Zipper tape and containers with zipper tape

Abstract

The zipper tape comprises a first resin portion formed from a resin composition whose main polymer is polyolefin and including a pair of base strips and engaging portions that protrude from opposing surfaces of the pair of base strips and are engageable with each other, and a second resin portion formed from a resin composition whose main polymer is polyester and covering the surfaces of at least one pair of base strips opposite the engaging portions.

Description

[Technical Field]

[0001] The present invention relates to a zipper tape and a container with the zipper tape. [Background technology]

[0002] In packaging for foods, pharmaceuticals, and the like, the inner layer that comes into contact with the contents is often made of a polyolefin resin film primarily composed of polyethylene or polypropylene, which has excellent safety and heat-sealing properties. However, because polyolefin resins have high permeability and adsorption properties for aroma components, when used as an inner layer material, they can emit a plastic odor or can reduce the product value due to the migration or adsorption of medicinal and aromatic components from the contents. Therefore, packaging that uses PET (polyethylene terephthalate) as an inner layer, which is less susceptible to the migration or adsorption of medicinal and aromatic components from the contents, is known.

[0003] For example, Patent Document 1 describes a zippered bag that uses PET as the inner layer. The bag described in Patent Document 1 has an inner layer formed from heat-sealable PET, and the zipper member is formed from a mixed resin in which PET and a polyester-based elastomer are blended in a specific ratio, or a mixed resin in which a compatibilizer is added to PET and polyethylene. This makes the zipper member fusion-bondable to the PET inner layer of the bag and gives the zipper member flexibility, making it easy to open and close. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 6309925 Summary of the Invention [Problem to be solved by the invention]

[0005] However, when forming a zipper member from a mixed resin as described in Patent Document 1, the flexibility of the zipper member and the fusion strength with PET vary greatly depending on the blend ratio, making it difficult to balance these two. More specifically, if the PET ratio is high, the zipper member is insufficiently flexible, making it difficult to open and close, while if the PET ratio is low, the fusion strength with the PET inner layer of the bag is insufficient. Therefore, it is not easy to stabilize the quality of the zipper member in the zipper bag described in Patent Document 1.

[0006] Therefore, an object of the present invention is to provide a zipper tape that can be securely fused to a container body having an inner layer containing PET while maintaining functionality as a zipper tape, such as stable sealing properties and a moderate opening feel, and a container with zipper tape in which such zipper tape is fused to the container body. [Means for solving the problem]

[0007] According to one aspect of the present invention, there is provided a zipper tape comprising: a first resin portion formed from a resin composition whose main polymer is polyolefin and including a pair of base strips and engaging portions protruding from opposing surfaces of the pair of base strips and capable of engaging with each other; and a second resin portion formed from a resin composition whose main polymer is polyester and covering the surfaces of at least one pair of base strips opposite the engaging portions. According to the above configuration, the engaging portion of the zipper tape is formed from a resin composition containing polyolefin as the main polymer, thereby maintaining the functionality of the zipper tape, such as stable sealing performance and a suitable opening feel. Furthermore, the joining surface is formed from a resin composition containing polyester as the main polymer, thereby enabling the sealant layer to reliably fuse the zipper tape to the container body containing PET.

[0008] According to another aspect of the present invention, there is provided a container with zipper tape, comprising the above zipper tape and a container body to which the zipper tape is fused. For example, by forming a container with zipper tape by fusing the zipper tape to a container body whose sealant layer contains PET, it is possible to achieve both the functionality of the PET layer and the functionality of the zipper tape.

[0009] As described above, the present invention can provide a zipper tape that can be securely fused to a container body having an inner layer containing PET while maintaining the functionality of the zipper tape, such as stable sealing properties and a moderate opening feel, and a container with zipper tape that can achieve both the functionality of the container body and the zipper tape by fusing such zipper tape to the container body. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a plan view of a bag with a zipper tape according to a first embodiment of the present invention. [Figure 2] 2 is a cross-sectional view of the zipper tape bag shown in FIG. 1 taken along line II-II. [Figure 3] FIG. 4 is a cross-sectional view of a bag with a zipper tape according to a second embodiment of the present invention. [Figure 4] FIG. 10 is a cross-sectional view of another example of a bag with a zipper tape according to the second embodiment of the present invention. [Figure 5] FIG. 10 is a cross-sectional view of yet another example of a bag with a zipper tape according to the second embodiment of the present invention. [Figure 6] FIG. 10 is a cross-sectional view of a bag with a zipper tape according to a third embodiment of the present invention. [Figure 7] FIG. 11 is a cross-sectional view of a bag with a zipper tape according to a modified example of the third embodiment. [Figure 8] FIG. 10 is a cross-sectional view of a bag with a zipper tape according to a fourth embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In this specification and drawings, components having substantially the same functional configurations are designated by the same reference numerals, and redundant description will be omitted.

[0012] In this specification, the term "main polymer" refers to the component that is most abundant among the constituent components of each layer. When each layer is composed of n polymer components (n is an integer of 2 or more), the term refers to a component that is contained in an amount of 100 / n% or more, preferably 100 / n x 1.2% or more. The fact that a polymer is the main polymer can be determined by analysis using infrared spectroscopy, NMR, DSC, etc. It should be noted that impurities may be contained within a range that does not impair the effects of the present invention.

[0013] (First embodiment) Fig. 1 is a plan view of a bag with zipper tape according to a first embodiment of the present invention, and Fig. 2 is a cross-sectional view of the bag with zipper tape shown in Fig. 1 taken along line II-II. As shown in Figs. 1 and 2, the bag with zipper tape 1 according to the first embodiment includes a film 10 that forms a bag body having a first surface 11A and a second surface 11B, and a zipper tape 20.

[0014] The film 10 is formed, for example, of a single-layer or multi-layer thermoplastic resin. More specifically, the film 10 may include a layer formed of low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), or polypropylene (PP). PP may be homopolypropylene (HPP), random polypropylene (RPP), or block polypropylene (BPP). When the film 10 is multilayered, the surface substrate may be biaxially oriented polypropylene (OPP), biaxially oriented polyethylene terephthalate (OPET), or biaxially oriented nylon (ONy). The film 10 may also include a layer of an inorganic material formed by aluminum vapor deposition or lamination of aluminum foil. In this embodiment, the sealant layers on the first surface 11A and the second surface 11B of the film 10, i.e., the layers facing the zipper tape 20, are formed of a resin composition whose main polymer is heat-sealable PET (polyethylene terephthalate).

[0015] In this embodiment, two sheets of film 10 are joined together at bottom seal 12 and side seal 13 to form a bag having first surface 11A and second surface 11B. However, in another embodiment, first surface 11A and second surface 11B may be formed by folding back a single sheet of film 10 at a portion corresponding to side seal 13. Alternatively, a portion where film 10 is folded inward at a portion corresponding to bottom seal 12 or side seal 13 in the example of FIG. 1, i.e., a gusset, may be formed. In this case, the gusset may be formed by film 10, or by another film joined to film 10. Furthermore, zipper tape bag 1 may be a standing pouch that can be placed upright by forming a gusset at the bottom.

[0016] In this embodiment, the opening 14 of the zipper tape-attached bag 1 is formed by forming the bottom seal 12 and the side seal 13 but not the top seal. However, in another embodiment, a top seal may be formed in addition to the bottom seal 12 and the side seal 13, and the opening 14 may be formed in the zipper tape-attached bag 1 later by cutting between the top seal and the zipper tape 20. In yet another embodiment, the bottom seal 12 may not be formed, i.e., the zipper tape-attached bag 1 may be provided without being sealed on the side opposite the zipper tape 20. In this case, the bottom seal 12 is formed after the zipper tape-attached bag 1 is filled with contents. The present invention can also be applied to bags of various known configurations and containers other than bags, as long as the zipper tape is fused.

[0017] 2, the zipper tape 20 comprises a first member 20A fused to the first surface 11A of the film 10 and a second member 20B fused to the second surface 11B. The first member 20A and the second member 20B each comprise polyolefin portions 21A and 21B formed from a resin composition primarily containing polyolefin, adhesive resin layers 22A and 22B, and polyester portions 23A and 23B formed from a resin composition primarily containing polyester. The polyolefin portions 21A and 21B each comprise base strips 211A and 211B and engaging portions 212A and 212B protruding from opposing surfaces of the base strips 211A and 211B, respectively. The polyester portions 23A, 23B cover the sides of the base strips 211A, 211B opposite the engaging portions 212A, 212B, and form bonding surfaces 231A, 231B with the first and second surfaces 11A, 11B of the film 10. The adhesive resin layers 22A, 22B are located between the polyolefin portions 21A, 21B and the polyester portions 23A, 23B, and bond these portions together. Such a zipper tape 20 can be formed, for example, by co-extrusion molding the resins of the respective portions.

[0018] The adhesive resin layers 22A, 22B are formed from adhesive resins such as polyethylene, acid-modified polyolefin, epoxy-containing monomer-ethylene copolymer, copolymer of ethylene-(meth)acrylic acid ester and dicarboxylic acid anhydride monomer, ethylene-vinyl acetate copolymer, ethylene-isobutyl acrylate copolymer, polyamide resin, thermoplastic polyester, polyvinyl acetate and its copolymer, and styrene-based, polyester-based, and olefin-based elastomers. The use of these adhesive resins can achieve higher interlayer bonding strength between the polyolefin portions 21A, 21B and the polyester portions 23A, 23B. This prevents pinholes from forming between the layers of the zipper tape 20 at the side seal portion 13, which would otherwise reduce the aroma retention of the zipper tape bag 1 when the zipper tape bag 1 shown in FIG. 1 is molded.

[0019] In the zipper tape 20 described above, the engaging portions 212A and 212B formed by the polyolefin portions 21A and 21B are engageable with each other. In the example shown in FIG. 2, the engaging portion 212A has a male cross-sectional shape, and the engaging portion 212B has a female cross-sectional shape. The engaging portions 212A and 212B engage with each other to close the zipper tape 20 and seal the opening 14 of the zipper tape-attached bag 1. The shapes of the engaging portions of various known zipper tapes, such as those combining claws, hooks, or knobs, are not limited to male and female shapes. Two or more sets of engaging portions may be provided on a pair of polyolefin portions. In either case, the engaging portions 212A and 212B are irregularly shaped portions protruding from the base strips 211A and 211B, each having a substantially rectangular cross-section. In order to maintain the shape of such irregularly shaped portions, reliably seal the opening 14 when the engaging portions 212A, 212B engage, and provide a suitable opening sensation when the engagement is released, it is advantageous to form the engaging portions 212A, 212B in the polyolefin portions 21A, 21B, which have polyolefin as the main polymer.

[0020] On the other hand, when the sealant layers on the first surface 11A and the second surface 11B of the film 10 are formed of a resin composition containing heat-sealable PET as the main polymer, the fusion strength between the polyolefin and the heat-sealable PET is low, making it difficult to directly fusion-bond the polyolefin portions 21A and 21B that form the engagement portions 212A and 212B to the first surface 11A and the second surface 11B. Therefore, in this embodiment, the surfaces of the polyolefin portions 21A and 21B opposite the engagement portions 212A and 212B are covered with polyester portions 23A and 23B, and the bonding surfaces 231A and 231B formed on the polyester portions 23A and 23B are fused to the first surface 11A and the second surface 11B of the film 10, respectively. Because the fusion strength between the polyester and the heat-sealable PET is high, the polyester portions 23A and 23B can be stably fused to the first surface 11A and the second surface 11B. The polyolefin portions 21A, B and the polyester portions 23A, 23B may be bonded in any manner, but in this embodiment, the polyolefin portions 21A, B and the polyester portions 23A, 23B are bonded using adhesive resin layers 22A, 22B.

[0021] According to the first embodiment of the present invention as described above, the engaging portions 212A, 212B of the zipper tape 20 are formed from a resin composition having polyolefin as the main polymer, thereby maintaining the functionality of the zipper tape, such as stable sealing and a moderate opening feel, while the joining surfaces 231A, 231B are formed from a resin composition having polyester as the main polymer, thereby enabling the zipper tape 20 to be reliably fused to the first surface 11A and the second surface 11B of the film 10, whose sealant layer contains PET.

[0022] (Second embodiment) Fig. 3 is a cross-sectional view of a bag with zipper tape according to a second embodiment of the present invention. As shown in Fig. 3, the bag with zipper tape 2 according to the second embodiment includes a film 10 and a zipper tape 40. The structure of the film 10 is the same as that of the first embodiment, and therefore a duplicated description will be omitted below.

[0023] 3, the zipper tape 40 comprises a first member 40A fused to the first surface 11A of the film 10 and a second member 40B fused to the second surface 11B. The first member 40A and the second member 40B each include polyolefin portions 21A and 21B, adhesive resin layers 42A and 42B, and polyester portions 43A and 43B. Note that the base strips 211A and 211B and engagement portions 212A and 212B of the polyolefin portions 21A and 21B are the same as those in the first embodiment, and therefore a repeated description will be omitted.

[0024] The polyester portions 43A, 43B are formed of a resin composition containing polyester as the main polymer, as in the first embodiment, and cover the surfaces of the base strips 211A, 211B opposite the engaging portions 212A, 212B, thereby forming joining surfaces 231A, 231B. Additionally, in this embodiment, the polyester portions 43A, 43B include raised portions 432A, 432B that cover the end surfaces 213A, 213B of the base strips 211A, 211B in the width direction (the vertical direction in FIG. 3) of the zipper tape 40. Here, the raised portions 432A, 432B are raised portions at both widthwise end portions of the cross-sectional shape of the polyester portions 43A, 43B. In the illustrated example, the rising portions 432A, 432B cover the entire end faces 213A, 213B, but the rising portions 432A, 432B may cover only a portion of the end faces 213A, 213B, specifically only the sides closer to the polyester portions 43A, 43B.

[0025] The adhesive resin layers 42A, 42B are formed from, as in the first embodiment, for example, polyethylene, acid-modified polyolefin, epoxy group-containing monomer-ethylene copolymer, copolymer of ethylene-(meth)acrylic acid ester and dicarboxylic acid anhydride monomer, ethylene-vinyl acetate copolymer, ethylene-isobutyl acrylate copolymer, polyamide resin, thermoplastic polyester, polyvinyl acetate and its copolymer, styrene-based, polyester-based, olefin-based elastomer, etc., and are formed not only on the surface opposite the engaging portions 212A, 212B of the base strips 211A, 211B but also around the end surfaces 213A, 213B and between the polyester portions 43A, 43B.

[0026] In this embodiment, in addition to achieving the same effects as in the first embodiment described above, the polyester portions 43A, 43B cover the widthwise end faces 213A, 213B of the base strips 211A, 211B, thereby preventing the formation of pinholes in the side seal portion 13 (see Figure 1) where the first member 40A and the second member 40B of the zipper tape 40 are joined to each other together with the first surface 11A and the second surface 11B of the film 10.

[0027] More specifically, for example, when forming the side seal portion 13 by fusion, the resin of the polyolefin portions 21A, 21B melts, causing the end faces 213A, 213B of the base strips 211A, 211B to protrude from the polyester portion. If the polyolefin resin comes into contact with the resin of the sealant layer on the first surface 11A or the second surface 11B, that portion may not be fused, resulting in the formation of pinholes. In this embodiment, by covering the end faces 213A, 213B of the base strips 211A, 211B with the raised portions 432A, 432B of the polyester portions 43A, 43B, it is possible to prevent the formation of pinholes due to contact between the resin of the polyolefin portions 21A, 21B and the resin of the sealant layer on the first surface 11A or the second surface 11B. Even if the polyester portions 43A and 43B do not have the shape called the rising portions 432A and 432B, the same effect can be obtained if they are formed in a shape that can similarly cover the end faces of the base strips 211A and 211B.

[0028] FIG. 4 is a cross-sectional view of another example of a zipper tape bag according to the second embodiment of the present invention. In the zipper tape bag 2A shown in FIG. 4, the width of the zipper tape 40 is similar to that of the example shown in FIG. 3, but the polyolefin portions 41A and 41B form narrow base strips 411A and 411B. The widths of the base strips 411A and 411B may be similar to or narrower than the engaging portions 212A and 212B, as in the illustrated example. As a result, in the illustrated example, the polyester portions 43A and 43B form slab-like portions 433A and 433B that extend outward in the width direction beyond the end faces 213A and 213B of the base strips 411A and 411B.

[0029] In the illustrated example, the slab-like portions 433A, 433B cover the end faces 213A, 213B of the base strips 411A, 411B, but in other examples, the slab-like portions 433A, 433B may cover only a portion of the end faces 213A, 213B, specifically only the side closer to the polyester portions 43A, 43B, or the slab-like portions 433A, 433B may not cover the end faces 213A, 213B. In this case, a step is formed between the base strips 411A, 411B and the slab-like portions 433A, 433B on the inner surfaces of the first and second members 40A, 40B of the zipper tape 40 that face each other.

[0030] FIG. 5 is a cross-sectional view of yet another example of a zipper tape-attached bag according to the second embodiment of the present invention. In the zipper tape-attached bag 2B shown in FIG. 5, the zipper tape 40 includes two sets of polyolefin portions formed of a resin composition containing polyolefin as the primary polymer: polyolefin portions 41A, 41B and polyolefin portions 44A, 44B. The polyolefin portions 44A, 44B are similarly configured to the polyolefin portions 41A, 41B, and include narrow base strips 441A, 441B and engaging portions 442A, 442B configured similarly to the engaging portions 212A, 212B described above. In the illustrated example, the polyolefin portions 41A, 41B and the polyolefin portions 44A, 44B are arranged side by side in the width direction of the zipper tape 40, thereby forming a so-called double zipper.

[0031] In the illustrated example, since the base strips 411A, 411B, 441A, 441B of the polyolefin portions 41A, 41B, 44A, 44B are narrow, the polyester portions 43A, 43B form slab portions 433A, 433B at both widthwise ends of the zipper tape 40 as in the example of Fig. 4, and also form slab portions 434A, 434B between the base strip 411A and the base strip 441A and between the base strip 411B and the base strip 441B, respectively. In this specification, the slab portions (slab portions 433A, 433B and slab portions 434A, 434B) refer to portions of the zipper tape 40 where the polyester portions 43A, 43B are not joined to the polyolefin portions when viewed in the thickness direction of the zipper tape 40, and where the zipper tape 40 is formed by the slab-shaped (single plate) polyester portions 43A, 43B.

[0032] In the example described above with reference to Figures 4 and 5, the base strips of the polyolefin portions 41A, 41B, 44A, 44B are formed to have a narrow width, and slab-like portions 433A, 433B, 434A, 434B formed by the polyester portions 43A, 43B are formed at both ends of the width of the zipper tape 40 and between the multiple polyolefin portions arranged in parallel in the width direction. This minimizes the bonding area between the polyolefin portions 41A, 41B, 44A, 44B and the polyester portions 43A, 43B, and suppresses deformation of the zipper tape 40 due to warping or the like at the bonding portions.

[0033] The double zipper described above with reference to FIG. 5 can also be used in other examples. For example, in the example shown in FIG. 4, a double zipper may be formed by two engagement portions 212A, 212B projecting from opposing surfaces of base strips 411A, 411B. Also, in the example shown in FIGS. 2 and 3, a double zipper may be formed by two engagement portions 212A, 212B projecting from opposing surfaces of base strips 211A, 211B. In other embodiments and modifications described below, a double zipper may also be formed by two engagement portions projecting from opposing surfaces of the base strips. Alternatively, three or more engagement portions may project from opposing surfaces of the base strips.

[0034] (Third embodiment) Fig. 6 is a cross-sectional view of a bag with zipper tape according to a third embodiment of the present invention. As shown in Fig. 6, the bag with zipper tape 3 according to the third embodiment includes a film 10 and a zipper tape 60. The structure of the film 10 is the same as that of the first embodiment, and therefore a duplicated description will be omitted below.

[0035] 6, the zipper tape 60 comprises a first member 60A fused to the first surface 11A of the film 10 and a second member 60B fused to the second surface 11B. The first member 60A and the second member 60B each include polyolefin portions 61A, 61B, adhesive resin layers 62A, 62B, and polyester portions 63A, 63B.

[0036] The polyolefin portions 61A, 61B are formed of a resin composition containing polyolefin as the main polymer, as in the first embodiment, and include base strips 611A, 611B and engaging portions 212A, 212B protruding from opposing surfaces of the base strips 611A, 611B. The engaging portions 212A, 212B are similar to those in the first embodiment, and therefore a redundant description will be omitted. Similarly to the first embodiment, the base strips 611A, 611B have a surface facing the engaging portions 212A, 212B and a surface opposite the engaging portions 212A, 212B. Additionally, in this embodiment, stepped portions 614A, 614B having shapes corresponding to folded portions 633A, 633B of the polyester portions 43A, 43B (described later) are formed at both ends of the base strips 611A, 611B in the width direction (the vertical direction in FIG. 6) of the zipper tape 60. In this embodiment, the steps 614A, 614B are part of the surfaces of the base strips 611A, 611B on the engagement portions 212A, 212B side.

[0037] The polyester portions 63A, 63B are made of a resin composition containing polyester as the main polymer, as in the second embodiment, and cover the surfaces of the base strips 611A, 611B opposite the engaging portions 212A, 212B to form joining surfaces 231A, 231B. In addition, the polyester portions 63A, 63B include raised portions 432A, 432B that cover the end surfaces 213A, 213B of the base strips 611A, 611B in the width direction of the zipper tape 60. Furthermore, in this embodiment, the polyester portions 63A, 63B include turned portions 633A, 633B that cover the stepped portions 614A, 614B of the base strips 611A, 611B. Here, the turned-back portions 633A, 633B are portions where the tips of the rising portions 432A, 432B, which have both widthwise ends raised in the cross-sectional shape of the polyester portions 63A, 63B, are bent back toward the inside in the widthwise direction. As described above, in this embodiment, the step portions 614A, 614B are part of the surface of the base strips 611A, 611B facing the engagement portions 212A, 212B. Therefore, the turned-back portions 633A, 633B partially cover the surface of the base strips 611A, 611B facing the engagement portions 212A, 212B. Note that in another example, the base strip may have a substantially rectangular cross-section without a step, and the turned-back portions 633A, 633B may partially cover the flat surface of the base strip facing the engagement portion.

[0038] The adhesive resin layers 62A, 62B are formed from, as in the first embodiment, for example, polyethylene, acid-modified polyolefin, epoxy group-containing monomer-ethylene copolymer, copolymer of ethylene-(meth)acrylic acid ester and dicarboxylic acid anhydride monomer, ethylene-vinyl acetate copolymer, ethylene-isobutyl acrylate copolymer, polyamide resin, thermoplastic polyester, polyvinyl acetate and its copolymer, styrene-based, polyester-based, olefin-based elastomer, etc., and are formed not only on the surface opposite to the engaging portions 212A, 212B of the base strips 611A, 611B, but also around the end surfaces 213A, 213B and the step portions 614A, 614B and between the polyester portions 63A, 63B.

[0039] In this embodiment, in addition to the same effects as those of the second embodiment, the polyester portions 63A, 63B cover not only the widthwise end faces 213A, 213B of the base strips 611A, 611B but also part of the faces on the engaging portions 212A, 212B side, thereby more reliably preventing pinholes from being formed in the side seal portion 13 (see FIG. 1 ) where the first member 60A and the second member 60B of the zipper tape 60 are joined together with the first surface 11A and the second surface 11B of the film 10. More specifically, for example, when the side seal portion 13 is formed by fusion bonding, if the resin of the polyolefin portions 61A, 61B melts and flows over the rising portions 432A, 432B and comes into contact with the resin of the sealant layer on the first surface 11A or the second surface 11B, pinholes may be formed due to the low fusion strength between the resins. In this embodiment, the polyester portions 63A, 63B cover the surfaces of the base strips 611A, 611B facing the engaging portions 212A, 212B with the turned-up portions 633A, 633B, thereby more reliably preventing the formation of pinholes due to contact between the resin of the polyolefin portions 61A, 61B and the resin of the sealant layer on the first surface 11A or the second surface 11B. Note that even if the polyester portions 63A, 63B do not have a shape that is called a turned-up portion 633A, 633B, a similar effect can be obtained if the polyester portions 63A, 63B are formed in a shape that can similarly partially cover the surfaces of the base strips 211A, 211B facing the engaging portions 212A, 212B.

[0040] (Variation) Fig. 7 is a cross-sectional view of a zipper tape bag according to a modified example of the third embodiment. In the zipper tape bag 3A shown in Fig. 7, the turned-up portions 633A, 633B of the polyester portions 63A, 63B are stretched and reach the bases of the engagement portions 212A, 212B. In this case, the bases of the engagement portions 212A, 212B are not covered by the turned-up portions 633A, 633B, so that the polyester portions 63A, 63B partially cover the surfaces of the base strips 211A, 211B facing the engagement portions 212A, 212B, just as in the example described above with reference to Fig. 6. However, in the example of Fig. 7, the stepped portions 614A, 614B are not formed.

[0041] The second and third embodiments described above can prevent pinhole formation when forming the side seal portion 13 on the zipper tape-attached bags 2 and 3. When the inner layer of the film 10 is formed from a resin composition containing PET, the zipper tape-attached bags have excellent aroma retention, and preventing pinhole formation can further improve aroma retention. Even without a structure for preventing pinhole formation, as in the first embodiment, significant pinholes may not form depending on the material and dimensions of the polyolefin portions 21A and 21B. Furthermore, pinhole formation may be tolerable depending on the performance required of the zipper tape-attached bag 1. For similar reasons, the second and third embodiments can also be selected appropriately depending on the need and degree of pinhole prevention.

[0042] FIG. 8 is a cross-sectional view of a zipper tape-attached bag according to a fourth embodiment of the present invention. In the zipper tape-attached bag 4 shown in FIG. 8, the engagement portions of the polyolefin portions 71A and 71B in the first portions 70A and 70B of the zipper tape 70 form a sealed engagement portion in which the male member 712A and the female member 712B come into surface contact with each other. Such a sealed engagement portion is described, for example, in Japanese Patent Application Laid-Open No. 8-268445. In this embodiment, the sealed engagement portion formed by the male member 712A and the female member 712B of the zipper tape 70 improves the sealing performance and pressure resistance of the zipper tape-attached bag 4. Note that in the example shown in FIG. 8, the polyolefin portions 71A and 71B include narrow base strips 411A and 411B, as in the examples described above with reference to FIGS. 4 and 5. However, it is also possible to combine a sealed engagement portion with a non-narrow base strip, as in the examples described with reference to the other figures. [Example]

[0043] The zipper tape bag 1 of the first embodiment of the present invention described above with reference to FIG. 2 was used as Example 1, the zipper tape bag 2 of the second embodiment described above with reference to FIG. 3 was used as Example 2, the zipper tape bag 3 of the third embodiment described above with reference to FIG. 6 was used as Example 3, and the zipper tape 60 was used as Example 3. The heat sealability of the zipper tapes 20, 40, and 60 relative to a sealant layer formed of a resin composition containing heat-sealable PET as the main polymer, and the presence or absence of pinholes in the side seal portion 13 of the zipper tape bags 1, 2, and 3 were evaluated.

[0044] In zipper tapes 20, 40, and 60 of Examples 1 to 3, polyolefin segments 21A, 21B, 61A, and 61B were made of linear low-density polyethylene with a density of 915 kg / m and a melt flow rate of 4.0 g / min. Adhesive resin layers 22A, 22B, 42A, 42B, 62A, and 62B were made of an adhesive resin containing low-density polyethylene, ethylene-propylene rubber, and an alicyclic resin in a ratio of 63:23:14 (units: wt%). Polyester segments 23A, 23B, 43A, 43B, 63A, and 63B were made of crystalline polyester (a 6:4 blend of Vylon SI-173 and GM-913 manufactured by Toyobo Co., Ltd.). These raw material compositions were extruded using an extruder and then water-cooled to produce zipper tapes 20, 40, and 60.

[0045] As a comparative example, the polyester portions 23A, 23B were omitted from the zipper tape 20 of the first embodiment, and a zipper tape consisting of polyolefin portions 21A, 21B and adhesive resin layers 22A, 22B was produced using the same raw material composition and molding method as above, and joined to the same film 10 as in the first embodiment to form a bag with zipper tape.

[0046] The evaluation results of the heat sealability and the presence or absence of pinholes in Examples 1 to 3 and the Comparative Example are shown in Table 1. The evaluation methods are as follows.

[0047] (1) Heat sealability Using a Toyo Seiki Seisakusho "Thermal Gradient Tester," the zipper tapes of Examples 1 to 3 and the Comparative Example were sealed with a laminate film of PET#12 / heat-sealable PET#20 (total thickness 32μ) at a sealing time of 1.0 second, a sealing pressure of 2.0 MPa, and a sealing temperature of 180°C to obtain evaluation samples. The heat seal strength (N / 15mm) between the zipper tape and the laminate per 15mm width was measured using an Imada "Digital Force Gauge." The tensile speed during seal strength measurement was 300mm / min. In Table 1, heat seal strengths of 15 (N / 15mm) or greater were evaluated as OK, and those less than 15 (N / 15mm) were evaluated as NG.

[0048] (2) Presence or absence of pinholes Ink-colored alcohol was sealed inside the zipper tape bags of Examples 1 to 3 and the Comparative Example, and the presence or absence of pinholes was evaluated in the side seal portion 13. In Table 1, cases where the colored alcohol did not leak from the side seal portion are shown as OK, and cases where the colored alcohol leaked from the side seal portion are shown as NG.

[0049] [Table 1]

[0050] The above examples and comparative examples demonstrate that in each embodiment of the present invention, the heat sealability of the zipper tape is improved when the sealant layer is formed from a resin composition containing heat-sealable PET as the main polymer. Regarding pinholes in the side seal portion, the improvement in Example 1 was smaller than in Examples 2 and 3. However, as mentioned above, Example 1 can be selected depending on the necessity and degree of pinhole prevention.

[0051] Although the preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings, the present invention is not limited to these examples. It is clear that a person skilled in the art to which the present invention pertains can conceive of various modifications or alterations within the scope of the technical ideas described in the claims, and it is understood that these also naturally fall within the technical scope of the present invention. [Explanation of symbols]

[0052] 1, 2, 3...bag with zipper tape, 10...film, 11A...first surface, 11B...second surface, 12...bottom seal portion, 13...side seal portion, 14...opening, 20, 40, 60...zipper tape, 20A, 40A, 60A...first member, 20B, 40B, 60B...second member, 21A, 21B, 61A, 61B...polyolefin portion, 211A, 211B, 611A, 611B...base strip, 212A, 212B...engagement portion, 22A, 22B, 42A, 42B, 62A, 62B...adhesive resin layer, 23A, 23B, 43A, 43B, 63A, 63B...polyester portion, 231A, 231B...joint surface.

Claims

1. A first resin portion formed of a resin composition having polyolefin as the main polymer, including first and second base strips and first and second engaging portions respectively protruding from opposing surfaces of the first and second base strips and capable of engaging with each other; a second resin portion formed of a resin composition containing polyester as a main polymer and covering at least the surfaces of the first and second base strips opposite to the first and second engagement portions; an adhesive resin layer located between the first resin portion and the second resin portion; A zipper tape comprising: the second resin portion has rising portions which are portions where both end portions of the first base strip in the width direction of the zipper tape rise, and the rising portions at least partially cover end faces of the first base strip in the width direction of the zipper tape, The adhesive resin layer is formed between the first resin portion and the second resin portion, wrapping around an end face of the first base strip in the width direction of the zipper tape.

2. 2. The zipper tape according to claim 1, wherein the second resin portion further partially covers a surface of the first base strip on the side of the first engaging portion that continues from an end face of the first base strip in the width direction of the zipper tape.

3. 3. The zipper tape according to claim 1, wherein the second resin portion forms a slab-shaped portion extending outward in the width direction of the zipper tape beyond an end face of the second base strip in the width direction of the zipper tape.

4. the first resin portion includes a plurality of resin portions arranged in parallel in the width direction of the zipper tape, The zipper tape according to claim 1 , wherein the second resin portion forms a slab-shaped portion between the plurality of resin portions.

5. The zipper tape according to claim 1 , wherein the first and second engaging portions include sealed engaging portions in which a male member and a female member are in surface contact with each other.

6. The zipper tape according to any one of claims 1 to 5; a container body to which the zipper tape is fused; A container with a zipper tape.

7. 7. The container with zipper tape according to claim 6, wherein a layer of the container body facing the zipper tape is formed from a resin composition containing heat-sealable PET as a main polymer.

8. The container with zipper tape according to claim 6 or 7, wherein the container body forms a bag.

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