METHOD FOR MANUFACTURING A FLAT CLOSURE AND FLAT CLOSURE

Abstract

A method for producing a surface closure (1) according to the present invention comprises a forming step of shaping the surface closure (1) by feeding a synthetic resin into a molding device (41) in which cavities (42b) are provided, a separation step of separating the dome elements (10) from the cavities (42b), and a deformation removal step of deforming the dome elements (10) by heating the separated dome elements (10) to remove deformations that have occurred in the dome elements (10). This allows the production of a surface closure made of synthetic resin, which contains a saturated polyester resin as its main component, without any factors that hinder the recycling of the saturated polyester resin.

Description

Technical area

[0001] The present invention relates to a method for producing a surface closure and to a surface closure. Background technology

[0002] To date, a surface fastener is known in which a loop part with a plurality of loops (female surface fastener part) and a male surface fastener part, which can be attached to and detached from the loop part, are used in combination. The male surface fastener part is also referred to as a hook part. It should be noted that in the following description, a male surface fastener part is simply referred to as a "surface fastener part," and a description of a surface fastener part refers to a male surface fastener part. The surface fastener comprises, for example, a flat, plate-shaped base area and a plurality of dome links that are integrally provided on the base area and extend from it.

[0003] For example, the unexamined Japanese patent application Publication No. 2020-28381 (PTL1) describes a surface closure used in products such as clothing. PTL1 discloses that, for example, a thermoplastic resin such as polypropylene, polyester, nylon, polybutylene, terephthalate, or a copolymer thereof is used as a surface closure material. Reference list of patent specifications

[0004] PTL1: Unexamined Japanese patent application Publication No. 2020-28381 Invention Summary Technical task

[0005] In recent years, due to environmental concerns, resource conservation, and other factors, efforts have intensified to recycle synthetic resins (plastics) and similar materials. For example, clothing, such as used clothing, is collected, and synthetic resins like polyester resins are recycled from this collected clothing. Furthermore, progress is being made in mono-materialization recycling of synthetic resins, where a product is manufactured from a single material, to minimize environmental impact, increase recycling efficiency, and so on. For example, when recycling clothing or similar items, it is desirable to use a polyethylene terephthalate resin (hereafter abbreviated as PET resin), meaning the entire product is made from a single PET resin material.

[0006] On the other hand, in the known surface closure, as described, for example, in PTL 1, the surface closure is usually formed from a synthetic resin containing an elastomer (e.g., a polyester elastomer or a polyurethane elastomer) or similar, whereby it should be noted that, for example, a molten synthetic resin is extruded uniformly and a body formed in a mold can be easily removed from the mold (or easily separated) in one step during the production of the surface closure.

[0007] However, many factors are known to hinder the recycling of synthetic resins. For example, in the case of products made from a saturated polyester resin (especially PET resin), an elastomer contained in known surface closures is one of the factors that impedes recycling. Therefore, for products such as clothing to which a surface closure is attached, in order to enable the monomaterialization of products made from a saturated polyester resin (especially PET resin), there is a need to develop surface closures made from a saturated polyester resin that do not contain factors that hinder recycling, such as an elastomer.

[0008] The present invention was developed in view of the above problems and an object of the invention is to provide a method for producing a surface seal made of synthetic resin which contains a saturated polyester resin (e.g. a PET resin) as a main component and which has no factor which hinders the recycling of the saturated polyester resin and is to provide a surface seal which is produced by the method. Solution to the task

[0009] A method for producing a surface closure according to the present invention, in order to achieve the above objective, is a method for producing a surface closure in which a surface closure is produced from synthetic resin, wherein the surface closure comprises a base region and a plurality of dome members provided at the base region, wherein the dome members each have a stem section extending from the base region and a dome section located at a front end section of the stem section, characterized in that the method comprises a forming step of shaping the surface closure by feeding the synthetic resin to a molding device in which cavities are provided; a separation step of separating the dome members from the cavities;and includes a deformation removal step of deforming the dome members after the separation step by heating the separated dome members in order to eliminate any deformation that may have occurred in the dome members.

[0010] The method for producing a surface closure according to the present invention is preferably designed such that the dome members are deformed in the shape removal step into shapes that essentially correspond to the shapes of the cavities.

[0011] The method for producing a surface seal according to the present invention is preferably designed such that a synthetic resin is used which contains as its main component a saturated thermoplastic polyester resin which contains terephthalic acid as an acid component and ethylene glycol as a glycol component.

[0012] In this case, it is preferred that the saturated polyester resin contains a recycled polyethylene terephthalate resin.

[0013] The method for producing a surface closure according to the present invention is preferably designed such that the dome members are heated to a glass transition temperature of the synthetic resin of -20°C or higher and a glass transition temperature of the synthetic resin of +20°C or lower during the deformation removal step.

[0014] The method for producing a surface seal according to the present invention is preferably designed such that a synthetic resin with a melt flow rate of 30 g / 10 min or more and 100 g / 10 min or less is used as the synthetic resin.

[0015] The method for producing a surface seal according to the present invention is preferably designed such that a synthetic resin is used which has a number-average molar mass Mn of 10,000 or more and 30,000 or less and a polydispersity Mw / Mn of 2.0 or more and 3.0 or less.

[0016] Next, a surface closure according to the present invention is a surface closure made of synthetic resin, comprising a base region extending longitudinally along a device direction and a plurality of dome members provided at the base region, wherein the dome members each have a stem section extending from the base region and a dome section located at a front end section of the stem section, characterized in that a main component of the synthetic resin is a saturated thermoplastic polyester resin containing terephthalic acid as an acid component and ethylene glycol as a glycol component, the maximum extent of each dome member in a transverse direction orthogonal to the device direction is 0.2 mm or more and 1.0 mm or less, and the plurality of dome members has a density of 30 dome members / cm². 2 or more and 100 dome links / cm 2or are arranged less.

[0017] In the case of surface sealing according to the present invention, it is preferred that the synthetic resin has a melt flow rate of 30 g / 10 min or more and 100 g / 10 min or less.

[0018] In the surface sealing according to the present invention, it is preferred that the number-average molar mass Mn of the synthetic resin is 10,000 or more and 30,000 or less, and that the polydispersity Mw / Mn of the synthetic resin is 2.0 or more and 3.0 or less.

[0019] In the surface sealing according to the present invention, it is preferred that the saturated polyester resin contains a recycled polyethylene terephthalate resin. Advantageous effects of the invention

[0020] According to the method for producing a surface closure as described in the present invention, it is possible to produce a surface closure made of synthetic resin containing a saturated polyester resin (e.g., a PET resin) as its main component and which does not exhibit any factors that hinder the recycling of the saturated polyester resin. Therefore, the use of the surface closure provided by the present invention can lead to the realization of monomaterialization, in which the entire product to which the surface closure is applied, such as a garment, is made of a single synthetic resin, thus allowing for the efficient recycling of the saturated polyester resin. Brief description of the drawings [ Fig. 1] Fig. Figure 1 is a schematic view that schematically represents a manufacturing device used in a method for producing a surface closure according to an embodiment of the present invention. [ Fig. 2] Fig. Figure 2 is a schematic view showing a roller section of a forming roll of the manufacturing device. Fig. 1 schematically represents. [ Fig. 3] Fig. Figure 3 is a schematic side view of first dome members of a surface closure according to an embodiment of the present invention, viewed from a width direction (transverse direction). [ Fig. 4] Fig. Figure 4 is a schematic side view of second dome members of a surface closure according to an embodiment of the present invention, viewed from the width direction (transverse direction). [ Fig. 5] Fig. Figure 5 is a schematic front view of a relevant part of the surface closure seen from a longitudinal direction (device direction MD). [ Fig. 6] Fig. 6 is a side view showing a first coupling element immediately after it has been removed from the forming roller of the manufacturing device. Fig. 1 has been separated, and is shown schematically. [ Fig. 7] Fig. 7 is a side view showing a second coupling element immediately after it has been removed from the forming roller of the manufacturing device. Fig. 1 has been separated, and is shown schematically. Description of the embodiments

[0021] A suitable embodiment of the present invention is described in detail below with reference to the drawings.

[0022] Fig. Figure 1 is a schematic view in which a manufacturing device used in the present embodiment is schematically depicted and Fig. Figure 2 is a schematic view showing a section of a mold roll. Fig. 3 and Fig. 4 are side views of dome members of a surface closure according to the present embodiment and Fig. Figure 5 is a front view of the dome sections.

[0023] It should be noted that in the following description, the forward-backward direction is the direction along which the surface sealant or a resin thereof is transported in a manufacturing step or a manufacturing device of the surface sealant, or a direction along the length of a surface sealant manufactured to be of considerable length. Furthermore, the forward-backward direction corresponds to the device direction MD. In this case, the side in the transport direction [downstream] with respect to the transport direction described above is, by definition, the front, and the side opposite the transport direction [upstream] is, by definition, the back.

[0024] The left-right direction is a direction along a transverse direction CD orthogonal to the fixture direction MD during the surface closure manufacturing step, or a width direction orthogonal to the front-back direction and along a flat or substantially flat upper surface (first surface) of a base area. The top-bottom direction is a direction orthogonal to the flat or substantially flat upper surface of the base area and is also referred to as the thickness direction or height direction of the surface closure. Furthermore, the top-bottom direction is a direction orthogonal to both the fixture direction MD and the transverse direction CD. In this case, the direction in which the dome members extend with respect to the base area is defined as the upward direction, and the opposite direction to the upward direction is defined as the downward direction.

[0025] First, a surface closure 1 produced according to a manufacturing process in accordance with the present embodiment is described.

[0026] In the present embodiment, a manufacturing device 30 is used as described in Fig. Figure 1 is used to produce a surface closure 1 made of synthetic resin, in which a plurality of dome elements 10 are formed in one piece on a base area 5 which has a flat plate shape, as shown in Figure 1. Fig. Figures 3 to 5 illustrate this surface closure 1. It is elongated along the device direction MD of the manufacturing step. It should be noted that, in the present invention, the longitudinal extent (extension along the forward-backward direction) and the lateral extent (extension along the left-right direction) of the surface closure 1 are not specifically limited, and that the size of the surface closure 1 can be changed, for example, by cutting the surface closure 1.

[0027] The surface seal 1 according to the present embodiment is formed from a synthetic resin which, as its main component, contains a saturated polyester resin (in particular a PET resin) exhibiting high thermoplasticity and high crystallinity. In this case, the synthetic resin from which the surface seal 1 is formed contains a PET resin as its main component and preferably contains no components that hinder the recycling of the PET resin (hindering materials), for example, elastomers, synthetic resins other than PET resin, materials other than synthetic resins, and so on. It should be noted that the components described above that hinder recycling may be present in the synthetic resin of the surface seal 1; however, in this case, it is provided that the concentration of such recycling-hindering components is 1 wt% or less for reasons of recyclability.

[0028] In the present invention, the PET resin is a saturated polyester resin containing terephthalic acid as an acid component and ethylene glycol as a glycol component, and exhibiting thermoplasticity. The main component of the resin is the component that constitutes the largest proportion in the entire surface seal 1. For example, in the present embodiment, the proportion of PET resin (main component) is preferably 90% by weight or more, and in particular 95% by weight or more, of the resin from which the surface seal 1 is composed. In this case, the resin containing PET resin as the main component does not contain any components that, as described above, hinder the recycling of the PET resin, but may contain additives and auxiliary substances that do not hinder the recycling of the PET resin, such as a lubricant and a stabilizing agent.

[0029] By producing a surface seal 1 with the aforementioned synthetic resin, which contains PET resin as its main component (that is, a pure PET resin that does not contain any components that hinder the recycling of the PET resin, such as elastomers), the produced surface seal 1 can be suitablely used in mono-material products made from the PET resin (for example, clothing). In addition, the PET resin from mono-material products to which the surface seal 1 is attached can be efficiently recycled.

[0030] Furthermore, in the present embodiment, the PET resin from which the surface closure 1 is formed consists of recycled PET resin recycled from PET resin products, for example, PET bottles (100% recycled PET resin). In this case, the recycled PET resin contains 0.5 mol% or more and 5.0 mol% or less of isophthalic acid. Isophthalic acid is a substance added to PET resin to improve, for example, the transparency of products such as PET bottles and to enhance their processability. Generally, recycled PET resin, which is recycled from PET bottles or similar materials, contains isophthalic acid in the aforementioned proportion.

[0031] In the present embodiment, the surface closure 1 is formed from a PET resin which has a percentage of 100% recycled PET resin as described above, thereby achieving the effects of saving environmental resources, reducing the amount of waste, reducing greenhouse gas emissions, etc.

[0032] In the present embodiment, the surface closure 1 is formed from a synthetic resin (PET resin) having a melt flow rate (MFR) of 30 g / 10 minutes or more and 100 g / 10 minutes or less, a number-average molar mass Mn of 10000 or more and 30000 or less, and a polydispersity Mw / Mn of 2.0 or more and 3.0 or less.

[0033] If the melt flow rate (MFR) of the resin is 30 g / 10 minutes or more, it is easy to melt the resin (PET resin) by heating it when forming the surface closure 1, and the resin's flowability can be increased, allowing the molten resin to be continuously fed from a nozzle unit 46 of the manufacturing device 30 to a forming roller 41, as described later. If the MFR of the resin is 100 g / 10 minutes or less, cavities 42b for dome members 10, provided on the forming roller 41, can be easily filled with the molten resin. Furthermore, the strength of the formed dome members 10 can be easily ensured. It should be noted that the melt flow rate (MFR) in the present invention is a value measured by the MFR measurement method (Method B) specified in JIS K7210.

[0034] If the number-average molar mass Mn of the resin is 10,000 or more, the viscosity of the molten resin can be increased accordingly to improve extrusion stability. Furthermore, the strength of the dome elements 10 of the surface closure 1 to be produced can be easily ensured. If the number-average molar mass Mn of the resin is 30,000 or less, the flowability of the molten resin can be adequately ensured, and the cavities 42b of the mold roller 41 can be easily filled with the molten resin.

[0035] If the polydispersity Mw / Mn of the resin is 2.0 or higher, the occurrence of the phenomenon of resin sticking at low temperatures can be reduced, and the resin can be easily melted for a short time, thereby increasing its moldability. If the polydispersity Mw / Mn of the resin is 3.0 or lower, the strength of the dome elements 10 can be easily ensured.

[0036] It should be noted that in the present invention, the term PET resin includes recycled PET resin that has been recycled from PET bottles or similar materials, and virgin PET resin that has been obtained from petroleum. This means that the surface closure 1 according to the present invention can be made not only from recycled PET resin, but also from virgin PET resin derived from petroleum, or from a mixture of recycled PET resin and virgin PET resin. Alternatively, in the present invention, the surface closure 1 can be made not from PET resin, but from a thermoplastic saturated polyester resin, which is not PET resin.

[0037] The surface closure 1, made from a PET resin (recycled PET resin) according to the present embodiment, comprises, as shown in Fig. Figures 3 to 5 show a thin, plate-shaped base region 5 extending along the front-back direction and a plurality of dome members 10 extending from an upper surface of the base region 5. The base region 5 has an upper surface (first surface) and a lower surface (second surface) located on the side opposite the upper surface. The upper and lower surfaces of the base region 5 are each flat or substantially flat and are arranged parallel to each other.

[0038] The base region 5 has a thickness (expansion along the top-bottom direction) of 100 µm or more and 300 µm or less. If the thickness of the base region 5 is 100 µm or more, it can be stably formed during a forming step of the surface closure 1, which will be described later. Additionally, the plurality of dome members 10 can be stably supported by the base region 5. If the thickness of the base region 5 is 300 µm or less, the surface closure 1 can exhibit suitable flexibility. It should be noted that, according to the present invention, the shape and size of the base region 5 are not specifically restricted.

[0039] The multitude of coupling elements 10 are provided integrally at the base region 5. The coupling elements 10 according to the present embodiment are divided into first coupling elements 10a (relative to Fig. 3), in which the upper end sections of the coupling members 10 are aligned opposite to the transport direction (towards the rear) of the device direction MD, and into second coupling members 10b (relative to Fig. 4), in which the front end sections of the coupling members 10 are aligned in the transport direction (towards the front) of the device direction MD, are divided.

[0040] In the surface closure 1, a plurality of first dome elements 10a are arranged at uniform intervals along the front-back direction, thus forming a row of first dome elements parallel to the front-back direction. Additionally, a plurality of second dome elements 10b are arranged at uniform intervals along the front-back direction, thus forming a second row of dome elements parallel to the front-back direction. In the surface closure 1 according to the present embodiment, a plurality of first dome element rows and a plurality of second dome element rows are provided. The first dome element rows and the second dome element rows are arranged alternately along the width direction of the surface closure 1.It should be noted that in the present invention the arrangement of the coupling elements 10 (the first coupling elements 10a and the second coupling elements 10b) is not specifically restricted and can be changed depending on, for example, the shape of the products for which the surface closure 1 is used.

[0041] Each of the dome members 10 (each of the first dome members 10a and the second dome members 10b) has at least one undercut area (undercut) 15 at which the dome members 10 cannot be pulled out of a cavity 42b, which will be described later, while retaining the original shape, when the dome member 10 is pulled out of the cavity 42b of the form roll 41 during the production of the surface closure 1.

[0042] Each of the first dome members 10a has a first main section 11 extending from the base area 5 in an inverted J-shape, such that a front end section is oriented opposite to the transport direction along the device direction MD, and has a pair of a left and a right rib 13, and as for example in Fig. Figure 5 shows the first main section 11 and the ribs 13 formed in a single piece, with the first main section 11 sandwiched between the left and right ribs 13. Each of the second dome members 10b has a second main section 12 extending from the base region 5 in an inverted J-shape, such that a front end section is aligned in the transport direction of the device direction MD, and has a pair of left and right ribs 13, and, as shown for example in Fig. Figure 5 shows the second main section 12 and the ribs 13 formed integrally in a mold, in which the second main section 12 is sandwiched between the left and right ribs 13. It should be noted that in the present invention, the dome members can be formed without ribs.

[0043] The first main section 11 of the first dome elements 10a and the second main section 12 of the second dome elements 10b have shapes that are symmetrical to each other with respect to the front-back direction, for example in a side view ( Fig. 3 and Fig. 4), in which each of the dome members 10 is considered along the left-right direction. In addition, the first main section 11 and the second main section 12 each have a stem section 16 extending upwards from the base region 5, and a dome section (dome head section) 17 extending from a front end section (upper end section) of the stem section 16 to one side of the device direction MD.

[0044] According to the present embodiment, the stem section 16 has a shape in which its length (extension in the forward-backward direction) gradually decreases along a direction away from the base region 5. The dome section 17 is designed such that it extends from a position at an upper end section including the upper end of the stem section 16 to one side of the forward-backward direction (forward or backward) and is curved in a direction toward the base region 5. It should be noted that, in the present embodiment, the direction away from the base region 5 and the direction toward the base region 5 are, respectively, upward and downward directions with respect to the top-down direction.

[0045] In a side view ( Fig. 3 and Fig. 4) In each dome member 10, the dome section 17 has a shape that tapers towards the front end of the dome section 17. The lower surface of the dome section 17 has a curved area that is concave upwards. This shape of the dome section 17 allows a loop or loop part to be hooked onto the dome member 10. Furthermore, in the dome members 10 according to the present embodiment, the dome section 17 of the first main section 11 and the dome section 17 of the second main section 12 are designed as the undercut 15 described above.

[0046] The left and right ribs 13, which are provided on each of the dome members 10, have a symmetrical shape with respect to the left-right direction. Each of the ribs 13 is formed in a shape that, in a side view ( Fig. 3 and Fig. 4) The dome members 10 are symmetrical about the center along the front-back direction. In addition, each rib 13 has a shape in which the length of the rib gradually decreases in one direction away from the base region 5.

[0047] As in Fig. Figure 5 shows that the first main section 11 and the left and right ribs 13 of the first dome element 10a have the same maximum height relative to each other. The second main section 12 and the left and right ribs 13 of the second dome element 10b also have the same maximum height relative to each other. Furthermore, the first dome element 10a and the second dome element 10b are designed such that they have the same maximum height relative to each other.

[0048] The width of each first main section 11 and second main section 12 is 0.2 mm or more, preferably 0.4 mm or more. This allows for the production of a surface closure 1 with the in Fig. The manufacturing device 30 shown in Figure 1 allows the cavities 42b of the dome sections 10, provided on the forming roller 41, to be easily filled with synthetic resin (recycled PET resin), with the surface closure 1 being formed in a molten state. This enables the shapes of the dome sections 17 to be formed exactly according to the cavities 42b. Additionally, since the left and right ribs 13 of the dome sections 10 are located on the outside of the first main section 11 and the second main section 12 with respect to the left-right direction, the cavities 42b can be easily filled with the synthetic resin. The total width of each dome section 10, including the left and right ribs 13, can be 0.4 mm or more, preferably 0.6 mm or more. It should be noted that the ribs 13 can be formed with a lower height than the height of the first main section 11 and the second main section 12.The shapes of the ribs 13 are not particularly restricted, but it is preferred that the left and right ribs 13 are adjacent to the first main section 11 or the second main section 12 and are formed integrally with the first main section 11 or the second main section 12.

[0049] Furthermore, the coupling elements 10 according to the present embodiment are designed such that the total width of each coupling element 10 is 1.0 mm or less, preferably 0.8 mm or less. In this case, when the surface closure 1, which has been manufactured according to the present embodiment, couples with a loop part, loops of the loop part can easily hook onto the respective coupling element 10 of the surface closure 1, thereby enabling the surface closure 1 to be stably coupled to the loop part.

[0050] In the present embodiment, the maximum vertical extension (expansion in the top-bottom direction) of each dome member 10 from the base area 5 is 0.45 mm or more and 1.40 mm or less, and the maximum longitudinal extension (expansion in the front-back direction) of the dome member 10 is 0.30 mm or more and 1.67 mm or less. Because the maximum vertical extension of the dome member 10 is 0.45 mm or more and / or the maximum longitudinal extension is 0.30 mm or more, a loop of the loop part can easily hook onto the dome member 10. Because the maximum vertical extension of the dome member 10 is 1.40 mm or less and / or the maximum longitudinal extension is 1.67 mm or less, the surface closure 1 can have a suitable softness and a pleasant texture.

[0051] In the present embodiment, the plurality of dome elements 10 are arranged along a regular grid pattern, with the dome elements 10 being arranged along the front-back and left-right directions. In this case, the plurality of dome elements 10 are arranged on the base region 5 such that the arrangement density of the dome elements 10 is significantly lower than, for example, that of the surface closure disclosed in PTL 1. In particular, the plurality of dome elements 10 has a density of 30 dome elements / cm². 2 or more and 90 dome links / cm 2 or less arranged.

[0052] This is due to the fact that the arrangement density of the dome elements is 10 30 dome elements / cm². 2or more, if the surface closure 1 is coupled with a loop part according to the present embodiment, it can be ensured that the coupling strength of the surface closure 1 with the loop part is sufficient. In particular, for example, when using the surface closure 1 in products such as clothing, the generally required coupling strength of the surface closure 1 can be reliably achieved.

[0053] Because the arrangement density of the dome elements is 10 90 dome elements / cm 2 If the area undercut is less than or equal to the area undercut, the number of dome elements 10 per surface, which have an undercut 15, can be reduced, and thus, in a separation step described later, a formed surface closure 1 can be easily separated from the forming roll 41. Additionally, the flexibility of the surface closure 1 to be produced can be improved.

[0054] It should be noted that in the present invention the arrangement of the dome members is not limited to the grid pattern in which the dome members are arranged regularly in the front-back direction and in the left-right direction as described above, and, for example, a plurality of dome members could be arranged regularly on the base area in a different arrangement, for example staggered, or could be arranged randomly on the base area, depending, for example, on the shape and properties of the products in which the surface closure is used.

[0055] Next, the manufacturing device 30, with which the surface closure 1 described above is manufactured according to the present embodiment, will be described with reference to Fig. 1 described.

[0056] The manufacturing device 30 according to the present embodiment comprises a forming device 40 that forms the surface closure 1, a receiving roller 50 that separates the surface closure 1 from the forming device 40, and a heating device 60 that is arranged in the transport direction with respect to the receiving roller 50.

[0057] The forming device 40 according to the present embodiment comprises a forming roller 41, which is driven to rotate in one direction, and a nozzle unit 46, which is attached to the side of the outer surface of the forming roller 41. The forming roller 41 comprises a roller section 42, which serves for forming, and a rotatable drive roller 43, which rotates the roller section 42 at a defined speed in one direction. The rotatable drive roller 43 can rotate a plurality of ring plates 42a, which concentrically form the roller section 42, simultaneously and at the same speed.

[0058] As in Fig. As shown in Figure 2, the roller section 42 consists of a plurality of torus-shaped ring plates (mold plates) 42a, each of which has a defined thickness and which are stacked on top of each other in the transverse direction CD or in the direction of the axis of rotation of the mold roller 41, wherein the roller section 42 has a circular column shape with a hollow central area.

[0059] A large number of cavities 42b (not in Fig. The cavities 42b of the dome elements 10 (as shown in Figure 2), which can be formed the dome elements 10 of the surface closure 1 described above, are provided on outer surface sections of the roller section 42 at equal intervals with respect to the circumferential direction of the ring plates 42a. In this case, the cavities 42b of the dome elements 10 are provided on the outer surface sections of the roller section 42 in accordance with the arrangement of the dome elements 10 in the surface closure 1 to be produced.

[0060] For example, in the present embodiment, a ring plate 42a has a plurality of cavities 42b with which each of the first main sections 11 of the first dome members 10a, the second main sections 12 of the second dome members 10b, and the ribs 13 of the first dome members 10a or the second dome members 10b can be formed. Furthermore, the roller section 42 also includes ring plates 42a that are used to form voids (areas in which no dome members 10 are formed) between dome members 10 that are adjacent to each other with respect to the width direction. The ring plates 42a for voids are provided without cavities 42b.

[0061] In this case, the cavities 42b in each ring plate 42a are provided on outer surface sections of the ring plate 42a using known conventional technologies such as electrical discharge machining (EDM), laser processing, or etching. Furthermore, a cavity 42b, with which a dome element 10 can be formed, is created from three types of ring plates 42a, each having cavities for a rib 13 (on the left side), the first main section 11 or the second main section 12, and the other rib 13 (on the right side). These three types of ring plates 42a are aligned with each other along the circumferential direction of the ring plates 42a and stacked along the transverse direction CD. By adjusting the number of ring plates 42a used, the width of the ribs 13, the first main section 11, and the second main section 12 can be adjusted as needed.

[0062] In the forming roller 41 according to the present embodiment, a cavity 42b, which is provided at the roller section 42 for forming a dome member 10 (that is, a cavity 42b formed by stacking three types of ring plates 42a), has, in the present embodiment, essentially the same shape as the dome member 10 of the surface closure 1 to be produced. Accordingly, the cavity 42b provided on the forming roller 41 for the dome member 10 has a space in which the undercut 15 of the dome member 10 described above is formed.

[0063] Here, the expression "essentially the same shape" refers to two shapes that have the same shape and to two shapes that have approximately the same shape. For example, the expression "that the cavities 42b of the mold roll 41 and the dome members 10 have the same shape" means that when the shape of the cavities 42b, viewed in the transverse direction CD, and the shape of a dome member 10, viewed in the width direction, are superimposed, the two shapes completely overlap. The expression "that the cavities 42b of the mold roll 41 and the dome members 10 have approximately the same shape" means that, for example, when the shape of the cavities 42b, viewed in the transverse direction CD, and the shape of a dome member 10, viewed in the width direction, are superimposed, the two shapes overlap in an area of ​​80% or more, preferably in an area of ​​90% or more.

[0064] The forming roller 41 according to the present embodiment comprises a cooling jacket (not shown) in which a coolant circulates within the rotatable drive roller 43 to efficiently cool the surface closure 1, which is formed on an outer surface of the forming roller 41. Additionally, a coolant tank (not shown) is provided below the forming roller 41, so that at least part of the forming roller 41 is immersed in the coolant of the coolant tank.

[0065] The nozzle unit 46 is configured to continuously supply molten resin to the forming roller 41. In particular, the nozzle unit 46 comprises a flow path 47 through which molten resin can flow, a nozzle end 48 positioned so that it is oriented towards the forming roller 41, and a feed opening on the nozzle end 48 that opens and is suitable for continuously extruding (or ejecting) the molten resin from the feed opening towards the forming roller 41.

[0066] The receiving roller 50 comprises a pair consisting of an upper squeeze roller 51 and a lower squeeze roller 52, which squeeze the surface closure 1 formed on the forming roller 41 from above and below and pull the surface closure 1. The upper squeeze roller 51 and the lower squeeze roller 52 each have a surface layer on their respective outer surfaces, which is not shown but is made of an elastomer such as a polyurethane elastomer.

[0067] The heating device 60 is mounted opposite the receiving roller 50 with respect to the device direction MD in the transport direction. The heating device 60 is set to heat the surface closure 1, which has been separated from the forming roller 41 and is transported in the transport direction, to a specified temperature for a specified time.

[0068] It should be noted that in the present invention, the specific structure, shape, size, heating means, and so on of the heating device are not specifically restricted. According to the present embodiment, the heating device 60 is set to heat the flat closure 1 separated from the forming roll 41 during transport of the flat closure 1; alternatively, according to the present invention, the heating device can be set such that, for example, the flat closure 1, which is separated from the forming roll 41, is wound around a pick-up roll (not shown), and the pick-up roll is then held in the heating device to heat the flat closure 1 together with the pick-up roll in a state in which the flat closure 1 is wound around the pick-up roll.

[0069] Next, a description of the manufacturing process for producing the surface closure 1 from a synthetic resin containing a PET resin as its main component is given, using the manufacturing device 30 described above, including the molding device 40, the receiving roller 50 and the heating device 60.

[0070] In the present invention, in order to improve the recyclability of resin products, attempts were made to use a resin as the material for the surface seal 1 which contains a saturated polyester resin (in particular a recycled PET resin) as a main component. For this purpose, various experiments were repeatedly carried out to produce a surface seal using the molding device with the molding roller described above. As a result, it was discovered that the following problems occur when producing a surface seal using a PET resin (in particular a PET resin containing recycled PET resin).

[0071] In particular, it was found that when molding using a PET resin containing recycled PET resin, the PET resin exhibits, for example, the following properties: the temperature range in which the PET resin can be melted and processed is extremely small; when the PET resin is cooled from a molten state, the flowability of the PET resin decreases rapidly; and the cooled PET resin hardens easily.Furthermore, due to these properties of PET resin, when manufacturing a surface closure by feeding a PET resin containing recycled PET resin to a forming roll, it is very difficult, due to a combination of various factors, to form dome links into a suitable shape for interlocking with a loop part, whereby this is a material-specific problem and it has been recognized that PET resin containing recycled PET resin is a material that is difficult to process as a material for a surface closure 1.

[0072] In light of the above, the inventors of the present invention have repeatedly conducted experiments and studies to produce a surface closure made of a PET resin containing recycled PET resin. The results show that deformation of a molten body (dome element) made of PET resin causes changes in the shape of the molten body, and that these changes can subsequently be removed by heating the molten body within a specific temperature range. Furthermore, the removal of these changes by heating allows the molten body to be deformed back into its original shape before the changes occurred. This result has led to the completion of the present invention.

[0073] In particular, a method for producing a surface closure 1 according to the present invention comprises at least one forming step of forming a surface closure 1 with the forming roller 41 of the forming device 40 described above, a separation step of separating the surface closure 1 from the forming roller 41 with the aid of the receiving roller 50 in order to generate shape changes within the dome members 10, and a shape change removal step of deforming the dome members 10 to their original state by heating at least the dome members 10 of the separated surface closure 1 in order to remove the shape changes of the dome members 10.

[0074] In the forming step, the first step involves placing the product in the Fig. In the manufacturing device 30 shown in Figure 1, a molten synthetic resin (PET resin) is continuously fed from the nozzle unit 46 to the outer surface of the molding roller 41. During this process, the PET resin is fed from the nozzle unit 46 while being heated to a temperature equal to or greater than the melting point of the PET resin plus 60°C or less. Furthermore, the molding roller 41 is rotated counterclockwise by the rotatable drive roller 43. Fig. 1 rotated at a constant rotational speed.

[0075] This allows the base area 5 to be continuously formed between the outer surface of the rotating forming roller 41 and the nozzle end 48 of the nozzle unit 46. Additionally, since the cavities 42b provided on outer surface sections of the forming roller 41 are filled with the molten PET resin, dome elements 10 (first dome elements 10a and second dome elements 10b) can be formed in the cavities 42b. Thus, as in Fig. Figures 3 to 5 show a surface closure 1 in which a large number of dome elements 10 are provided in one piece at the base area 5, formed in and near the outer surface sections of the forming roller 41.

[0076] In the forming step according to the present embodiment, heating the PET resin supplied by the nozzle unit 46 to a temperature corresponding to the melting point of the resin + 60°C or less, as described above, prevents the PET resin from decomposing. Additionally, an excessive increase in the flowability of the molten PET resin can be prevented, and the cavities 42b of the forming roller 41 can be consistently filled with the PET resin.

[0077] Furthermore, in the present embodiment, the resin supplied to the molding roller 41 as described above is a resin that contains recycled PET resin as its main component and has a melt flow rate (MFR) of 30 g / 10 minutes or more and 100 g / 10 minutes or less. Additionally, the present embodiment uses a resin with a number-average molar mass (Mn) of 10,000 or more and 30,000 or less, and a polydispersity (Mw / Mn) of 2.0 or more and 3.0 or less. This allows the molten recycled PET resin to be supplied continuously from the nozzle unit 46 to the molding roller 41. Furthermore, the cavities 42b of the coupling elements 10 provided on the molding roller 41 can be filled more consistently with the molten resin.Accordingly, a large number of dome elements 10 with the same shapes (or essentially the same shapes) as the cavities 42b provided on the form roller 41 can be stably formed on the outer surface sections of the form roller 14.

[0078] Furthermore, in the present embodiment, the maximum value of the lateral extent (extension in the transverse direction CD) of each cavity 42b of the dome members 10, provided on the forming roller 41, is set to 0.4 mm or more, preferably 0.6 mm or more, corresponding to the total lateral extent of each dome member 10 to be formed. This ensures that the molten resin flows more consistently into the cavities 42b of the forming roller 41 to fill them.

[0079] In this forming step, the surface closure 1, formed on the forming roller 41, rotates together with the forming roller 41 towards the receiving roller 50, while being held by the forming roller 41. At this time, the surface closure 1 is cooled by a coolant circulating in the rotatable drive roller 43 of the forming roller 41 and by being immersed in a coolant from the coolant tank (not shown); therefore, the surface closure 1 can harden (solidify) for a short time before being rotated towards the position of the receiving roller 50.

[0080] Next, the separation step of separating the surface closure 1 formed in the forming step described above from the forming roller 41 is carried out.

[0081] In this separation step, the surface closure 1 is squeezed and held by the upper and lower squeeze rollers 51 and 52 of the receiving roller 50 in the top-bottom direction, with the upper and lower squeeze rollers 51 and 52 each rotating, allowing the surface closure 1 to be pulled away from the upper and lower squeeze rollers 51 and 52 with a strong force. Thus, the dome members 10 of the surface closure 1 can be pulled out of the cavities 42b provided on outer surface sections of the forming roller 41, and the base region 5 of the surface closure 1 can be pulled away from the outer surface sections of the forming roller 41, thereby separating the surface closure 1 from the forming roller 41.

[0082] At this time, the dome members 10 formed in the cavities 42b of the forming roller 41 each have, as described above, a first main section 11 and a left and right rib 13, or a second main section 12 and a left and right rib 13. Furthermore, when the surface closure 1 is separated from the forming roller 41, the dome members 10 are each pulled out of the cavities 42b of the continuously rotating forming roller 41, while the base area 5 of the surface closure 1 is bent so that it is curved.

[0083] In this case, in the dome sections 10, the dome section 17 of each of the first main sections 11 and the second main sections 12 extends from the main section 16 in the direction in which the forming roller 41 rotates, thus becoming an undercut 15 that cannot be pulled out of the cavities 42b in its original form. Furthermore, the left and right ribs 13 of the first dome sections 10a and the second dome sections 10b also have shapes that make it difficult to pull them out of the cavities 42b of the rotating forming roller 41 in their original form.

[0084] Therefore, by forcefully pulling the formed surface closure 1 with the receiving roller 50, the dome elements 10 of the surface closure 1 are forcibly pulled out of the cavities 42b of the forming roller 41, thereby allowing the surface closure 1 to be separated from the forming roller 41. Furthermore, simultaneously with the separation of the surface closure 1, the dome elements 10 are separated from the cavities 42b of the forming roller 41. Fig. 3 and Fig. The three depicted forms correspond to the respective ones in Fig. 6 and Fig. The 7 depicted shapes are deformed, resulting in a change in the shape of the dome members 10. At this point, when the dome members 10 are in Fig. 6 and Fig. The 7 depicted shapes generate shape changes in the areas, each originating from the shapes shown in Fig. 3 and Fig. 4 are shown, deform.

[0085] More precisely, for example in the case of a second dome element 10b, this second dome element 10b, which is located in a cavity 42b, is described in Fig. The shape shown in section 4 is forcibly pulled from the receiving roller 50 and extracted from the cavity 42b, as shown in the diagram. Fig. Figure 7 shows that the stem section 16 and the dome section 17 of the second main section 12 deform significantly, such that the dome section 17 of the second main section 12 is oriented upwards. Additionally, the left and right ribs 13 of the second dome member 10b deform such that the upper end sections of the ribs 13 are inclined relative to the device direction MD opposite to the transport direction.

[0086] A first dome element 10a, which is located in a cavity 42b, is in Fig. The shape shown in Figure 3 is pulled out of the cavity 42b by means of the receiving roller 50, whereby the first main section 11 deforms such that the dome section 17 shifts upwards on the first main section 11, and the left and right ribs 13 of the first dome member 10a deform such that the upper end sections of the ribs 13 are as shown in Figure 3. Fig. 6 shown are inclined with respect to the device direction MD opposite to the transport direction.

[0087] Furthermore, in the surface closure 1 according to the present embodiment as described above, the multitude of dome elements 10 at the base area 5 has a low density of 90 dome elements / cm². 2or less provided. This prevents problems, for example, that the surface closure 1 gets stuck on the forming roller 41 and cannot be removed, while in the separation step the dome members 10 are pulled out of the cavities 42b and deform, and it allows the surface closure 1 to separate stably from the forming roller 41.

[0088] The surface closure 1, separated from the forming roller 41 by means of the receiving roller 50, is then transported to the heating device 60. Furthermore, in the heating device 60, to which the surface closure 1 has been fed, the deformation removal step of removing the deformations of the coupling elements 10 by heating the surface closure 1 is carried out.

[0089] In this deformation removal step, the surface closure 1 is heated by the heating device 60 in a temperature range corresponding to the glass transition temperature of the synthetic resin (recycled PET resin) that forms the surface closure 1, ± 20°C. By subjecting the surface closure 1 to heat treatment in this temperature range, the deformations produced in the dome elements 10 in the separation step described above are removed, and the dome elements 10 of the surface closure 1 deform from the deformations in Fig. 6 and Fig. The 7 distorted shapes shown are essentially the same as the respective ones in Fig. 3 and Fig. The three depicted shapes of the cavities 42b correspond to the form roller 41.

[0090] At this point, if the heating temperature of the surface seal 1 in the deformation removal step is equal to or higher than the glass transition temperature of the resin (-20°C), deformations that have occurred in the dome elements 10 can be permanently removed. If the heating temperature of the surface seal 1 is equal to or lower than the glass transition temperature of the resin (+20°C), the progression of resin crystallization can be inhibited, and the surface seal 1 being produced can achieve suitable softness and flexibility.

[0091] The heat treatment of the surface closure 1 is preferably carried out by the heating device 60 for 10 minutes or longer. A heating time of 10 minutes or more can reliably remove any deformations that have occurred in the coupling elements 10. On the other hand, performing the heat treatment of the surface closure 1 for 60 minutes is sufficient to remove any deformations that have occurred in the coupling elements 10. Accordingly, with regard to productivity, manufacturing costs, etc., the heating time of the surface closure 1 is preferably 60 minutes or less, in particular 45 minutes or less.

[0092] Through this shape-change elimination step, the surface closure 1 according to the present embodiment is produced with a plurality of dome elements 10, which are shown in the illustrations in Fig. 3 to 5 correspond.

[0093] It should be noted that in the deformation removal step according to the present embodiment, the surface closure 1 is heated while it is being transported. However, according to the present invention, the deformation that has occurred in the coupling elements 10 can also be removed by, for example, winding the surface closure 1, which has been separated from the forming roller 41, around a pick-up roller (not shown), as described above, and then holding this pick-up roller in the heating device so that the surface closure 1 is heated together with the pick-up roller in a state in which the surface closure 1 is wound around the pick-up roller.By performing the heat treatment in this manner with a surface closure 1 wound around a pick-up roller, a larger number of surface closures 1 can be heated for a short time, thereby making the deformation removal step more efficient.

[0094] The surface closure 1, which has undergone the shape correction step, is then removed from the heating device 60 and collected, for example by being wound around a collection roller or similar device. Alternatively, the surface closure 1 can be collected after it has been transported from the heating device 60 to a cutting unit (not shown) and cut to a predetermined width and / or length in the cutting unit.It should be noted that the method for producing a surface closure 1 according to the present embodiment may, in addition to the forming step, the cutting step and the deformation removal step as described above, include a further step in which the surface closure 1 is processed or subjected to treatment, for example a stretching step of stretching the surface closure 1 along the device direction MD.

[0095] The surface closure 1 according to the present embodiment, which has been produced by the manufacturing process described above, is formed from a PET resin (recycled PET resin) which does not contain any factor that hinders recycling, such as an elastomer, and can thus be recycled like PET bottles or similar and reused as recycled PET resin.

[0096] Accordingly, the surface closure 1 according to the present embodiment can be suitably used in products such as clothing made from a single PET resin (monomaterial products). Furthermore, the use of a surface closure 1 according to the present embodiment can enable monomaterialization, in which an entire product to which a surface closure is attached, such as a garment, is formed from a single PET resin. As a result, the efficiency of PET resin recycling can be improved. In addition, benefits such as the conservation of environmental resources, the reduction of waste, and the reduction of greenhouse gas emissions can be expected, contributing to the achievement of the Sustainable Development Goals (SDGs).

[0097] Furthermore, in the surface closure 1 according to the present embodiment, a plurality of coupling elements 10 are formed with shapes that can couple with the loops of a loop part and are formed from a PET resin that contains no elastomers, and are thus designed to be harder than, for example, typical conventional surface closures. Accordingly, even if, as described above, the arrangement density of the coupling elements 10 in the surface closure 1 is significantly higher than in typical conventional surface closures (up to 90 coupling elements / cm²), the overall strength of the coupling elements is not significantly reduced. 2 or less reduced, the surface closure 1 can be stably coupled with a loop part.

[0098] Furthermore, in the surface closure 1 according to the present embodiment, the dome elements 10 are each designed to have a width greater than that of typical conventional surface closures, and a PET resin (recycled PET resin) with a molecular weight ratio (MFR), a number-average molar mass (Mn), and a polydispersity (Mw / Mn) within the specified ranges is used as the resin for forming the surface closure 1. This allows the cavities 42b of the forming roller 41 to be continuously filled with the molten resin when the dome elements 10 are formed with the forming roller 41 of the forming device 40, thus enabling the dome elements 10 to be formed stably with predetermined shapes.

[0099] It should be noted that the present invention is not limited to the embodiment described above and that various modifications can be made, as long as these modifications result in a substantially the same configuration as that of the present invention and exhibit similar effects in operation.

[0100] For example, in the surface closure 1 according to the present embodiment described above, the dome members 10 each have a first main section 11 or a second main section 12, which have a distorted J-shape, and a left and a right rib 13. However, the shape of the dome members is not specifically restricted according to the present invention, as long as the dome members have a shape in which, during the separation step of separating the surface closure from the forming roll, shape changes can occur in at least part of a dome member (that is, a shape that has an undercut that cannot be pulled out of a cavity of the forming roll without changing the original shape).

[0101] For example, in the present invention, each of the dome members of the surface closure can have a shape in which, for example, the first main section 11 and the second main section 12 are each formed in an inverted J-shape according to the embodiment described above, and the left and right ribs 13, which are attached to the outside of the main sections with respect to the left-right direction, are formed in one piece. Alternatively, each dome member can have a palm-like or mushroom-like shape, both of which are generally known from the prior art.

[0102] Furthermore, in the embodiment described above, the surface closure 1 is provided with a plurality of first dome elements 10a and a plurality of second dome elements 10b, which have mutually symmetrical shapes. However, in the present invention, a surface closure can be equipped with only one type of dome elements of the same shape or with three or more types of dome elements with different shapes.

[0103] In the manufacturing process according to the embodiment described above, the forming device 40, including the forming roller 41, is set to rotate, and the nozzle unit 46, which is positioned so that it is aligned with the forming roller 41, is used to form the surface closure 1. However, in the present invention, the device and the method for forming the surface closure are not specifically limited as long as the surface closure can be formed into a cavity by supplying a molten resin.

[0104] For example, in the present invention, the surface closure 1 can be formed not with a molding device 40 as described in the embodiment, but with a twin-roll molding device. The twin-roll molding device has a molding roll with a plurality of cavities on an outer surface section and a pressure roll that is positioned so that it is oriented towards the molding roll and rotates in a direction opposite to the direction of rotation of the molding roll. If a twin-roll molding device is used, the base area can be formed by introducing a resin between the molding roll and the pressure roll, and a plurality of dome elements can be formed in cavities of the molding roll. In this way, a surface closure similar to the surface closure 1 as described above can be formed.Finally, after the surface closure has been formed, when the surface closure is separated from the forming roll of the two-roll forming device, the dome members can be deformed in such a way that changes in shape occur in the dome members. Reference symbol list 1 Surface closure 5 Basic area 10 dome link 10a First coupling element 10b Second dome element 11 First Main Section 12 Second Main Section 13th rib 15 Undercut (undercut shape) 16 Main section 17 Dome section (dome head section) 30 Manufacturing device 40 Forming device 41 Form roll 42 Roll section 42a Ring plate (form plate) 42b Cavity 43 Swivel drive roller 46 nozzle unit 47 Flow path 48 Nozzle end 50 pickup roller 51 Upper squeeze roller 52 Lower squeeze roller 60 Heating device CD transverse direction MD Device Direction QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] JP 2020-28381 [0003, 0004]

Claims

[1] Method for producing a surface closure (1) in which a surface closure (1) is produced from synthetic resin, wherein the surface closure (1) comprises a base area (5) and a plurality of dome members (10) provided on the base area (5), wherein the dome members (10) each have a stem section (16) extending from the base area (5) and a dome section (17) located at a front end section of the stem section (16), characterized by , that the procedure exhibits: a forming step of the forming of the surface closure (1) by supplying the synthetic resin to a forming device (41) in which cavities (42b) are provided; a separation step of separating the dome members (10) from the cavities (42b); and a shape change removal step of deforming the dome members (10) after the separation step by heating the separated dome members (10) in order to remove any shape change that may have occurred in the dome members. [2] Method for producing a surface closure according to claim 1, characterized by , that the dome members (10) are deformed in the shape-change removal step into shapes that essentially correspond to the shapes of the cavities (42b). [3] Method for producing a surface closure according to claim 1 or 2, characterized by , that the synthetic resin used is a synthetic resin which contains as its main component a saturated thermoplastic polyester resin, which contains terephthalic acid as an acid component and ethylene glycol as a glycol component. [4] Method for producing a surface closure according to claim 3, characterized bythat the saturated polyester resin contains a recycled polyethylene terephthalate resin. [5] Method for producing a surface closure according to any one of claims 1-4, characterized by , that the dome members (10) are heated to a glass transition temperature of the synthetic resin of -20°C or higher and a glass transition temperature of the synthetic resin of +20°C or lower during the deformation removal step. [6] Method for producing a surface closure according to any one of claims 1 to 5, characterized by , that a synthetic resin with a melting rate of 30 g / 10 min or more and 100 g / 10 min or less is used. [7] Method for producing a surface closure according to any one of claims 1 to 5, characterized by , that the synthetic resin used has a number-average molar mass Mn of 10,000 or more and 30,000 or less and a polydispersity Mw / Mn of 2.0 or more and 3.0 or less. [8] Surface closure made of synthetic resin, comprising a base area (5) extending elongated along a device direction (MD) and a plurality of dome members (10) provided on the base area (5), wherein the dome members (10) each have a stem section (16) extending from the base area (5) and a dome section (17) located at a front end section of the stem section (16), characterized by , that A main component of the synthetic resin is a saturated thermoplastic polyester resin, which contains terephthalic acid as an acid component and ethylene glycol as a glycol component. the maximum extent of each coupling member (10) in a transverse direction (CD) orthogonal to the device direction (MD) is 0.2 mm or more and 1.0 mm or less and the multitude of dome elements (10) with a density of 30 dome elements / cm² 2 or more and 100 dome links / cm2 or are arranged less. [9] Surface closure according to claim 8, characterized by that the synthetic resin has a melting flow rate of 30 g / 10 min or more and 100 g / 10 min or less. [10] Surface closure according to claim 8 or 9, characterized by , that a number-average molar mass Mn of the synthetic resin 10,000 or more and 30,000 or less and a polydispersity Mw / Mn of the synthetic resin is 2.0 or more and 3.0 or less. [11] Surface closure according to one of claims 8 to 10, characterized by that the saturated polyester resin contains a recycled polyethylene terephthalate resin.

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