JP2006305886A - Sealant film, packaging material, lid material, and container - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sealant film which has low-temperature heat sealability and easy peelability and is provided with sufficient shielding properties even when white printing or the formation of a foamed resin layer is not carried out, and also to provide a packaging material having the sealant film, a lid material made of the packaging material, and a container having the lid material. <P>SOLUTION: In the sealant film 10, a shielding layer 12 containing specified high density polyethylene (b-1) as a main component and a specified amount of titanium dioxide (b-2) is laminated on one side of a seal layer 11 containing specified amounts of linear low density polyethylene (a-1) produced by a metallocene catalyst or a single site catalyst and at least one resin (a-2) selected from the group consisting of an ethylene-propylene copolymer, ethylene-butene copolymer, propylene-butene copolymer, ethylene-propylene-butene copolymer, and polybutene-1. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a sealant film, a packaging material provided with the sealant film, a lid made of the packaging material, and a container provided with the lid.

Processed foods such as miso, curry, stew, and yogurt are often filled and distributed in resin containers. For example, a resin lid is heat-sealed on the resin container body. Is in the form of
The lid material used for such a container is heat-sealed and attached to a container body in which processed foods as contents are already put. Therefore, the lid material is required to be able to reliably heat-seal (low-temperature heat-sealability) at as low a temperature as possible so that the contents are not heated. In addition, the lid can be easily peeled off from the container body when taking out the contents (easy peel property), can shield light from the point of preservation of the contents, and the contents are adhesive. In some cases, it is desired that the appearance of the contents attached to the inner surface of the lid member is not visible from the outside (shielding property) from the appearance of the product.

Such a laminated structure of the lid material is generally a sealant film, an aluminum foil and a protective film in order from the sealing surface side of the lid material. The sealant film imparts easy peel properties to the cover material, the aluminum foil imparts shielding properties and barrier properties, and the protective film protects the easily damaged aluminum foil and provides printing and decorativeness. Printing may be provided as a printing layer separately from the protective film (for example, Patent Document 1).
However, lid materials using aluminum foil have problems such as difficulty in inspecting the contents of the foreign matter with a metal detector, and residue remaining during incineration. For this reason, the appearance of a cover material that does not use aluminum foil is desired. For example, a sealant film that has been subjected to white printing to develop a shielding property, a barrier film, and a biaxial foam Some have a stretched polypropylene layer.
Japanese Patent Laid-Open No. 06-031876

  However, since the production of such a laminated film requires a printing process, the productivity is not good. Further, since the shielding property is insufficient only with white printing, a biaxially stretched polypropylene layer whitened by foaming is provided, but the foamed material in this way has a problem of low tear strength.

  The present invention has been made in view of the above circumstances, and has a low-temperature heat-sealing property and an easy peel property, and also has a sufficient shielding property without performing white printing or forming a foamed resin layer. It is an object to provide a sealant film, a packaging material provided with the sealant film, a lid made of the packaging material, and a container provided with the lid.

As a result of intensive research on a sealant film having a low-temperature heat-sealing property, an easy peel property, and a shielding property, the present inventors have found that the above-described problems can be solved by using a film having the following constitution. Has been completed.
That is, this invention relates to the sealant film shown by the following (1)-(5), the packaging material using the same, the cover material which consists of this packaging material, and the container provided with this cover material.
(1) 60 to 90% by mass of linear low density polyethylene (a-1) produced by a metallocene catalyst or a single site catalyst, an ethylene-propylene copolymer, an ethylene-butene copolymer, and a propylene-butene copolymer On one side of the sealing layer containing 10 to 40% by mass of at least one resin (a-2) selected from the group consisting of a polymer, an ethylene-propylene-butene terpolymer, and polybutene-1, the density is 0. A sealant film comprising a high-density polyethylene (b-1) of .945 to 0.970 g / cm ³ as a main component and a shielding layer containing 5 to 10% by mass of titanium dioxide (b-2) laminated. .
(2) A part of the linear low density polyethylene (a-1) is replaced with the low density polyethylene (a-11), and the blending ratio of the low density polyethylene (a-11) is 30% by mass in the seal layer. The sealant film according to (1), which is the following.
(3) The linear low density polyethylene (a-1) has a density of 0.890 to 0.935 g / cm ³ and a melt flow rate of 2 to 20 g / 10 minutes. The sealant film according to (1) or (2).
(4) The sealant film according to any one of (1) to (3), wherein the high-density polyethylene (b-1) has a melt flow rate of 1 to 15 g / 10 minutes.
(5) A support layer mainly composed of a linear low density polyethylene (c-1) produced by a metallocene catalyst or a single-site catalyst is laminated on the shielding layer side (1) to The sealant film according to any one of (4).
(6) A packaging material comprising the sealant film according to any one of (1) to (5).
(7) The packaging material according to (6), comprising a gas barrier layer and / or a protective layer.
(8) A lid material comprising the packaging material according to (6) or (7).
(9) A container comprising the lid material according to (8).

  According to the present invention, it is possible to provide a sealant film having a low-temperature heat-sealing property, an easy peel property, and a shielding property, a packaging material provided with the sealant film, a lid made of the packaging material, and a container provided with the lid material. . Further, since the sealant film of the present invention has sufficient shielding properties, it is not necessary to perform white printing or use other layers such as a foamed resin layer in combination, and the productivity and tear strength In addition, there is no problem, and a lighter lid material can be provided by reducing the number of layers.

Hereinafter, the present invention will be described in detail.
FIG. 1 shows an example of the sealant film 10 of the present invention, in which a shielding layer 12 is laminated on one side of a sealing layer 11.
The seal layer 11 is composed of a linear low density polyethylene (a-1) (hereinafter also referred to as “component (a-1)”) produced by a metallocene catalyst or a single site catalyst, and ethylene-propylene copolymer. At least one resin (a-2) selected from the group consisting of a polymer, an ethylene-butene copolymer, a propylene-butene copolymer, an ethylene-propylene-butene terpolymer, and polybutene-1 (hereinafter referred to as “ (A-2) component ”.), And by including such a component (a-1) and component (a-2) at a specific ratio, It expresses both sex and easy peel properties.

  The linear low density polyethylene used for the seal layer 11 is a linear low density polyethylene (hereinafter sometimes referred to as “mLLDPE”) (a-1) produced by a metallocene catalyst or a single site catalyst.

  Here, the metallocene catalyst is, for example, “next-generation polymer industrialization technology using a metallocene catalyst” (Tetsugo Harada, DISK Corporation, P.13, 1994) or “high functionalization of olefin-based and styrene-based resins” (Inc. Technical Information Association, P.13, 2000) and the like, but typical definitions are described here. As generally defined herein, metal atoms such as zirconium, titanium, hafnium and at least one cyclopentadienyl are described. A catalyst comprising a complex with a ring-containing compound, that is, a cyclopentadienyl complex salt can be mentioned. Examples of the cocatalyst include boron compounds such as triphenyl (hydroxyphenyl) borate and tris- (pentafluorophenyl) (4-hydroxyphenyl) borate, and alumoxane such as methylalumoxane, but are not limited thereto. Absent. In addition, a certain kind of metallocene catalyst is a typical single site catalyst, and hereinafter, the metallocene catalyst in the present invention means a metallocene catalyst and / or a single site catalyst.

  mLLDPE is a copolymer mainly composed of one or more olefins selected from ethylene and α-olefins having 3 to 20 carbon atoms. The α-olefin having 3 to 20 carbon atoms is preferably one having 3 to 12 carbon atoms, specifically, propylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene. 1-octene, 1-decene, 1-dodecene and the like. Content of C3-C20 alpha olefin which occupies for a copolymer is 30 mol% or less normally, Preferably it is the range of 2-20 mol%.

The density (measured according to JIS K 7112 D method) of mLLDPE is preferably 0.890 to 0.935 g / cm ³ , more preferably 0.892 to 0.933 g / cm ³ , and particularly preferably 0. 894 to 0.931 g / cm ³ . When the density is less than 0.890 g / cm ³ , the heat seal strength is too strong, and when this sealant film 10 is used for the lid, the easy peel property when peeling the lid may be inferior, If it exceeds 0.935 g / cm ³ , the feathering (fluffing) phenomenon at the time of peeling tends to occur.

  On the other hand, the melt flow rate (hereinafter referred to as “MFR”) is preferably in the range of 2 to 25 g / 10 minutes, more preferably in the range of 6 to 22 g / 10 minutes, and even more preferably in the range of 7 to 20 g / 10 minutes. When the MFR is less than 2 g / 10 minutes, the heat seal strength is too strong, and the easy peel property tends to be inferior when the sealant film 10 is used as a lid. Also, when the lid is peeled off, a white peeling mark is formed on the peeling surface of either the lid or the container body where the lid has been heat-sealed to show that the seal has been reliably made (whitening property) Is preferable, but such whitening property tends to be insufficient. On the other hand, when it exceeds 20 g / 10 minutes, when polybutene-1 is selected as the resin (a-2) described later, the compatibility with polybutene-1 tends to be poor and a feathering phenomenon tends to occur. The MFR is a value measured at a temperature of 190 ° C. and a load of 21.18 N according to JIS K 7210 test condition 4.

  The resin (a-2) contained in the seal layer is composed of an ethylene-propylene copolymer, an ethylene-butene copolymer, a propylene-butene copolymer, an ethylene-propylene-butene terpolymer, and polybutene-1. At least one selected from the group, but among these, since it has excellent low temperature heat sealability, ethylene-butene copolymer, propylene-butene copolymer, ethylene-propylene-butene terpolymer, polybutene -1 butene copolymer is preferable, and polybutene-1 is more preferable.

  The ethylene-propylene copolymer used for the seal layer 11 has an ethylene content of 65 to 85% by mass and an MFR of 0.2 to 20 g measured at a temperature of 230 ° C. and a load of 21.18 N in accordance with JIS K 7210. / 10 minutes are good. When the ethylene content is less than 65% by mass, the low temperature heat sealability and the whitening property are inferior. On the other hand, if it exceeds 85% by mass, the easy peel property is inferior. Preferably, it is 65-82 mass%, More preferably, it is 70-80 mass%. When the MFR is less than 0.2 g / 10 minutes, the easy peel property is inferior. On the other hand, if it exceeds 20 g / 10 minutes, the whitening property and moldability are inferior, which is not preferable. Preferably, it is 0.2-18 g / 10min, More preferably, it is 0.5-15g / 10min.

  The ethylene-butene copolymer used in the seal layer 11 has an ethylene content of 70 to 98% by mass and an MFR measured at a temperature of 230 ° C. and a load of 21.18 N in accordance with JIS K 7210 of 0.1 to 20 g. / 10 minutes are good. When the ethylene content is less than 70% by mass, the heat resistance is inferior, and the peeling appearance, that is, the appearance of the peeling surface when this sealant film is used as a lid material is not good, and the whitening property is also insufficient. Absent. On the other hand, if it exceeds 98% by mass, the easy peel property and the whitening property are inferior. Preferably, it is 72-96 mass%, More preferably, it is 75-95 mass%. As for MFR, when it is less than 0.1 g / 10 min, the easy peel property is inferior, which is not preferable. On the other hand, if it exceeds 10 minutes / 10 minutes, the peel appearance and whitening property are inferior, which is not preferable. Preferably, it is 0.2-9 g / 10min, More preferably, it is 0.5-8g / 10min.

  The propylene-butene copolymer used for the seal layer 11 has a propylene content of 75 to 98% by mass, an MFR measured at a temperature of 230 ° C. and a load of 21.18 N in accordance with JIS K 7210 of 0.1 to 20 g / Good for 10 minutes. When the propylene content is less than 75% by mass, the easy peel property is inferior. On the other hand, if it exceeds 98% by mass, the easy peel property, the whitening property and the low temperature heat seal property are inferior, which is not preferable. When the MFR is less than 0.1 g / 10 minutes, the easy peel property is inferior. On the other hand, if it exceeds 20 g / 10 min, the peel appearance and the whitening property are inferior. Preferably, it is 0.5-18 g / 10 minutes, More preferably, it is 1-15 g / 10 minutes.

An ethylene-propylene-butene terpolymer (hereinafter sometimes referred to as “PEB”) is a copolymer mainly composed of propylene, ethylene and butene-1, and is usually a resin obtained by a multistage copolymerization method. It is.
The PEB used for the sealing layer 11 is preferably one having a crystallization peak temperature (Tcp) of 75 to 90 ° C. and a crystallization energy (ΔH) of 55 to 80 J / g as measured by a differential scanning calorimeter (DSC). . Although it does not specifically limit about the melting temperature (Tmp) of PEB, the thing of the range of 125-145 degreeC is good.
Here, Tcp and ΔH are about 3 to 5 mg of a precisely weighed sample set in DSC, heated to a sample temperature of 230 ° C., held for 5 minutes, and then up to 30 ° C. at a rate of 20 ° C./min. This value is obtained by lowering the temperature.

  Regarding the composition ratio of PEB, since the low-temperature heat sealability is excellent, the propylene content is 96 to 72% by mass, the ethylene content is 1 to 10% by mass, and the butene-1 content is 3 to 18% by mass. Is good. The propylene content is preferably 95.3 to 75 mass%, particularly preferably 94.5 to 77 mass%. As ethylene content, 1.2-8 mass% is preferable, and 1.5-7 mass% is especially suitable. Moreover, as butene-1 content, 3.5-17 mass% is preferable, and 4.0-16 mass% is especially suitable.

  Polybutene-1 (hereinafter referred to as “PB”) is polymerized using butene-1 monomer as a raw material, and is the same kind of polyolefin as polyethylene and polypropylene. In general, PB has a high molecular weight and high isotacticity. As a polymerization method, a method of polymerizing using a Ziegler-Natta catalyst and a butene-1 monomer as a solvent, or a solution polymerization method using a hydrocarbon solvent such as hexane or heptane is used.

  Since PB has a lower secondary transition point than polypropylene, its elastic modulus at room temperature or low temperature is higher than that of polypropylene [D. G. Natta et. al: J. et al. Polymer Sci. Vol. 25 p119 (1957)] is known as a polymer having rubber elasticity.

PB is used as a pipe raw material, a tube, and a modifier because it is superior to polyethylene and polypropylene in mechanical properties such as tensile strength, impact strength, and tear strength.
In the film field, PB is used for the purpose of imparting low-temperature heat-sealing properties or imparting easy peel properties by blending with other resins.
Regarding the properties and uses of these PBs, for example, “Latest Laminating Handbook”, pages 861 to 866 (1989) published by the Processing Technology Research Group and “ID Rubin, Poly (1-Butene) -its Preparation and Properties”, Gordon and Breach Science Publishers, inc. , New York (1968) and the like.

  In the present invention, the PB used for the seal layer 11 preferably has an MFR according to ASTM D1238E of 0.5 to 15 g / 10 min, more preferably 0.8 to 12 g / 10 min. A range of / 10 minutes is even more preferred. When the MFR is less than 0.5 g / 10 min, the heat seal strength becomes too high and the easy peel property may be inferior. On the other hand, when it exceeds 15 g / 10 min, if the seal portion is peeled off, feathering of the peeled portion will occur. The phenomenon may occur or the whitening property at the time of peeling may be inferior.

About the melting point of PB, the thing of the range of 100-140 degreeC by the method by a differential scanning calorimeter (DSC) is good. When the melting point is 100 ° C. or lower, if the seal part is peeled off, a feathering phenomenon of the peeled part occurs or the whitening property tends to be poor. On the other hand, heat seal strength exceeding 140 ° C., low temperature heat sealability and whitening property tend to be inferior.
These PBs are sold, for example, by Shell Chemical Co., Ltd. and Mitsui Chemicals as “Brand Name: Bureon” and can be suitably used.

The mixing ratio of mLLDPE (a-1) and resin (a-2) constituting the seal layer 11 is 60 to 90% by mass for mLLDPE (a-1), and 10 to 40 for resin (a-2). % By mass. Preferably, the component (a-1) is 65 to 85% by mass, the component (a-2) is 15 to 35% by mass, particularly preferably the component (a-1) 65 to 75% by mass, and the component (a-2). Is 25 to 35% by mass.
Here, when the component (a-1) is less than 60% by mass, the low temperature heat sealability, the heat seal strength, and the whitening property tend to decrease, which is not preferable. In addition, a feathering phenomenon is likely to occur during peeling. On the other hand, when it exceeds 90 mass%, it may seal other than the part which is going to heat seal at the time of heat sealing other than the fall of whitening property. As a result, it is difficult to take out the contents from a packaging body such as a bag formed from the packaging material provided with the sealant film 10, or the easy peel property of the lid formed from the same packaging material is reduced, Furthermore, these packages and lids may be inferior in appearance, which is not preferable.
Further, when the component (a-2) is less than 10% by mass, the easy peel property is inferior, which is not preferable. On the other hand, if it exceeds 40% by mass, feathering during peeling tends to occur, which is not preferable.

  Thus, by including the component (a-1) and the component (a-2) at a specific ratio, the seal layer 11 exhibits both low-temperature heat sealability and easy peel property.

The sealing layer 11 may contain low-density polyethylene (a-11) (hereinafter also referred to as “LDPE” or simply “(a-11) component”) in a range of 30 mass% or less. By adding LDPE to the sealing layer 11 in this range, easy peel properties, moldability, whitening properties, and the like can be adjusted.
In addition, (a-11) component is added here in the form which substitutes a part of (a-1) component. That is, when the (a-11) component is added to the seal layer 11 composed of the (a-1) component and the (a-2) component, the blending ratio of the (a-2) component does not change, and (a-1) The blending ratio of the component is reduced by the blending ratio of the component (a-11).
Although there is no restriction | limiting in particular as LDPE, The density measured based on JISK7112D method is 0.910-0.925g / cm < ³ >, Temperature 190 degreeC according to JISK7210, Load 21. The MFR measured at 18N is preferably 20 g / 10 min or less. The density is preferably 0.912 to 0.924 g / cm ³ , particularly 0.915 to 0.923 g / cm ³ . The MFR is preferably 15 g / 10 min or less, and particularly preferably 0.1-10 g / 10 min.

The shielding layer 12 constituting the sealant film 10 is mainly composed of high density polyethylene (b-1) having a density of 0.945 to 0.970 g / cm ³ , and 5 to 10% by mass of titanium dioxide (b-2). It is formed including.
Thus, by providing the shielding layer 12 containing titanium dioxide (b-2), for example, when this sealant film 10 is used as a packaging material or a cover material, the contents are difficult to see from the outside, and the product is used as a product. It is preferable from the aspect of appearance, and the preservability of the contents can be enhanced by its light shielding property. Moreover, by using high-density polyethylene (b-1) as the main component, the sealant film 10 has excellent water vapor barrier properties, a wide heat seal temperature range, and excellent heat seal strength stability and low temperature heat seal properties. Easy peel properties are also good, making it suitable for use as a packaging material or lid. Here, when titanium dioxide (b-2) is contained in, for example, the sealing layer 11 described above, the heat-sealing property of the sealing layer 11 is lowered. On the other hand, when titanium dioxide (b-2) is contained in the support layer 13 described later, sufficient light-shielding properties are obtained. Cannot be obtained.
In addition, a main component means 50 mass% or more here. Further, the shielding layer 12 may contain other resins such as polyolefin resin within a range in which HDPE is a main component. In such a case, titanium dioxide (b-2) may be mixed with other polyolefin resin in advance to form a master batch, which may be blended with HDPE.

The high density polyethylene (b-1) (hereinafter sometimes referred to as “HDPE”) used for the shielding layer 12 has a density of 0.945 to 0.970 g / cm ³ and 0.952 to 0.965 g / cm ^3. The range of cm ³ is preferable, and the range of 0.953 to 0.962 g / cm ³ is more preferable. When the density is less than 0.945 g / cm ³ , the rigidity of the film is lowered, the workability is deteriorated, and the whitening property at the time of peeling is inferior. On the other hand, when it exceeds 0.970 g / cm ³ , there is a problem that the low temperature heat sealability and the whitening property are impaired.

  Based on JIS K 7210 of HDPE, MFR measured at a temperature of 190 ° C. and a load of 21.18 N is preferably in the range of 1 to 15 g / 10 minutes, more preferably in the range of 2 to 13 g / 10 minutes, and 3 to 12 g / Even more preferred is a range of 10 minutes. When the MFR is less than 1 g / 10 min, the low-temperature heat sealability and whitening property tend to be inferior. On the other hand, when the MFR exceeds 15 g / 10 min, the film tends to tear in the vertical direction or the feathering phenomenon occurs at the time of peeling. May occur.

As the titanium dioxide (b-2) contained in the shielding layer 12, any of rutile type, anatase type and the like can be used, but there is no particular limitation, but in terms of shielding properties, the average particle size is 0.01 to 5 μm. It is preferred to use particles. More preferably, it is 0.03-3 micrometers. When the average particle size is in these preferred ranges, the concealability is excellent, so there is no need to increase the content of the particles and there is no possibility that the film moldability will deteriorate.
Moreover, 5-10 mass% is contained in the shielding layer 12 for titanium dioxide (b-2). When the content is less than 5% by mass, the shielding effect of the shielding layer 12 is insufficient. On the other hand, when the content exceeds 10% by mass, the sealing strength between the shielding layer 12 and the sealing layer 11 and a support layer described later is obtained. Decrease

As another form of the sealant film 10 of the present invention, a form in which a support layer 13 containing mLLDPE (c-1) as a main component is further laminated on the shielding layer 12 side as shown in FIG. The sealant film 10 provided with such a support layer 13 is preferable because of less curling. In addition, a main component means 50 mass% or more here.
As mLLDPE (c-1) used for the support layer 13, the thing similar to mLLDPE (a-1) which forms the sealing layer 11 illustrated previously can be used preferably.
As another form, although illustration is abbreviate | omitted, the sealant film of the form which the sealing layer 11 laminated | stacked on both surfaces of the shielding layer 12 can also be illustrated.

  The thickness of the sealant film 10 can be set as appropriate, but if it is in the range of 20 to 70 μm, it is suitable for use as a packaging material and further as a lid, preferably 20 to 60 μm, particularly preferably 25 to 50 μm.

Regarding the thickness ratio of the sealing layer 11 and the shielding layer 12, the sealing layer 11: shielding layer 12 is preferably in the range of 0.05 to 0.3: 0.95 to 0.7, preferably 0.07 to 0. .25: 0.93-0.75, more preferably in the range of 0.1-0.2: 0.9-0.8.
When the thickness ratio of the sealing layer 11 is less than 0.05, when heat sealing is performed, a part where the shielding layers 12 are partially heat sealed occurs, and the heat seal strength is increased. When opening a packaging body such as a bag formed from a packaging material provided with or a lid material, there may be a problem that the end of the heat seal is cut and it is difficult to take out the contents. On the other hand, when the thickness ratio of the seal layer 11 exceeds 0.3, feathering may occur or the water vapor barrier property of the sealant film 10 may be lowered. When providing the support layer 13, the thickness can be suitably selected from the surface of curling suppression, and it is preferable that it is specifically the same thickness as the seal layer 11.

The manufacturing method of the sealant film 10 is not particularly limited, and a known molding method may be used. For example, an additive is added to the resin component of each layer of the sealant film 10 as necessary, and the components are mixed with a mixer such as a mixing roll, a Banbury mixer, a Henschel, a tumbler, and a ribbon blender, and then kneaded using an extruder. Examples of the method include processing by pelletization or direct dry blending, and then forming into a film by an extrusion lamination molding method, a coextrusion inflation molding method, a coextrusion T-die molding method, or the like.
Among these, when the sealant film 10 is produced by a coextrusion molding method, a film having an excellent whitening property can be obtained by forming a film at an extrusion temperature of 160 to 250 ° C. and cooling at a cooling temperature of 40 to 80 ° C. .

  As described above, the sealant film 10 of the present invention is provided as necessary on the sealing layer 11, the shielding layer 12 laminated on one side of the sealing layer 11, and the surface of the shielding layer 12 opposite to the sealing layer 11. The support layer 13 is provided and can be used as it is as a packaging material. However, the provision of the gas barrier layer and the protective layer further improves the storage stability of the contents and the film strength. It can be a packaging material.

The gas barrier layer and the protective layer are obtained by laminating the sealant film 10 with or without an adhesive.
Examples of the gas barrier layer include aluminum foil, metal vapor deposited film, silicon oxide vapor deposited film, polyamide resin, vinyl chloride resin, saponified ethylene-vinyl acetate copolymer, and a layer in which a protective layer is coated with polyvinyl alcohol. Can be mentioned.
Specific examples of the protective layer include a polyester resin layer, a polyamide resin layer, and a polycarbonate resin layer.
When providing both a gas barrier layer and a protective layer, the form which laminated | stacked the gas barrier layer and the protective layer one by one on the opposite side of the seal layer 11 in the sealant film 10 is preferable.
Moreover, you may use for this packaging material further laminating | stacking another polyolefin resin layer in the range which does not impair the objective of this invention.
As a method for obtaining the packaging material, a known extrusion laminate molding method, dry laminate molding method, or the like can be used.

  Such a packaging material can be used for various applications, but is a lid in a form that is attached to the container body by heat sealing and opened by peeling, or a bag in which the sealing layers 11 are fused together by heat sealing. Suitable for forming packaging bodies such as bodies. In particular, such a packaging material has a sealant film that combines a low-temperature heat-sealing property, an easy peel property, and an excellent shielding property, and is therefore filled with an adhesive processed food such as miso. It is particularly suitable for use on container lids. In addition, since such a packaging material has a water vapor barrier property and is excellent in preservability, has a whitening property, and can be confirmed to have been reliably sealed before opening, a lid for a container for processed food As preferred.

The material of the container body to which the lid material is heat-sealed is not particularly limited, but the sealant film 10 of the present invention is excellent in easy peel property from a resin mainly composed of polyolefin, particularly polypropylene. Therefore, it is preferable that at least a portion to which the lid member is attached is formed from a resin whose main component is homopolypropylene. Specifically, a container body composed of three layers in which a layer made of ethylene-vinyl alcohol copolymer (EVOH) is disposed between two layers mainly composed of homopolypropylene can be exemplified. An adhesive layer may be disposed between the three layers.
In addition, as a material of the container, in addition to the polypropylene, polyolefin such as polyethylene and poly-4-methylpentene-1, polyester, polystyrene, and the like can be given.

  For the constituent materials of the layers constituting the sealant film 10 and the packaging material described above, other additives commonly used for thermoplastic resins (for example, antioxidants, weather resistance stabilizers, antistatic agents, lubricants). , Anti-blocking agents, anti-fogging agents, dyes, pigments, oils, waxes, fillers, etc.) and other thermoplastic resins can be appropriately blended within the range not impairing the object of the present invention.

  For example, examples of such additives include 2,5-di-t-butylhydroquinone, 2,6 di-t-butyl-p-cresol, 4,4′-thiobis- (6- t-butylphenol), 2,2-methylene-bis (4-methyl-6-tert-butylphenol), octadecyl 3- (3 ′, 5′-di-t-butyl-1′-hydroxyphenyl) propionate, 4,4 '-Thiobis- (6-butylphenol), UV absorbers include ethyl-2-cyano-3, 3-diphenyl acrylate, 2- (2'-hydroxy-5-methylphenyl) benzotriazole, 2-hydroxy-4- Octoxybenzophenone, dimethyl phthalate, diethyl phthalate, wax, liquid paraffin, phosphate ester as plasticizer, antistatic agent Interslit slit monostearate, sorbitan monopalmitate, sulfated oleic acid, polyethylene oxide, carbon wax, ethylene bisstearamide, butyl stearate as a lubricant, fatty acid amide (stearic amide, oleic amide, erucic amide, etc. ), Carbon black, phthalocyanine, quinacridone, indoline, azo pigment, titanium oxide, bengara, etc. as colorants, glass fiber, asbestos, mica, wollastonite, calcium silicate, aluminum silicate, calcium carbonate, blocking as fillers Examples of the inhibitor include silicate type (calcium silicate, aluminum silicate, etc.), silicone type, zeolite type, talc, polymethyl methacrylate (PMMA) particles and the like. As specific examples of the addition method and addition amount, silicate 6000 to 12000 ppm, PMMA particles 2,000 to 6,000 ppm, fatty acid amide 300 to 1,000 ppm, and support layer 13 silicate 4 By adding 2,000 to 8,000 ppm, it is possible to obtain a laminated film that satisfies the main problems of the present invention and is further excellent in blocking resistance. Furthermore, if the additive is granular, the average particle size is preferably 0.05 μm to 20 μm, more preferably 0.1 to 10 μm or less.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to these Examples.

[Resin used]
PE1: Single-site catalyst linear low-density polyethylene having an MFR of 15 g / 10 min and a density of 0.912 g / cm ³ .
PE2: A high-pressure low-density polyethylene using a peroxide having an MFR of 5.0 g / 10 min and a density of 0.918 g / cm ³ .
PE3: Zigler-Natta linear low-density polyethylene having an MFR of 2 g / 10 min and a density of 0.929 g / cm ³ .

PE4: A high-pressure low-density polyethylene using a peroxide having an MFR of 3.5 g / 10 min and a density of 0.924 g / cm ³ .
PE5: Single-site catalyst linear low-density polyethylene having an MFR of 3.5 g / 10 min and a density of 0.921 g / cm ³ .
PE6: Zigler-Natta linear low density polyethylene having an MFR of 2.8 g / 10 min and a density of 0.932 g / cm ³ .

HDPE1: A high density polyethylene having an MFR of 7.6 g / 10 min and a density of 0.958 g / cm ³ .
HDPE2: High density polyethylene having an MFR of 8.6 g / 10 min and a density of 0.945 g / cm ³ .

PB1: “trade name: Burelon BL4000” manufactured by Mitsui Chemicals, Inc., which is polybutene-1 having an MFR of 1.8 g / 10 min, a density of 0.915 g / cm ³ , and a melting point of 125 ° C.
PB2: “Buron BL7000” manufactured by Mitsui Chemicals, Inc., which is polybutene-1 having an MFR of 20 g / 10 min, a density of 0.917 g / cm ³ , and a melting point of 123 ° C.
PB3: “Brand: Bureon M2181” manufactured by Mitsui Chemicals, Inc., which is polybutene-1 having an MFR of 1.0 g / 10 min, a density of 0.900 g / cm ³ , and a melting point of 75 ° C.

PEP: “trade name: TAFMER P” manufactured by Mitsui Chemicals, which is an ethylene-propylene copolymer having an MFR of 5.4 g / 10 min and a density of 0.87 g / cm ³ .
PEB: “trade name: TAFMER A” manufactured by Mitsui Chemicals, which is an ethylene-butene copolymer having an MFR of 3.6 g / 10 min and a density of 0.88 g / cm ³ .
PPB: “trade name: Crylell 722RCXP” manufactured by Sun Allomer Co., which is a propylene-butene copolymer having an MFR of 10 g / 10 min and a density of 0.90 g / cm ³ .
PEPB: “trade name: Adsy5C37F” manufactured by Sun Allomer Co., Ltd., which is an ethylene-propylene-butene terpolymer having an MFR of 5.5 g / 10 min and a density of 0.90 g / cm ³ . Tcp, ΔH, and Tmp are 84.5 ° C., 63.1 J / g, and 135 ° C., respectively.

PP1: Propylene-ethylene random copolymer having an ethylene content of 6.5% by mass, a temperature of 230 ° C., and a load of 2.16 kg of MFR of 20 g / 10 min.
PP2: Homopolypropylene having a temperature of 230 ° C. and a load of 2.16 kg of MFR of 8.5 g / 10 min.

(Examples 1-9 and Comparative Examples 1-5)
[Creation of specimen]
[Kneading process]
The composition and pelletization of each component of the sealing layer and each component of the shielding layer shown in Table 1 were performed as follows.
(A-1) component and (a-2) component of the seal layer constituting material, and further (a-11) component if necessary mixed with a tumbler, and then a twin-screw extruder manufactured by Kobe Steel Co., Ltd. (KTX37 type) ) At a temperature of 190 to 210 ° C. At this time, 4,000 ppm of PMMA particles were added as an antiblocking agent.
On the other hand, in accordance with JIS K 7210, a titanium dioxide masterbatch containing 50% by mass of titanium dioxide having an average particle size of 2 μm in a homopolypropylene having an MFR measured at a temperature of 230 ° C. and a load of 21.18 N of 7 g / 10 min was prepared. A predetermined amount of the component (b-2) is added to the component (b-1) of the shielding layer constituent material using the masterbatch, and a temperature of 230 is used using a Kobe Steel Works twin screw extruder (KTX37 type). Pelletized at 0 ° C.

[Manufacture of sealant film]
A sealant film was prepared at a die temperature of 210 ° C. and a cooling temperature of 70 ° C. using a T-die film molding machine manufactured by Toshiba Machine Co., Ltd. having a diameter of 65 mmφ and a die width of 1,300 mm, using each of the kneaded pellets. . In addition, the layer structure and thickness of the film were set to 2 layers of 2 layers of seal layer / shield layer = 8 μm / 32 μm or 3 layers of 3 layers of seal layer / shield layer / support layer = 6 μm / 28 μm / 6 μm.
[Manufacture of packaging materials]
Next, a nylon film made of a polyamide resin having a thickness of 15 μm and a polyester film having a thickness of 12 μm were laminated on the surface opposite to the seal layer of the sealant film by a urethane-based adhesive by a dry laminating method to obtain a packaging material.

[Heat seal]
The sealant film surfaces of the packaging material were put together and heat sealing was performed using a heat sealer manufactured by Tester Sangyo Co., Ltd. at a pressure of 0.2 MPa and a time of 1 second. The heat seal temperatures were 120 ° C, 140 ° C and 160 ° C.

[Method of measuring physical properties]
[Heat sealability]
A test piece after heat sealing at each temperature was cut out to a width of 15 mm, and the heat seal strength was determined by peeling at 180 ° using a tensile tester (RTA-100 type) manufactured by Orientec Co., Ltd. under a tensile speed of 300 mm / min. . The test was conducted at 10 points, and the average value was obtained. In addition, the heat seal temperature is three points of 120 ° C., 140 ° C., and 160 ° C. as described above.
[Shielding]
Haze: Total haze was measured in accordance with the method of JIS K 7105.
Permeability: A small amount of miso was allowed to adhere to the sealing layer side of the lid, and visually judged from the opposite side according to the following criteria.
○: The color of miso on the miso-attached part is not visible.
X: The color of miso on the miso-attached part is seen through.

As is apparent from Table 1, the heat seal strength at each heat seal temperature was appropriate for each example, and it had both low temperature heat sealability at 120 to 160 ° C. and easy peel property. In addition, each of the examples had no significant variation in the heat seal strength between the heat seal temperatures, and was excellent in the stability of the heat seal strength. Further, these materials also had sufficient shielding properties.
On the other hand, in Comparative Examples 1 to 3 in which a component other than the linear low density polyethylene produced by a metallocene catalyst or a single site catalyst was used as the component (a-1) of the seal layer, the heat sealability was poor. Specifically, in Comparative Example 1, when the heat seal temperature is 160 ° C., the heat seal strength is rapidly increased as compared with the case of 120 ° C. or 140 ° C., and the heat seal temperature range is narrow. The stability of the seal strength was poor. In Comparative Example 2, the heat seal strength at each temperature was too weak, and in Comparative Example 3, the heat seal strength at each temperature was too strong. Moreover, since the thing of the comparative examples 4 and 5 did not contain an appropriate amount of titanium dioxide (b-2) in the shielding layer, shielding property was inadequate.

It is sectional drawing which shows an example of the sealant film of this invention. It is sectional drawing which shows another example of the sealant film of this invention.

Explanation of symbols

10 Sealant Film 11 Seal Layer 12 Shielding Layer 13 Support Layer

Claims (9)

60 to 90% by mass of linear low density polyethylene (a-1) produced by a metallocene catalyst or a single site catalyst, an ethylene-propylene copolymer, an ethylene-butene copolymer, a propylene-butene copolymer, On one side of a sealing layer containing 10 to 40% by mass of at least one resin (a-2) selected from the group consisting of ethylene-propylene-butene terpolymer and polybutene-1,
A sealant comprising a high-density polyethylene (b-1) having a density of 0.945 to 0.970 g / cm ³ as a main component and a shielding layer containing 5 to 10% by mass of titanium dioxide (b-2) laminated. the film.   A part of the linear low density polyethylene (a-1) is replaced with the low density polyethylene (a-11), and the blending ratio of the low density polyethylene (a-11) is 30% by mass or less in the seal layer. The sealant film according to claim 1. The linear low-density polyethylene (a-1) has a density of 0.890 to 0.935 g / cm ³ and a melt flow rate of 2 to 20 g / 10 minutes. The sealant film described in 1.   The sealant film according to any one of claims 1 to 3, wherein the high-density polyethylene (b-1) has a melt flow rate of 1 to 15 g / 10 min.   The support layer mainly composed of a linear low density polyethylene (c-1) produced by a metallocene catalyst or a single site catalyst is laminated on the shielding layer side. The sealant film according to crab.   A packaging material comprising the sealant film according to any one of claims 1 to 5.   The packaging material according to claim 6, further comprising a gas barrier layer and / or a protective layer.   A lid material comprising the packaging material according to claim 6 or 7. A container comprising the lid according to claim 8.

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