Laminates and packaging

Abstract

To provide a laminate and a package thereof, having excellent hand tearability even though as being a mono-material.SOLUTION: A laminate 10 includes a sealant layer 11 formed from a polyolefin-based resin and a substrate layer 12 formed from a polyolefin-based resin and is provided with a cut 14 which does not perforate the laminate 10 in its thickness direction and is formed by removing at least a part of the substrate layer 12 in the thickness direction by laser beam irradiation.SELECTED DRAWING: Figure 1

Description

Technical Field

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

Background Art

[0002] In paragraph 0010 of Patent Document 1, as a film conventionally used for packaging bags, a laminated film is described in which a base film such as biaxially stretched polypropylene, biaxially stretched polyamide, or biaxially stretched polyester is laminated with a polyolefin resin such as low-density polyethylene, linear low-density polyethylene, ethylene-vinyl acetate copolymer, or polypropylene as a sealant layer. Further, in paragraph 0014 of Patent Document 1, it is described that a half-cut line is formed by a laser.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In recent years, regarding the collection after use of plastic container packaging, a packaging bag containing two or more types of resins has a problem that it is difficult to recycle as plastic container packaging. In order to facilitate recycling, a monomaterial container packaging using a single resin has been proposed. As a single resin, a polyethylene-based resin is inexpensive and easy to process, but since its absorbability of energy rays is low, it is difficult to form a half-cut line even when irradiated with a laser.

[0005] The present invention has been made in view of the above circumstances, and an object thereof is to provide a laminate and a package that are monomaterial and excellent in tearability.

Means for Solving the Problems

[0006] To solve the aforementioned problems, the present invention provides a laminate having a sealant layer formed from a polyolefin resin and a base material layer formed from a polyolefin resin, characterized in that a cut is formed by removing at least a portion of the base material layer in the thickness direction by laser irradiation without penetrating the laminate in the thickness direction.

[0007] The polyolefin resin may also be a polyethylene resin. The cut may be formed from the side of the substrate layer to a portion in the thickness direction of the layer adjacent to the sealant layer. The laminate may have an stretched polyethylene resin layer, and the cut may be formed from the side of the base layer to the stretched polyethylene resin layer. At least a portion of the sealant layer may contain the laser absorber. At least a portion of the substrate layer may contain the laser absorber. A coating or printed layer containing the laser absorber may be formed on the outermost surface of the laminate, opposite to the innermost layer of the laminate, at least at the location where the break is formed. The layer adjacent to the sealant layer may be an oriented polyethylene resin layer. In the aforementioned substrate layer, the polyethylene resin layer may be laminated with the ethylene-vinyl alcohol copolymer layer by co-extrusion.

[0008] A metal vapor deposition layer may be formed on the surface of the substrate layer facing the sealant layer. The base layer comprises a first base layer located on the side closer to the sealant layer in the thickness direction of the laminate, and a second base layer located on the side further away from the sealant layer. The first base layer may be a stretched polyethylene resin layer, and a metal vapor deposition layer may be formed on the surface of the first base layer facing the second base layer. The stretched polyethylene resin layer of the first base material layer may be a biaxially oriented polyethylene resin layer. The thickness of the first substrate layer may be 40 μm or less. The sealant layer and the substrate layer may be laminated with an adhesive layer that absorbs the laser in between.

[0009] Furthermore, the present invention provides a packaging body formed from the laminate. The aforementioned packaging may be a refill pouch. [Effects of the Invention]

[0010] According to the present invention, it is possible to provide laminates and packaging materials that are monomaterial yet exhibit excellent tearability by hand. [Brief explanation of the drawing]

[0011] [Figure 1] This is a cross-sectional view illustrating a laminate according to the first embodiment. [Figure 2] This is a cross-sectional view illustrating a laminate according to the second embodiment. [Figure 3] This is a cross-sectional view illustrating a laminate according to the third embodiment. [Figure 4] This is a cross-sectional view illustrating a laminate according to the fourth embodiment. [Figure 5] This is a cross-sectional view illustrating a laminate according to the fifth embodiment. [Modes for carrying out the invention]

[0012] The present invention will be described below based on preferred embodiments. The laminate of the embodiment has a sealant layer formed from a polyolefin resin and a base layer formed from a polyolefin resin. A cut is formed in the laminate by removing at least a portion of the base layer in the thickness direction by laser irradiation, without penetrating the laminate in the thickness direction.

[0013] The laser is not particularly limited as long as it is a laser used for resin processing such as films, and examples include solid lasers, gas lasers, fiber lasers, semiconductor lasers, excimer lasers, etc. The wavelength of the laser may be in any of the infrared region, visible light region, or ultraviolet region. For example, a CO2 laser is preferably used because its output wavelength is in the infrared region with a relatively long wavelength of about 9 to 11 μm, and it has excellent resin processing properties.

[0014] When a film is irradiated with a laser having a long wavelength, the film locally generates heat at the irradiated location, and a part of the resin is removed. By removing the resin in a narrow width, a linear cut is formed. The cut may be linear and continuous in the length direction, or may be a broken line or dotted line that is intermittent in the length direction. The length direction of the cut may be linear, or may be curved or bent.

[0015] Polyolefin resins such as polyethylene-based resins have a relatively simple molecular structure, so their infrared absorption wavelength bands are limited, and it is difficult to absorb the energy of the laser. However, since polyolefin resins have a relatively low melting point, when energy is absorbed by the material, processing such as melting and cutting can be performed relatively easily. Therefore, by disposing a material that absorbs the laser in or near the polyethylene-based resin layer, the polyethylene-based resin layer can be easily processed.

[0016] In conventional laminated films, since a PET film or the like is used as the base material layer, when the PET film absorbs the laser, cuts such as half-cut lines can be easily formed in the laminated film. However, in the case of a monomaterial film mainly composed of a polyolefin resin layer, it is necessary to dispose a material that absorbs the laser according to the position and depth of the cut.

[0017] Next, referring to FIG. 1, the laminate 10 of the first embodiment will be described. This laminate 10 has a sealant layer 11 formed from a polyolefin resin and a base material layer 12 formed from a polyolefin resin laminated via an adhesive layer 13. In the base material layer 12, a cut 14 is formed by removing at least a part in the thickness direction by laser irradiation. The cut 14 may open to the outer surface of the base material layer 12.

[0018] At least a part of the base material layer 12 can form the cut 14 in the base material layer 12 by containing a laser absorber. The resin layer containing the laser absorber in the base material layer 12 can be formed from a polyolefin resin such as a polyethylene resin or a polypropylene resin. When the base material layer 12 has two or more polyolefin resin layers, at least one of them may be a polyolefin resin layer containing a laser absorber. By providing the cut 14, easy cutability and hand tearability by tearing can be imparted without using a blade.

[0019] The laser absorber is not particularly limited, and examples include carbon-based materials such as carbon black, inorganic materials such as titanium oxide and iron oxide, coloring materials such as pigments and dyes, and resin materials such as acrylic resins and polyester resins. When blending a laser absorber into the polyolefin resin layer, the laser absorber may be made into a powder and melt-kneaded.

[0020] The depth of the cut 14 can be adjusted as appropriate. The cut 14 may be formed only in a part in the thickness direction of the base material layer 12, or the cut 14 may reach the adhesive layer 13. The sealant layer 11 may be formed from a polyethylene resin layer that does not contain a laser absorber so that the cut 14 does not penetrate the sealant layer 11. In this case, when the cut 14 reaches the sealant layer 11 by laser irradiation, since the laser penetrates the sealant layer 11, processing of the sealant layer 11 can be suppressed.

[0021] To suppress the transmission of the laser through the sealant layer 11, at least a portion of the sealant layer 11 may contain a laser absorber. The resin layer containing the laser absorber in the sealant layer 11 can be formed from a polyolefin resin such as polyethylene resin or polypropylene resin. If the sealant layer 11 has two or more polyolefin resin layers, at least one of them should contain a laser absorber. This prevents the laser irradiated from the substrate layer 12 from penetrating the sealant layer 11 and acting on unintended areas.

[0022] The sealant layer 11 is preferably formed from a sealant resin. Examples of sealant resins include polyethylene-based resins with relatively low density, such as linear low-density polyethylene (LLDPE) and low-density polyethylene (LDPE), or unstretched polyethylene-based resins and polypropylene-based resins. The sealant layer 11 may be formed from one type of polyolefin-based resin, or it may contain two or more types of polyolefin-based resins.

[0023] The thickness of the sealant layer 11 is not particularly limited, but for example, it can be about 50 to 180 μm. The sealant layer 11 may be a single-layer sealant film or a multi-layer sealant film. A multi-layer sealant film can be formed by laminating two or more layers of film-like sealant resin using methods such as co-extrusion, extrusion lamination, sandwich lamination, or heat lamination. The multi-layer sealant film may also include a resin layer such as EVOH.

[0024] The base layer 12 may be a polyolefin resin layer stretched by biaxial stretching, uniaxial stretching, or the like, or an unstretched polyolefin resin layer. Examples of base layer 12 include polyethylene resins with relatively high density such as medium-density polyethylene (MDPE) and high-density polyethylene (HDPE), or polypropylene resins. The base layer 12 may be formed from one type of polyolefin resin, or it may contain two or more types of polyolefin resins. The thickness of the base layer 12 is not particularly limited, but for example, it is about 10 to 50 μm. The base layer 12 may have a multilayer structure. A multilayer base layer 12 can be formed by laminating two or more resin layers without using adhesives by co-extrusion, extrusion lamination, sandwich lamination, heat lamination, or the like. A structure in which multiple base layers are laminated with an adhesive layer in between will be described later.

[0025] The polyethylene resin used in the sealant layer 11 or the base layer 12 may be an ethylene homopolymer or an ethylene-based copolymer. Examples of monomers other than ethylene (comonomers) include one or more α-olefins such as 1-butene, 1-hexene, and 1-octene, cyclic olefins such as norbornene, and vinyl monomers such as vinyl acetate, vinyl chloride, and acrylic acid. When comonomers are used in the polyethylene resin, there may be one or more comonomers.

[0026] The proportion of ethylene in the constituent monomers of the polyethylene resin is preferably 50% by weight or more, and may be, for example, 80 to 100% by weight. The ethylene or comonomer used in the polyethylene resin may be a compound derived from fossil resources such as petroleum, or a compound derived from biomass such as plants. The material forming the polyethylene resin layer may be one type of polyethylene resin, or a blend of two or more types of polyethylene resins. The polyethylene resin layer may also contain recycled polyethylene.

[0027] Polypropylene (PP) resin may be used for the sealant layer 11 or the base layer 12. The polypropylene resin may be a homopolymer of propylene (homoPP), or a random copolymer (randomPP) or block copolymer (blockPP) of propylene-ethylene copolymer, etc. Examples of monomers other than propylene (comonomers) include one or more of α-olefins such as ethylene, 1-butene, 1-hexene, and 1-octene, and vinyl monomers such as vinyl acetate, vinyl chloride, and acrylic acid. When comonomers are used in the polypropylene resin, there may be one or more comonomers. The proportion of propylene in the constituent monomers of the polypropylene resin is preferably 50% by weight or more, for example, 80 to 100% by weight. The polypropylene resin layer may also contain recycled polypropylene.

[0028] The resin contained in the sealant layer 11 or the base layer 12 may be solely a polyolefin resin, solely a polyethylene resin, or solely a polypropylene resin. The sealant layer 11 or the base layer 12 may also contain additives other than resin. Additives are not particularly limited, but examples include antioxidants, lubricants, antiblocking agents, flame retardants, ultraviolet absorbers, light stabilizers, antistatic agents, colorants, crosslinking agents, etc. The additives may be components that are compatible with the resin or components that are not compatible with the resin.

[0029] The sealant layer 11 and the substrate layer 12 may be joined via an adhesive layer 13, such as by dry lamination. Although not specifically shown, extrusion lamination, heat lamination, etc., may also be used without interposing an adhesive layer 13 between the sealant layer 11 and the substrate layer 12. At least one of the sealant layer 11 or the substrate layer 12 may be subjected to surface treatment such as ozone treatment, plasma treatment, corona treatment, discharge treatment, or flame treatment.

[0030] The adhesive layer 13 may be formed from an adhesive or from an anchor coating agent. The material used to form the adhesive layer 13 is not particularly limited, but examples include urethane compounds, epoxy compounds, isocyanate compounds, polyethyleneimine, and organotitanium compounds such as titanium alkoxide. The thickness of the adhesive layer 13 can be, for example, approximately 0.1 to 10 μm, 1 to 6 μm, or 3 to 4 μm. The adhesive layer 13 may contain resin or it may be a resin-free adhesive layer.

[0031] To form a cut 14 in the substrate layer 12 and suppress the transmission of the laser through the sealant layer 11, the adhesive layer 13 may absorb the laser. The adhesive or other material may have a structure that absorbs the laser, or the above-mentioned laser absorber may be added to the adhesive or other material. It is preferable that the laminate 10 has at least one laser absorbing layer selected from the laser-absorbing sealant layer 11, the laser-absorbing substrate layer 12, and the laser-absorbing adhesive layer 13.

[0032] Next, with reference to Figure 2, the laminate 20 of the second embodiment will be described. In this laminate 20, a sealant layer 21, a first base layer 22, and a second base layer 23, each formed from a polyolefin resin, are laminated via adhesive layers 24 and 25. A cut 26 is formed from the second base layer 23 to the first base layer 22, where at least a portion in the thickness direction is removed by laser irradiation. In the thickness direction of the laminate 20, the first base layer 22 is located closer to the sealant layer 21, and the second base layer 23 is located further away from the sealant layer 21.

[0033] By having a polyolefin resin layer containing a laser absorber in at least one of the first substrate layer 22 and the second substrate layer 23, a cut 26 can be formed in the substrate layers 22 and 23. The cut 26 may be formed continuously with the adhesive layer 25 between the first substrate layer 22 and the second substrate layer 23. The depth of the cut 26 can be adjusted as appropriate, and the cut 26 may be formed only in a part of the thickness direction of the first substrate layer 22, or the cut 14 may reach the adhesive layer 24. It is preferable that the cut 26 penetrates the second substrate layer 23. In the illustrated example, the cut 26 is formed from the side of the second substrate layer 23 to a part of the thickness direction of the first substrate layer 22, which is a resin layer adjacent to the sealant layer 11. In the same manner as in the first embodiment, the cut 26 may not penetrate the sealant layer 21, or the laser may not pass through the sealant layer 21.

[0034] The laminate 20 of the second embodiment can be manufactured in the same manner as the laminate 10 of the first embodiment, except that it has two layers each of base material layers 22, 23 and adhesive layers 24, 25. The material of the sealant layer 21 may be the same as that of the sealant layer 11 of the first embodiment. The material of the base material layers 22, 23 may be the same as that of the base material layer 12 of the first embodiment. The material of the adhesive layers 24, 25 may be the same as that of the adhesive layer 13 of the first embodiment.

[0035] Although not specifically shown in the figures, in the laminates 10 and 20 of the first or second embodiment, a printed layer may be provided on one or both sides of the base material layers 12, 22, and 23. The printed layer can be formed by printing ink in a solid or patterned manner using printing methods such as gravure printing, letterpress printing, offset printing, screen printing, and inkjet printing. The thickness of the printed layer is not particularly limited, but is approximately 0.5 to 10 μm. The printed layer may be formed on the entire surface of the base material layers 12, 22, and 23, or on a part of the surface. Two or more printed layers may be stacked on top of each other. The printed layer may also be omitted.

[0036] In the first or second embodiment, it is preferable that the total weight of the laminates 10 and 20 is 80% by weight or more of the specified resin and the total weight of materials other than the specified resin is 20% by weight or less, and more preferably that the total weight of the specified resin is 90% by weight or more and the total weight of materials other than the specified resin is 10% by weight or less. This makes it possible to realize a monomaterial material of the specified resin even if laser absorbers, adhesives, etc. are used in the laminates 10 and 20. Examples of the specified resin include any of polyolefin resins, polyethylene resins, or polypropylene resins. The laminates 10 and 20 may use two or more resins that correspond to the specified resin.

[0037] Next, with reference to Figure 3, a laminate 30 of the third embodiment will be described. In this laminate 30, a sealant layer 31 formed from a polyolefin resin and a base layer 32 formed from a polyolefin resin are laminated together via an adhesive layer 33. A laser absorption layer 34 containing a laser absorbent is formed on the outer surface of the base layer 32, and cuts 35 are formed in the base layer 32 by removing at least a portion of the thickness direction by laser irradiation. The outer surface of the base layer 32 is the outermost surface of the laminate 30 when the sealant layer 31 is the innermost layer.

[0038] The laser absorption layer 34 may be a coated layer formed from varnish or the like. A heat-resistant varnish that allows the laser absorption layer 34 to be formed by drying and curing after application is preferred. The varnish may contain a resin and a solvent, or it may contain a solvent-free resin. The solvent in the varnish can be appropriately selected considering the performance when applied to polyethylene resins, etc. Powdered laser absorbers may also be blended into the varnish. The resin used to form the varnish is not particularly limited, but examples include one or more of urethane resins, acrylic resins, epoxy resins, polymethylpentene resins, cyclic olefin resins, unsaturated polyester resins, alkyd resins, polyimide resins, polyamide-imide resins, and polyamide resins.

[0039] The laser absorption layer 34 may be a printed layer formed from printing ink or the like. The ink for forming the printed layer may contain a coloring agent such as a pigment or dye, and a binder. The binder is not particularly limited, but examples include polyamide, polyurethane, polyester, polyvinyl chloride, polyvinyl acetate, vinyl chloride-vinyl acetate copolymer, acrylic polymer, polybutadiene, and cyclocompound rubber. The ink may contain a solvent such as water, an organic solvent, or a vegetable oil. After printing, the ink can be dried by the evaporation of the solvent or the curing of the ink. Heating, ultraviolet irradiation, etc., may be performed to accelerate the drying of the ink.

[0040] The laminate 30 of the third embodiment can be manufactured in the same manner as the laminate 10 of the first embodiment, except that it has a laser absorption layer 34. The configurations of the sealant layer 31, the base layer 32, and the adhesive layer 33 may be the same as those of the sealant layer 11, base layer 12, and adhesive layer 13 of the first embodiment, respectively.

[0041] In the laminate 30 of the third embodiment, the sealant layer 31 and the substrate layer 32 may or may not contain a laser absorbent. When the laser absorption layer 34 is heated by laser irradiation, at least a portion of the substrate layer 32 is removed, forming a cut 35. If the substrate layer 32 contains a laser absorbent, the substrate layer 32 is also heated and removed by laser irradiation, forming a cut 35.

[0042] The base layer 32 may consist of two or more layers, but if the base layer 32 does not contain a laser absorbent, it is preferable to have only one base layer 32, and to use a resin layer stretched by biaxial stretching, uniaxial stretching, etc. In the illustrated example, a cut 35 is formed up to a part in the thickness direction of the base layer 32, which is a resin layer adjacent to the sealant layer 31. Since the cut 35 is formed by the heat generated by the laser absorption layer 34, the base layer 32 does not need to contain a laser absorbent, making it easier to stretch the base layer 32. By using a resin film stretched by biaxial stretching, uniaxial stretching, etc., which has high dimensional stability, as the base layer 32, it becomes easier to form the laser absorption layer 34 on the base layer 32 by coating or printing.

[0043] The laser absorption layer 34 may be formed in a pattern in the region where the cut 35 is formed within the plane of the laminate 30. For example, if the cut 35 is formed linearly, the laser absorption layer 34 may be formed in a linear or strip shape including the width and length of the cut 35. The pattern of the laser absorption layer 34 is not particularly limited and may cover the entire surface of the laminate 30, or it may cover a portion of the laminate, such as a linear, strip, zigzag, polygonal, or circular shape. The pattern may be applied or printed by gravure printing. If the laser absorption layer 34 is visible due to coloring or the like, markings related to the cut 35 may be created along with characters or designs.

[0044] Next, with reference to Figure 4, the laminate 40 of the fourth embodiment will be described. This laminate 40 is made up of a sealant layer 41, a first resin layer 42, and a second resin layer 43, each formed from a polyolefin resin. A cut 46 is formed from the second resin layer 43 to the first resin layer 42, where at least a portion in the thickness direction is removed by laser irradiation. The sealant layer 41 and the first resin layer 42 are laminated together via an adhesive layer 44. The first resin layer 42 and the second resin layer 43 are laminated together via a laser absorption layer 45.

[0045] At least one of the resin layers 42 and 43 may be used as a base layer. The first resin layer 42 may be used as the first base layer, and the second resin layer 43 may be used as the second base layer. The second resin layer 43 may be the base layer, and the first resin layer 42 may be an intermediate resin layer interposed between the base layer and the sealant layer.

[0046] The laser absorption layer 45 may be formed from a resin that can be co-extruded with the polyethylene resin of the resin layers 42 and 43 and has laser-absorbing properties. Examples of such resins include ethylene-vinyl alcohol copolymer (EVOH). Laminating the polyethylene resin and the EVOH resin layer by co-extrusion allows for the formation of a thin EVOH resin layer, thus maintaining the recyclability of the polyethylene resin. Furthermore, the EVOH resin layer can provide barrier properties. In this case, the substrate may be formed from three co-extruded layers: the resin layers 42 and 43 and the laser absorption layer 45.

[0047] EVOH can be obtained by copolymerizing ethylene with a vinyl ester monomer, saponifying the resulting copolymer, and converting the vinyl ester units to vinyl alcohol units. Examples of vinyl ester monomers include vinyl carboxylates such as vinyl formate, vinyl acetate, vinyl butyrate, and vinyl benzoate. The barrier properties of EVOH improve as the proportion of vinyl alcohol units increases, but the moisture resistance decreases, so it is preferable to have an appropriate ethylene content. For example, the ethylene content of EVOH is 20 to 60 mol%. The degree of saponification of EVOH is not limited to 100 mol%, but for example, 80 mol% or more is preferred.

[0048] The laser absorption layer 45 between the first resin layer 42 and the second resin layer 43 may be a printed layer formed from printing ink, similar to the laser absorption layer 34 in the third embodiment. Alternatively, a printed layer may be formed on the outer surface of the first resin layer 42, and the printed layer on the first resin layer 42 side and the second resin layer 43 may be bonded together with an adhesive layer (not shown). Alternatively, a printed layer may be formed on the inner surface of the second resin layer 43, and the printed layer on the second resin layer 43 side and the first resin layer 42 may be bonded together with an adhesive layer (not shown). The resin layers 42 and 43 on which the printed layer is formed are preferably substrate layers.

[0049] The laminate 40 of the fourth embodiment can be manufactured in the same manner as the laminate 20 of the second embodiment, except that it has a laser absorption layer 45. The configurations of the sealant layer 41, the first resin layer 42, the second resin layer 43, and the adhesive layer 44 may be the same as those of the sealant layer 21, the first substrate layer 22, the second substrate layer 23, and the adhesive layers 24, 25 of the second embodiment, respectively.

[0050] A further resin layer may be provided between the first resin layer 42 and the sealant layer 41. For example, to improve the tearability of the laminate 40, it is preferable to provide a stretched polyethylene resin layer that has been stretched by biaxial stretching, uniaxial stretching, or the like. The second resin layer 43 may be a base layer and the first resin layer 42 may be a stretched polyethylene resin layer. It is preferable that a cut is formed from the base layer side to the stretched polyethylene resin layer. A resin layer such as an unstretched polyethylene resin layer may be laminated between the stretched polyethylene resin layer having the cut 46 and the sealant layer 41 by extrusion or the like. In this case, the cut 46 does not need to reach the resin layer such as the unstretched polyethylene resin layer. The resin layers included in the laminate 40 may sequentially include four types: a base layer, a stretched polyethylene resin layer, an unstretched polyethylene resin layer, and a sealant layer. The adhesive layer 44 may be omitted, and the laminate may be constructed by laminating the base layer in the following order: second resin layer 43 / laser absorption layer 45 / first resin layer 42 of stretched polyethylene resin / unstretched polyethylene resin layer / sealant layer 41. If the base layer or the stretched polyethylene resin layer contains a laser absorbent, the laser absorption layer 45 between the layers may be omitted.

[0051] Alternatively, a stretched polyethylene resin layer, stretched by biaxial stretching, uniaxial stretching, or the like, may be used as the first resin layer 42 adjacent to the sealant layer 41, and the laminate may be constructed in the order of second resin layer 43 of the base layer / laser absorption layer 45 / first resin layer 42 of the stretched polyethylene resin / adhesive layer 44 / sealant layer 41. Alternatively, the adhesive layer 44 may be omitted, and the laminate may be constructed in the order of second resin layer 43 of the base layer / laser absorption layer 45 / first resin layer 42 of the stretched polyethylene resin / sealant layer 41. In these examples, the resin layer adjacent to the sealant layer 41 is a single-layer stretched polyethylene resin layer. In the illustrated example, a cut 46 is formed from the second resin layer 43 side of the base layer to a part in the thickness direction of the first resin layer 42 adjacent to the sealant layer 41.

[0052] Next, with reference to Figure 5, a laminate 50 of the fifth embodiment will be described. This laminate 50 has a sealant layer 51, a first base layer 52, and a second base layer 53, each formed from a polyolefin resin. The sealant layer 51 and the first base layer 52 are laminated together via an adhesive layer 54. A metal vapor deposition layer 55 is formed on the outer surface of the first base layer 52, and the metal vapor deposition layer 55 and the second base layer 53 are laminated together via an adhesive layer 56.

[0053] Since the metal vapor deposition layer 55 is a laser reflection layer, it can suppress laser penetration into the sealant layer 51 and the first substrate layer 52. By forming a thin metal vapor deposition layer 55, the recyclability of the polyolefin resin can be maintained. Furthermore, the metal vapor deposition layer 55 can also provide barrier properties. The metal to be deposited is not particularly limited, but examples include metals or alloys such as aluminum (Al), titanium (Ti), zinc (Zn), tin (Sn), and chromium (Cr).

[0054] When forming a metal vapor deposition layer 55 on the first base layer 52, it is preferable that the first base layer 52 is a stretched polyethylene resin layer in order to control the vapor deposition. The metal vapor deposition layer 55 may be formed on a single film of the first base layer 52. Alternatively, the metal vapor deposition layer 55 may be formed on the first base layer 52 of a multilayer film laminated with a sealant layer 51 via an adhesive layer 54. The stretched polyethylene resin layer of the first base layer 52 may be a uniaxially oriented resin layer or a biaxially oriented resin layer.

[0055] The stretching direction of the stretched polyethylene resin layer in the first base layer 52, etc., is not particularly limited, but may be in the transport (MD) direction or the intersecting (TD) direction. Biaxial stretching in the MD and TD directions is also possible. Examples of stretching ratios include about 2 to 10 times. The stretching direction in uniaxial or biaxial stretching may be an oblique direction intersecting the MD and TD directions. The stretched polyethylene resin layer is preferably made of HDPE, MDPE, LLDPE, or LDPE, with LLDPE being more preferred.

[0056] The second substrate layer 53, which is positioned outside the metal vapor deposition layer 55, may contain a laser absorber. The first substrate layer 52, which is positioned inside the metal vapor deposition layer 55, does not need to contain a laser absorber. The thickness of the first substrate layer 52 may be 40 μm or less, and more preferably 25 μm or less. This ensures that the material can be torn by hand when the cut 57 does not reach the first substrate layer 52. If the first substrate layer 52 is a uniaxially oriented resin layer, the direction of uniaxial stretching can be aligned with the direction of the cut 57 to facilitate fracture along the cut 57.

[0057] The laminate 50 of the fifth embodiment can be manufactured in the same manner as the laminate 20 of the second embodiment, except that it has a metal vapor deposition layer 55. The configurations of the sealant layer 51, the first base layer 52, the second base layer 53, and the adhesive layers 54, 56 may be the same as those of the sealant layer 21, the first base layer 22, the second base layer 23, and the adhesive layers 24, 25 of the second embodiment, respectively.

[0058] Although not specifically shown in the figures, in the laminate 50 of the fifth embodiment, the first base layer 52 and the adhesive layer 56 may be omitted, and the layers may be laminated in the order of sealant layer 51 / adhesive layer 54 / metal vapor deposition layer 55 / base layer 53. In this way, by forming the metal vapor deposition layer 55 on the surface of the base layer 53 that faces the sealant layer 51, a gap 57 is formed in the base layer 53, and the transmission of the laser through the sealant layer 51 can be suppressed. There may be two or more base layers 53 laminated outside the metal vapor deposition layer 55. A resin layer may be further provided between the metal vapor deposition layer 55 and the sealant layer 51.

[0059] The laminates 10, 20, 30, 40, and 50 of the above-described embodiments are laminated films mainly composed of polyolefin resin and can be used for various applications. The method for forming the laminated film is not particularly limited, but examples include dry lamination, extrusion lamination, heat lamination, co-extrusion, and coating. Different methods may be used to laminate each layer. The sealant layers 11, 21, 31, 41, and 51 can be placed facing each other and the laminates 10, 20, 30, 40, and 50 can be joined by fusion.

[0060] The laminate of the embodiment can be used to manufacture packaging. It is sufficient that at least one component of the packaging is formed from the laminate of the embodiment. Examples of packaging include pouches, bags, tubes, containers, sleeve packaging, strip packaging, and lids. Specific examples of packaging bags include three-sided sealed bags, four-sided sealed bags, pillow bags, gusset bags, and standing pouches. If the laminate is a flexible laminated film, a flexible packaging can be formed. Because it is easy to refill and dispose of, it can be suitably used for refillable packaging such as refill pouches.

[0061] The packaging may have a filling opening, a dispensing spout, etc. For example, the top of the packaging may have an opening between the front and rear body members, which can be used for filling or dispensing the contents. After filling with contents, the body members may be joined together to seal the packaging. The dispensing spout may be formed in a shape that protrudes thinly from the top or corner of the packaging.

[0062] The non-penetrating cuts 14, 26, 35, 46, and 57 described above are preferably formed to cross the body or spout of the packaging. The process of forming the cuts 14, 26, 35, 46, and 57 may be performed on the laminates 10, 20, 30, 40, and 50 before bag making, or on the packaging after bag making.

[0063] To facilitate opening the packaging, in addition to forming the non-penetrating cuts 14, 26, 35, 46, and 57 described above in the opening portion, notches or other notches that penetrate the laminate may be formed around the opening portion. The notches that penetrate the laminate are formed in the sealing portion where the inner surfaces of the laminate are joined to ensure the airtightness of the packaging.

[0064] The dimensions of the packaging are not particularly limited, but for example, for refillable containers, the height is approximately 100-500 mm, the width is approximately 70-300 mm, and the filling volume is approximately 100 cm³. 3 ~5000cm 3 The degree can be mentioned. The state of the contents can be fluids such as liquids, powders, and granules. The type of contents is not particularly limited, but can be detergents, chemicals, cosmetics, pharmaceuticals, beverages, seasonings, inks, paints, fuels, etc.

[0065] The packaging may be formed solely from the laminates 10, 20, 30, 40, and 50 of the embodiment, or it may be combined with auxiliary components such as labels, tags, straws, and outer boxes. From a recycling standpoint, it is preferable that the auxiliary components can be separated from the packaging.

[0066] Although the present invention has been described above based on preferred embodiments, the present invention is not limited to the embodiments described above, and various modifications are possible without departing from the spirit of the invention. Modifications include the addition, substitution, omission, and other changes to the components. [Explanation of Symbols]

[0067] 10, 20, 30, 40, 50... Laminate 11, 21, 31, 41, 51…Sealant layer 12,22,23,32,52,53…Base material layer 13,24,25,33,44,54,56...adhesive layer 14, 26, 35, 46, 57... breaks 34, 45… Laser absorption layer 42, 43… Resin layer 55...Metal deposition layer

Claims

1. A laminate comprising a sealant layer formed from polyethylene resin and a base material layer formed from polyethylene resin, At least a portion of the laminate contains a laser absorber or a resin having laser-absorbing properties. The aforementioned base layer is a biaxially oriented polyethylene resin layer. At least a portion of the substrate layer contains the laser absorber, A laminate characterized in that a cut is formed in the laminate without penetrating in the thickness direction, by removing at least a portion of the thickness direction of the base layer by laser irradiation, and the cut is formed from the side of the base layer to a portion of the thickness direction of the layer adjacent to the sealant layer.

2. The substrate layer comprises a first substrate layer located on the side closer to the sealant layer in the thickness direction of the laminate, and a second substrate layer located on the side further away from the sealant layer. The first substrate layer is adjacent to the sealant layer, The laminate according to claim 1, characterized in that the first base material layer is a biaxially oriented polyethylene resin layer.

3. The laminate according to claim 2, characterized in that the second base material layer is a uniaxially oriented polyethylene resin layer.

4. The laminate according to claim 2 or 3, characterized in that a metal vapor deposition layer is formed on the surface of the first substrate layer facing the second substrate layer.

5. The laminate according to any one of claims 2 to 4, characterized in that the thickness of the first substrate layer is 40 μm or less.

6. The laminate according to any one of claims 2 to 5, characterized in that the first substrate layer and the second substrate layer are laminated with an adhesive layer that absorbs the laser.

7. The laminate according to any one of claims 1 to 6, characterized in that at least a portion of the sealant layer contains the laser absorber.

8. The laminate according to any one of claims 1 to 7, characterized in that a coating layer or printed layer containing the laser absorber is formed at least at the location where the cut is formed on the outermost surface of the laminate, which is opposite to the innermost layer of the laminate.

9. The laminate according to any one of claims 1 to 8, characterized in that, in the base material layer, the polyethylene resin layer is laminated with the ethylene-vinyl alcohol copolymer layer by co-extrusion.

10. The laminate according to any one of claims 1 to 9, characterized in that a metal vapor deposition layer is formed on the surface of the substrate layer that is on the sealant layer side.

11. The laminate according to any one of claims 1 to 10, characterized in that the sealant layer and the substrate layer are laminated via an adhesive layer that absorbs the laser.

12. A packaging body formed from a laminate according to any one of claims 1 to 11.

13. The packaging according to claim 12, characterized in that it is a refill pouch.

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