Fitting device and bag with fitting device

Abstract

The present invention provides a fitting device that has good moldability and is resistant to shrinkage and deformation due to heat, and a bag body with the fitting device using the fitting device. [Solution] A fitting device comprising a male fitting member 10 having a male fitting portion 12 provided along the longitudinal direction on the surface 11a of a strip-shaped first base material 11, and a female fitting member 20 having a female fitting portion 22 provided along the longitudinal direction on the surface 21a of a strip-shaped second base material 21, wherein the male fitting portion 12 and the female fitting portion 22 are detachably fitted together, and the results of thermal shrinkage stress measurement using a thermomechanical analyzer (TMA device) are: (1) the temperature TA at the stress increase initiation point (A) is 70°C or more and 140°C or less, (2) the load LB at the maximum stress point (B) is 1mN or more and 200mN or less, and (3) the numerical value of the slope between (A) and (B) is 0.1 or more and 10 or less.

Description

[Technical Field]

[0001] The present invention relates to a fitting device and a bag body with a fitting device. [Background technology]

[0002] In various fields such as food, pharmaceuticals, and general merchandise, bags with fasteners are widely used, in which a fastener is attached to the inner surface near the opening of the bag body to seal the opening in an openable and closable manner. It is crucial that the mating portion of a fitting does not break even after repeated opening and closing. Therefore, during production, the mating portion must be well-formed when the resin is extruded from the mold. To provide good moldability, polypropylene resin (PP), which has a high modulus of elasticity, is widely used as the material for fittings. However, the welding temperature of polypropylene resin is high, which can cause seal wrinkles in appearance and degrade product quality. Furthermore, the material for fittings also requires a certain degree of flexibility to provide airtightness.

[0003] To address these challenges, conventionally, resins with specific formulations that have a low welding temperature and flexibility have been used as materials for mating parts. Patent Document 1 discloses a fitting device using a random copolymer containing propylene and an α-olefin having 4 or more carbon atoms. According to the fitting device disclosed in Patent Document 1, when used in a bag made of PP film, relatively good flexibility and the effect of lowering the welding temperature can be obtained. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2001-240082 [Overview of the Initiative] [Problems that the invention aims to solve]

[0005] Fittings that exhibit good moldability require hardness, and therefore resins with high melting points are used. In Patent Document 1, the sealing temperature is relatively high at 180°C or higher, and there was a problem that the bag body would shrink due to heat welding when the fitting was attached to the bag body, resulting in wrinkles in appearance. On the other hand, if a resin with a low melting point is simply used for the fitting, thermal shrinkage of the fitting itself may occur, making the fitting prone to deformation. Furthermore, when providing fittings that have good moldability and are resistant to thermal shrinkage and deformation, there is a need for physical property values ​​that can serve as a guideline when compounding multiple resins.

[0006] The present invention aims to provide a fitting device that has good moldability and is resistant to thermal shrinkage and deformation, and a bag body with the fitting device using the fitting device. [Means for solving the problem]

[0007] The present invention includes the following embodiments. [1] A fitting device comprising a male fitting member having a male fitting portion provided along the longitudinal direction on the surface of a strip-shaped first base material, and a female fitting member having a female fitting portion provided along the longitudinal direction on the surface of a strip-shaped second base material, wherein the male fitting portion and the female fitting portion are detachably fitted together, A fitting device whose thermal shrinkage stress measurement using a thermomechanical analyzer (TMA device) satisfies the following conditions (1) to (3). (1) Temperature T at the stress increase initiation point (A) A However, the temperature must be between 70°C and 140°C. (2) Load L at the point of maximum stress (B) B However, it is between 1 mN and 200 mN. (3) The numerical value of the slope between (A) and (B) is between 0.1 and 10. [2] In (2) above, the load L at the point of maximum stress (B) B However, it is between 1mN and 20mN. The fitting device according to [1], wherein the numerical value of the slope between (A) and (B) is 0.1 or more and 5 or less, in the above (3). [3] The first base material and the second base material each include a main layer and a seal layer provided on a side opposite to the male fitting portion and the female fitting portion of the main layer. The fitting tool according to [1] or [2]. [4] The first base material and the second base material each include an intermediate layer provided between the main layer and the seal layer. The fitting tool according to [3]. [5] A fitting tool according to any one of [1] to [4], and a bag body for accommodating contents. A bag body with a fitting tool, wherein the fitting tool is attached to the inner surface of the bag body.

Effects of the Invention

[0008] According to the present invention, it is possible to provide a fitting tool having good moldability and being less likely to undergo shrinkage and deformation due to heat, and a bag body with a fitting tool using the fitting tool.

Brief Description of the Drawings

[0009] [Figure 1] FIG. 1 is a schematic perspective view showing the fitting tool of the present embodiment. [Figure 2] FIG. 2 is a cross-sectional view taken along the arrow in II-II of FIG. 1. [Figure 3] FIG. 3 is a diagram showing an example of the result of measuring the thermal shrinkage stress using a TMA apparatus in the fitting tool of the present embodiment. [Figure 4] FIG. 4 is a schematic front view showing the bag body 100 with a fitting tool of the present embodiment. [Figure 5] FIG. 5 is a schematic perspective view showing the state where the bag body 100 is opened.

Modes for Carrying Out the Invention

[0010] [Fitting Tool] Hereinafter, an example of the fitting tool of the present invention will be shown and described based on the drawings. In the following description, the dimensions and the like of the illustrated figures are merely examples, and the present invention is not necessarily limited thereto, and it can be appropriately modified and implemented without changing the gist thereof.

[0011] As shown in Figures 1 and 2, the fitting device 1 of one embodiment comprises a male fitting member 10 having a male fitting portion 12 provided along the longitudinal direction on the surface 11a of a strip-shaped first base material 11, and a female fitting member 20 having a female fitting portion 22 provided along the longitudinal direction on the surface 21a of a strip-shaped second base material 21.

[0012] An example of the male fitting portion 12 shown in Figures 1 and 2 comprises a stem 12a rising from the surface 11a of the first base material 11, which is the surface facing the second base material 21, and a head 12b provided at the tip of the stem 12a, which is larger than the stem 12a and has a substantially semicircular cross-section. The female fitting portion 22 comprises a pair of arm portions 22a and 22b rising in an arc shape in cross-section from the surface 21a of the second base material 21, which is the surface facing the first base material 11, and a recess 22c is formed inside these arm portions 22a and 22b. The male fitting portion 12 and the female fitting portion 22 are detachably fitted together by the head portion 12b of the male fitting portion 12 fitting into the recess portion 22c of the female fitting portion 22. The configuration of the male fitting portion 12 and the female fitting portion 22 is not limited to the configurations shown in Figures 1 and 2, as long as they are detachably fitted together.

[0013] As shown in Figure 2, the first substrate 11 comprises a main layer 13, a seal layer 14 provided on the opposite side of the main layer 13 from the male fitting portion 12 and the female fitting portion 22, and an intermediate layer 15 provided between the main layer 13 and the seal layer 14.

[0014] The material forming the main layer 13 is not particularly limited, and any material used as a base material for known fitting devices can be used. Examples include low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), high-density polyethylene (HDPE), polyethylene such as ethylene-α-olefin copolymer, polypropylene (PP), ethylene-vinyl acetate copolymer, ethylene-methacrylic acid copolymer, polyester resin (polyethylene terephthalate, polyethylene naphthalate, etc.), and polyamide resin (nylon, etc.). Among these, polyolefin resins such as polyethylene and polypropylene are preferred in terms of the balance between rigidity and flexibility, and it is more preferable to include at least one of LDPE and LLDPE. The material forming the main layer may be used alone, or two or more may be used in combination.

[0015] The material used to form the seal layer 14 is not particularly limited, and examples include LLDPE, unoriented polypropylene, ethylene-vinyl acetate copolymer, ionomer, and polyester resin. Among these, LLDPE is preferred in terms of flexibility and low-temperature sealing properties. The material used to form the seal layer may be used alone or in combination of two or more materials.

[0016] The material forming the intermediate layer 15 is not particularly limited, and any material known to be used as a base material for fittings can be used. Examples include polyethylene such as low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), high-density polyethylene (HDPE), and ethylene-α-olefin copolymers, polypropylene (PP), ethylene-vinyl acetate copolymer, ethylene-methacrylic acid copolymer, polyester resin (polyethylene terephthalate, polyethylene naphthalate, etc.), and polyamide resin (nylon, etc.). Among these, polypropylene (PP) or a material with a density of 930 kg / m³ is particularly suitable because the fitting has sufficient rigidity. 3 The above resins are preferred, and high-density polyethylene (HDPE) is particularly preferred.

[0017] The main layer 13, the sealing layer 14, and the intermediate layer 15 may contain known additives such as stabilizers, antioxidants, lubricants, antistatic agents, colorants, and molding aids, as needed.

[0018] The width W1 of the first base material 11 is preferably 2 mm or more, and more preferably 3 mm or more, because it is easier to obtain sufficient seal strength when heat-sealed to the bag body. The width W1 of the first base material 11 is preferably 60 mm or less, and more preferably 40 mm or less, because it is highly flexible, easy to handle, and less prone to deformation of the fittings during distribution and storage. The lower and upper limits of the width W1 of the first base material 11 can be arbitrarily combined, for example, 3 mm or more and 40 mm or less is preferred.

[0019] The thickness of the first base material 11 is preferably 0.1 mm or more, and more preferably 0.12 mm or more, since sufficient seal strength can be easily obtained when it is heat-sealed to the bag body. The thickness of the first base material 11 is preferably 0.4 mm or less, and more preferably 0.3 mm or less, since it has excellent flexibility and is easy to handle. The lower and upper limits of the thickness of the first base material 11 can be arbitrarily combined, for example, 0.1 mm or more and 0.4 mm or less is preferred.

[0020] The thickness of the main layer 13 is preferably 0.01 mm or more, and more preferably 0.03 mm or more, since it has sufficient rigidity. The thickness of the main layer 13 is preferably 0.4 mm or less, and more preferably 0.3 mm or less, since it has excellent flexibility and is easy to handle. The lower and upper limits of the thickness of the main layer 13 can be arbitrarily combined, for example, 0.01 mm or more and 0.4 mm or less is preferred.

[0021] The thickness of the seal layer 14 is preferably 0.01 mm or more, and more preferably 0.02 mm or more, because it is easier to obtain sufficient seal strength when heat-sealed to the bag body. The thickness of the seal layer 14 is preferably 0.2 mm or less, and more preferably 0.1 mm or less, because it is highly flexible and easy to handle. The lower and upper limits of the thickness of the seal layer 14 can be arbitrarily combined, for example, 0.02 mm or more and 0.1 mm or less is preferred.

[0022] The thickness of the intermediate layer 15 is preferably 0.02 mm or more, and more preferably 0.05 mm or more, in order to have sufficient rigidity. The thickness of the intermediate layer 15 is preferably 0.3 mm or less, and more preferably 0.2 mm or less, in order to have good point sealing properties (suppressing the occurrence of pinholes in the crushed portion during the point sealing process in which the fitting device is crushed when forming the side seal portion of the assembly). The lower and upper limits of the thickness of the intermediate layer 15 can be arbitrarily combined, for example, 0.05 mm or more and 0.2 mm or less is preferred.

[0023] The second base material 21 has the same configuration as the first base material 11, and comprises a main layer 23, a seal layer 24 provided on the opposite side of the main layer 23 from the male fitting portion 12 and the female fitting portion 22, and an intermediate layer 25 provided between the main layer 23 and the seal layer 24.

[0024] The materials used to form the main layer 23, the seal layer 24, and the intermediate layer 25 are not particularly limited, and the same materials as those exemplified for forming the main layer 13, the seal layer 14, and the intermediate layer 15 can be exemplified, and the preferred embodiments are also the same.

[0025] The main layer 23, the sealing layer 24, and the intermediate layer 25 may contain known additives such as stabilizers, antioxidants, lubricants, antistatic agents, colorants, and molding aids, as needed. The materials forming the main layer 13, the sealing layer 14, and the intermediate layer 15 may be the same as, or they may be different from, the materials forming the main layer 23, the sealing layer 24, and the intermediate layer 25.

[0026] The preferred width W2 of the second base material 21 is the same as the preferred width W1 of the first base material 11. The width W1 of the first base material 11 and the width W2 of the second base material 21 may be the same or different. The preferred thicknesses of the second substrate 21, main layer 23, seal layer 24, and intermediate layer 25 are the same as the preferred thicknesses of the first substrate 11, main layer 13, seal layer 14, and intermediate layer 15. The thicknesses of the first substrate 11, main layer 13, seal layer 14, and intermediate layer 15 and the thicknesses of the second substrate 21, main layer 23, seal layer 24, and intermediate layer 25 may be the same or different.

[0027] The mass ratio of the main layer, seal layer, and intermediate layer in the entire mating device is preferably 10% to 95% by mass for the main layer, 5% to 30% by mass for the seal layer, and 60% or less by mass for the intermediate layer (totaling 100% by mass) relative to the total mass of the mating device, and more preferably 50% to 93% by mass for the main layer, 8% to 20% by mass for the seal layer, and 10% to 45% by mass for the intermediate layer (totaling 100% by mass). If the mass ratio of the main layer, seal layer, and intermediate layer is within the above range, good moldability is achieved, and thermal shrinkage and deformation are easily suppressed.

[0028] As shown in Figure 3, the mating device 1 satisfies the following conditions (1) to (3) when subjected to thermal shrinkage stress measurement using a thermomechanical analyzer (TMA device). In Figure 3, the X axis represents temperature (°C), the first Y axis represents thermomechanical analysis value (μm), and the second Y axis represents load (mN). (1) Temperature T at the stress increase initiation point (A) A However, the temperature must be between 70°C and 140°C. (2) Load L at the point of maximum stress (B) B However, it is between 1 mN and 200 mN. (3) The numerical value of the slope between (A) and (B) is between 0.1 and 10.

[0029] (Thermomechanical analysis device: TMA device) The TMA device used for measurement is not particularly limited, and commercially available devices can be used. An example of a commercially available TMA device is the Hitachi High-Tech Science TMA device (product name: TMA / SS 7100).

[0030] (sample) The sample used for measuring the heat shrinkage stress using the TMA device was obtained by cutting the first base material (strip-shaped base part not including the first fitting part) of the fitting tool along the direction along the fitting part (length: 30 mm, width: 4 mm, thickness: 0.15 mm), and setting the sample length to 20 mm when setting it on the jig.

[0031] (Measurement conditions) For the measurement of heat shrinkage stress using the TMA device, the following measurement conditions are used. · Measurement mode: Tensile mode · Heating rate: 3 (°C / min) · Temperature range: 25 - 190 (°C) Note that the upper limit of the temperature was measured up to a temperature 15 °C higher than the highest melting point among the melting points of the resins to be blended. · Atmosphere used: High purity nitrogen (N2)

[0032] The stress increase start point (A) is, as shown in Figure 3, the intersection point of the extrapolation lines (extension lines of the straight line parts) on the high temperature side and the low temperature side of the TMA curve. Also, the temperature T of the stress increase start point (A) A is the temperature (°C) at the above intersection point. The temperature TA of the stress increase start point (A) is 70 °C or higher, preferably 100 °C or higher, and more preferably 115 °C or higher. The temperature T of the stress increase start point (A) A being 70 °C or higher results in good heat resistance and less likely to cause shrinkage and deformation due to heat. Also, when making a bag, wrinkles on the appearance are less likely to occur. On the other hand, the temperature T of the stress increase start point (A) A is 140 °C or lower, preferably 138 °C or lower, and more preferably 135 °C or lower. The temperature T of the stress increase start point (A) A being 140 °C or lower results in excellent flexibility, excellent sealing performance of the fitting part and point sealing performance. Also, when the first base material and the second base material are single layers, heat sealing at a low temperature becomes possible. The temperature T of the stress increase start point (A) A The lower limit and the upper limit can be arbitrarily combined. For example, 70 °C or higher and 140 °C or lower are preferable, and 100 °C or higher and 135 °C or lower are more preferable.

[0033] The point of maximum stress (B) is the maximum value of the TMA curve, as shown in Figure 3. Also, the load L at the point of maximum stress (B) B This represents the load (mN) at the maximum value mentioned above. Load L at the point of maximum stress (B) B The load L at the point of maximum stress (B) is 1 mN or more, preferably 1.2 mN or more, and more preferably 1.3 mN or more. B When the force is 1 mN or greater, it exhibits excellent flexibility, as well as superior sealing performance and point sealing capabilities at the mating joint. On the other hand, the load L at the point of maximum stress (B) B The load L at the point of maximum stress (B) is 200 mN or less, preferably 130 mN or less, and more preferably 20 mN or less. B If the thermal energy is 200 mN or less, the shape is less likely to change due to heat. Load L at the point of maximum stress (B) B The lower and upper limits can be combined in any way; for example, 1 mN to 200 mN is preferred, and 1 mN to 20 mN is more preferred.

[0034] The slope between the intersection point (A) and the maximum value (B) is 0.1 or greater, preferably 0.8 or greater, and more preferably 1.2 or greater. When the value of the slope is 0.1 or greater, the flexibility is excellent, and the degree of airtightness of the mating part and point sealing are excellent. On the other hand, the slope between the intersection point (A) and the maximum value (B) is 10 or less, preferably 8 or less, and more preferably 5 or less. When the value of the slope is 10 or less, the heat resistance is good, and shrinkage and deformation due to heat are less likely to occur. In addition, wrinkles are less likely to occur in appearance during bag making. The lower and upper limits of the slope between the intersection point (A) and the maximum value (B) can be arbitrarily combined. For example, a value of 0.1 or more and 10 or less is preferred, and a value of 0.8 mN or more and 5 mN or less is more preferred.

[0035] In fitting device 1, by using a resin with a high melting point, adjusting the composition ratio with other resins, and adjusting the thickness of the layer, the temperature T of the stress increase initiation point (A) can be reduced. AThis can be increased. On the other hand, by using a resin with a low melting point, adjusting the composition ratio with other resins, and adjusting the thickness of the layer, the temperature T of the stress increase initiation point (A) can be increased. A It can be reduced. Furthermore, in the fitting device 1, the load L B The type of resin has a significant influence. Therefore, by adjusting the thickness, resin type, and resin composition ratio, the load L at the point of maximum stress (B) can be adjusted. B It can be adjusted. Furthermore, in the fitting device 1, the slope between the intersection point (A) and the maximum value (B) can be reduced by using a resin with a high melting point and rigidity, adjusting the composition ratio with other resins, and making the layer thicker. On the other hand, the slope between the intersection point (A) and the maximum value (B) can be increased by using a resin with a low melting point and rigidity, adjusting the composition ratio with other resins, and making the layer thicker.

[0036] (Manufacturing method) The method for manufacturing the fitting device 1 is not particularly limited, and known methods can be used. For example, one method involves preparing resin materials for forming the main layer, seal layer, and intermediate layer by melt-kneading or the like, and then co-extruding them using an extruder equipped with a composite shaped die for forming a multilayer male or female fitting member having an intermediate layer in a specific region.

[0037] Methods for mixing materials include dry mixing using a super mixer, Henschel mixer, etc. One method of melt-mixing involves supplying the raw materials to a melt-mixing machine such as a single-screw extruder, twin-screw extruder, Banbury mixer, kneader, or mixing rolls, and then melt-mixing the materials. Molding methods include extrusion molding, injection molding, inflation molding, and vacuum forming.

[0038] [Bag with interlocking mechanism] The bag with a fitting of the present invention is a bag with a fitting that is equipped with the fitting of the present invention. The bag with a fitting of the present invention can adopt known embodiments other than being equipped with the fitting of the present invention. The following describes a bag with a fitting device, which is an example of an embodiment.

[0039] The example of the fitted bag 100 shown in Figure 4 (hereinafter also simply referred to as "bag 100") comprises a bag body 50 for containing contents and a fitted device 1 attached to the inner surface of the upper part inside the bag body 50.

[0040] The bag body 50 has a rectangular shape when viewed from the front. The fitting device 1 is provided on the inner surface of the upper side of the bag body 50, extending in the direction of the shorter side of the bag body 50. Note that the shape of the bag body 50 is not limited to a rectangle.

[0041] The bag body 50 is sealed with contents (not shown) enclosed inside. The bag body 50 is obtained by overlapping a first film material 52 and a second film material 54 and heat-sealing all four peripheral edges 56. At the peripheral edges 56, both ends of the fitting device 1 are heat-sealed together with the first film material 52 and the second film material 54.

[0042] The first film material 52 and the second film material 54 can be used to weld the fitting device 1 to the film material by heat sealing, and a laminated film having at least a sealant layer and a base material layer on the inner side is preferred.

[0043] Examples of substrate layers in laminated films include linear low-density polyethylene, low-density polyethylene, high-density polyethylene, polyester, biaxially oriented nylon, and biaxially oriented polypropylene. Examples of sealant layers in laminated films include linear low-density polyethylene, unoriented polypropylene, ethylene-vinyl acetate copolymer, and ionomer. The laminated film may be provided with functional layers such as a barrier layer. Furthermore, the first film material 52 and the second film material 54 may be single-layer films consisting only of a sealant layer.

[0044] The bag body 50 has a cutting guide line 58 provided on the upper side of the fitting device 1, along the fitting device 1. The cutting guide line 58 is a linearly processed portion of the bag body 50 that assists in cutting. Examples of cutting guide lines 58 include weakening lines provided in the cutting guide line 58 portions of the first film material 52 and the second film material 54. Weakening lines can be formed by providing a portion of the film material that is thinner than the surrounding area. In addition, weakening lines can also be formed by perforations or rows of pores. Furthermore, the cutting guide line 58 is not limited to a weakening line, but may also be a line formed by printing or the like that indicates the position to be cut with scissors, a cutter, etc.

[0045] A notch 60 is formed at the end of the cutting guide line 58 in the peripheral edge 56. The shape of the notch 60 is not particularly limited, and a triangular or semicircular cutout can be used. Alternatively, the notch 60 may be a cut in the peripheral edge 56.

[0046] Figure 5 is a schematic perspective view showing the bag 100 opened. The bag 100 can be opened by cutting and removing the upper part of the bag body 50 along the cutting guide line 58 from the notch 60, thereby forming an opening 62 at the top. The opening 62 formed in the bag body 100 can be repeatedly opened and closed by attaching and detaching the male fitting member 10 and the female fitting member 20 of the fitting device 1.

[0047] Preferred embodiments of the present invention have been described above with reference to the attached drawings, but the present invention is not limited to these examples. The shapes and combinations of the constituent members shown in the above examples are merely examples, and can be modified in various ways based on design requirements, etc., without departing from the spirit of the present invention. [Examples]

[0048] The present invention will be specifically described below with reference to examples, but the present invention is not limited to the following description.

[0049] [Raw materials] The raw materials used in this example are shown in Table 1 below. The MFR (Metal Fuel Limit) is a value measured in accordance with JIS K 7210-1 under the conditions of a temperature of 190°C and a load of 2.16 kg.

[0050] [Table 1]

[0051] [Evaluation Method] (Thermomechanical analyzer (TMA device): Heat shrinkage stress measurement) For the measurements, we used a TMA device manufactured by Hitachi High-Tech Science (product name: TMA / SS 7100). Furthermore, for the thermal shrinkage stress measurement using the TMA device, the first base material (strip-shaped base portion excluding the first mating portion) of the fitting device prepared in each example was cut with the direction along the mating portion as the longitudinal direction (length: 30 mm, width: 4 mm, thickness: 0.15 mm), so that the sample length when set in the jig was 20 mm. The following measurement conditions were used for TMA measurement. • Measurement mode: Tensile mode • Heating rate: 3°C / min Temperature range: 25~190 (°C) The upper limit of the temperature was measured up to 15°C higher than the highest melting point among the resins being blended. • Operating environment: High-purity nitrogen (N2)

[0052] (Moldability) The shape of the fittings fabricated in each example was visually inspected, and the moldability of the fittings during bag making was evaluated according to the following evaluation criteria. ○: The shape of the fitting was formed stably. ×: The shape of the fitting is unstable, or there are inconsistencies in the thickness of the base material.

[0053] (Heat resistance) The shape of the fasteners fabricated in each example was visually inspected, and the heat resistance (shrinkage and deformation due to heat) of the fasteners during bag making was evaluated according to the following evaluation criteria. ○: Did not deform due to heat. ×: Deformed by heat.

[0054] [Example 1] A composite shaped die was prepared to form a male and female fitting member, which have a two-layer structure excluding the intermediate layer, as illustrated in Figures 1 and 2. As the resin material X-1 for forming the main layer, PP1 was melt-kneaded using an extruder with a diameter of 50 mm and an L / D ratio of 30 at a molding temperature of 190°C. As the resin material Y-1 for forming the sealing layer, 40 parts by mass of PP3 and 60 parts by mass of LLDPE5 were melt-kneaded using an extruder with a diameter of 30 mm and an L / D ratio of 30 at a molding temperature of 170°C. Resin materials X-1 and Y-1 were introduced into a composite shaped die and extruded. The resulting material was then cooled and solidified in a cooling water bath to obtain a fitting with a tape width of 13 mm and a total thickness of 0.15 mm for both the first and second base materials. The mass ratio of the main layer to the sealing layer was set to 90:10.

[0055] [Example 2] A composite irregular die was prepared for forming a male and female fitting member with the same three-layer structure as the fitting device 1 illustrated in Figures 1 and 2. As resin material X-1 for forming the main layer, 40 parts by mass of LDPE1, 40 parts by mass of LLDPE1, and 20 parts by mass of LLDPE2 were melt-kneaded at a molding temperature of 170°C using an extruder with a diameter of 50 mm and an L / D ratio of 30. As the resin material Y-2 for forming the sealing layer, LLDPE6 was melt-kneaded at a molding temperature of 170°C using an extruder with a diameter of 30 mm and an L / D ratio of 30. HDPE1 was used as the resin material Z-2 for forming the intermediate layer, and was melt-kneaded at a molding temperature of 190°C using an extruder with a diameter of 30 mm and an L / D ratio of 30. Resin materials X-1, Y-1, and Z-1 were introduced into a composite shaped die and extruded. The resulting material was then cooled and solidified in a cooling water bath to obtain a fitting with a tape width of 13 mm and a total thickness of 0.15 mm for both the first and second base materials. The mass ratio of the main layer, intermediate layer, and sealing layer was set to 60:30:10.

[0056] [Comparative Example 1] The fitting device was manufactured in the same manner as in Example 1, except that the resin material X for forming the main layer and the resin material Y for forming the sealing layer were changed as shown in Table 1, no intermediate layer was provided, the mass ratio of the main layer to the sealing layer was 90:10, and the molding temperature of the main layer was 170°C.

[0057] [Comparative Examples 2-4] A fitting device was manufactured in the same manner as in Example 1, except that the resin material X for forming the main layer was changed as shown in Table 1, the intermediate layer and seal layer were omitted, the mass ratio of the main layer, intermediate layer and seal layer was set to 100:0:0, and the molding temperature was set to 150-200°C (40-50°C higher than the melting point of the resin used) depending on the melting point of the resin used.

[0058] Table 1 shows the composition of the main layer, intermediate layer, and sealing layer for each example, as well as the evaluation results.

[0059] [Table 2]

[0060] As shown in Table 1, the results of thermal shrinkage stress measurement using a thermomechanical analyzer (TMA device) show that (1) the temperature T at the stress increase initiation point (A) A However, the fittings of Example 1 and Example 2, which have a temperature of 70°C to 140°C, (2) a load LB at the maximum stress point (B) of 1 mN to 200 mN, and (3) a slope value between (A) and (B) of 0.1 to 10, exhibited excellent moldability and heat resistance (less prone to shrinkage and deformation due to heat).

[0061] On the other hand, the results of thermal shrinkage stress measurement using a TMA device showed that (1) the temperature T at the stress increase initiation point (A) A In Comparative Examples 1 and 2, where the temperature was below 70°C and (2) the load LB at the maximum stress point (B) was greater than 200 mN, the fittings exhibited unstable shape or uneven thickness in the base material during bag making, resulting in deformation due to heat. Furthermore, the fitting device in Comparative Example 3 was too rigid, making stable molding impossible. Furthermore, the fitting of Comparative Example 4 showed the following results from thermal shrinkage stress measurement using a thermomechanical analyzer (TMA device): (1) The temperature T at the stress increase initiation point (A) A However, the temperature is between 70°C and 140°C, and (2) the load L at the point of maximum stress (B) B However, although the value was between 1 mN and 200 mN, the slope between (3)(A) and (B) exceeded 10, indicating that the shape of the fitting was unstable during bag making, or that there were inconsistencies in the thickness of the base material. [Explanation of symbols]

[0062] 1... Fitting device, 10... Male fitting member, 11... First base material, 11a... Surface, 12... Male fitting part, 13... Main layer, 14... Seal layer, 15... Intermediate layer, 20... Female fitting member, 21... Second base material, 21a... Surface, 22... Female fitting part, 23... Main layer, 24... Seal layer, 25... Intermediate layer, 50... Bag body, 100... Bag body with fitting device.

Claims

1. A fitting device comprising a male fitting member having a male fitting portion provided along the longitudinal direction on the surface of a strip-shaped first base material, and a female fitting member having a female fitting portion provided along the longitudinal direction on the surface of a strip-shaped second base material, wherein the male fitting portion and the female fitting portion are detachably fitted together, A fitting device whose thermal shrinkage stress measurement using a thermomechanical analyzer (TMA device) satisfies the following conditions (1) to (3). (1) Temperature T at the stress increase initiation point (A) Ａ However, the temperature must be between 70°C and 140°C. (2) Load L at the point of maximum stress (B) Ｂ However, it is between 1 mN and 200 mN. (3) The numerical value of the slope between (A) and (B) is between 0.1 and 10.

2. In (2) above, the load LB at the point of maximum stress (B) is 1 mN or more and 20 mN or less. The fitting device according to claim 1, wherein, in (3) above, the numerical value of the slope between (A) and (B) is 0.1 or more and 5 or less.

3. The fitting device according to claim 1 or 2, wherein the first substrate and the second substrate each comprise a main layer and a sealing layer provided on the side of the main layer opposite to the male fitting portion and the female fitting portion.

4. The fitting device according to claim 3, wherein the first substrate and the second substrate each include an intermediate layer provided between the main layer and the sealing layer.

5. A bag body with a fitting device, comprising a fitting device according to any one of claims 1 to 4, and a bag body for containing contents, wherein the fitting device is attached to the inner surface of the bag body.

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