Sheet winding method

Abstract

To provide a sheet winding method, a sheet roll and a sheet roll storage method that can maintain the printability of an APET sheet for a long period of time.SOLUTION: The present invention is a method of winding a sheet, wherein an amorphous polyethylene terephthalate sheet is rolled with a resin sheet or a paper sheet sandwiched as an interlayer material. In addition, a sheet roll is a sheet roll rolled into a roll, in which the resin sheet or the paper sheet is sandwiched between the lower layer amorphous polyethylene terephthalate sheet and the upper layer amorphous polyethylene terephthalate sheet as an interlayer material. Furthermore, in a method for storing sheet rolls, the sheet rolls are stored in an environment where the temperature is 23°C or 25°C and the humidity is 50% or less.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention The present invention relates to a sheet winding method. [Background technology]

[0002] Conventionally, amorphous polyethylene terephthalate (hereinafter referred to as "APET") has been used as a sheet to be printed on, such as printing paper and packaging. Printing includes not only printing letters and the like, but also solid patterns.

[0003] APET sheets are produced by extruding raw materials using a T-die or the like and winding them into a roll (see Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 04-275125 Summary of the Invention [Problem to be solved by the invention]

[0005] However, if a rolled APET sheet is stored for a long period of time (for example, about one month after the date of manufacture), the surface condition of the upper and lower layers may change due to direct contact between them, and also due to the influence of moisture (water) in the air, causing the layers to adhere to each other and become difficult to separate. As a result, the printability of the APET sheet may deteriorate (see Figure 1).

[0006] The present invention has been made in view of the above problems, and has as its object to provide a method for winding an amorphous polyethylene terephthalate sheet, which can maintain the printability of the sheet for a long period of time. [Means for solving the problem]

[0007] In order to solve the above problems, the present invention provides a sheet winding method, which comprises extruding an amorphous polyethylene terephthalate sheet into a continuous strip using a T-die, then quenching the amorphous polyethylene terephthalate sheet and winding it around a core into a multi-layer roll, and inserting a resin sheet or a paper sheet as an interlayer material between the inner and outer layers of the amorphous polyethylene terephthalate sheet during winding onto the multi-layer roll, The amorphous polyethylene terephthalate sheet is formed to a thickness of 20 μm or more and 200 μm or less, and the arithmetic mean roughness Ra is is 0.10, The resin sheet or paper sheet is characterized by having an arithmetic mean roughness Ra of 2.90 or less and 0.01 or more greater than the arithmetic mean roughness Ra of the amorphous polyethylene terephthalate sheet. The amorphous polyethylene terephthalate sheet has a solubility parameter of 10.7. The resin sheet is preferably formed to a thickness of 20 μm or more and 100 μm or less, and the solubility parameter of the molding material is preferably less than 9.1 or more than 12.7. [Effects of the Invention]

[0008] According to the present invention, Amorphous polyethylene terephthalate sheet Sheets that can maintain printability for a long period of time This method can provide a winding method. Furthermore, when winding into a multi-layer roll, a resin sheet or paper sheet is inserted as an interlayer material between the inner and outer layers of the amorphous polyethylene terephthalate sheet, allowing the amorphous polyethylene terephthalate sheet and the resin sheet or paper sheet to be simultaneously wound in an overlapping state. Furthermore, since the thickness of the amorphous polyethylene terephthalate sheet is 20 μm or more and 200 μm or less, it can be used as printing paper or packaging. Furthermore, since the arithmetic mean roughness Ra of the resin sheet or paper sheet is 2.90 or less and is 0.01 or more greater than the arithmetic mean roughness Ra of the amorphous polyethylene terephthalate sheet, scratches can be prevented from becoming a problem even when the amorphous polyethylene terephthalate sheet is used in a manner that poses a problem. According to the invention of claim 2, since the solubility parameter of the molding material of the resin sheet is less than 9.1 or more than 12.7, the printability of the amorphous polyethylene terephthalate sheet can be maintained and the occurrence of scratches and sticking can be suppressed. In addition, the sheet roll can be expected to be stored appropriately even in high-temperature and high-humidity storage conditions. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a table showing Experimental Example 1 in which the printability of conventional APET sheets was evaluated under different storage environments. [Figure 2] 10 is a table showing Experimental Example 2 in which the performance of APET sheets according to embodiments of the present invention using different types of interlayer materials was evaluated. [Figure 3] 10 is a table showing Experimental Example 3 in which changes in performance of an APET sheet according to an embodiment of the present invention were evaluated under different storage environments. [Figure 4]10 is a table showing Experimental Example 4 in which changes in printability of the APET sheet of Example 21 under different storage environments were evaluated. DETAILED DESCRIPTION OF THE INVENTION

[0010] A preferred embodiment of the sheet winding method according to the present invention will be described below.

[0011] Amorphous polyethylene terephthalate sheets (hereinafter referred to as "APET sheets") are produced as non-crystalline, unstretched sheets by extruding a molding material obtained by polycondensing terephthalic acid or dimethyl terephthalate with ethylene glycol, followed by rapid cooling.

[0012] The APET sheet produced in this way has the same excellent strength, transparency, and chemical resistance as the PET sheet, and although it has inferior heat resistance compared to the PET sheet, it has excellent printability.

[0013] In the final process of sheet production, this APET sheet is wound into a roll with a length of about 500 m to 5,000 m and a diameter of about 250 mm to 600 mm. The winding tension when winding the APET sheet is usually about 10 N to 100 N.

[0014] APET sheets have a thickness of, for example, about 8 μm to 300 μm, and sheets with a thickness of 20 μm to 200 μm are generally used as printing paper and packaging. The width of the APET sheet can be set arbitrarily by slitting, but the maximum width is about 2000 mm.

[0015] Other physical properties of the APET sheet include, for example, an arithmetic mean surface roughness Ra (hereinafter simply referred to as "surface roughness Ra") of 0.10 to 3.00, and a solubility parameter (hereinafter referred to as "SP value") of 10.7.

[0016] (Experimental Example 1) Here, the printability of the APET sheet (roll) was evaluated under storage conditions in which the storage period and storage temperature were changed. FIG. 1 is a table showing Experimental Example 1, which evaluated the performance of conventional APET sheets under different storage environments.

[0017] The experimental conditions and evaluation criteria were as follows: the storage temperature was changed from 25°C to 40°C, and after a specified number of days had passed at each storage temperature, gravure printing was performed on both sides of the APET sheet, and the presence or absence of print (paint) voids was checked using a defect detector. Those with print voids were rated as "X", and those without print voids were rated as "O". The APET sheet used was 880 mm wide, 0.2 mm (200 μm) thick, 1300 mm long (diameter approximately 580 mm), and had a surface roughness Ra of 0.10.

[0018] As shown in Figure 1, the results of Experimental Example 1 showed that when stored under standard test conditions (JIS standard) of 25°C temperature and 50% humidity, printability was maintained for up to 25 days, but printability deteriorated after 30 days. When stored at a temperature of 30°C and humidity of 50%, printability was maintained for up to 20 days, but printability deteriorated after 25 days. When stored at a temperature of 35°C and humidity of 50%, printability was maintained for up to 15 days, but printability deteriorated after 20 days. When stored at a temperature of 40°C and humidity of 50%, printability had already deteriorated after 15 days.

[0019] It should be noted that the standard conditions for the JIS standard allow for a temperature of 23°C, which is better than 25°C, and it was confirmed that in this case the deterioration of printability would be delayed by approximately one to three days. On the other hand, even at 25°C, if the humidity is 80% or higher, it was confirmed that the deterioration of printability will be accelerated by about 3 to 5 days, and it was predicted that the deterioration will be accelerated by about 5 to 10 days as the temperature increases.

[0020] Thus, when an APET sheet is stored in a wound roll, its printability deteriorates over time, even in a relatively favorable environment.

[0021] Therefore, in an embodiment of the present invention, when an extruded APET sheet is wound around a core such as a paper tube, a resin tube, or a metal tube by a winding device of a sheet manufacturing apparatus, a resin sheet (film) or a paper sheet is inserted (sandwiched) as an interlayer material and wound simultaneously in an overlapping state.

[0022] The sheet roll wound into a roll has a resin sheet or paper sheet sandwiched between the upper layer of APET and the lower layer of APET as an interlayer material, and this is repeated from the innermost layer to the outermost layer.

[0023] If the interlayer material is a paper sheet, it should be similar to the interlayer paper used when winding carrier tape, for example, with a basis weight of 20 g / m 2 ~100g / m 2 Any type of paper can be used, including ordinary kraft paper, neutral kraft paper, dust-free paper, industrial miscellaneous paper, unbleached wrapping paper, newspaper roll paper, and special paper.

[0024] On the other hand, when the interlayer material is a resin sheet, it is similar to the interlayer film used when winding the carrier tape, and examples include those formed from molding materials such as polyethylene (PE), (crystalline) polyethylene terephthalate (PET), acrylonitrile (AN), polystyrene (PS), polyvinyl alcohol (PVA), etc. However, it is desirable to avoid using some of these in poor environments (high temperature and humidity) described below. The thickness of the resin sheet may be, for example, about 20 μm to 100 μm.

[0025] (Experimental Example 2) Here, several types of interlayer materials were used to evaluate the printability and other performance of the APET sheet depending on the type of interlayer material. FIG. 2 is a table showing Experimental Example 2 in which the performance of APET sheets according to embodiments of the present invention using different types of interlayer materials was evaluated.

[0026] The experimental conditions and evaluation criteria were as follows: each sheet roll was stored for 30 days in an environment with a storage temperature of 23°C and humidity of 50%, after which gravure printing was performed on both sides of the APET sheet, and the sheet was visually inspected for scratches and adhesion. A defect detector was also used to check for print (paint) voids. Items that encountered problems were rated as "X", and items that did not encounter problems were rated as "O". The overall evaluation was given as "O" for good results, "X" for poor results, and "△" for results that were acceptable under certain conditions. The APET sheets used were the same as those used in Experimental Example 1.

[0027] As a result of Experimental Example 2, as shown in Figure 2, Comparative Example 1 was an APET sheet wound using a conventional winding method, and adhesion occurred between the upper and lower layers, which resulted in deformation when peeled off, and the printability was not good.

[0028] In Example 1, sticking occurred between the APET sheet and the PE sheet, but when they were peeled off, only the PE sheet, which had low strength, deformed, and no deformation occurred in the APET sheet, so printability was good, but the PE sheet was difficult to reuse, so the overall evaluation was △. The sticking was thought to have occurred because the surface roughness Ra of the PE sheet used was close to that of the APET.

[0029] Examples 2 to 5 had good printability and were also good in overall evaluation.

[0030] In Examples 6 to 8, detailed observation revealed that fine scratches had occurred on the surface of the APET sheet, but since there was no problem with the visibility of letters and patterns, the printability was deemed good and the overall evaluation was △. The scratches were thought to have been caused by the high surface roughness Ra of the PET sheet, PE sheet, and paper sheet used.

[0031] Thus, compared to a conventional sheet roll made of only APET sheets, a sheet roll with an interlayer material sandwiched therebetween can extend the period of printability. Furthermore, when the APET sheet is used in a manner where scratches are an issue, it is preferable to use an interlayer material of a resin sheet or paper sheet with a surface roughness Ra of 2.90 or less and at least 0.01 greater than the surface roughness Ra of the APET sheet.

[0032] (Experimental Example 3) Next, we evaluated the changes in performance, such as printability, of APET sheets using multiple types of interlayer materials when stored under worse environments. FIG. 3 is a table showing Experimental Example 3 in which changes in performance of an APET sheet according to an embodiment of the present invention were evaluated under different storage environments.

[0033] The experimental conditions and evaluation criteria were as follows: each sheet roll was stored for 30 days in an environment with a storage temperature of 23°C and humidity of 50%, and another environment with a storage temperature of 40°C and humidity of 80%; then, gravure printing was performed on both sides of the APET sheet, and the sheet was visually inspected for scratches and adhesion; and a defect detector was used to check for print (paint) voids; those that encountered problems were rated as "X" and those that did not encounter problems were rated as "O." The overall evaluation was given as "O" for good results, "X" for poor results, and "△" for results that were acceptable under certain conditions. The APET sheet used was the same as in Experimental Example 1.

[0034] As a result of Experimental Example 3, as shown in FIG. 3, Comparative Examples 11 to 13 exhibited good printability after storage in a favorable environment of a storage temperature of 23°C and humidity of 50%, but exhibited poor printability after storage in a poor environment of a storage temperature of 40°C and humidity of 80%.

[0035] Furthermore, in an environment of 40°C temperature and 80% humidity, sticking occurred in Comparative Example 11, resulting in slight deformation of the APET sheet, sticking occurred in Comparative Example 12, resulting in slight deformation of the APET sheet, and sticking occurred in Comparative Example 13, resulting in slight deformation of the APET sheet.

[0036] The sticking was thought to have occurred because the SP values ​​of the PS, PET, and PVA sheets used were close to that of the APET sheet. In particular, under high-temperature and high-humidity storage conditions, decomposition of the resin components of the molding material for the APET sheet and bleeding out of low-molecular-weight components were observed. In Comparative Examples 11 to 13, sticking occurred and printability deteriorated after 15 days.

[0037] Examples 11 and 12 exhibited good printability not only in good environments but also in poor environments, and the overall evaluation was also good. The comparative example 12 is the same sheet roll as the example 2 of the experimental example 2.

[0038] Thus, when the APET sheet is stored in a high-temperature, high-humidity environment, it is preferable to use a resin sheet whose SP value is far from (i.e., not close to) the SP value of the APET sheet.

[0039] However, if a paper sheet is used as the interlayer material instead of the individual resin sheets used in Experimental Example 3, the moisture absorption properties of the paper sheet will promote the decomposition of the resin components of the APET sheet in contact with it, making it unsuitable for storage in a hot and humid environment.

[0040] (Experimental Example 4) Finally, in Example 21, the same PET sheet as in Example 2 of Experimental Example 2 was used as an interlayer material, and the changes in performance such as printability of the APET sheet when stored under a number of environments were evaluated. FIG. 4 is a table showing Experimental Example 4 in which the change in printability of the APET sheet of Example 21 under different storage environments was evaluated.

[0041] The experimental conditions and evaluation criteria were as follows: the storage temperature was changed from 25°C to 40°C, and after a specified number of days had passed at each storage temperature, gravure printing was performed on both sides of the APET sheet, and the presence or absence of print (paint) voids was checked using a defect detector. Those with print voids were rated as "X", and those without print voids were rated as "O". The APET sheet used was the same as in Experimental Example 1.

[0042] As a result of Experimental Example 4, as shown in Figure 4, when stored under standard test conditions (JIS standard) of a temperature of 25°C and humidity of 50%, printability was maintained for up to 31 days, and printability was also maintained after 35 days. When stored at a temperature of 30°C and humidity of 50%, printability was maintained for up to 30 days, but printability deteriorated after 31 days. When stored at a temperature of 35°C and humidity of 50%, printability was maintained for up to 25 days, but printability deteriorated after 30 days. When stored at a temperature of 40°C and humidity of 50%, printability was maintained for up to 15 days, but printability deteriorated after 20 days.

[0043] As described above, the APET sheet of Example 21 can maintain its printability for at least 10 days under favorable conditions compared to the conventional product shown in Figure 1. It was also confirmed that it can maintain its printability for at least 15 days even under adverse conditions.

[0044] According to the above experimental examples 1 to 4, in the case of a sheet roll made of only an APET sheet, the printability deteriorates before the storage period of 30 days is maintained, but in the case of a sheet roll sandwiched between layers as in this embodiment, the printability can be maintained even after the storage period of 30 days.

[0045] However, if the surface roughness Ra of the resin sheet or paper sheet is too large compared to the surface roughness Ra of the APET sheet, minute scratches will occur due to misalignment (friction) during winding, so the surface roughness Ra of the resin sheet or paper sheet should be less than 3.00, more preferably 2.90 or less. Conversely, if the surface roughness Ra of the resin sheet or paper sheet is too small compared to the surface roughness Ra of the APET sheet, sticking will occur, so it is preferable that the surface roughness Ra of the resin sheet or paper sheet be 0.01 or more greater than the surface roughness Ra of the APET sheet.

[0046] Furthermore, in typical printing factories, sheet rolls are stored in warehouses where the temperature and humidity are kept constant, so the above measures are sufficient and do not pose any particular problems. However, when the sheet rolls are stored in poor environments (warehouses) that are not air-conditioned, further measures, that is, the selection of more favorable winding conditions, become necessary.

[0047] Therefore, when stored under high-temperature and high-humidity conditions, it is preferable that the resin sheet used has a molding material whose solubility parameter (SP value) is not within the range of 9.1 or more and 12.7 or less, in other words, is less than 9.1 or more than 12.7. If a paper sheet is sandwiched instead of a resin sheet, problems due to the close solubility parameters do not occur, but problems arise due to the hygroscopicity of the paper sheet, so it is still not recommended to store under high-temperature and high-humidity conditions.

[0048] As described above, the sheet winding method of the embodiment according to the present invention involves winding an amorphous polyethylene terephthalate sheet into a roll with a resin sheet or a paper sheet sandwiched between the sheets as an interlayer material. Furthermore, the sheet roll of an embodiment according to the present invention is a sheet roll wound into a roll shape, in which a resin sheet or a paper sheet is sandwiched between a lower amorphous polyethylene terephthalate sheet and an upper amorphous polyethylene terephthalate sheet as an interlayer material. This allows the printability of the APET sheet to be maintained, and also allows the storage period of the APET sheet or sheet roll to be at least 30 days in an environment with a temperature of 23°C or 25°C and a humidity of 50% or less.

[0049] The resin sheet or paper sheet of the embodiment has an arithmetic mean surface roughness Ra of 2.90 or less, which is 0.01 or more greater than the arithmetic mean surface roughness Ra of the APET sheet. When the APET sheet and the interlayer material are wound together, scratches may occur due to friction, but by limiting the arithmetic surface roughness Ra of the interlayer material, the printability of the APET sheet can be maintained and scratches and sticking can be prevented.

[0050] The resin sheet of the embodiment has an arithmetic surface roughness Ra that satisfies the above value, and the solubility parameter (SP value) of the molding material is less than 9.1 or more than 12.7. This allows the printability of the APET sheet to be maintained, and further reduces the occurrence of scratches and sticking. Furthermore, the storage period can be at least 30 days even in an environment of 40°C and 80% humidity.

[0051] In an embodiment of the present invention, a sheet roll is stored in an environment where the temperature is 23°C or 25°C and the humidity is 50% or less. This allows the sheet to be stored for at least 30 days. Furthermore, by selecting the resin sheet appropriately as described above, the sheet can be stored for at least 30 days even in an environment where the temperature is 40°C and the humidity is 80%.

[0052] Although the preferred embodiments of the present invention have been described in detail above, the present invention is not limited to the above-described embodiments, and various modifications and changes are possible within the scope of the gist of the present invention as set forth in the claims.

[0053] In the above embodiment, a continuous strip of APET sheet is wound into a roll, but the present invention is also applicable to a form in which individual APET sheets are stacked (layered) for storage.

Claims

1. A method for winding a sheet, comprising extruding an amorphous polyethylene terephthalate sheet into a continuous strip using a T-die, then quenching the amorphous polyethylene terephthalate sheet and winding it around a core into a multi-layer roll, and inserting a resin sheet or a paper sheet as an interlayer material between an inner peripheral layer and an outer peripheral layer of the amorphous polyethylene terephthalate sheet during winding onto the multi-layer roll, The amorphous polyethylene terephthalate sheet is formed to a thickness of 20 μm or more and 200 μm or less and has an arithmetic mean roughness Ra of 0.10, A method for winding a sheet, wherein the resin sheet or paper sheet has an arithmetic mean roughness Ra of 2.90 or less and is 0.01 or more greater than the arithmetic mean roughness Ra of the amorphous polyethylene terephthalate sheet.

2. The amorphous polyethylene terephthalate sheet has a solubility parameter of 10.7, 2. The sheet winding method according to claim 1, wherein the resin sheet is formed to a thickness of 20 μm or more and 100 μm or less, and the solubility parameter of the molding material is less than 9.1 or more than 12.7.

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