Stacked body and packaging container

Abstract

The present invention provides a laminate which can manufacture the same heat seal layer film as the film for heat seal layer in the laminate of the present invention using the resin recovered from the packaging container or the like formed of the laminate of the present invention, and is suitable for recycling. A laminate characterized by comprising at least a base material layer having a melting point Tm1 in an outer layer and a heat seal layer having a melting point Tm2 in an inner layer, 24°C ≤ Tm1 - Tm2 ≤ 152°C.

Description

Technical Field

[0001] This invention relates to laminates and packaging containers. Background Technology

[0002] Previously, polyethylene terephthalate (PET) bottles and plastic containers were the target of container packaging recycling laws. Typical PET bottles, containing only PET resin, are easy to recycle, and same-level recycling has been established. On the other hand, plastic containers usually contain multiple resins, and the difficulty in separating these resins creates various problems during recycling.

[0003] As an example of the aforementioned plastic container packaging, there are known packaging bags using a laminated structure. This laminate is manufactured by separately molding two films—a PET film in the base film and a polyethylene film in the heat-sealing layer—and then dry-laminating them using a urethane adhesive or similar method (see, for example, Patent Document 1). Here, the polyethylene film used in the heat-sealing layer uses low-density polyethylene or linear low-density polyethylene as the main resin, and its melting point varies depending on the product grade, but is typically around 110°C. Furthermore, the melting point of the PET used in the base film varies depending on the product grade, but is typically around 260°C.

[0004] Therefore, when reusing the recycled resin obtained from crushing the packaging bag to manufacture a heat-sealing film similar to the heat-sealing film in the laminate, since the recycled resin contains PET, the molding temperature of the film needs to be set to approximately 280°C, which is slightly higher than the melting point of PET. However, when molding the film at approximately 280°C, problems arise for the low-melting-point decomposition products such as paraffin oil and low-molecular-weight compounds contained in the polyethylene film. These problems include carbonization of the low-melting-point decomposition products, excessive oil fumes during molding, contamination of the extrusion molding rollers, and increased molding pressure during extrusion. Therefore, if the molding temperature is set below 280°C, the PET cannot melt sufficiently, resulting in problems such as fisheyes, pinholes, and reduced film quality.

[0005] Furthermore, laminates for packaging containers with excellent pinhole resistance using polyamide as the substrate layer are known in the past (see, for example, Patent Document 2). However, polyamide may become a prohibited substance during chemical recycling, therefore, considering full recycling, it is believed that the use of polyamide in the laminate should be controlled as much as possible.

[0006] Existing technical documents

[0007] Patent documents

[0008] Patent Document 1: Japanese Patent Application Publication No. 2022-154135

[0009] Patent Document 2: Japanese Patent Application Publication No. 2022-163548 Summary of the Invention

[0010] The problem that the invention aims to solve

[0011] In view of the above, the object of the present invention is to provide a laminate that can be manufactured using resin recovered from packaging containers or the like formed from the laminate of the present invention to produce a heat-sealing film identical to the heat-sealing film in the laminate of the present invention, and is suitable for recycling.

[0012] Another object of the present invention is to provide a packaging container formed using the above-described recyclable laminate.

[0013] Here, recycling refers to using recycled resin, which is made from "packaging containers made from recycled resin", to remanufacture the "packaging containers made from recycled resin".

[0014] Solution for solving the problem

[0015] According to the present invention, a laminate is provided, characterized in that it comprises at least an outer substrate layer having a melting point Tm1 and an inner heat-sealing layer having a melting point Tm2, ​​wherein 24°C ≤ Tm1 - Tm2 ≤ 152°C.

[0016] In the sealing film of the present invention, the following scheme is preferred.

[0017] (1) The heat-sealing layer consists of at least three layers, with a recycled layer between two layers made of virgin polyolefin.

[0018] (2) The recycled layer has a melting point Tm3, Tm3≤250℃.

[0019] (3) The substrate layer is formed from a stretched film of polybutylene terephthalate.

[0020] (4) The virgin polyolefin of the heat-sealing layer is polyethylene, and all three layers of the heat-sealing layer are unstretched films.

[0021] (5) There is an evaporation layer using inorganic materials or inorganic oxides between the substrate layer and the heat seal layer.

[0022] (6) At least one of the two layers composed of virgin polyolefin is a colored layer.

[0023] (7) The substrate layer and the heat-sealing layer are laminated using an adhesive.

[0024] (8) The laminate does not contain polyethylene terephthalate and polyamide.

[0025] (9) A packaging container that uses the laminate.

[0026] Invention Effects

[0027] The laminate of the present invention comprises a substrate layer having a melting point Tm1 in the outermost layer and a heat-sealing layer having a melting point Tm2 in the innermost layer, wherein 24°C ≤ Tm1 - Tm2 ≤ 152°C. This laminate is suitable for recycling and can be manufactured using resin recovered from packaging containers or the like formed from the laminate to produce a heat-sealing film identical to the heat-sealing film in the laminate. Here, by setting the difference between the melting point Tm1 and the melting point Tm2 within the aforementioned range, the molding temperature during recycling can be set low, thus preventing problems such as carbonization of low-melting-point decomposition products contained in the polyethylene film, generation of fumes, contamination of the extrusion molding rollers, and increased molding pressure during extrusion.

[0028] Furthermore, in the laminate of the present invention having the layer structure described above, by utilizing this layer structure to form a vapor-deposited layer using inorganic materials or inorganic oxides between the substrate layer and the heat-sealing layer, the gas barrier properties of the laminate can be improved. In addition, by making at least one of the two layers composed of the virgin polyolefin a coloring layer, the appearance properties can be improved. Attached Figure Description

[0029] Figure 1 This is a schematic side sectional view illustrating a first embodiment of the laminate structure of the present invention.

[0030] Figure 2 This is a schematic side sectional view illustrating a second embodiment of the laminate structure of the present invention.

[0031] Figure 3 This is a schematic side sectional view illustrating a third-order layer structure of the laminate of the present invention.

[0032] Figure 4 This is a schematic side sectional view illustrating a fourth embodiment of the layered structure of the laminate of the present invention.

[0033] Figure 5 This is a schematic diagram showing an example of a liquid replacement bag, which is an example of a packaging container of the present invention. Detailed Implementation

[0034] Hereinafter, embodiments for carrying out the present invention will be described with reference to the accompanying drawings. It should be noted that the present invention is not limited to these embodiments. It should be noted that the laminate of the present invention is used for heat-sealed packaging containers; therefore, in the packaging container, the heat-sealing layer side becomes the inner layer, and the substrate layer side becomes the outer layer.

[0035] <Layered Body>

[0036] Figure 1 This is a schematic side sectional view illustrating the layer structure of a first embodiment of the laminate of the present invention, showing a laminate 100, wherein the heat-sealing layer 4 is composed of three layers, with a recycled layer 3 between two layers composed of virgin polyolefin layers 2, and the heat-sealing layer 4 and the substrate layer 1 are dry-laminated by an adhesive layer 5. Here, from the viewpoint of improving the thermal conductivity of the heat-sealing layer 4 during heat sealing, the thickness of the substrate layer 1 is preferably 40 μm or less, more preferably 30 μm or less. The lower limit of the thickness is not particularly limited, but it is preferably 1 μm or more. Furthermore, from the viewpoint of ensuring sufficient adhesion during heat sealing, the thickness of the heat-sealing layer 4 is preferably 50 μm or more, more preferably 60 μm or more. The upper limit of the range of the thickness of the heat-sealing layer 4 is not particularly limited, for example, it is preferably 500 μm or less, more preferably 400 μm or less. The thickness of the recycled layer 3 is not particularly limited, 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 0.1 to 30 μm.

[0037] The virgin polyolefin layer 2 is made of virgin polyolefin. There are no particular limitations on the virgin polyolefin, as long as it is a heat-sealing virgin polyolefin. Preferred materials include polyethylene selected from low-density polyethylene (LDPE) or linear low-density polyethylene (LLDPE), or unstretched polypropylene (CPP), with polyethylene being more preferred. Alternatively, different polyolefins such as LDPE and LLDPE can be used in combination. Furthermore, the polyolefin can be derived from petroleum feedstocks, plant-based feedstocks, or mixtures thereof. Moreover, from the perspective of excellent heat-sealing properties, it is preferable that all three layers of the heat-sealing layer 4 are unstretched films.

[0038] The recycled layer 3 comprises so-called recycled resin, which is obtained through various processes such as crushing, washing with alkali, filtration in a molten state, and extraction with organic solvents, using recycled materials from the manufacture of used plastic packaging containers or waste materials from the manufacture of plastic packaging containers as raw materials. Here, in order to reduce the molding temperature during film formation, the recycled resin preferably does not contain PET, and furthermore, it preferably contains almost no polyamide, which may be a prohibited substance during chemical recycling. Furthermore, since the resin used is specific, it is preferable to use recycled resin made from waste materials from the manufacture of the laminate of the present invention, and even more preferably, recycled resin made from waste materials from the manufacture of the virgin polyolefin layer 2.

[0039] Here, "almost no polyamide" means no polyamide, or if it is present, it contains less than 5% by mass relative to the total amount of recycled resin.

[0040] The heat-sealing layer 4 contains recycled resin in the recycled layer 3. However, if the proportion of recycled resin used increases, the amount of virgin polyolefin contained in the heat-sealing layer 4 becomes relatively less, thus significantly reducing heat-sealing properties and other physical properties. Therefore, from the viewpoint of avoiding such a reduction in physical properties, the content of recycled resin in the heat-sealing layer 4 is preferably 15-90% by mass, and more preferably 15-60% by mass.

[0041] Furthermore, from the viewpoint of more reliably avoiding a reduction in the heat-sealing performance of the heat-sealing layer 4, for example, when the thickness of the recycled layer 3 is set to 100 μm, it is preferable to set the thickness of the virgin polyolefin layers 2 on both the upper and lower sides to be about 10 to 60 μm (relative to the thickness of the heat-sealing layer 4 of 10 to 60%).

[0042] Furthermore, the recycled layer 3 can be formed solely from recycled resin, but preferably includes virgin polyolefin. Under the premise of satisfying the numerical range of recycled resin content in the heat-sealing layer 4 and the thickness ratio of the recycled layer 3 to the upper and lower virgin polyolefin layers 2, the mass ratio of recycled resin to virgin polyolefin is preferably in the range of 99:1 to 25:75. Here, 50:50 represents a 2-fold dilution, and 25:75 represents a 4-fold dilution. The recycled layer 3 is formed by co-extrusion molding using particles containing recycled resin and virgin polyolefin particles. Furthermore, since polyolefin deteriorates at molding resin temperatures above 250°C, the melting point Tm3 of the recycled layer 3 is preferably ≤250°C, more preferably ≤240°C, and particularly preferably ≤230°C. Additionally, the virgin polyolefin used in the recycled layer 3 is preferably the same as that used in the virgin polyolefin layer 2, but it can also be different.

[0043] Furthermore, since the recycled layer 3 contains components such as polyester resins, adhesives, and colorants, ester decomposition inhibitors such as carbodiimide compounds can be added to suppress the decrease in strength caused by the reduction in molecular weight, etc., resulting from these components. Furthermore, to further improve dispersibility, compatibilizing materials can also be included. Examples of polar groups that can be used as compatibilizing materials include: organic isocyanate groups, carboxylic anhydride groups, carboxylic acid groups, amino groups, hydroxyl groups, epoxy groups, and acrylate groups. Preferably, acid-modified olefin resins or imine-modified olefin resins, acrylate-glycidyl methacrylate copolymer olefin resins, and ethylene vinyl acetate copolymer saponifications are preferred.

[0044] In addition, within the range that does not impair physical properties, it can be combined with lubricants, ultraviolet absorbers, plasticizers, crystal nucleating agents, fillers, hydrolysis inhibitors, flame retardants, antistatic agents, antifogging agents, and antiblocking agents.

[0045] The substrate layer 1 has a melting point Tm1, and a resin with a melting point Tm1 that is lower than that of PET (approximately 260°C) can be used. Examples include polybutylene terephthalate (melting point 230°C), high-density polyethylene (melting point 130-150°C), stretched polypropylene (OPP, melting point 165°C), polystyrene (melting point 240°C), polyvinylidene chloride (melting point 210°C), polychlorotrifluoroethylene (melting point 220°C), cellulose acetate (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 160-183°C), and polyvinyl alcohol (melting point 200°C). Among them, polybutylene terephthalate, polystyrene, polyvinylidene chloride, polychlorotrifluoroethylene, and acetyl cellulose with melting points in the range of 210–240°C are preferred, with polybutylene terephthalate being even more preferred. These can be used alone or in combination.

[0046] This invention relates to a laminate comprising a substrate layer having a melting point Tm1 in at least the outer layer and a heat-sealing layer having a melting point Tm2 in the inner layer, characterized in that 24°C ≤ Tm1 - Tm2 ≤ 152°C. For example, when uniaxially stretched high-density polyethylene (melting point Tm1: 134°C) is used in the substrate layer and unstretched low-density polyethylene (melting point Tm2: 110°C) is used in the heat-sealing layer, Tm1 - Tm2 is 24 (134 - 110 = 24)°C. When the substrate layer is replaced with polybutylene terephthalate (melting point Tm1: 225°C), Tm1 - Tm2 is 115 (225 - 110 = 115)°C. Here, the melting point is determined using differential scanning calorimetry (DSC).

[0047] Furthermore, Tm1-Tm2 is preferably 51℃≤Tm1-Tm2≤125℃. For example, when stretched polypropylene (melting point Tm1: 165℃) is used in the substrate layer and unstretched low-density polyethylene (melting point Tm2: 110℃) is used in the heat-sealing layer, Tm1-Tm2 is 55 (165-110=55)℃.

[0048] To manufacture two types of three-layer structures, or as described later, consisting of two virgin polyolefin layers 2 and a recycled layer 3. Figure 4The heat-sealing layer 4 is manufactured by casting film production, which uses three or five extruders. The components are dry-mixed and then melt-blended in the extruders. The blend is co-extruded into a film through a T-die. The extruded three-layer or three-layer five-layer film-like melt is then solidified by contact with cooling rollers and wound up. The components can be in the form of film-like pulverized material, granules, pellets, or liquid. Here, the film-like pulverized material can be scraps of film generated during the implementation of this invention. In blow molding, which is commonly used for heat-sealing film production and extrusion of bag-shaped films, the presence of incompatible foreign matter in the polyolefin can easily lead to openings and uneven thickness. If a fine-mesh filter is used to remove foreign matter, the production speed is significantly reduced. In contrast, in cast film production, it is easy to obtain high-quality films with no openings and minimal thickness unevenness, without the need for fine-mesh filters, thus suppressing the reduction in production speed. Here, the heat-sealing layer 4 is not limited to the two types of three-layer or three types of five-layer structures; the required number and variety of layers can be used, but since it includes the recycling layer 3, it is preferably composed of at least three layers.

[0049] The substrate layer 1 is formed separately from the heat-sealing layer 4 using known means and methods such as an extruder. Since it is used as an outer layer, it is required to improve the film strength, thermal properties, etc. Therefore, the substrate layer 1 is preferably a stretched film. Either uniaxial stretching or biaxial stretching can be used for stretching. Considering further improvement in film strength, biaxial stretching is more preferred.

[0050] The substrate layer 1 and the heat-sealing layer 4 are laminated together using an adhesive layer 5 formed by an adhesive. Examples of such adhesives include known 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. From the perspective of flexibility and high impact resistance, it is preferable to include a urethane-based adhesive.

[0051] Figure 2 This is a schematic side sectional view illustrating a second embodiment of the laminated body of the present invention, showing a laminated body 200, which is, in addition to Figure 1 In addition to the layer structure of the first embodiment described herein, a laminate having an inorganic or inorganic oxide vapor-deposited layer 6 on the surface of the heat-sealing layer 4 side of the substrate layer 1 is provided.

[0052] As the inorganic material, silicon (Si), aluminum (Al), magnesium (Mg), calcium (Ca), potassium (K), tin (Sn), sodium (Na), boron (B), titanium (Ti), lead (Pb), zirconium (Zr), yttrium (Y) and other inorganic materials can be used. Aluminum (Al) is preferred as the inorganic material suitable for packaging containers.

[0053] As the inorganic oxide, SiO can be used. X AlO X Wait until that by MO X (Where, M represents an inorganic element, and the value of X varies depending on the inorganic element.) The inorganic oxide is represented by the following values: silicon (Si) 0–2, aluminum (Al) 0–1.5, magnesium (Mg) 0–1, calcium (Ca) 0–1, potassium (K) 0–0.5, tin (Sn) 0–2, sodium (Na) 0–0.5, boron (B) 0–1.5, titanium (Ti) 0–2, lead (Pb) 0–1, zirconium (Zr) 0–2, and yttrium (Y) 0–1.5. In the above examples, when X=0, it is a completely inorganic substance and not an inorganic oxide, therefore it is excluded. Silicon oxide or aluminum oxide is preferred as a suitable material for packaging containers; from the perspective of transparency, SiO2 or AlO2 is particularly preferred.

[0054] The vapor-deposited layer 6 is formed using known techniques such as plasma CVD, which improves the gas barrier properties of the laminate. Furthermore, when the laminate 200 is used in a packaging container, it serves to cover coloring caused by recycled resin. This vapor-deposited layer 6 is a thin layer with a thickness of approximately 0.001 to 1 μm. To further improve the gas barrier properties, a cross-linked reactive coating of carboxylic acid and metal, or a coating film dispersing metal oxides, can be included on the thin layer.

[0055] Figure 3 This is a schematic side sectional view illustrating a third-order layer structure of the laminate of the present invention, showing a laminate 300, which is... Figure 1The layer structure of the first embodiment described herein is similar, but the heat-sealing layer 4 consists of three layers: a heat-sealing layer 4 and a recycled layer 8, which contains recycled resin used as a raw material for packaging containers formed from the laminate of the present invention, and the heat-sealing layer 4 and the substrate layer 1 are dry-laminated together by an adhesive layer 5. Here, the heat-sealing layer 7 contains a coloring pigment, and the recycled layer 8 contains recycled resin used as a raw material for packaging containers formed from the laminate of the present invention. Apart from this, the same thickness, material composition, etc., as the heat-sealing layer 2 and the recycled layer 3 can be used. The heat-sealing layer 7 has the function of covering the coloring caused by the recycled resin when the laminate 300 is used as a packaging container. In addition, the laminate 300 has colored virgin polyolefin layers 7 on both sides of the recycled layer 8, but it is also possible to use a virgin polyolefin layer 2 without colored pigments on one side. In this case, in order to perform the above-mentioned functions, it is preferable to set the outer side of the recycled layer 8 as the colored virgin polyolefin layer 7 and the inner side as the virgin polyolefin layer 2.

[0056] The coloring pigments contained in the coloring virgin polyolefin layer 7 can be: white pigments such as titanium dioxide, zinc white, and calcium carbonate; black pigments such as carbon black and iron black; red pigments such as iron oxide red, cadmium red, and molybdenum orange; blue pigments such as cobalt blue and Prussian blue; and yellow pigments such as cadmium yellow, etc., which are known coloring pigments. When a printing layer for a trade name, pattern, etc., is provided on either side of the substrate layer 1, white pigments are preferred if the coloring virgin polyolefin layer 7 is to be used as the printing underlayer.

[0057] Figure 4 This is a schematic side sectional view showing a fourth embodiment of the laminate structure of the present invention, illustrating a laminate 400 formed by dry lamination of a substrate layer 1 having a printed layer (not shown) on its lower surface, a substrate layer 1 having a vapor-deposited layer 6 on its upper surface, and a heat-sealing layer 4 via two adhesive layers 5. Here, the heat-sealing layer 4 consists of five layers: it has two layers consisting of recycled white virgin polyolefin layers 9 containing recycled resin used as raw material for packaging containers formed from the laminate of the present invention and white pigment, which are respectively in contact with the inner sides of two layers consisting of virgin polyolefin layers 2; further inside the two recycled white virgin polyolefin layers 9 is a mixed recycling layer 10, which contains the recycled resin contained in the recycled layer 3, the recycled resin used as raw material for packaging containers formed from the laminate of the present invention, and virgin polyolefin. It should be noted that, for the aforementioned recycled white virgin polyolefin layer 9, if the degree of coloring of the recycled resin is high, there is a possibility that the appearance of the laminate 400 may be damaged. Therefore, in order to avoid the occurrence of the aforementioned problem, if the degree of coloring of the recycled resin is high, it may contain only white pigment and not the aforementioned recycled resin.

[0058] The laminates 100 to 400 of the first to fourth embodiments are not limited to each embodiment, and the layers can be appropriately combined as needed. For example, the vapor-deposited layer 6 in the laminate 200 can be combined with the laminate 300, the colored virgin polyolefin layer 7 in the laminate 300 can replace the virgin polyolefin layer 2 in the laminates 100 and 200, and the heat-sealing layer 4 in the laminate 400 can replace the heat-sealing layer 4 in the laminates 100 to 300, etc.

[0059] In the laminate of the present invention having the above-described layer structure, each layer may contain other components besides the resin, such as deodorants, antioxidants, lubricants, modifiers, antiblocking agents, and other commonly known additives used in resins.

[0060] Packaging Containers

[0061] Figure 5 This is a schematic diagram illustrating an example of a liquid replacement bag as an example of a packaging container according to the present invention. The liquid replacement bag has a main body 11 and a bottom 12. The main body 11 is composed of two laminated sheets of the present invention, and the bottom 12 is composed of one laminated sheet of the present invention or a laminated sheet formed from raw materials. A side seal 13 and a top seal 15 are formed by heat-sealing the two laminated sheets constituting the main body 11. Furthermore, a bottom seal 14 is formed by heat-sealing the two laminated sheets constituting the main body 11 and the one laminated sheet constituting the bottom 12. An upwardly protruding nozzle 16 is provided at one corner of the upper part of the main body 11. An easy-tear line 17 is provided at the nozzle 16, and the bag is opened by cutting the front end portion 18 of the nozzle 16 using the easy-tear line 17, thereby forming an outlet for dispensing contents. By inserting the outlet into the inlet of other containers such as plastic bottles or glass bottles and tilting the replacement bag, the contents can be dispensed into other containers. Examples of contents that can be included in a replacement bag for liquids include detergents, bleach, fabric softeners, starching agents, shampoos, conditioners, cosmetics, and deodorants.

[0062] The method for manufacturing a packaging container according to the present invention includes a step of heat-sealing the laminate of the present invention. In this manufacturing method, since the packaging container is manufactured using the laminate of the present invention, a packaging container with excellent heat-sealing properties and high sealing strength at the sealing portion can be obtained. Furthermore, since surface melting can be suppressed during heat sealing, a packaging container with a good appearance can be obtained.

[0063] The following illustrates an example of a method for manufacturing the packaging container of the present invention. First, two laminates of the present invention are prepared and overlapped with heat-sealing layers facing each other. Next, a sealing knife set to a predetermined temperature is pressed onto the surface of the substrate layer corresponding to the sealing portion. The temperature at which the laminate is heat-sealed also depends on the melting point Tm1 of the substrate layer, but from the viewpoint of fully melting the heat-sealing layer and obtaining high sealing strength, it is preferably 130°C or higher, more preferably 145°C or higher, and even more preferably 160°C or higher. The sealing portion can be formed such that one side is left open for filling the contents. Thus, a packaging container is obtained. Then, the contents are filled from the remaining side of the opening, and said side is heat-sealed, thereby obtaining a packaging container filled with contents.

[0064] Example

[0065] The present invention will now be described in detail through embodiments. It should be noted that the present invention is not limited to the embodiments.

[0066] <Using Resin>

[0067] Substrate resin A: Polybutylene terephthalate, melting point 225℃.

[0068] Substrate resin B: Polyethylene terephthalate, melting point 260℃.

[0069] Heat-sealing resin C: linear low-density polyethylene (LLDPE) with a melting point of 107℃.

[0070] The difference between the melting point (Tm1) of the substrate resin A and the melting point (Tm2) of the heat-sealing resin C was calculated to be 118℃ (225-107=118), and the difference between the melting point (Tm1) of the substrate resin B and the melting point (Tm2) of the heat-sealing resin C was calculated to be 153℃ (260-107=153).

[0071] <Extrusion Test>

[0072] Under the extrusion conditions shown in Table 1, a twin-screw compounding extruder ULTnano manufactured by TECHNOVEL Co., Ltd. was used. A mixture of particles of the aforementioned base resin A or B and heat-sealing resin C was used as the raw material resin for extrusion molding. The change in resin pressure over time was measured using a sensor installed in the die. The change in resin pressure over time in extrusion tests using only heat-sealing resin C particles was used as a control for evaluation. The wire mesh was 120 mesh / 40 mesh from the upstream side. Regarding C1 to C5 in Table 1, the set temperatures of the heaters in each part of the screw from near the hopper (C1) to near the die (C5) are shown. Furthermore, the die temperature is the molding temperature.

[0073] [Table 1]

[0074]

[0075] (Control experiment)

[0076] Particles of heat-sealing resin C were used alone, and extrusion tests were conducted under extrusion conditions (1). The change in resin pressure was recorded every 10 minutes for 40 minutes, as shown in Table 2. Notably, the resin pressure did not increase.

[0077] (Example 1)

[0078] An extrusion test was conducted using a mixed resin, in which the particles of base resin A and heat-sealing resin C were premixed at a weight ratio of 20 / 80, under extrusion conditions (1). Resin pressure changes were recorded over 40 minutes and are shown in Table 2. Similar to the control experiment, no significant increase in resin pressure was observed.

[0079] (Comparative Example 1)

[0080] An extrusion test was conducted using a mixed resin prepared by pre-mixing the particles of base resin B and heat-sealing resin C at a weight ratio of 20 / 80 under extrusion conditions (1). Resin pressure changes were recorded over 40 minutes and are shown in Table 2. Unlike the control experiment, after 30 minutes, the resin pressure increased, and an unstable flow of resin was generated from the extruder. This was attributed to the excessively low molding temperature of the mixed resin for base resin B.

[0081] (Comparative Example 2)

[0082] An extrusion test was conducted using a mixed resin prepared by pre-mixing the particles of base resin B and heat-sealing resin C at a weight ratio of 20 / 80 under extrusion conditions (2). Changes in resin pressure were recorded, but the test was interrupted after 10 minutes when a large amount of fumes were generated from the front end of the extruder. This was attributed to the excessively high molding temperature of the mixed resin for heat-sealing resin C.

[0083] [Table 2]

[0084]

[0085] Based on the results of Example 1 and Comparative Example 1, when the difference between the melting point (Tm1) of the base resin A and the melting point (Tm2) of the heat-sealing resin C, "Tm1-Tm2", is 118°C, the mixed resin of the base resin and the heat-sealing resin can be extruded under the same extrusion conditions as when the heat-sealing resin is used alone. However, when "Tm1-Tm2" is 153°C, it is difficult to extrude the mixed resin of the base resin and the heat-sealing resin under the same extrusion conditions as when the heat-sealing resin is used alone.

[0086] Explanation of reference numerals in the attached figures

[0087] 1: Substrate layer;

[0088] 2: Native polyolefin layer;

[0089] 3: Recycling layer;

[0090] 4: Heat-sealing layer;

[0091] 5: Adhesive layer;

[0092] 6: Evaporated coating;

[0093] 7: Colored virgin polyolefin layer;

[0094] 8: Recycling layer;

[0095] 9: Recycle the white virgin polyolefin layer;

[0096] 10: Mixed recycling layer;

[0097] 11: Main body;

[0098] 12: Bottom;

[0099] 13: Side seal;

[0100] 14: Bottom seal;

[0101] 15: Top sealing;

[0102] 16: Injection nozzle;

[0103] 17: Easy-tear line;

[0104] 18: Front-end section;

[0105] 100: Layered structure of the first type;

[0106] 200: Layered body of the second type;

[0107] 300: Third-party stacked bodies;

[0108] 400: Fourth-mode stack.

Claims

1. A laminated body, characterized in that, It includes a substrate layer having a melting point Tm1 in the outer layer and a heat-sealing layer having a melting point Tm2 in the inner layer, where 24℃≤Tm1-Tm2≤152℃.

2. The laminated body according to claim 1, wherein, The heat-sealing layer consists of at least three layers, with a recycled layer between two layers made of virgin polyolefin.

3. The laminated body according to claim 2, wherein, The recycled layer has a melting point Tm3, where Tm3 ≤ 250℃.

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

5. The laminated body according to claim 2, wherein, The virgin polyolefin of the heat-sealing layer is polyethylene, and all three layers of the heat-sealing layer are unstretched films.

6. The laminate according to claim 1 or 2, wherein, An evaporated layer using inorganic materials or inorganic oxides is present between the substrate layer and the heat-sealing layer.

7. The laminated body according to claim 2, wherein, At least one of the two layers composed of virgin polyolefin is a colored layer.

8. The laminate according to claim 1 or 2, wherein, The substrate layer and the heat-sealing layer are laminated using an adhesive.

9. The laminate according to claim 1 or 2, wherein, The laminate does not contain polyethylene terephthalate or polyamide.

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

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