Multilayer materials and packaging containers

Abstract

The invention relates to a multilayer material suitable for recycling, from which a heat-sealing film similar to the heat-sealing film in the multilayer material of the invention can be fabricated using recycled plastic obtained from packaging or similar containers containing the multilayer material of the invention. The invention also relates to a multilayer material comprising a matrix material with a melting temperature Tm1 at least one outer layer, and a heat-sealing layer with a melting temperature Tm2 at one inner layer, wherein the multilayer material is characterized by 24°C ≤ Tm1 - Tm2 ≤ 152°C.

Description

Laminate and packaging container

[0001] The present invention relates to a laminate and a packaging container.

[0002] Conventionally, polyethylene terephthalate (hereinafter referred to as "PET") bottles and plastic containers and packaging have been subject to the Container and Packaging Recycling Law, and because ordinary PET bottles contain only PET resin, they are easy to recycle, and horizontal recycling has been established. On the other hand, plastic containers and packaging usually contain multiple types of resins, and because it is difficult to separate these multiple types of resins, various problems arise when recycling them.

[0003] One example of such plastic container packaging is a packaging bag using a laminate manufactured by using a PET film as the base film and a polyethylene film as the heat-seal layer, molding the two films separately, and then dry-laminating them with a urethane adhesive or the like (see, for example, Patent Document 1). The polyethylene film used in the heat-seal layer uses low-density polyethylene or linear low-density polyethylene as the main resin, and its melting point is generally about 110°C, although it depends on the product grade. The melting point of the PET used in the base film is generally about 260°C, although it also depends on the product grade.

[0004] Therefore, when the recycled resin obtained by crushing the packaging bags is reused to produce a film for a heat-seal layer similar to the film for the heat-seal layer in the laminate, the molding temperature for the film must be set to approximately 280°C, slightly higher than the melting point of PET, because the recycled resin contains PET. However, molding the film at approximately 280°C is too high for the low-melting-point decomposition products contained in the polyethylene film, such as paraffin oil and low-molecular-weight compounds, and problems such as carbonization of the low-melting-point decomposition products, the generation of large amounts of oily smoke during molding, contamination of the extrusion molding rolls, and an increase in molding pressure during extrusion occur. Therefore, if the molding temperature is set lower than 280°C, the PET will not melt sufficiently, resulting in problems such as the occurrence of fish eyes, pinholes, and the like, which degrade the quality of the film.

[0005] Furthermore, laminates for packaging containers that use polyamide as a substrate and have excellent pinhole resistance are also known (see, for example, Patent Document 2). However, polyamide may be a contraindicated substance when chemically recycling is performed, and therefore, in consideration of recycling in general, it is considered that its use in such laminates should be avoided as much as possible.

[0006] JP 2022-154135 A JP 2022-163548 A

[0007] In view of the above circumstances, an object of the present invention is to provide a laminate suitable for recyclability, which allows the production of a film for a heat seal layer similar to the film for a heat seal layer in the laminate of the present invention, using a resin recycled from a packaging container or the like made of the laminate of the present invention. A further object of the present invention is to provide a packaging container formed using the above-mentioned laminate suitable for recyclability. Here, recyclability means that the "packaging container or the like manufactured using recycled resin" is manufactured again using recycled resin made from "packaging container or the like manufactured using recycled resin."

[0008] According to the present invention, at least the outer layer has a melting point Tm １ The substrate layer has a melting point Tm ２A laminate comprising a heat seal layer having a temperature of 24°C or less Tm １ -Tm ２ A laminate is provided which is characterized by a temperature of ≦152°C.

[0009] The sealant film of the present invention preferably has the following features: (1) The heat seal layer has at least three layers, including two layers made of virgin polyolefin and a recycled layer between them. (2) The recycled layer has a melting point Tm ３ and Tm ３ ≦250°C. (3) The base layer is made of a stretched film of polybutylene terephthalate. (4) The virgin polyolefin in the heat-seal layer is polyethylene, and all three layers in the heat-seal layer are unstretched films. (5) A vapor-deposited layer using an inorganic substance or inorganic oxide is present between the base layer and the heat-seal layer. (6) At least one of the two layers made of virgin polyolefin is a colored layer. (7) The base layer and the heat-seal layer are laminated using an adhesive. (8) The laminate does not contain polyethylene terephthalate or polyamide. (9) A packaging container using the laminate.

[0010] The laminate of the present invention has a melting point Tm １ The substrate layer has a melting point Tm ２ A laminate comprising a heat seal layer having a temperature of 24°C or less Tm １ -Tm ２ ≦152°C, and a film for a heat seal layer similar to the film for a heat seal layer in the laminate can be produced using a resin recycled from a packaging container or the like made of the laminate, thereby making it possible to provide a laminate suitable for re-recycling. １ and melting point Tm ２ By setting the difference between the above values ​​within the above range, it is possible to set a low molding temperature during recycling, thereby making it possible to prevent problems such as carbonization of low-melting-point decomposition products contained in the polyethylene film, generation of oily smoke, contamination of the extrusion molding rolls, and an increase in molding pressure during extrusion.

[0011] Furthermore, in the laminate of the present invention having the layer structure described above, by utilizing this layer structure and forming a vapor-deposited layer using an inorganic substance or inorganic oxide between the base layer and the heat-sealable layer, the gas barrier properties of the laminate can be improved. Also, by making at least one of the two layers made of the virgin polyolefin a colored layer, the appearance characteristics can be improved.

[0012]

[0023] Fig. 1 is a schematic cross-sectional side view showing the layer structure of a first embodiment of the laminate of the present invention.

[0024] Fig. 2 is a schematic cross-sectional side view showing the layer structure of a second embodiment of the laminate of the present invention.

[0025] Fig. 3 is a schematic cross-sectional side view showing the layer structure of a third embodiment of the laminate of the present invention.

[0026] Fig. 4 is a schematic cross-sectional side view showing the layer structure of a fourth embodiment of the laminate of the present invention.

[0027] Fig. 5 is a schematic view showing an example of a refill pouch for liquid, which is an example of a packaging container according to the present invention.

[0013] Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. However, the present invention is not limited to these embodiments. Note that, since the laminate of the present invention is used in a heat-sealed packaging container, in the packaging container, the heat-seal layer side is the inner layer and the base layer side is the outer layer.

[0014] <Laminate> FIG. 1 is a schematic cross-sectional side view showing the layer structure of a first embodiment of the laminate of the present invention. The laminate 100 is composed of three layers: a heat-seal layer 4, which is composed of two virgin polyolefin layers 2 and a recycled layer 3 sandwiched between them; and the heat-seal layer 4 and a base layer 1 are dry-laminated with an adhesive layer 5. The thickness of the base layer 1 is preferably 40 μm or less, more preferably 30 μm or less, from the viewpoint of improving thermal conductivity to the heat-seal layer 4 during heat-sealing. While the lower limit of the thickness is not particularly limited, it is preferably, for example, 1 μm or more. Furthermore, the thickness of the heat-seal layer 4 is preferably 50 μm or more, more preferably 60 μm or more, from the viewpoint of ensuring sufficient adhesion during heat-sealing. While the upper limit of the thickness range of the heat-seal layer 4 is not particularly limited, it is preferably, for example, 500 μm or less, more preferably 400 μm or less. The thickness of the recycled layer 3 is not particularly limited, but is preferably 2 to 400 μm, more preferably 10 to 200 μm. The thickness of the adhesive layer 5 is not particularly limited, but is preferably set to, for example, 0.1 to 30 μm.

[0015] The virgin polyolefin layer 2 is produced using virgin polyolefin. The virgin polyolefin is not particularly limited as long as it is a virgin polyolefin having heat-sealability. However, it is preferable to use polyethylene selected from low-density polyethylene (LDPE) or linear low-density polyethylene (LLDPE), or unstretched polypropylene (CPP), and it is even more preferable to use polyethylene. Furthermore, a mixture of different polyolefins, such as a mixture of low-density polyethylene (LDPE) and linear low-density polyethylene (LLDPE), may also be used. Furthermore, the polyolefin may be derived from petroleum-derived materials, plant-derived materials, or a mixture thereof. Furthermore, it is preferable that all three layers in the heat-sealable layer 4 are unstretched films, as this provides excellent heat-sealability.

[0016] The recycled layer 3 contains a so-called recycled resin obtained by using recovered used plastic packaging containers or waste materials recovered during the manufacture of plastic packaging containers, etc., through various processes such as crushing, washing with alkali, filtration in a molten state, and extraction with an organic solvent. The recycled resin preferably does not contain PET to lower the molding temperature during film formation, and preferably contains almost no polyamide, which may be a contraindication substance during chemical recycling. Since the resin used is clear, recycled resins made from waste materials or products recovered during the manufacture of the laminate of the present invention are preferred, and recycled resins made from waste materials recovered during the manufacture of the virgin polyolefin layer 2 are even more preferred. Here, "almost no polyamide" means that the recycled resin does not contain polyamide, or if it does contain polyamide, it contains less than 5% by mass of the total recycled resin.

[0017] The heat seal layer 4 contains a recycled resin in the recycled layer 3, but as the proportion of recycled resin used increases, the amount of virgin polyolefin used in the heat seal layer 4 etc. decreases relatively, resulting in a significant deterioration in heat sealability and other physical properties. Therefore, from the viewpoint of avoiding such deterioration in physical properties, the recycled resin content in the heat seal layer 4 is preferably 15 to 90% by mass, and more preferably 15 to 60% by mass.

[0018] In order to more reliably avoid a decrease in the heat sealability of the heat seal layer 4, it is preferable that, for example, when the thickness of the recycled layer 3 is 100 μm, the thickness of the virgin polyolefin layers 2 on both the upper and lower sides be set to about 10 to 60 μm (10 to 60% of the thickness of the heat seal layer 4).

[0019] Furthermore, the recycled layer 3 may be formed solely of recycled resin, but preferably contains virgin polyolefin. Provided that the recycled resin content in the heat seal layer 4 satisfies the above-mentioned numerical range and the thickness ratio between the recycled layer 3 and the upper and lower virgin polyolefin layers 2, the mass ratio of recycled resin to virgin polyolefin is preferably within the range of recycled resin:virgin polyolefin = 99:1 to 25:75. Here, 50:50 is a two-fold dilution, and 25:75 is a four-fold dilution. The recycled layer 3 is formed by co-extrusion molding using recycled resin-containing pellets and virgin polyolefin pellets. The melting point Tm of the recycled layer 3 is also preferably within the range of 99:1 to 25:75. ３ Since polyolefin deteriorates at molding resin temperatures of 250°C or higher, for example, Tm ３ Preferably, Tm ３ It is more preferable that Tm ３ It is particularly preferable that the temperature is ≦230°C. Furthermore, the virgin polyolefin used in the recycled layer 3 is preferably the same as the virgin polyolefin used in the virgin polyolefin layer 2, but may be different. Furthermore, since the recycled layer 3 contains components such as polyester resins, adhesives, and colorants, an ester decomposition inhibitor such as a carbodiimide compound may be included to suppress strength reduction associated with molecular weight reduction and other factors caused by these components, and a compatibilizer to improve dispersibility may also be included. Examples of polar groups in the compatibilizer include organic isocyanate groups, carboxylic acid anhydride groups, carboxylic acid groups, amino groups, hydroxyl groups, epoxy groups, and acrylate groups. Acid-modified olefin resins, imine-modified olefin resins, acrylic acid ester-glycidyl methacrylate copolymer olefin resins, and saponified ethylene-vinyl acetate copolymers are preferred. Other additives that do not impair physical properties include lubricants, ultraviolet absorbers, plasticizers, crystal nucleating agents, fillers, hydrolysis inhibitors, flame retardants, antistatic agents, antifogging agents, and antiblocking agents.

[0020] The substrate layer 1 has a melting point Tm １ and the melting point Tm１ Resins having a melting point lower than the melting point of PET, which is about 260°C, can be used, such as polybutylene terephthalate (melting point 230°C), high-density polyethylene (melting point 130 to 150°C), oriented polypropylene (OPP, melting point 165°C), polystyrene (melting point 240°C), polyvinylidene chloride (melting point 210°C), polychlorotrifluoroethylene (melting point 220°C), acetylcellulose (melting point 230°C), polysulfone (melting point 200°C), polycarbonate (melting point 150°C), polyacetal (melting point 181°C), ethylene-vinyl alcohol copolymer (melting point 160 to 183°C), polyvinyl alcohol (melting point 200°C), etc. Among these, polybutylene terephthalate, polystyrene, polyvinylidene chloride, polychlorotrifluoroethylene, and acetylcellulose, which have melting points in the range of 210 to 240°C, are preferred, with polybutylene terephthalate being more preferred. These may be used alone or in combination.

[0021] The present invention provides a coating material having a melting point Tm １ The substrate layer has a melting point Tm ２ A laminate comprising a heat seal layer having a temperature of 24°C or less Tm １ -Tm ２ For example, the substrate layer is made of uniaxially oriented high density polyethylene (melting point Tm １ : 134°C), and the heat seal layer is made of unstretched low density polyethylene (melting point Tm ２ Tm when using １ -Tm ２ is 24 (134-110=24) ° C., and the substrate layer is made of polybutylene terephthalate (melting point Tm １ Tm when replaced with １ -Tm ２ is 115 (225-110=115)°C. Here, the melting point was measured using a differential scanning calorimeter (DSC).

[0022] In addition, the Tm １ -Tm ２ is 51 ° C. or less Tm １ -Tm ２For example, the base layer may be made of oriented polypropylene (melting point Tm １ : 165°C), and the heat seal layer is made of unstretched low density polyethylene (melting point Tm ２ Tm when using １ -Tm ２ is 55 (165-110=55)°C.

[0023] The heat seal layer 4 is produced by cast film formation using three or five extruders to produce a laminate consisting of two virgin polyolefin layers 2 and two recycled layers 3, or three types and five layers as shown in Figure 4 below. The components are dry blended and fed into the extruders for melt-kneading, co-extruded into a film from a T-die, and the extruded two-type, three-layer, or three-type, five-layer film is solidified by contacting it with a cooling roll and wound up. The components may be fed in the form of film-like fragments, pellets, granules, or liquid. The film-like fragments may be film scraps generated during the implementation of the present invention. In inflation molding, which is typically used to extrude bag-shaped films to produce heat sealant films, the presence of incompatible foreign matter in the polyolefin tends to result in holes and thickness variations. Passing the material through a fine-mesh filter to remove the foreign matter significantly reduces production speed. In contrast, in the case of cast film production, it is easy to obtain a high-quality film without holes and with little thickness deviation, and since there is no need to pass the film through a fine mesh filter, a decrease in production speed can be suppressed. Here, the heat-sealing layer 4 is not limited to the two-kind three-layer or three-kind five-layer configuration, and the number of types and the number of layers can be used as needed, but since the recycled layer 3 is included, it is preferable that the heat-sealing layer 4 consists of at least three layers.

[0024] The base material layer 1 is formed by a known means or method using an extruder or the like, separately from the heat seal layer 4. Since the base material layer 1 is used as an outer layer and is therefore required to have improved film strength, thermal properties, etc., it is preferable that the base material layer 1 is a stretched film, and the stretching may be either uniaxial or biaxial, but biaxial stretching is more preferable since it improves the film strength, etc.

[0025] The base material layer 1 and the heat seal layer 4 are laminated using an adhesive layer 5 made of an adhesive. Examples of the adhesive include known adhesives such as urethane-based, epoxy-based, acid-modified polyolefin-based, polyester-based, polyether-based, and polyamide-based adhesives. The adhesive layer 5 may contain one or more of these adhesives. It is preferable that the adhesive layer 5 contains a urethane-based adhesive because it is flexible and impact-resistant.

[0026] FIG. 2 is a schematic cross-sectional side view showing the layer structure of a second embodiment of the laminate of the present invention, and shows a laminate 200 having, in addition to the layer structure of the first embodiment shown in FIG. 1 , a vapor-deposited layer 6 using an inorganic substance or inorganic oxide on the surface of the base material layer 1 facing the heat seal layer 4.

[0027] Examples of inorganic substances that can be used include silicon (Si), aluminum (Al), magnesium (Mg), calcium (Ca), potassium (K), tin (Sn), sodium (Na), boron (B), titanium (Ti), lead (Pb), zirconium (Zr), and yttrium (Y). However, aluminum (Al) is preferred as it is suitable for packaging containers.

[0028] The inorganic oxide may be SiO Ｘ , AlO Ｘ MO etc. Ｘ(wherein, M represents an inorganic element, and the value of X varies depending on the inorganic element.) can be used. Here, the value of X can range from 0 to 2 for silicon (Si), 0 to 1.5 for aluminum (Al), 0 to 1.5 for magnesium (Mg), 0 to 1 for calcium (Ca), 0 to 1 for potassium (K), 0 to 0.5 for tin (Sn), 0 to 2 for sodium (Na), 0 to 0.5 for boron (B), 0 to 1.5 for titanium (Ti), 0 to 2 for lead (Pb), 0 to 1 for zirconium (Zr), and 0 to 1.5 for yttrium (Y). However, in the above, when X=0, it is completely inorganic, not an inorganic oxide, and is therefore excluded. Silicon oxide or aluminum oxide is preferred as a material suitable for packaging containers, and SiO is preferred because of its transparent appearance. ２ or AlO ２ is particularly preferred.

[0029] The vapor-deposited layer 6 is formed using a known technique such as plasma CVD, and has the effect and function of improving the gas barrier properties of the laminate and concealing coloration caused by recycled resins when the laminate 200 is used as a packaging container. Such a vapor-deposited layer 6 is a thin layer having a thickness of about 0.001 to 1 μm. In order to further improve the gas barrier performance, the thin layer may contain a coating film formed by a crosslinking reaction between a carboxylic acid and a metal, or a coating film in which a metal oxide is dispersed.

[0030] Figure 3 is a schematic cross-sectional side view showing the layer structure of a third embodiment of the laminate of the present invention. This is similar to the layer structure of the first embodiment shown in Figure 1, but the heat-seal layer 4 is composed of three layers: two colored virgin polyolefin layers 7 containing a coloring pigment, and a recycled layer 8 containing a recycled resin made from packaging containers formed from the laminate of the present invention, and the heat-seal layer 4 and the base layer 1 are dry-laminated with an adhesive layer 5 to form a laminate 300. Here, except that the colored virgin polyolefin layer 7 contains a coloring pigment, and the recycled layer 8 contains a recycled resin made from packaging containers formed from the laminate of the present invention, the thickness, material composition, etc. can be the same as those of the virgin polyolefin layer 2 and the recycled layer 3, respectively. The colored virgin polyolefin layer 7 has an effect and function of concealing coloration caused by the recycled resin when the laminate 300 is used for packaging containers. Furthermore, the laminate 300 has colored virgin polyolefin layers 7 on both sides of the recycled layer 8, but a virgin polyolefin layer 2 that does not contain a color pigment may be used on one side. In this case, in order to exert the above-mentioned effects and functions, it is preferable that the outer layer side of the recycled layer 8 be the colored virgin polyolefin layer 7 and the inner layer side be the virgin polyolefin layer 2.

[0031] The color pigment contained in the colored virgin polyolefin layer 7 may be any known color pigment, such as white pigments such as titanium oxide, zinc white, calcium carbonate, etc., black pigments such as carbon black, iron black, etc., red pigments such as red iron oxide, cadmium red, molybdenum orange, etc., blue pigments such as cobalt aluminate, Prussian blue, etc., and yellow pigments such as cadmium yellow, etc. When a printed layer containing a trade name, pattern, etc. is provided on either side of the base layer 1, it is preferable to use a white pigment, considering that the colored virgin polyolefin layer 7 serves as a printing base layer.

[0032] 4 is a schematic cross-sectional side view showing the layer structure of a fourth embodiment of the laminate of the present invention, illustrating a laminate 400 in which a base layer 1 having a printed layer (not shown) on its lower surface, a base layer 1 having a vapor-deposited layer 6 on its upper surface, and a heat-seal layer 4 are dry-laminated with two adhesive layers 5. Here, the heat-seal layer 4 has two layers, each consisting of a virgin polyolefin layer 2 and a recycled white virgin polyolefin layer 9 containing a recycled resin made from a packaging container formed from the laminate of the present invention and a white pigment, respectively, and further inside the two layers, a mixed recycled layer 10 containing the recycled resin contained in the recycled layer 3, a recycled resin made from a packaging container formed from the laminate of the present invention, and virgin polyolefin. Regarding the recycled white virgin polyolefin layer 9, if the recycled resin is highly colored, the appearance of the laminate 400 may be impaired. Therefore, to avoid this problem, if the recycled resin is highly colored, the recycled white virgin polyolefin layer 9 may contain only a white pigment without containing the recycled resin.

[0033] The laminates 100 to 400 of the first to fourth embodiments are not limited to the respective embodiments, and the layers can be appropriately combined as needed. For example, the vapor-deposited layer 6 of the laminate 200 can be combined with the laminate 300, the colored virgin polyolefin layer 7 of the laminate 300 can be combined in place of the virgin polyolefin layer 2 of the laminates 100 and 200, and the heat-seal layer 4 of the laminate 400 can be combined in place of the heat-seal layer 4 of the laminates 100 to 300.

[0034] In the laminate of the present invention having the above-described layer structure, each layer may contain, as a component other than the resin, known additives that are used in ordinary resins, such as deodorants, antioxidants, lubricants, modifiers, and antiblocking agents.

[0035] <Packaging Container> Figure 5 is a schematic diagram showing an example of a liquid refill pouch, which is an example of a packaging container according to the present invention. The liquid refill pouch has a body 11 and a bottom 12. The body 11 is composed of two laminates according to the present invention, and the bottom 12 is composed of one laminate according to the present invention or a laminate made of virgin material. Side seals 13 and a top seal 15 are formed by heat-sealing the two laminates that make up the body 11. A bottom seal 14 is formed by heat-sealing the two laminates that make up the body 11 and the single laminate that makes up the bottom 12. A nozzle 16 protruding upward is provided at one corner of the upper part of the body 11. A perforation line 17 is provided in the nozzle 16, and a tip 18 of the nozzle 16 is cut along the perforation line 17 to open the pouch, forming a spout for dispensing the contents. The contents can be poured into another container by inserting the spout into the injection port of the other container, such as a plastic bottle or a glass bottle, and tilting the refill pouch. Examples of contents of liquid refill pouches include detergent, bleach, fabric softener, laundry starch, shampoo, conditioner, cosmetics, deodorant, etc.

[0036] The method for producing a packaging container according to the present invention includes a step of heat-sealing the laminate according to the present invention. Since the laminate according to the present invention is used to produce a packaging container in this production method, a packaging container having excellent heat-sealability and high sealing strength at the sealed portion can be obtained. Furthermore, since melting of the surface during heat sealing can be suppressed, a packaging container with a good appearance can be obtained.

[0037] An example of a method for manufacturing a packaging container according to the present invention is shown below. First, two laminates according to the present invention are prepared and stacked so that the heat-sealable layers face each other. Next, a seal bar set to a predetermined temperature is applied to the surface of the base layer corresponding to the sealed portion. The temperature at which the laminate is heat-sealed is set to the melting point Tm of the base layer. １Although it depends on the temperature, from the viewpoint of sufficiently melting the heat-seal layer and obtaining high seal strength, the temperature is preferably 130°C or higher, more preferably 145°C or higher, and even more preferably 160°C or higher. The sealed portion can be formed leaving one side for filling the contents. This results in a packaging container. The contents are then filled from the remaining open side, and the side is heat-sealed to obtain a packaging container filled with the contents.

[0038] The present invention will be described in more detail below with reference to examples, although the present invention is not limited to these examples.

[0039] <Resins used> Base resin A: Polybutylene terephthalate, melting point 225°C Base resin B: Polyethylene terephthalate, melting point 260°C Heat sealant resin C: Linear low-density polyethylene (LLDPE), melting point 107°C

[0040] The melting point (Tm １ ) and the melting point (Tm ２ ) difference (Tm １ -Tm ２ ) is 118°C (225-107=118), and the melting point (Tm １ ) and the melting point (Tm ２ ) difference (Tm １ -Tm ２ ) is calculated to be 153°C (260-107=153).

[0041] <Extrusion Test> Under the extrusion conditions shown in Table 1, a twin-screw kneading extruder ULT nano manufactured by Technovel Corporation was used to extrude a mixture of pellets of the base resin A or B and pellets of the heat sealant resin C as the raw material resin. The change in resin pressure over time was measured using a sensor installed in the die, and the change in resin pressure over time in an extrusion test using only pellets of the heat sealant resin C was used as a control for evaluation. The wire mesh was 120 mesh / 40 mesh from the upstream side. C1 to C5 in Table 1 indicate the heater setting temperatures in each section of the screw from C1, which is the section near the hopper, to C5, which is the section near the die. The die temperature is the molding temperature.

[0042]

[0043] (Control Experiment) An extrusion test was carried out using pellets of heat sealant resin C alone under extrusion condition (1), and the change in resin pressure was recorded every 10 minutes for 40 minutes, and the results are shown in Table 2. There was no particular increase in resin pressure.

[0044] Example 1 An extrusion test was carried out under extrusion condition (1) using a mixed resin prepared by pre-mixing pellets of base resin A and heat sealant resin C at a weight ratio of 20 / 80. The change in resin pressure was recorded for 40 minutes and is shown in Table 2. As with the control experiment, there was no particular increase in resin pressure.

[0045] Comparative Example 1: An extrusion test was conducted under extrusion condition (1) using a mixed resin prepared by pre-mixing pellets of base resin B and heat sealant resin C at a weight ratio of 20 / 80. The change in resin pressure was recorded for 40 minutes and is shown in Table 2. Unlike the control experiment, after 30 minutes, as the resin pressure increased, surging occurred, causing the amount of resin extruded from the extruder to become unstable. This was thought to be due to the molding temperature of the mixed resin being too low for base resin B.

[0046] Comparative Example 2: An extrusion test was conducted under extrusion condition (2) using a mixed resin prepared by pre-mixing pellets of base resin B and heat sealant resin C at a weight ratio of 20 / 80. The change in resin pressure was recorded, but the test was interrupted before 10 minutes had elapsed due to a large amount of oily smoke being generated from the tip of the extruder. This was thought to be due to the molding temperature of the mixed resin being too high for heat sealant resin C.

[0047]

[0048] From the results of Example 1 and Comparative Example 1, the melting point (Tm １ ) and the melting point (Tm ２ ) difference "Tm １ -Tm ２When the "Tm" is 118°C, the mixed resin of the base resin and the heat sealant resin can be extruded under the same extrusion conditions as when the heat sealant resin is used alone. １ -Tm ２ When the "temperature" was 153°C, it was difficult to extrude the mixed resin of the base resin and the heat sealant resin under the same extrusion conditions as when the heat sealant resin was used alone.

[0049] 1: Base material layer 2: Virgin polyolefin layer 3: Recycled layer 4: Heat seal layer 5: Adhesive layer 6: Vapor deposition layer 7: Colored virgin polyolefin layer 8: Recycled layer 9: Recycled white virgin polyolefin layer 10: Mixed recycled layer 11: Body 12: Bottom 13: Side seal 14: Bottom seal 15: Top seal 16: Nozzle portion 17: Perforation line 18: Tip portion 100: Laminate of first type 200: Laminate of second type 300: Laminate of third type 400: Laminate of fourth type

Claims

1. At least the outer layer has a melting point Tm １ The base layer has a melting point Tm ２ A laminate comprising a heat seal layer having a temperature of 24° C.≦Tm １ -Tm ２ ≦152° C.

2. The laminate according to claim 1, wherein said heat seal layer comprises at least three layers, with a recycled layer between two layers of virgin polyolefin.

3. The recycled layer has a melting point Tm ３ and Tm ３ 3. The laminate of claim 2, wherein the temperature is ≦250° C.

4. The laminate according to claim 1 or 2, wherein the substrate layer is made of a stretched polybutylene terephthalate film.

5. The laminate according to claim 2, wherein the virgin polyolefin of said heat seal layer is polyethylene and all three layers in said heat seal layer are unoriented films.

6. The laminate according to claim 1 or 2, which has a vapor-deposited layer using an inorganic substance or an inorganic oxide between the substrate layer and the heat seal layer.

7. The laminate according to claim 2, wherein at least one of the two layers made of virgin polyolefin is a colored layer.

8. The laminate according to claim 1 or 2, wherein the base layer and the heat seal layer are laminated together using an adhesive.

9. The laminate of claim 1 or 2, wherein the laminate is free of polyethylene terephthalate and polyamide.

10. A packaging container using the laminate according to claim 1 or 2.

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