJ is used to perform fractal analysis on the contour image using a box-counting method to calculate the fractal dimension D. Specifically, the size of a pixel (length of one side a) is changed, and the number (N(a)) of parts having a signal value contained in the pixel (pixels in black parts because the background color is white in this embodiment) is counted, and the slope of each double logarithm (log(a) vs log(N(a))) graph is found, whereby the fractal dimension D can be calculated.

[0031] The persistent homology value N of the first surface 11A of the sealant 10 10 can be found, for example, as follows: The grayscale image (496 pixels x 496 pixels) obtained in the calculation of the fractal dimension D described above is reduced to a size of 120 pixels x 120 pixels, and then, for example, using image analysis software ImageJ (image analysis freeware developed by the National Institutes of Health (NIH)), threshold processing (Image-Adjust-Treshold: Otsu is selected) is performed on the reduced-sized grayscale image to convert the grayscale image into a binary image so that the convex parts on the first surface 11A of the sealant 10 are white and the concave parts are black. Note that, if a grayscale image of a size of 120 pixels x 120 pixels can be obtained using a white light interference optical microscope, it is not necessary to reduce the grayscale image. Alternatively, the grayscale image may be converted into a binary image so that the convex parts on the first surface 11A of the sealant 10 are black and the concave parts are white.

[0032] The scale of the recess is calculated for the binarized image using persistent homology. Persistent homology is an image analysis method for characterizing the transition of m-dimensional (in this embodiment, m=1) holes in an object (in this embodiment, a set of white points in the binarized image). Features related to the arrangement of points can be investigated by persistent homology. In this embodiment, the scale of the recess located between the protrusions is calculated. Specifically, when each white point in the object is gradually enlarged in a circular shape, the white points are connected in the process, and a ring-shaped complex having a cavity at approximately the center is formed. When each white point is enlarged in this state, the cavity disappears. Then, the diameter X of each white point at the time when the ring-shaped complex is generated (hereinafter referred to as the "generation diameter") and the diameter Y of each white point on the circle at the time when the cavity disappears (hereinafter referred to as the "disappearance diameter") are calculated. The generation diameter X and disappearance diameter Y of the ring complexes formed in the binarized image are converted to μm scale and calculated using statistical analysis software (e.g., R's TDA (Topological Data Analysis) library, etc.). Then, the number of ring complexes that satisfy the following formula is calculated. Y≧X+10 The persistent homology value N 10 can be obtained by acquiring the grayscale images of a number of arbitrarily selected locations (for example, three locations) on the first surface 11A of the sealant 10 and calculating the average value of the number of the annular complexes from each image.

[0033] The fractal dimension D of the first surface 11A may be in the range of 1.50 to 1.90, preferably in the range of 1.70 to 1.85, and more preferably in the range of 1.70 to 1.80. 10 It is sufficient that the value is 1.0 or more, and is preferably in the range of 2.0 to 10.0, and more preferably in the range of 3.0 to 9.0.

[0034] The thickness T10 of the sealant 10 shown in Figures 1 to 3 can be appropriately set depending on the desired thickness and desired heat seal strength of the transport package for the silicone material composed of a packaging material containing the sealant 10, and may be, for example, about 30 to 60 µm.

[0035] The first layer 111, which corresponds to the first portion located on the first surface side 11A of the sealant 10 shown in Figs. 1 and 2, is a layer containing, for example, low density polyethylene (hereinafter referred to as "LDPE") as a main component to which no slip agent is substantially added. By containing LDPE as a main component of the first layer 111, it is possible to suppress the volatilization of low molecular weight components of the sealant. By making the first layer 111 a layer to which no slip agent is substantially added, it is possible to suppress the occurrence of surface irregularities caused by the slip agent, and therefore, it is possible to suppress the fractal dimension D of the first surface 11A of the sealant 10 from being in the range of 1.50 to 1.90 and the persistent homology value N of the first surface 11A from being in the range of 1.50 to 1.90. 10 It becomes easy to make it 1.0 or more.

[0036] Examples of slip agents include particles such as calcium carbonate and talc, and surfactants such as silicone resin and quaternary ammonium salt compounds. By reducing or substantially not using the slip agent, it is possible to suppress the risk of unevenness caused by the shape and size of the slip agent and unevenness caused by affinity with other components of the first layer 111 such as LDPE occurring on the sealant surface. In this embodiment, "substantially no slip agent is added" means that the fractal dimension D of the first surface 11A is in the range of 1.50 to 1.90 and the persistent homology value N of the first surface 11A is in the range of 1.50 to 1.90. 10is in the range of 1.0 or more. In the present embodiment, a slip agent is substantially not added, but the present invention is not limited to this. For example, by using flat particles or small particles, or by adjusting the type and amount of a surfactant to generate desired unevenness, the fractal dimension D of the first surface 11A of the sealant 10 can be set in the range of 1.50 to 1.90 and the persistent homology value N of the first surface 11A can be set in the range of 1.50 to 1.90. 10 may be set to 1.0 or more.

[0037] The LDPE content of the first layer 111 of the sealant 10 shown in Figs. 1 and 2 is 50% by mass to 100% by mass with respect to the total amount of the resin components. The first layer 111 may contain multiple types of LDPE with different densities, molecular weight distributions, etc. In addition to LDPE, the first layer 111 may contain a resin with heat sealability, such as linear low density polyethylene (hereinafter referred to as "LLDPE"), high density polyethylene (hereinafter referred to as "HDPE"), or polypropylene (hereinafter referred to as "PP"), in an amount of 0% by mass to 50% by mass with respect to the total amount of the resin components. By combining multiple types of resins with different affinities, the unevenness occurring in the first layer 111 can be adjusted, and the fractal dimension D of the first surface 11A of the sealant 10 can be set in the range of 1.50 to 1.90 and the persistent homology value N of the first surface 11A can be set in the range of 1.50 to 1.90. 10 It becomes possible to adjust the viscosity to 1.0 or more. In the sealant 10 shown in Figures 1 and 2, the first layer 111 contains LDPE as a main component, but is not limited to this, and for example, the first layer 111 may contain 50 mass % to 100 mass % of a resin having heat sealability, such as LLDPE, HDPE, or PP, relative to the total amount of the resin components, or may not contain LDPE.

[0038] The third layer 113, which corresponds to the third portion located on the second surface 11B side of the sealant 10 shown in Fig. 1, is also a layer containing, for example, LDPE as a main component to which no slip agent has been added, similar to the first layer 111. However, in this embodiment, similar to the first layer 111, the third layer 113 is not limited to a layer containing, for example, LDPE as a main component to which no slip agent has been added, and may contain, for example, 50% by mass to 100% by mass of a resin having heat sealability, such as LLDPE, HDPE, or PP, relative to the total amount of the resin components, or may not contain LDPE.

[0039] The second layer 112 corresponding to the second portion of the sealant 10 shown in FIG. 1 and FIG. 2 is, for example, a layer containing LLDPE. If the volatile components (outgas components derived from the sealant 10) derived from the sealant 10 located in the innermost layer of the transport packaging of the silicon material adhere to the silicon material such as the silicon wafer or polysilicon, which is the content, there is a risk of causing defects in the semiconductor device manufactured using the silicon wafer. Therefore, it is desirable that the volatile components derived from the sealant 10 are as small as possible. In order to reduce the volatile components derived from the sealant 10, it is desirable to reduce the thickness T10 of the sealant 10. In this regard, since LLDPE has higher elasticity and higher resistance to bending than LDPE, the thickness T10 of the sealant 10 can be relatively reduced by using LLDPE as the sealant 10.

[0040] In addition, since the resin case 51 is housed in the silicon material transport package 40 and then degassed and packaged from the silicon material transport package 40, the sealant 10 contained in the packaging material constituting the silicon material transport package 40 is required to have good conformability. In this respect, the use of LLDPE also improves the conformability of the sealant 10. However, since the pressure during polymerization of LLDPE is lower than the pressure during polymerization of LDPE, low molecular components are generated and volatilized more easily than LDPE. Therefore, as shown in FIG. 1, the second layer 112 containing LLDPE is positioned between the first layer 111 and the third layer 113 mainly composed of LDPE, so that the thickness T10 of the sealant 10 can be made relatively thin and the volatilization of low molecular components from LLDPE can be prevented.

[0041] The content of LLDPE in the second layer 112 of the sealant 10 shown in Fig. 1 and Fig. 2 is 20% by mass to 100% by mass, preferably 30% by mass to 80% by mass, and more preferably 40% by mass to 60% by mass, based on the total amount of the resin components. In addition to LLDPE, the second layer 112 may contain a heat-sealable resin such as LDPE, HDPE, or PP in an amount of 0% by mass to 80% by mass based on the total amount of the resin components. Since the affinity between the LLDPE in the second layer 112 and the LDPE that is the main component of the first layer 111 or the third layer 113 is relatively high, it is preferable that the second layer 112 contains LDPE in addition to LLDPE. Furthermore, HDPE or PP, which has a relatively low affinity with LLDPE, may be added to intentionally form unevenness on the surface. In the embodiment shown in Figures 1 and 2, second layer 112 contains 20% by mass to 100% by mass of LLDPE relative to the total amount of resin components, but is not limited to this. For example, second layer 112 may contain less than 20% by mass of LLDPE relative to the total amount of resin components, or may contain more than 50% by mass of a resin having heat sealability such as LDPE, HDPE, or PP relative to the total amount of resin components, or may not contain LDPE.

[0042] By adjusting the raw materials and processing of the second layer 112, the fractal dimension D of the first surface 11A of the sealant 10 is in the range of 1.50 to 1.90, and the persistent homology value N of the first surface 11A is in the range of 1.50 to 1.90. 10 can be in the range of 1.0 or more. The surface shape of the first surface 11A of the sealant 10 changes depending on the unevenness of the interface between the second layer 112 and the first layer 111 and the affinity between the raw material of the second layer 112 and the raw material of the first layer 111. For example, by adding a slip agent such as particles or a surfactant to the second layer 112, reducing the amount of slip agent used in the second layer 112 or not adding any slip agent, forming the first layer 111 after pressing the second layer 112 with a printing plate to obtain a desired surface shape, or selecting a material for the second layer 112 that has low affinity or high affinity with the raw material of the first layer 111, the surface shape of the first surface 11A of the sealant 10 can be adjusted to have a fractal dimension D in the range of 1.50 to 1.90 and a persistent homology value N of the first surface 11A. 10 can be 1.0 or more.

[0043] In the sealant 10 shown in Fig. 3, the sealant substrate 11 of a single layer structure contains LDPE and LLDPE. In this sealant substrate 11, the blending ratio of LDPE to LLDPE may be about 1:1 to 7:3. By blending more LDPE than LLDPE, the amount of LDPE present on the first surface 11A side of the sealant substrate 11 can be increased, and the thickness T10 of the sealant 10 can be reduced by the LLDPE, preventing the volatilization of low molecular weight components. The fractal dimension D and persistent homology value N of the first surface 11A of the sealant 10 shown in Fig. 3 are 10 can be adjusted in the same manner as the first layer 111 of the sealant 10 shown in FIG.

[0044] The sealant 10 in this embodiment can be manufactured using a conventionally known film forming method. For example, the sealant 10 shown in Fig. 1 can be manufactured by laminating the third layer 113, the second layer 112, and the first layer 111 using a coating method such as a die coating method, an extrusion inflation method, or the like. The sealant 10 shown in Figs. 2 and 3 can also be manufactured using a coating method, an extrusion inflation method, or the like.

[0045] [Packaging material] FIG. 4 is a partially enlarged cut end view showing the schematic configuration of a packaging material according to one embodiment of the present disclosure, and FIG. 5 is a partially enlarged end view showing the schematic configuration of another aspect of a packaging material according to one embodiment of the present disclosure.

[0046] As shown in FIG. 4, the packaging material 20 has a laminated structure in which the sealant 10 is laminated on one side of the base material 21 so that the second surface 11B is in contact with the base material 21. The base material 21 is made of one resin material or a laminate of two or more resin materials selected from, for example, polyolefins such as polyethylene and polypropylene, polyesters such as polyethylene terephthalate and polybutylene terephthalate, polyamides such as nylon, polyimides, cycloolefin copolymers, etc. In addition, in the packaging material 20 shown in FIG. 5, the base material 21 is made of a laminate of two resin materials (a first resin layer 211 and a second resin layer 212), and the first resin layer 211 functions as an adhesive layer for the second surface 11B of the sealant 10. In this case, for example, the first resin layer 211 is made of polyethylene (PE), and the second resin layer 212 is made of polyethylene terephthalate (PET).

[0047] The sealant 10 in the packaging material 20 has a fractal dimension D of the first surface 11A in the range of 1.50 to 1.90, and a persistent homology value N 10When the viscosity is 1.0 or more, the material has good slip properties, good transparency, and good cleanability. As a result, when silicon wafers or polysilicon are packed in a transport package 40 for a silicon material (see FIG. 7) manufactured from the packaging material 20, it is possible to prevent the visibility of the inside of the transport package 40 for a silicon material from being deteriorated by the sealant 10. In addition, it is possible to easily check whether or not a foreign object is attached to the first surface 11A of the sealant 10 in the transport package 40 for a silicon material.

[0048] As shown in FIG. 5, the packaging material 20 may have a gas barrier layer 22 between the substrate 21 and the sealant 10. By having the gas barrier layer 22, it is possible to prevent the intrusion of gases and the like that contaminate the surface of the silicon material or react with the silicon material from the outside of the transport package 40 of the silicon material produced from the packaging material 20. The gas barrier layer 22 may be, for example, a vapor deposition film in which an inorganic oxide such as aluminum oxide or silicon oxide or an inorganic nitride such as silicon nitride is vapor deposited on a resin layer (for example, a PET layer, etc.). In particular, gas barrier layers of aluminum oxide or silicon oxide are preferable because they have good transparency. The gas barrier layer 22 may also be a metal vapor deposition film in which a metal such as aluminum is vapor deposited, or a metal foil such as aluminum. Note that when the packaging material 20 has these metal vapor deposition films or metal foils between the substrate 21 and the sealant 10, the transparency of the packaging material 20 is not ensured, but the transport package 40 of the silicon material produced from the packaging material 20 can be imparted with light shielding properties in addition to gas barrier properties. In addition, in this embodiment, since the sealant 10 has good transparency, it is easier to check whether or not foreign matter is attached to the first surface 11A of the sealant 10 in the transport packaging 40 of the silicone material made from the packaging material 20.

[0049] FIG. 6 is a schematic diagram showing the configuration of an example of a manufacturing apparatus capable of manufacturing a packaging material according to an embodiment of the present disclosure. The above-mentioned packaging material 20 may be manufactured by a conventionally known method for manufacturing a film or the like. For example, as shown in FIG. 6, the packaging material 20 may be manufactured using a manufacturing apparatus 60 having a first roll 61, a second roll 62, a third roll 63, and a T-die 64. In such a manufacturing apparatus, the resin material constituting the first resin layer 211 is extruded in a film form from the T-die 64 between the second surface 11B of the sealant 10 and the second resin layer 212, and is pressed against the first roll 61, the second roll 62, and the third roll 63 and cooled, thereby producing the packaging material 20.

[0050] [Silicon material transport packaging] FIG. 7 is a perspective view showing a schematic configuration of a transport package for a silicon material according to one embodiment of the present disclosure, and FIGS. 8 and 9 are perspective views showing a schematic configuration of a package for a silicon material according to one embodiment of the present disclosure.

[0051] As shown in Fig. 7, the transport package 40 for the silicon material in this embodiment is a packaging bag that becomes substantially cuboid (substantially rectangular parallelepiped) when unfolded, and is composed of a first side film 41, a second side film 42, a first gusset film 43, and a second gusset film 44. The first side film 41, the second side film 42, the first gusset film 43, and the second gusset film 44 are all composed of the packaging material 20. The transport package 40 for the silicon material is configured such that the first surface 11A of the sealant 10 is located in the innermost layer and the other surface side of the base material 21 is located in the outermost surface of each of the first side film 41, the second side film 42, the first gusset film 43, and the second gusset film 44.

[0052] In the transport package 40 for a silicone material, a first heat-sealed portion HS1 is formed by overlapping one of two opposing side edges of a first side film 41 with one of two opposing side edges of a folded first gusset film 43 and welding them together by heat sealing, a second heat-sealed portion HS2 is formed by overlapping the other side edge of the first side film 41 with one of two opposing side edges of a folded second gusset film 44 and welding them together by heat sealing, a third heat-sealed portion HS3 is formed by overlapping one of two opposing side edges of a second side film 42 with the other side edge of the folded first gusset film 43 and welding them together by heat sealing, and a fourth heat-sealed portion HS4 is formed by overlapping the other side edge of the second side film 42 with the other side edge of the folded second gusset film 44 and welding them together by heat sealing. The side edges of the first side film 41 and the second side film 42, which are located opposite the bottom heat seal part HSB where the side edges of the first side film 41 and the second side film 42 are overlapped and welded by heat sealing, are not heat sealed and form an opening 45 of the silicone material transport package 40.

[0053] In a state where a large number of transport packages 40 for silicon material, in which the first gusset film 43 and the second gusset film 44 are folded, are stacked, the first side film 41 or the second side film 42 is adsorbed and held and lifted upward, thereby opening the opening 45. A resin case 51 (see FIG. 8) for storing a silicon wafer 52 or polysilicon 53 (see FIG. 9) is placed in the transport package 40 for silicon material through the opened opening 45, and the respective side edges of the first side film 41 and the second side film 42 at the opening 45 are overlapped and heat-sealed to form an upper heat-sealed part HST, thereby producing the package 50 for silicon material (see FIGS. 8 and 9).

[0054] In the silicone transport package 40 shown in FIG. 7, the fractal dimension D of the first surface 11A of the sealant 10 of the first side film 41, the second side film 42, the first gusset film 43, and the second gusset film 44 is in the range of 1.50 to 1.90, and the persistent homology value N 10 is 1.0 or more. The first surface 11A is located on the innermost surface of the transport package 40 for the silicon material, and when the first side film 41 or the second side film 42 is adsorbed and held and lifted upward, the opening 45 can be easily opened, and the resin case 51 can be easily accommodated in the transport package 40 for the silicon material through the opened opening 45. In addition, since the sealant 10 has good transparency, the visibility of the silicon wafer 52, the resin case 51, or the polysilicon 53 packaged in the transport package 40 for the silicon material can be improved. Note that, when a metal deposition film or metal foil is provided on the side of the substrate 21 of the packaging material 20 opposite to the sealant 10, the transparency of the transport package 40 for the silicon material is not ensured, but gas barrier properties and light shielding properties can be imparted to the transport package 40 for the silicon material. In addition, since good transparency is ensured in the sealant 10 provided on the side opposite the metal vapor deposition film or metal foil of the substrate 21, it is easy to check whether or not foreign matter is attached to the first surface 11A of the sealant 10 in the transport packaging 40 made of silicone material.

[0055] The above-described embodiments are described for the purpose of facilitating understanding of the present disclosure, and are not described for the purpose of limiting the present disclosure. Therefore, the elements disclosed in the above-described embodiments are intended to include all design matters and equivalents that fall within the technical scope of the present disclosure.

[0056] The package 50 of the silicon material in this embodiment may have the above-mentioned transport package 40 of the silicon material as an inner bag and further have an outer bag having the same configuration. In this case, the silicon wafer 52 or polysilicon 53 may be housed in the transport package 40 of the silicon material as the inner bag, and further housed in the outer bag. The packaging material constituting each of the first side film 41, the second side film 42, the first gusset film 43, and the second gusset film 44 of this outer bag may be the packaging material 20 shown in Figs. 4 and 5, or may be a laminate formed by laminating a resin film having an antistatic function (for example, PTME-RT or Emblem ERT (product name, manufactured by Unitika Ltd.), a gas barrier layer 22, a first resin layer 211, and a sealant 10 in this order).

[0057] The transport package 40 of the silicone material in this embodiment may not have the first gusset film 43 and the second gusset film 44. In this case, the first side film 41 and the second side film 42 may be heat-sealed at the three side edges with the first surfaces 11A of the sealant 10 facing each other. EXAMPLES

[0058] The present disclosure will be described in more detail below by way of examples, but the present disclosure is not limited to the following examples.

[0059] Example 1 The first layer 111 is made of low-density polyethylene with substantially no added slip agent (so-called additive-free LDPE, manufactured by Ube Maruzen Polyethylene Co., Ltd., product name: UBE Polyethylene B128), and the second layer 112 is made of low-density polyethylene with substantially no added slip agent (so-called additive-free LDPE, manufactured by Ube Maruzen Polyethylene Co., Ltd., product name: UBE Polyethylene B128) and linear low-density polyethylene with substantially no added slip agent (so-called additive-free LLDPE, Prime Polyethylene Co., Ltd., product name: UBE Polyethylene B128). A molten mixture (mixing ratio = 1:1 (by mass)) of polyethylene (manufactured by Ube Maruzen Polyethylene Co., Ltd., product name: UltZex 3500ZA) and low-density polyethylene with substantially no added slip agent (so-called additive-free LDPE, manufactured by Ube Maruzen Polyethylene Co., Ltd., product name: UBE Polyethylene B128) were used as the constituent material of the third layer 113, and a sealant 10 having the structure shown in Figure 1 (first layer 111 (film thickness: 8 μm), second layer 112 (film thickness: 24 μm), third layer 113 (film thickness: 8 μm)) was produced by a multi-layer co-extrusion inflation method.

[0060] The fractal dimension D and the persistent homology value N on the first surface 11A of the first layer 111 of the sealant 10 produced as described above 10 In order to calculate this, a white light interference optical microscope (manufactured by Zygo, product name: NewView6300) was used to capture images under the following conditions, and a grayscale image (496 pixels x 496 pixels) was obtained.

[0061] [Measurement conditions] Measurement equipment: White light interference optical microscope (Zygo, product name: NewView6300) Objective lens: 50x Zoom lens: 1x Measurement pixel count: 496 pixels x 496 pixels Field of view: 216μm x 216μm [Analysis conditions] Analysis software: MetroPro ver8.3.2 Removed: Cylinder FilterType: None

[0062] The grayscale image was subjected to threshold processing (Image-Adjust-Treshold: Otsu was selected) using the image analysis software ImageJ (freeware for image analysis developed by the National Institutes of Health (NIH)) to convert the grayscale image into a binary image so that the convex parts of the first surface 11A were white and the concave parts were black.

[0063] The binarized image was converted into a contour image (white background, contour width 2 pixels) by contour extraction processing (Process-Find Edges) using the image analysis software ImageJ.

[0064] The contour image is subjected to fractal analysis by the box-counting method using the image analysis software ImageJ, and the fractal dimension D is calculated. Specifically, the size of the pixel (length of one side a) is changed, and the number (N(a)) of parts having a signal value contained in the pixel (pixels in black parts because the background color is white in this embodiment) is counted, and the slope of each double logarithm (log(a) vs log(N(a))) graph is found to calculate the fractal dimension D. The results are shown in Table 1.

[0065] In addition, in order to calculate the persistent homology value, grayscale images (496 pixels x 496 pixels) of three arbitrarily selected locations on the first surface 11A were reduced to a size of 120 pixels x 120 pixels, and then threshold processing (Image-Adjust-Treshold: Otsu was selected) was performed on the grayscale images using the image analysis software ImageJ (free image analysis software developed by the National Institutes of Health (NIH)) to convert each grayscale image into a binary image so that the convex parts of the first surface 11A were white and the concave parts were black.

[0066] For each binarized image, the scale of the concave portion was calculated using persistent homology. Specifically, regarding the birth diameter X and the death diameter Y, using statistical analysis software (TDA library of R), the birth diameter X and the death diameter Y were calculated in μm scale for all the cyclic complexes in the binarized image. Then, the number of cyclic complexes satisfying the following formula was calculated for each of the three binarized images, and the average value N 10 was calculated. The results are shown in Table 1. Y≧X + 10

[0067] The coefficient of kinetic friction of the first layer 111 of the sealant 10 was measured using a friction measuring machine (manufactured by Toyo Seiki Seisakusho, product name: Friction Measuring Machine TR-2), and the slipperiness of the first surface 11A of the sealant 10 was evaluated according to the following criteria. The results are shown in Table 1. <Slipperiness Evaluation Criteria> 〇: The coefficient of kinetic friction is less than 0.45. ×: The coefficient of kinetic friction is 0.45 or more.

[0068] The mapability of the sealant 10 was measured using a mapping measuring machine (manufactured by Suga Test Instruments Co., Ltd., product name: ICM-1T), and the transparency of the sealant 10 was evaluated according to the following criteria. The results are shown in Table 1. <Transparency Evaluation Criteria> 〇: At an optical brush width of 2 mm, the mapability is 60% or more. ×: At an optical brush width of 2 mm, the mapability is less than 60%.

[0069] Furthermore, the volatile components from the sealant 10 were analyzed by GC / MS under the following conditions to obtain a mass spectrum, and the cleanliness of the sealant 10 was evaluated according to the following criteria. The results are shown in Table 1.

[0070] <GC / MS Conditions> · Gas chromatograph: GCMS-QP2010 (manufactured by Shimadzu Corporation) · Column: 670-15003-03 (length: 30 mm, inner diameter: 0.25 mm, manufactured by Shimadzu Corporation) · Column oven temperature: 50°C · Injection volume: 1 μL Carrier gas: He (57.1mL / min) Vaporizer temperature setting: 300℃ Measurement mode: Split

[0071] <Cleanliness evaluation> ◯: Peaks other than alkanes, and no peaks of 10 ppm or more in toluene conversion were detected. ×: A peak other than an alkane peak of 10 ppm or more calculated as toluene is detected.

[0072] Example 2 Pellets of low-density polyethylene with substantially no added slip agent (so-called additive-free LDPE, manufactured by Ube Maruzen Polyethylene, product name: UBE Polyethylene B128) and pellets of linear low-density polyethylene with substantially no added slip agent (so-called additive-free LLDPE, manufactured by Prime Polymer, product name: UltZex 3500ZA) were melt-mixed in a compounding ratio of 7:3 (by mass) and the sealant 10 shown in Figure 3 was produced by an inflation film formation method.

[0073] The fractal dimension D and the persistent homology value N on the first surface 11A of the sealant 10 produced as described above 10 was calculated in the same manner as in Example 1. In addition, the slipperiness of first surface 11A of sealant 10, the transparency of sealant 10, and the cleanliness of sealant 10 were evaluated in the same manner as in Example 1. The results are also shown in Table 1.

[0074] Comparative Example 1 The fractal dimension D and persistent homology value N on the first surface of a sealant made of linear low-density polyethylene (LLDPE, manufactured by Mitsui Chemicals Tohcello, product name: TUX MC-S) 10 was calculated in the same manner as in Example 1. In addition, the slipperiness of the first surface of the sealant, the transparency of the sealant, and the cleanliness of the sealant were evaluated in the same manner as in Example 1. The results are also shown in Table 1.

[0075] Comparative Example 2 A sealant was prepared by the inflation film forming method using pellets of high density polyethylene (HDPE, manufactured by Prime Polymer Co., Ltd., product name: HZ3600F). The fractal dimension D and persistent homology value N on the first surface of the prepared sealant were 10 was calculated in the same manner as in Example 1. In addition, the slipperiness of the first surface of the sealant, the transparency of the sealant, and the cleanliness of the sealant were evaluated in the same manner as in Example 1. The results are also shown in Table 1.

[0076] Comparative Example 3 Fractal dimension D and persistent homology value N on the first surface of a sealant made of linear low-density polyethylene (LLDPE, manufactured by Aicello, product name: N601) 10 was calculated in the same manner as in Example 1. In addition, the slipperiness of the first surface of the sealant, the transparency of the sealant, and the cleanliness of the sealant were evaluated in the same manner as in Example 1. The results are also shown in Table 1.

[0077] [Table 1]

[0078] From the results shown in Table 1, it is found that the fractal dimension D of the first surface 11A of the sealant 10 is within a predetermined range, and the persistent homology value N 10 It was confirmed that the fractal dimension D of the comparative example 1, which is less than 1.50, is in a predetermined range, and thus the fractal dimension D of the comparative example 1 is poor in terms of cleanliness. 10 In Comparative Examples 2 and 3, where the fractal dimension D of the first surface 11A of the sealant 10 is in the range of 1.50 to 1.90 and the persistent homology value N of the first surface 11A is in the range of 1.50 to 1.90, the transparency is poor. 10 It is believed that when the ratio is 1.0 or more, good lubricity, good transparency, and good cleanability can be achieved. [Explanation of symbols]

[0079] 10…Sealant 11A...Side 1 11B…Second side 20...Packaging materials 40...Transport packaging for silicon materials 50...Silicone material packaging

Claims

1. A sealant for use in a shipping package of a silicone material, comprising: The sealant has a first surface located on the silicone material side of the transport package and a second surface opposite to the first surface, the sealant has a first portion including the first surface and a second portion located closer to the second surface than the first portion, the first portion comprises low density polyethylene (LDPE) substantially free of added slip agents; the second portion comprises linear low density polyethylene (LLDPE) substantially free of added slip agent; The thickness of the sealant is 30 μm to 60 μm, The image clarity of the sealant at an optical comb width of 2 mm is 60% or more; The fractal dimension D of the first surface is in the range of 1.74 to 1.76, and the persistent homology value N of the first surface is １０ A sealant having a viscosity of 3.3 or more.

2. The sealant of claim 1 , wherein the first portion further comprises linear low density polyethylene (LLDPE), high density polyethylene (HDPE), or polypropylene (PP).

3. the sealant is a laminate having a first layer including the first surface and a second layer; The sealant of claim 1 or claim 2, wherein the first portion is the first layer.

4. the sealant is a laminate having a first layer including the first surface and a second layer; The sealant according to any one of claims 1 to 3, wherein the first portion is the first layer, and the second portion is the second layer.

5. the sealant further comprises a third portion including the second surface; 3. The sealant of claim 1 or claim 2, wherein the third portion comprises low density polyethylene (LDPE) substantially free of added slip agent.

6. the sealant is a laminate having, in that order, a first layer including the first surface, a second layer, and a third layer; The sealant of claim 5 , wherein the first portion is the first layer, the second portion is the second layer, and the third portion is the third layer.

7. The sealant of any one of claims 1 to 6, wherein the second portion further comprises low density polyethylene (LDPE) substantially free of added slip agents.

8. A sealant for use in a shipping package of a silicone material, comprising: the sealant is a single-layer body consisting of only one layer, the sealant having a sealant substrate having a first surface located on the silicone material side in the transport package and a second surface opposite to the first surface; The sealant base comprises low density polyethylene (LDPE) substantially free of added slip agents and linear low density polyethylene (LLDPE) substantially free of added slip agents; The content ratio of low density polyethylene (LDPE) to linear low density polyethylene (LLDPE) in the sealant is in the range of 1:1 to 7:3 on a mass basis, The thickness of the sealant base material is 30 μm to 60 μm, The image clarity of the sealant substrate at an optical comb width of 2 mm is 60% or more; The fractal dimension D of the first surface is in the range of 1.74 to 1.76, and the persistent homology value N of the first surface is １０ A sealant having a viscosity of 3.3 or more.

9. A packaging material comprising a substrate and the sealant according to any one of claims 1 to 8 provided on one surface of the substrate.

10. The packaging material according to claim 9 , further comprising a gas barrier layer provided on the surface of the substrate opposite the sealant.

11. The packaging material of claim 10 , wherein the gas barrier layer comprises aluminum oxide or silicon oxide.

12. A transport package for silicon material, which is made of the packaging material according to any one of claims 9 to 11.

13. A transport package for silicon material according to claim 12; and a silicon material contained in the transport packaging for the silicon material.

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