JP4603309B2 - Composite film for lid of distribution package - Google Patents

Description

  The present invention relates to a lid for a dispensing package. The “distribution package” in the present invention refers to, for example, jam, ketchup, sauce, paste, etc. on the bottom material 1 formed by deep drawing a soft film as shown in FIG. It is a package 20 obtained by containing a food having a good viscosity and fluidity and sealing the opening of the bottom material 1 with the lid material 2 of the present invention. The lid member 2 of the present invention is provided with a convex portion 3 that protrudes to the outside of the package 200, and a half cut 4 is formed on the surface portion of the lid member 2 so as to be orthogonal to the longitudinal direction of the convex portion 3. When the lid 2 of the package 200 is bent in the direction of the bottom 1, the bending stress is concentrated on the convex portion 3, the convex portion 3 is torn along the half cut 4, and the lid 2 is opened. Further, by pushing the lid material 2 so that the left and right sides of the lid member 2 are in close contact with each other, a fluid food or the like contained in the bottom member 1 is discharged from the opening by the pressing force of the lid member 2. Therefore, according to the distribution package 200, the contents inside the package 200 can be pushed out in the direction desired by the user without making the hands dirty by a simple operation of bending the lid member 2 and crushing it as it is. . The basic configuration of such a package is disclosed in Patent Document 1.

Conventionally, a laminated body formed by using vinyl chloride (hereinafter referred to as “PVC”) as a plastic sheet and bonding a PVC sheet and a coextruded film by a method such as a dry laminating method, as a lid for a distribution package. Was suitably used (see Patent Document 2). An example of the layer structure of such a laminate is shown below.
PVC sheet // coextruded film (EVOH layer / Ny layer / PE layer / seal layer)

  The notation “//” in the above layer structure indicates that the layers described before and after that are bonded by the dry lamination method, and “/” indicates that the layers described before and after that are bonded by the co-extrusion method. It shows that. The same notation is used in the following. “EVOH” means a saponified ethylene-vinyl acetate copolymer resin, and “Ny” means a polyamide resin.

  This Ny layer is indispensable for maintaining the melt tension in forming the coextruded film to 20 to 100 μm. On the other hand, since the Ny layer is tough, it may adversely affect the unsealing properties when used for a part of the layer structure, but it has a characteristic that PVC easily breaks (hereinafter referred to as “easy crackability”). Since it was excellent, there was no problem in the openability of the package.

On the other hand, due to environmental problems in recent years, vinyl chloride may generate chlorinated gas, which is considered harmful during waste incineration, so vinyl chloride is especially avoided by the food industry, and alternative materials are being sought. It was. As a layer structure not using such vinyl chloride, for example,
Stretched substrate // PS sheet // coextruded film (EVOH layer / Ny layer / adhesive layer / seal layer)
(See Patent Document 3). Here, “PS” means polystyrene resin. In this configuration, a PS sheet is dry-laminated on a stretched substrate, and a coextruded film is dry-laminated for the purpose of providing oxygen barrier properties and sealing properties. As the stretched base material, PS, polyethylene terephthalate resin (hereinafter referred to as “PET”), or polycarbonate resin (hereinafter referred to as “PC”) is used from the viewpoint of excellent fragility.
JP 59-103866 A JP-A-64-37370 JP-A-3-256862

  However, when PS, PET, or PC is used as the stretched substrate, if the Ny layer is present in the coextruded film structure, the sheet portion of PS, PET, or PC is cracked when the structure is bent and opened. However, the coextruded film that has been bonded has a problem that it is difficult to open only by being stretched and stretched.

  On the other hand, at the time of opening, it is also important that the sticky food, which is the contents, is discharged in a straight line in the direction intended by the user. In the above configuration, the crackability of the plastic sheet was good, but because of the Ny layer, the coextruded film did not follow the plastic sheet and did not discharge the contents as intended, and it was sideways when opened. There was also a problem that it might be scattered.

  Accordingly, the present invention is a composite for a lid material of a distribution package that enables good easy opening and discharge of contents while aiming while maintaining melt tension when a non-vinyl chloride plastic sheet is used. It is an object to provide a film.

  This invention discovered the composite film for the lid | cover materials of the distribution package which can eliminate the said problem. The composite film for a lid of a distribution package according to the present invention described below is a film in which a “plastic sheet” and a “coextruded film” are bonded together by an adhesive processing method. The “coextruded film” includes a “surface layer”, an “intermediate layer”, and a “seal layer”.

  The “plastic sheet” is the layer having the largest layer thickness in the composite film for the lid material of the distribution package, and is disposed on the surface opposite to the side to be sealed with the bottom material of the package. Further, the “surface layer” is a layer bonded to the plastic sheet by an adhesive processing method in the coextruded film. The “seal layer” is a layer that is disposed on the side opposite to the “surface layer” in the coextruded film and constitutes a joint surface with the bottom material. The “intermediate layer” is a layer sandwiched between the surface layer and the seal layer.

  A first aspect of the present invention is a composite film for a cover material of a distribution package in which a plastic sheet is laminated on the surface layer side of a coextruded film having a surface layer, an intermediate layer, and a seal layer in this order by an adhesive processing method. Each of the surface layer and the sealing layer is composed of at least one polyethylene resin (hereinafter referred to as “PE”) layer, and the intermediate layer has an ethylene content of 29 to 47 mol%. A composite film comprising a resin (hereinafter referred to as “EVOH”) layer and at least one adhesive layer.

  In the conventional film, the melt tension is maintained by the Ny layer to stabilize the film forming property of the coextruded film. However, according to the composite film of this aspect, it is difficult to maintain the melt tension because there is no Ny layer. However, by arranging LDPE in the PE layer, it is possible to stabilize the film forming property and to improve the easy-openability, so that the contents can be discharged as aimed. Become.

In the first aspect, PE first layer as the sealing layer, the first layer adhesive as the intermediate layer, EVOH layer and the adhesive second layer, and laminating the second layer PE as the table layer in this order It is preferable that a plastic sheet is laminated on the surface layer side of the coextruded film.

  Although the PE layer is bonded to the plastic layer, the suitability for bonding can be improved by applying a corona treatment to the PE second layer. Furthermore, HDPE is blended into the PE layer in order to improve the openability (film breakability). However, HDPE has poor sealing properties, and it is not appropriate to use the HDPE blended layer as a sealing layer. Therefore, a layer (PE first layer) different from the layer blended with HDPE is disposed as a sealing layer to ensure good sealing properties.

  In the first aspect (including modifications), the seal layer is preferably composed of at least two PE layers made of the same or different components.

  In this way, by making the PE layer in this way a two-layer structure, it is possible to improve the film breakability required for the unsealing property along with the cracking of the PS layer while maintaining good sealing properties. it can.

  In the first aspect (including modifications), PE is low density polyethylene (hereinafter referred to as “LDPE”), high density polyethylene (hereinafter referred to as “HDPE”), or a mixture thereof. It is preferable.

  By adopting such a configuration, it is possible to freely control the blending ratio of LDPE and HDPE, and to adjust the cracking property generated in the lid material when opening the package and the adhesive strength with EVOH. Further, by blending the two, a lid material excellent in a property (hereinafter referred to as “easy cracking property”) that can be easily cracked at the time of opening with HDPE while increasing the melt tension by LDPE to stabilize the film forming property. It becomes possible.

  In the first aspect (including modifications), the plastic sheet is selected from the group consisting of polystyrene, polycarbonate, and polyethylene terephthalate having an intrinsic viscosity (IV value) of 0.50 to 0.90 dl / g. It is also preferable that it is made of at least one material.

  When constituted in this way, a relatively inexpensive general-purpose resin can be used as the plastic sheet. Further, by setting the intrinsic viscosity (IV value) of these general-purpose resins to 0.50 dl / g or more, the impact resistance of the sheet can be maintained well, and brittle cracking is not caused even under low temperature conditions. By setting the intrinsic viscosity (IV value) to 0.90 dl / g or less, an appropriate viscosity can be obtained, and extrusion film formation can be performed satisfactorily.

  Moreover, in said 1st aspect (a modification is included), it is preferable that the thickness ratio of the plastic sheet with respect to the thickness of a coextruded film is 1.5-22.5.

  When configured in this way, the balance of the “tear” on the coextruded film side with respect to the “crack” of the plastic sheet is good, ensuring good openability and discharging the contents in the direction intended by the user. It becomes easy to make.

  Moreover, in said 1st aspect (a modification is included), it is preferable that ratio of the thickness of the EVOH layer with respect to the thickness of PE layer of a surface layer is 0.07-15.

  When comprised in this way, while being good as a lid | cover material of a distribution package, while being able to obtain oxygen barrier property, intensity | strength, openability, and the adhesiveness between each layer, a process can be made easy.

  Moreover, in said 1st aspect (a modification is included), it is preferable that the total thickness of each layer is 170-550 micrometers.

  In this way, the commercialization value as a distribution package is maintained with an appropriate film stiffness and tactile sensation without impairing the good opening properties and composite film moldability of the distribution package. can do.

  Moreover, in said 1st aspect (a modification is included), it is preferable that the adhesive strength of a coextruded film and a plastic sheet is 3.9-15N / 15mm.

  By making the adhesive strength between the coextruded film and the plastic sheet within the above range, when dispensing the flowable food contained in the package, the plastic sheet is cracked, and then the coextruded film side is stretched and split from the center. Since the opening is gradually opened, the opening behavior is good, and the fluid substance as the contents can be discharged toward the target as intended.

  A second aspect of the present invention is a lid for a distribution package formed by the composite film according to the first aspect (including the modification).

  According to the cover material concerning this aspect, it is possible to provide the distribution package provided with the characteristics of the coextruded composite film according to the first aspect.

  A third aspect of the present invention is a distribution package using the lid according to the second aspect.

  According to the distribution package according to this aspect, it is possible to provide the distribution package having the characteristics of the lid according to the second aspect.

  According to the composite film for a cover material of a distribution package obtained by bonding a plastic sheet and a co-extruded film of the present invention, when a non-vinyl chloride plastic sheet is used, good melt tension is maintained. It is possible to obtain a composite film that can be easily opened and the contents can be discharged aiming.

  Hereinafter, the present invention will be described based on embodiments shown in the drawings. FIG. 1 is a view showing a cross section of a composite film for a lid material of a distribution package according to an embodiment of the present invention. In the illustrated composite film 100 for a lid of a distribution package, a plastic sheet 10 and a co-extruded film 20 are bonded by dry lamination which is a kind of adhesive processing method. The coextruded film 20 has a surface layer 30, an intermediate layer 40, and a seal layer 50 laminated in this order from the plastic sheet 10 side. The surface layer 30 and the seal layer 50 are formed of PE. Further, in the intermediate layer 40, the adhesive second layer 41, the EVOH layer 42, and the adhesive first layer 43 are laminated in this order from the surface layer 30 side. Further, in the sealing layer 50, a PE first B layer 51 and a PE first A layer 52 are laminated in this order from the surface layer 30 side. In the composite film 100 for the lid material of the distribution package having such a layer structure, the plastic sheet 10 forms the thickest layer.

(PE layer)
In the composite film 100 for a lid material of the distribution package of this embodiment, a total of three layers including a PE first A layer 52, a PE first B layer 51 of the seal layer 50, and a PE second layer as the surface layer 30 as the PE layer. Is arranged.

  In the composite film 100 for a lid material of the distribution package of the present invention, it is essential that each of the surface layer 30 and the seal layer 50 has at least one PE layer. A first PE layer having a multilayer structure of the first A layer 52 and the PE first B layer 51 is preferable. For the PE first layers 51 and 52 having such a two-layer structure, it is preferable to use LDPE, HDPE, or a blend of LDPE and HDPE. In determining the blend ratio, the following considerations should be made while considering the layer thickness. That is, in the PE first A layer 52, it is preferable to increase the LDPE blending ratio in order to ensure the sealing property. On the other hand, the PE first B layer 51 needs to propagate the “cut” of the layer (film) with the crack of the plastic sheet 10 as the main constituent layer. Is also preferable. Specifically, the blending ratio of LDPE and HDPE is 40-80: 60-20, preferably 50-80: 50-20, and more preferably 60-80: 40-20. In this way, by controlling the blending ratio of LDPE and HDPE, it is possible to adjust the cracking property generated in the lid material when the package is opened. Further, by blending both, it is possible to increase the melt tension by LDPE and to stabilize the film forming property.

  Further, the PE second layer adjacent to the plastic sheet 10 and constituting the surface layer 30 uses LDPE, HDPE, or a blend of LDPE and HDPE, similarly to the PE first layers 51 and 52 described above. Is preferred. LDPE is mainly used to maintain melt tension and stabilize the film forming property, and further blend HDPE to impart film breakability.

LDPE used for each of these PE layers has a density of 0.92 to 0.94 g / cm ³ , a melt index of 0.5 to 2.0 g / 10 minutes (190 ° C.), and HDPE has a density of 0.94 to 0.96 g. / Cm ³ and a melt index of 0.5 to 10.0 g / 10 min (190 ° C.) are preferable. In the conventional configuration, since Ny is arranged in the co-extruded film configuration, there is a problem that even if the plastic sheet is broken, the co-extruded film portion is not cut and is not opened. Since the composite film 100 for a lid of a distribution package according to the present invention does not have a Ny layer, such troubles can be avoided.

  On the other hand, if the Ny layer is excluded from the composite film, the melt tension may be lowered, making it difficult to form a film. In the composite film 100 for the lid material of the distribution package according to the present invention, LDPE having a low melt tension is used as the PE, and HDPE is blended to improve the openability and maintain the film forming stability. By arranging a plurality of layers in the configuration, the melt tension was maintained and film formation stability was realized.

  The thickness of the PE first layer constituting the surface layer 30 and the PE first B layer 51 of the seal layer 50 is preferably 2 to 30 μm. More preferably, it is 3-20 micrometers, Most preferably, it is 5-15 micrometers. By keeping the thicknesses of the PE second layer 30 and the PE first B layer 51 within the above ranges, it becomes possible to keep the PE layer cut well when opened. The thickness of the PE first A layer 52 is preferably 2 to 30 μm, more preferably 3 to 20 μm, and particularly preferably 5 to 15 μm. By defining the thickness of each PE layer in this manner, it becomes possible to maintain good sealing properties while maintaining good cutting at the time of opening.

(EVOH layer)
The EVOH layer 42 in the lid cover composite film 100 of the distribution package according to the embodiment of the present invention has a function as an oxygen barrier layer. In the present invention, EVOH must have an ethylene content of 29 to 47 mol%. Preferably, the ethylene content of EVOH is 32 to 44 mol%, particularly preferably 35 to 40%. The saponification degree of EVOH is preferably 90 mol% or more, more preferably 95 mol% or more. By maintaining the ethylene content of EVOH and the degree of saponification within the above ranges, the coextrudability and film strength of the composite film 100 for a lid of the distribution package can be improved. The thickness of the EVOH layer 42 is preferably 2 to 30 μm. A more preferable range is 3 to 20 μm, particularly preferably 3 to 10 μm. If the thickness of the EVOH layer 42 is too thin, it becomes difficult to maintain good oxygen barrier properties. On the other hand, when the thickness of the EVOH layer 42 is too thick, the coextrudability of the film is deteriorated, and it is disadvantageous for maintaining the film strength.

  The thickness ratio of the EVOH layer 42 to the surface layer 10 is preferably 0.07 to 15. More preferably, it is 0.15-6.7, More preferably, it is 0.2-2.

(Adhesive layer)
In the present invention, the resin constituting the adhesive first layer and the second layers 41 and 43 adheres the PE second layer 30 and the EVOH layer 42, and the EVOH layer 42 and the PE first B layer 51 to a required strength. The polyolefin resin modified with an unsaturated carboxylic acid or a derivative thereof is preferably used. Examples of the unsaturated carboxylic acid include acrylic acid, methacrylic acid, maleic acid, fumaric acid, crotonic acid, itaconic acid, citraconic acid and the like. Moreover, ester and anhydride of these unsaturated carboxylic acids can also be used. Furthermore, examples of the derivatives include methyl acrylate, methyl methacrylate, ethyl acrylate, propyl acrylate, butyl acrylate, butyl methacrylate, vinyl acetate, glycidyl acrylate, glycidyl methacrylate, acrylamide, methacrylamide, sodium acrylate, and the like. . For example, the product name Admer manufactured by Mitsui Chemicals, Inc. is commercially available and is preferably used. Among these, in the case of bonding the EVOH layer 42 to the PE second layer 30 and the PE first B layer 51, a linear low density polyethylene (hereinafter referred to as “LLDPE”) type is preferably used.

  The thickness of the adhesive second layer 41 and the adhesive first layer 43 disposed between the PE second layer 30 and the EVOH layer 42 and between the EVOH layer 42 and the PE first B layer 51 is 2 to 30 μm. It is preferable that More preferably, it is 3-20 micrometers, Most preferably, it is 5-15 micrometers. By setting the thickness of the adhesive layers 41 and 43 within the above range, the adhesive strength between the EVOH layer 42 and the PE layers 30 and 51 can be maintained in a favorable range.

(Plastic sheet)
In the composite film 100 for a lid material of a distribution package according to an embodiment of the present invention, the plastic sheet 10 is disposed on the outermost layer side. The material of the plastic sheet constituting the composite film for the lid material of the distribution package of the present invention is not particularly limited. For example, polystyrene resin (hereinafter referred to as “PS”), polycarbonate resin (hereinafter referred to as “PS”). PC ”) and at least one material selected from the group consisting of polyethylene terephthalate resins (hereinafter referred to as“ PET ”) having an intrinsic viscosity (IV value) of 0.50 to 0.90 dl / g. It is preferable. For example, when the plastic sheet 10 is composed of PS, as the PS composing the plastic sheet 10, general-purpose polystyrene (hereinafter referred to as “GPPS”), impact-resistant polystyrene (hereinafter referred to as “HIPS”), styrene · The compound of a butadiene block copolymer (butadiene-based compound) alone or a blend thereof can be exemplified. GPPS does not contain a rubber component and is very easy to break. On the other hand, since HIPS is blended with a rubber component, it has a property that it is difficult to break. Therefore, by appropriately controlling the blend ratio of GPPS and HIPS, it is possible to adjust the cracking property generated in the lid material when the package is opened.

For GPPS, a heat-resistant grade having a flexural modulus of 3,200 to 3,300 MPa and a Charpy impact strength (notched) of 1.5 to 3.0 KJ / m ² is preferably used. Meanwhile, HIPS is flexural modulus 2,100～2,500MPa, Charpy impact strength (with notch) is high impact grade is preferably used in 13~16KJ / ^{m 2.}

  Examples of styrene / butadiene block copolymers include Asaflex, Tuffprene and Asaprene manufactured by Asahi Kasei Corporation. These melt flow rates are 1 g / 10 min [200 ° C. 5 Kg] or more, preferably 4 g / 10 min [200 ° C. 5 Kg] or more. By setting the melt flow rate within the above range, it becomes easy to ensure good coextrusion properties. Here, “melt flow rate (melt flow index): solution flow rate” is one of the measures indicating the fluidity of a polymer in a solution state, and is also referred to as “solution index”. The amount flowing out from a nozzle (orifice) having a prescribed size under a constant pressure and a constant temperature is measured with an extrusion type plastometer and expressed in units of g / 10 min. In general, the larger the melt flow rate value, the better the fluidity and workability at the time of melting, but the lower the tensile strength and stress cracking resistance. See ISO 1133 “Plastics—Measuring melt flow rate of thermoplastics” for specific measurement methods.

Moreover, when using PC as a material which comprises the plastic sheet 10, the said PC is
It is preferable that the standard type containing no flame retardant or weathering agent is suitable, has excellent heat resistance and cold resistance, and practically does not change performance from -40 ° C to 125 ° C.

  When PET is used as the plastic sheet, the intrinsic viscosity (IV value) of the PET is preferably in the range of 0.50 to 0.90 dl / g. More preferably, it is the range of 0.60-0.85 dl / g, More preferably, it is the range of 0.65-0.83 dl / g. By setting the intrinsic viscosity (IV value) to 0.50 dl / g or more, the impact resistance of the sheet can be maintained well, and brittle cracking does not occur even under low temperature conditions. On the other hand, by setting the intrinsic viscosity (IV value) to 0.90 dl / g or less, an appropriate viscosity can be obtained and extrusion film formation can be performed satisfactorily.

  The thickness of the plastic sheet 10 is preferably 150 to 450 μm. More preferably, it is 200-400 micrometers, Most preferably, it is 250-350 micrometers. If the thickness of the plastic sheet 10 is too thin, it will be difficult to obtain good openability when used as a lid for a distribution package. On the other hand, if the thickness of the plastic sheet 10 is too thick, an unnecessarily large force is required to bend when opening the pack product, and the thickness becomes unnecessarily high, resulting in an increase in cost and a reduction in commercial value as a distribution package. .

  Moreover, it is preferable that the thickness ratio of the plastic sheet with respect to the coextruded film 20 is 1.5-22.5. By controlling the thickness ratio within such a range, the balance between the cracking property of the plastic sheet 10 and the tearing property of the coextruded film 20 is improved, and a preferable opening property is given to the composite film 100 for the lid material of the distribution package. be able to.

(Adhesion processing)
In the present invention, the method for adhering the plastic sheet 10 and the coextruded film 20 is not particularly limited, and examples thereof include dry lamination and extrusion lamination. Moreover, it is also preferable to make adhesive strength 3.9-15N / 15mm width by an adhesive process. If the adhesive strength is too low, when the lid is folded and opened, the interlayer (adhesive layer) between the plastic sheet 10 and the coextruded film 20 is peeled off. If it becomes like this, the coextruded film 20 will be extended | stretched, the trouble which does not cut well and does not open will generate | occur | produce. That is, the plastic sheet 10 breaks, while the coextruded film 20 is a phenomenon that is not stretched but is stretched without being cut. When the adhesive strength is adjusted within the above range, the plastic sheet 10 is cracked, and then the coextruded film 20 is stretched while being stretched and gradually opens from the center portion, so that a satisfactory opening behavior is obtained. , Enabling the liquid as the contents to be ejected according to the target. In order to obtain such an adhesive strength, the adhesion processing layer is preferably 1 to 5 μm. A dry laminating method is preferably used as the bonding processing method. In such a case, as the adhesive, a polyester adhesive is suitably used as the main agent, and an isocyanate is suitably used as the curing agent. The dry lamination conditions are not particularly limited, but a coating amount of 2 g / m ² , a drying temperature of 40 ° C., a dry lamination speed of 10 to 20 m / min, and an aging time of 72 hours are suitable. Moreover, in order to make adhesive strength 3.9-15N / 15mm width, it is preferable to give surface treatments, such as a corona treatment, to the surface of PE 2nd layer which is an adhesive surface with the plastic sheet 10. FIG. The wettability after the corona treatment is preferably 46 dynes or more.

(Total film thickness)
Thus, the total thickness of the layers constituting the plastic sheet 10 and the coextruded film 20 is preferably about 170 to 550 μm. More preferably, it is 230-480 micrometers, Most preferably, it is 290-420 micrometers. If the total thickness of the film is too thin, the feel of the film will be weak, and when the contents of the package are pushed out, sufficient rigidity to crush the bottom material will not be obtained, and the commercial value as a distribution package will be reduced. descend. On the other hand, if the total thickness of the film is too thick, it is economically disadvantageous and the film feels hard, and in this case as well, the commercial value as a distribution package decreases.

(Openability)
As a factor affecting the openability,
(1) Crackability of plastic sheet 10 (2) Adhesive strength between plastic sheet 10 and coextruded film 20 (3) Coextruded film 20 Tearability and thickness include three factors. The plastic sheet 10 can make a break (half cut) in a straight line in the direction of cracking parallel to the thickness direction, and improve the propagation of cracks.

  (1) The crackability of the plastic sheet 10 varies depending on the blend ratio of PS, for example, when PS is used as the material. Increasing the GPPS ratio is easier to crack, and conversely increasing the HIPS ratio makes it difficult to crack. The crackability can be adjusted by this blend ratio.

  (2) The stronger the adhesive strength between the plastic sheet 10 and the coextruded film 20 is, the better. When the lid is folded and opened, the plastic sheet 10 which is the main constituent layer of the composite film 100 is peeled off when the interlayer is peeled off. The other layers, that is, the layers constituting the coextruded film 20 are stretched, causing troubles that do not cut well and do not open. That is, the plastic sheet 10 as the main constituent layer is cracked, while the other layers of the coextruded film 20 are stretched without being cut and are not opened. Controlling the adhesive strength to 3.9 to 15 N / 15 mm width is suitable for opening. Therefore, when the PE second layer 30 is bonded to the plastic sheet 10 as the main constituent layer by dry lamination, the adhesive strength can be maintained at a width of 3.9 to 15 N / 15 mm. 10 is broken, and then the remaining layers of the coextruded film 20 are stretched while being stretched, and the opening is gradually opened from the center. For this reason, it becomes a favorable opening behavior, and enables the fluid substance as the contents to be discharged toward the target as intended. Therefore, it is preferable to control the adhesive strength between the plastic sheet 10 and the coextruded film 20 to a width of 3.9 to 15 N / 15 mm. More preferably, the width is 6 to 12 N / 15 mm. The interlayer adhesive strength can be determined by measuring the maximum load when a 15 mm wide composite film is peeled off at a normal temperature by a tensile tester at a pulling rate of 200 mm / min. If it is lower than the appropriate value, peeling (delamination) occurs, and the plastic sheet 10 breaks, but each layer of the coextruded film 20 does not tear well and does not open, and the contents may not be discharged. Also, if the value is higher than the appropriate value, the plastic sheet 10 is opened in a form that follows the cracking direction, and when the contents pop out, the opening is not fixed, and a phenomenon occurs in which it flies in a direction different from the target. There is a risk that.

  (3) Regarding the tearability of the PE second layer 30, the PE first B layer 51, and the PE first A layer 52, the tearability can be achieved with LDPE, HDPE, or a blend of LDPE and HDPE. Can be adjusted. Higher density PE has better tearability. In order to fly the fluid substance, which is the contents described in (2), toward the target, it is necessary to adjust the elongation and tearability by the blend.

These are one embodiment of the present invention.
PE first A layer 52 / PE first B layer 51 / adhesive first layer 43 / EVOH layer 42 / adhesive second layer 41 / PE second layer 30 // plastic sheet 10
According to the composite film 100 for a lid material of a distribution package having a layer structure made of the above, the easy cracking property of the plastic sheet 10 and the coextruded film 20 (PE first A layer 52 / PE first B layer 51 / adhesive first Due to the easy tearability of the layer 43 / EVOH layer 42 / adhesive second layer 41 / PE second layer 30) and the aiming ability of the opening, smooth opening of the distribution package can be obtained. Furthermore, the PE first A layer 52 based on LDPE can exhibit good sealing properties. Furthermore, by arranging adhesive layers 43 and 41 composed of appropriate materials and thicknesses on both sides of the EVOH layer 42, the adhesive strength of each layer can be set appropriately, which also contributes to good opening properties. It becomes possible.

(package)
The field in which the composite film for lid of the distribution package of the present invention is used is mainly for lids for food containers and packaging. The film used for the bottom material is generally an unstretched coextruded film.
Ny layer / EVOH layer / seal layer. In general, this bottom material is formed to a depth of about 10 mm, and mayonnaise, ketchup, mustard, jam, etc. are placed therein and sealed to form a distribution container. Moreover, there exists a site | part currently shape | molded convexly toward the exterior of a package in the center part of a cover material, and the location corresponds to an opening. The lid member is heated and molded, and a convex portion is formed toward the outside of the container corresponding to the opening portion. The shape of the convex portion is intended to cause bending stress to concentrate on the opening portion when the container lid member is bent, the opening portion is torn, and the contents pop out. Examples of the shape of the other convex portion include a quadrangular pyramid shape, a semicircular shape (dome shape), and a cube. However, as long as the stress can be concentrated, the shape of the convex portion is not limited thereto. For molding, male-female molding is suitable for the purpose of sharpening the convex shape.

Furthermore, in order to concentrate bending stress, the following forms are effective.
(1) The cut is continuously put in the center of the formed convex shape at a depth of about 10 to 50% with respect to the total thickness of the lid with a cutting blade in the same direction as the direction in which the lid is folded.
(2) A cut line is formed in a dotted line shape at about 2 to 10 mm only at the apex portion of the molding convex portion. and so on.

On the other hand, it is preferable to use an unstretched coextruded composite film for the bottom material. As composition
The Ny layer / EVOH layer / PE layer is effective in terms of oxygen barrier properties, deep drawing suitability, and the tolerability of the lower heating hot plate (contact heating) of the preheater. In order to fill the viscous body as the contents, deep drawing is performed. As a process, after film heating (contact heating to a hot plate), a method of compressed air / vacuum forming is generally used. The heating temperature is preferably 85 to 110 ° C. The molded bottom material is filled with a viscous body, combined with the molded lid material, and heat-sealed. This seal is completely sealed without being peeled off at the seal surface interface of the lid bottom material. The package size is about 20 to 100 mm in length, 20 to 100 mm in width, and about 3 to 40 mm in depth. In the unsealing method, holding the both ends of the package with one hand and crushing the package in such a direction that the bottom material comes inward from the center of the lid material, the convex portion of the lid material is torn and the contents are discharged.

Examples of the present invention will be described below, but the present invention is not limited thereto.
The films of Examples 1 to 4 and the comparative example were formed by a combination of a co-extrusion method and a dry laminating method and evaluated.
Example 1
PS was used as a material for the plastic sheet, and the coextruded film and the dry laminate were adhered to make Example 1.
PS // LDPE (70) + HDPE (30) / Adhesive layer / EVOH / Adhesive layer / LDPE (70) + HDPE (30) / LDPE
(Example 2)
Example 2 was made by changing the LDPE / HDPE blend ratio of the PE constituting the PE second layer and PE first A layer in the coextruded film of Example 1.
PS // LDPE (50) + HDPE (50) / Adhesive layer / EVOH / Adhesive layer / LDPE (50) + HDPE (50) / LDPE
(Example 3)
Example 3 was obtained by changing the material of the plastic sheet of Example 2 from PS to APET.
APET // LDPE (50) + HDPE (50) / adhesive layer / EVOH / adhesive layer / LDPE (50) + HDPE (50) / LDPE
Example 4
Example 4 was obtained by changing the material of the plastic sheet of Example 2 from PS to PC.
PC // LDPE (50) + HDPE (50) / Adhesive layer / EVOH / Adhesive layer / LDPE (50) + HDPE (50) / LDPE
(Comparative example)
A comparative example is one in which vinyl chloride (PVC) is used for the plastic sheet and the coextruded film includes a polyamide (Ny) layer.
PVC // EVOH / Ny / adhesive layer / LDPE / LDPE
Table 1 summarizes the layer configurations of the films according to the above Examples and Comparative Examples, and the thicknesses of the respective layers.

  Table 2 summarizes the manufacturers and product names of the materials used in the respective layers of the above Examples and Comparative Examples.

  <Package manufacturing conditions>

A coextruded composite film having the following layer structure as a bottom material was molded under the following molding conditions. The layer thickness of each layer was Ny: 50 μm, EVOH: 10 μm, and LLDPE: 90 μm.
(Layer structure)
Bottom material: Ny / EVOH / LLDPE (seal layer)
(Molding condition)
Bottom material molding heating temperature: 150 ° C, Bottom material molding heating time: 3 seconds Lid material molding heating temperature: 160 ° C, Lid material molding heating time: 2 seconds Lid / bottom material sealing temperature: 160 ° C, Lid / bottom material sealing time : 2 seconds Contents: Water 15cc / pack

<Performance evaluation test method and evaluation criteria>
Five types of performance evaluation tests described below were conducted, and the composite film for lid materials of the distribution package was evaluated based on predetermined evaluation criteria.
(1) Interlayer adhesion strength with plastic sheet:
6-15 N / 15 mm width: Excellent 3.9-6 N / 15 mm width: Good 3.9 N / 15 mm width or less: Defect (2) Coextrusion film film cutting property: The package is opened, and how to cut the composite film portion is visually observed. Observed at.
No film residue or stringing at the opening. : 5
There is almost no film residue and stringing at the opening. : 4
Slight film residue and stringing are observed at the opening. : 3
Remaining film at opening and stringing are observed. : 2
There is noticeable film residue and stringing at the opening. : 1
(3) Crackability of plastic sheet: The package was opened and the linear crackability of the main constituent layer was evaluated.
It breaks linearly and smoothly without sticking. : 5
It breaks smoothly in a straight line. : 4
The sticky and hard to break breaks linearly. : 3
Does not break linearly. : 2
Even if it is sticky and hard to crack, it is not linear. : 1
(4) Openability (content discharge mode): A total of 50 packages were opened, and the direction in which the content was discharged was observed.
Dispense completely according to the aim. : 5
More than 90% is discharged as aimed. : 4
More than 50% is discharged according to the aim. : 3
Less than half of the items are discharged in the aiming direction. : 2
All discharge in a different direction from the target. : 1

<Evaluation results>
The evaluation test results are shown in Table 3.

  In Example 1, PS is used as a material constituting a plastic sheet. A PE layer is disposed on the top and bottom of the coextruded film that is dry-laminated on the plastic sheet, and an EVOH layer is bonded between both PE layers. It is arranged through layers. The composite film for the lid material of the distribution package of Example 1 that conforms to the range defined by the present invention showed an average result or an average result in each performance evaluation test.

  In Example 2, the blend ratio of LDPE and HDPE in the PE second layer and PE first B layer of the composite film of Example 1 was changed so that HDPE increased. It was recognized that the change in the blend ratio slightly improved the film film breakability and openability.

  In Example 3, the material of the plastic sheet of Example 1 was replaced with APET, and although the interlaminar adhesive strength was slightly improved, it was recognized that the performance regarding film breakability, crackability, and openability was slightly reduced. It was.

  In Example 4, the material of the plastic sheet of Example 1 was replaced with PC. The crackability was slightly improved, but the openability was slightly lowered.

  A comparative example shows the prior art which uses PVC as a plastic sheet, and when compared with the above-mentioned Example 1, although it is excellent in cracking property, since it has a Ny layer, it is in terms of film breakability and openability. Evaluation is inferior.

  Although the present invention has been described with reference to the most practical and preferred embodiments at the present time, the invention is limited to the embodiments disclosed herein. However, the present invention can be changed as appropriate without departing from the spirit or concept of the invention that can be read from the claims and the entire specification, and a composite film for a lid of a distribution package accompanying such a change is also within the technical scope of the present invention. Must be understood as encompassed by.

It is sectional drawing which shows the layer structure of the composite film for lid | cover materials of the distribution package of this invention. It is a perspective view which shows the external appearance of a distribution package.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Bottom material 2 Cover material 3 Convex part 4 Half cut 10 Plastic layer 20 Coextruded film 30 Surface layer (PE 2nd layer)
40 Intermediate Layer 41 Adhesive Second Layer 42 EVOH Layer 43 Adhesive First Layer 50 Sealing Layer 51 PE First B Layer 52 PE First A Layer

Claims (12)

On the surface layer side of the coextruded film having a surface layer, an intermediate layer and a seal layer in this order, a composite film for a cover material of a distribution package obtained by laminating a plastic sheet by an adhesive processing method,
Each of the surface layer and the sealing layer is composed of at least one polyethylene resin (PE) layer,
The intermediate layer is composed of an ethylene-vinyl acetate copolymer saponified resin (EVOH) layer having an ethylene content of 29 to 47 mol%, and at least one adhesive layer .
The composite film , wherein the PE layer is made of a mixture of low density polyethylene (LDPE) and high density polyethylene (HDPE) . The composite film of Claim 1 whose compounding ratio of LDPE and HDPE in the said PE layer is 40-80: 60-20. The first layer as the sealing layer, the first adhesive layer as the intermediate layer, the EVOH layer and the second adhesive layer, and the coextruded film in which the second PE layer as the surface layer is laminated in this order the composite film according to claim 1 or 2 plastic sheet is laminated. The composite film according to any one of claims 1 to 3, wherein the sealing layer is composed of at least two PE layers composed of the same or different components. The two PE layers are the PE first B layer on the intermediate layer side and the PE first A layer on the opposite side of the intermediate layer side, the PE first A layer is a layer made of LDPE, and PE The composite film according to claim 4, wherein the first B layer is a layer composed of a mixture of LDPE and HDPE. Said plastic sheet, polystyrene, polycarbonate, and the intrinsic viscosity (IV value) 0.50 to 0.90 dl / g at least one of claims formed of a material selected from the group consisting of polyethylene terephthalate 1 of 5 A composite film according to any one of the above. A composite film according to any one of claims 1 to 6 thickness ratio of the plastic sheet to the thickness of said co-extruded film is from 1.5 to 22.5. The composite film according to any one of claims 1 to 7 , wherein a ratio of the thickness of the EVOH layer to the thickness of the PE layer of the surface layer is 0.07 to 15. A composite film according to any one of claims 1-8 total thickness of the layers is 170～550Myuemu. The composite film according to any one of claims 1 to 9 , wherein an adhesive strength between the coextruded film and the plastic sheet is 3.9 to 15 N / 15 mm. The cover material of the distribution package formed with the composite film in any one of Claims 1-10 . A dispensing package using the lid material according to claim 11 .

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