JP6241112B2 - Sealant film - Google Patents

Description

  The present invention relates to a non-adsorptive sealant film in which the adsorption amount of organic compounds contained in contents such as pharmaceuticals, cosmetics and foods is reduced, a packaging material using the same, and a container comprising the same.

  More specifically, since the amount of adsorption of the organic compound in the content is reduced, the sealant film having a sealant film excellent in maintaining the quality of the content and excellent in heat sealability, packaging material, and more Related to the container.

Generally, a container consists of a packaging material having a base material layer and a sealant film.
As these sealant films, a thermoplastic resin is used, and in particular, a high-pressure low-density polyethylene resin (LDPE, density 0.910 to 0.925 g / cm ³ ) and the like are excellent in terms of laminate processability and heat sealability. It is used.

Although LDPE can achieve high adhesion strength by heat sealing, it is known that it can easily adsorb organic compound components. Therefore, the container having the sealant film made of LDPE as the innermost layer, that is, the layer in contact with the contents, easily adsorbs the organic compound component contained in the contents and easily changes or deteriorates the contents.
Further, for example, if an aluminum foil or the like is provided on LDPE in order to provide gas barrier properties, delamination occurs between the two layers, and it cannot be practically used.

On the other hand, in some cases, a medium density polyethylene resin (MDPE, density 0.926 to 0.940 g / cm ³ ) is used as the sealant film. However, MDPE has a drawback that a stable sealing temperature range cannot be obtained because the heat sealing temperature during box making (container molding) must be set higher than that of LDPE in order to obtain sufficient adhesion strength.

  Furthermore, when heat-sealed at such a high temperature, MDPE is oxidized and an oxidized odor is generated. Therefore, a container having a sealant film made of MDPE as the innermost layer has a drawback that the oxidized odor of the resin easily moves into the contents. Have

  In some cases, a polyester resin is used as the sealant film (Patent Document 1). However, since the polyester-based resin has poor heat sealability and is likely to cause a sealing failure at the time of box making, a container having a sealant film made of such a resin has drawbacks such as leakage of contents.

JP-A-5-162737

  The present invention solves the above problems and makes it difficult to adsorb organic compound components, that is, a non-adsorbent and excellent heat sealability, a packaging material using this as a sealant film, And it aims at providing the container which consists of it.

  As a result of various studies, the present inventor has found that a layer composed of a linear low-density polyethylene resin and a cyclic polyolefin-based resin achieves the above object as a sealant film.

The present invention is characterized by the following points.
1. A linear low density polyethylene resin layer, a first layer composed of a linear low density polyethylene resin and a cyclic polyolefin resin, and the first layer are a linear low density polyethylene resin and a cyclic polyolefin resin. A sealant film comprising three layers in which a second layer composed of a linear low-density polyethylene resin and a cyclic polyolefin-based resin having different mixing ratios is provided in this order.
2. 2. The sealant film according to 1, wherein the second layer contains an inorganic filler.
3. The packaging material which used the sealant film in any one of said 1-2 as a sealing layer.
4). A container obtained by box-forming the packaging material according to 3 above so that the sealant film is the innermost layer.

  The present invention is characterized in that the sealant film is composed of a linear low density polyethylene resin and a cyclic polyolefin resin. Furthermore, it is a sealant film which has a linear low density polyethylene resin layer adjacent to the said layer.

  It is known that a cyclic polyolefin-based resin has a high intermolecular force during melt film formation and causes aggregation between polymers. As a result, it is difficult to obtain a uniform film surface by agglomerating the resin throughout the film to form a knob-like gel mass. This tendency becomes more prominent at the time of film formation by the inflation method, and the resulting cyclic polyolefin-based resin film generates innumerable gel lumps on the entire surface.

  However, according to the present invention, the resin layer is a mixture of a linear low density polyethylene resin and a cyclic polyolefin resin, or the resin layer is further formed adjacent to the linear low density polyethylene resin layer. By doing so, non-uniform aggregation of molecules of the cyclic polyolefin resin is suppressed.

  Therefore, the sealant film of the packaging material of the present invention is easy to form, and can form a beautiful layer that is homogeneous and has good transparency. In addition, the generation of gel lumps can be suppressed during high-speed film formation by the inflation method.

  In such a sealant film of the present invention, the layer containing the cyclic polyolefin resin forms a close surface structure with a close distance between molecules based on the high intermolecular force of the cyclic polyolefin resin. The chain low density polyethylene resin layer exhibits high interlayer adhesion with the layer containing the cyclic polyolefin resin, and imparts good film forming stability to the layer containing the cyclic polyolefin resin. Therefore, the sealant film and the packaging material of the present invention having such a structure are difficult to adsorb components in the contents, that is, excellent in non-adsorption.

And the packaging material of this invention is excellent in the non-adsorption property with respect to especially a volatile component (1-menthol, camphor, etc.).
In addition, the sealant film of the present invention exhibits good heat sealing properties and can be heat sealed in a wide sealing temperature range. Therefore, even when heat-sealing at a low temperature similar to that of a general LDPE sealant, sufficient sealing strength is exhibited during box making. Therefore, processing is easy and there is little generation | occurrence | production of resin oxidation odor etc.

  Moreover, by making the innermost layer of the container a blend layer of a cyclic polyolefin-based resin and a linear low-density polyethylene resin, it is possible to ensure both sealing performance with the surface, adhesion, and non-adsorption. Moreover, the sealing performance between the inner surfaces is also improved.

  On the other hand, if the innermost layer is formed only of the cyclic polyolefin resin, a sufficient seal cannot be obtained, and if the innermost layer is made of only the polyethylene resin, non-adsorption cannot be secured, and the innermost layer and the layer adjacent thereto cannot be secured. It is not possible to prevent delamination, which is a delamination phenomenon occurring between the layers.

  That is, as the adsorption of the organic compound in the contents proceeds, the adsorbed component accumulates between the innermost layer and the adjacent layer, causing problems such as a reduction in cutability and delamination. Can be prevented.

  Further, the sealant film of the present invention is sandwich-laminated with a base material layer or a barrier layer through an intermediate layer made of, for example, a low density polyethylene resin (LDPE), or coextruded on the base material layer or the barrier layer. A packaging material is formed by coating.

  Therefore, the sealant film of the present invention can be produced easily and at low cost while maintaining excellent non-adsorbability and heat sealability, and there is no concern about residual solvent. Therefore, the expiration date of the contents can be significantly improved.

In addition, the intermediate layer provided in the preparation of the packaging material not only functions as an adhesive layer, but also melts by heat sealing at the time of box making and contributes to stable sealing by filling the gap generated in the stepped portion of the container. It enables filling of various contents including liquids.
Therefore, the sealant film of the present invention is particularly suitable for forming a packaging material or a container that is required to maintain the quality of contents.

It is a schematic sectional drawing which shows the sealant film of this invention. It is a schematic sectional drawing which shows the example about the layer structure of the packaging material using the sealant film of this invention.

The above-described present invention will be described in more detail below.
1. Layer structure of the sealant film of the present invention and a packaging material using the same FIG. 1 is a schematic cross-sectional view showing the sealant film of the present invention.
FIG. 2 is a schematic cross-sectional view showing an example of the layer structure of a packaging material using the sealant film of the present invention.

  As shown in FIG. 1, the sealant film of the present invention comprises a linear low density polyethylene resin layer 8, a first layer 3 composed of a cyclic polyolefin resin and a linear low density polyethylene resin, a cyclic polyolefin resin, This is a three-layered layer in which a second layer composed of a linear low-density polyethylene resin and an inorganic filler is provided in this order.

  The packaging material using the sealant film of the present invention is formed by three-layer co-extrusion of the intermediate layer 2, the first and second layers made of a cyclic polyolefin resin and a linear low-density polyethylene resin. 4 layers of the intermediate layer 2, the linear low density polyethylene resin layer 8, and the first and second layers made of the cyclic polyolefin resin and the linear low density polyethylene resin are formed by co-extrusion. You can also

  The packaging material using the sealant film of the present invention may further have a barrier layer 7 made of any gas barrier film or the like on the base material layer 1. In this case, the barrier layer 7 and the sealant film may be laminated via the intermediate layer 2. The base material layer 1 having the barrier layer 7 can be laminated by any method such as sandwich lamination or dry lamination.

The packaging material of the present invention may also have a layer made of an arbitrary polyethylene resin (PE) on the surface opposite to the sealant film as a surface protective layer serving as the outermost layer of the container. The surface protective layer can be laminated on the surface of the packaging material by extrusion coating a molten PE resin or by laminating a PE film by any method.
Hereinafter, the resin names used in the present invention are those commonly used in the industry. In the present invention, the density conforms to JIS K7112.

2. Sealant Film The sealant film of the present invention is characterized by comprising a linear low density polyethylene resin and a cyclic polyolefin resin. And since the sealant film containing this cyclic polyolefin resin becomes the outermost layer of the packaging material of the present invention, that is, the innermost layer of the container, it can exhibit excellent non-adsorbability.

(1) Structure of sealant film In one embodiment of the present invention, the sealant film is a two-layered layer made of a linear low-density polyethylene resin and a cyclic polyolefin-based resin, and the two layers are linear low-density polyethylene. The mixing ratio of the resin and the cyclic polyolefin resin is different.

  In this sealant film, a first layer composed of a linear low-density polyethylene resin and a cyclic polyolefin resin is disposed on the intermediate layer side, and a linear low-density polyethylene resin provided on the first layer. And the second layer made of a cyclic polyolefin resin contains an inorganic filler.

  In another aspect of the present invention, the sealant film is composed of a linear low density polyethylene resin layer, and a total of three layers, each of which is composed of a linear low density polyethylene resin and a cyclic polyolefin-based resin. The layers differ in the mixing ratio of the linear low density polyethylene resin and the cyclic polyolefin resin.

(A) First layer The first layer is mainly a layer for ensuring non-adsorption to organic compound components. Therefore, the mixing ratio of the first layer composed of the linear low-density polyethylene resin and the cyclic polyolefin resin is higher than that of the cyclic polyolefin resin.

The ratio of the cyclic polyolefin resin in the first layer is 90 to 99% by mass, preferably about 95 to 98% by mass, and the ratio of the linear low density polyethylene resin is 1 to 10% by mass, preferably 2 to 5% by mass. If the ratio of the cyclic polyolefin resin is larger than this, the processability is deteriorated, and if it is smaller than this, sufficient non-adsorption property cannot be ensured.
And the thickness of a 1st layer is about 3-10 micrometers. If the thickness is larger than this, the film formed thereby may become hard and wrinkles may occur.

(Ii) Second layer The second layer is mainly a layer for ensuring sealing properties. Therefore, the mixing ratio of the second layer composed of the linear low density polyethylene resin and the cyclic polyolefin resin is slightly higher than the ratio of the linear low density polyethylene resin.

  In addition, it is difficult to form a uniform layer by forming only the first layer, but it is smooth by coextrusion with the second layer in which the ratio of the linear low density polyethylene resin is high. Film formation becomes possible.

  The ratio of the cyclic polyolefin resin in the second layer is 30 to 50% by mass, preferably about 35 to 45% by mass, and the ratio of the linear low density polyethylene resin is 45 to 65% by mass, preferably It is about 55-60 mass%.

  Furthermore, the second layer can contain an inorganic filler in order to improve slipperiness during processing. This is because the lubricant or the like cannot be sprayed during processing when the contents are liquid.

  The addition amount of the inorganic filler is 0.5 to 5% by mass, preferably about 2 to 4% by mass with respect to the second layer. When the added amount of the inorganic filler is smaller than this, the filler is hardly exposed on the surface of the sealant film, and the effect of improving the slip failure is small. Moreover, since the filler will be saturated in the sealant film surface when it exceeds 5 mass%, even if it adds more filler, the effect corresponding to this cost is not acquired. In addition, when the saturated state is reached, seal inhibition occurs, and conversely, the seal start temperature may be increased.

  The thickness of the second layer is about 5 to 15 μm in consideration of tight sealability. If this layer is too thick, the absolute amount of the inorganic filler is increased, which adversely affects the sealing properties and functionality, and at the same time increases the cost. Furthermore, if it is too thin, it is difficult to obtain the effect of the inorganic filler, and the slipperiness is inferior.

  In this configuration, the total thickness of the sealant film and the thickness of each layer can be appropriately set according to the application of the container to be applied, but in order to obtain the sealing strength necessary for box making, and stable film formation For example, the total thickness is 5 to 30 μm, more preferably 10 to 20 μm, and if it is thicker than this, the rigidity of the container is increased and molding defects are caused, and the thickness is thinner. And sufficient adhesive strength cannot be obtained, and the sealing performance of the container may be impaired.

The thicker the first layer, the higher the non-adsorbability. However, if the thickness is too large, sufficient adhesive strength cannot be obtained, and the sealing performance of the container may be impaired.
On the other hand, if the thickness of the second layer is too thin, sufficient adhesive strength cannot be obtained, and the sealing performance of the container may be impaired.

  In another aspect of the present invention, the sealant film includes a linear low density polyethylene resin layer, a first layer composed of a linear low density polyethylene resin and a cyclic polyolefin resin, and the first layer is linear. A layer composed of a second linear low-density polyethylene resin and a cyclic polyolefin-based resin having different mixing ratios between the low-density polyethylene resin and the cyclic polyolefin-based resin, and a three-layered layer provided in this order. The second layer made of a linear low density polyethylene resin and a cyclic polyolefin resin provided on the layer contains an inorganic filler.

  The sealant film having a layer structure composed of these three layers has excellent laminate strength and content resistance, and can exhibit high sealing strength while maintaining good non-adsorption properties.

  The linear low density polyethylene resin layer is provided in order to improve the uniform coatability of the entire sealant film and the adhesion between the first layer and the intermediate layer, and the thickness of the layer is 5 to 5. It is 25 μm, more preferably 10 to 20 μm.

In this configuration, the total thickness of the sealant film and the thickness of each layer can be appropriately set according to the application of the container to be applied, but in order to obtain the sealing strength necessary for box making, and stable film formation For example, the total thickness is 15 to 60 μm, more preferably 20 to 40 μm, and if it is thicker than this, the rigidity of the container is increased, causing molding defects, and thinner than this. And sufficient adhesive strength cannot be obtained, and the sealing performance of the container may be impaired.
Further, the total thickness of the sealant film and the intermediate layer is about 20 to 80 μm, more preferably about 30 to 50 μm.

(2) Linear low density polyethylene resin (linear low density polyethylene resin)
The linear low-density polyethylene resin used for the sealant film of the present invention is a linear polyethylene having a density of 0.900 to 0.940 g / cm ³ , such as a single-site catalyst such as a metallocene catalyst or a Ziegler-Natta catalyst. And a copolymer obtained by copolymerizing ethylene and an α-olefin having 3 to 20 carbon atoms at a low temperature and a low pressure.

Specific examples of the α-olefin having 3 to 20 carbon atoms include propylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 1-octene, 1-nonene and 1-decene. , 1-dodecene and the like.
Examples of the copolymerization method include ethylene and α-olefin polymerization methods such as a low pressure method, a slurry method, a solution method, and a gas phase method.

  The linear low density polyethylene resin used in the present invention has 3 to 25 short chain branches per 1000 carbon atoms as short chain branches, but does not have long chain branches exceeding about 20 carbon atoms. Thus, it is distinguished from LDPE. Usually, in a linear low density polyethylene resin, the structural unit derived from ethylene is about 99.9 to 90 mol%, and the structural unit derived from α-olefin is about 0.1 to 10 mol%. In this invention, the linear low density polyethylene resin prepared with the metallocene catalyst can be used conveniently at the point which is excellent in structural uniformity.

  Examples of the linear low density polyethylene resin suitable for use in the present invention include Ube Maruzen Polyethylene Co., Ltd., Umerit 0520F, Sumitomo Chemical Co., Ltd. “Sumikasen” and the like.

  Further, the main component is a linear low density polyethylene resin as described above, and if necessary, an antioxidant, an ultraviolet absorber, a light stabilizer, an antistatic agent, an antiblocking agent, a flame retardant, You may add 1 type, or 2 or more types of additives, such as a crosslinking agent and a coloring agent.

(3) Cyclic polyolefin resin The cyclic polyolefin resin used in the present invention includes a ring-opening metathesis polymer (COP) obtained by polymerizing a cyclic olefin by a metathesis ring-opening polymerization reaction, and a cyclic olefin and an α-olefin (chain olefin). ), That is, a cyclic olefin copolymer (cyclic polyolefin resin).

  As the cyclic olefin, any cyclic hydrocarbon having an ethylenically unsaturated bond and a bicyclo ring can be used, particularly those having a bicyclo [2.2.1] hept-2-ene (norbornene) skeleton. preferable.

Specifically, bicyclo [2.2.1] hept-2-ene and derivatives thereof, tricyclo [4.3.0.1 ^2.5 ] -3-decene and derivatives thereof, tricyclo [4.4.0.1 ^2.5] -3-undecene and derivatives thereof, tetracyclo [4.4.0.1 ^2.5 .1 ^7.10] -3-dodecene and derivatives thereof, pentacyclo ^{[6.5.1.1 3.6 .0 2.7 .0 9.13]} - 4 pentadecene and its derivatives, pentacyclo ^{[7.4.0.1 2.5 .1 9.12 .0 8.13]} -3- pentadecene and its derivatives, pentacyclo ^{[6.5.1.1 3.6 .0 2.7 .0 9.13]} - 4,10 penta decadiene and its derivatives, pentacyclo ^{[8.4.0.1 2.5 .1 9.12 .0 8.13]} -3- hexadecene and it derivatives, and the like, without limitation. The cyclic olefin may have a polar group such as an ester group, a carboxyl group, and a carboxylic anhydride group as a substituent.

  As the α-olefin copolymerized with the cyclic olefin, ethylene, an α-olefin having 3 to 20 carbon atoms can be used, and specifically, ethylene, propylene, 1-butene, 1-pentene, 3-methyl. Examples include -1-butene, 1-hexene, 4-methyl-1-pentene, and preferably ethylene.

  In the present invention, the production of the ring-opening metathesis polymer is not particularly limited as long as it is a known ring-opening metathesis polymerization reaction, and can be produced by ring-opening polymerization of the above cyclic olefin using a polymerization catalyst. .

  In the production of the cyclic olefin copolymer, 25 to 45 mol% of α-olefin and 55 to 75 mol% of cyclic olefin are randomly polymerized using a single site catalyst such as a metallocene catalyst or a multisite catalyst. Is made by

Several ring-opening metathesis polymers and cyclic olefin copolymers preferably used in the present invention are commercially available. For example, TOPAS 8007F-500 manufactured by Polyplastics Co., Ltd., or “ZEONOR ^{(R )} "and poly plastic Co., Ltd. of" TOPAS ^(R) ", and the like.

  If necessary, one or more additives such as an antioxidant, an ultraviolet absorber, a light stabilizer, an antistatic agent, an antiblocking agent, a flame retardant, a crosslinking agent, and a colorant are added. May be.

(4) In the inorganic filler present invention, suitable inorganic fillers which may be _{used, SiO 2, AL 2 O 3} , TiO 2, ZnO, Fe 2 O 3, SnO 2, CeO 2, NiO, PbO, S 2 A filler made of Cl ₂ , ZnCl ₂ , FeCl ₂ , CaCO ₃ , B ₂ O _{3 and the} like and having an average particle diameter of 2 to 15 μm can be used, and preferably a filler of silicon oxide SiO ₂ is used. When the average particle size of the inorganic filler is less than 2 μm, there is no effect in improving the slipperiness, and when the average particle size exceeds 15 μm, the container surface is rubbed by the inorganic filler protruding on the surface of the film forming film. And hurt. In addition, in this invention, an average particle diameter means the particle size of the particle which exists most by particle size distribution measurement. The particle size distribution can be measured by a Coulter counter method.

(5) Method for producing sealant film In the present invention, the sealant film is preferably formed by a coextrusion method using a resin and a resin composition constituting each layer. By forming a film by the coextrusion method, high interlayer adhesion and good film forming stability can be obtained, non-adsorbability and heat sealability can be further improved, and a beautiful film can be obtained. In the present invention, the sealant film is particularly preferably formed by a coextrusion inflation method. By forming a film by the coextrusion inflation method, film formation can be performed at a low temperature, trouble due to a resin odor caused by heating is reduced, and interlayer adhesion is further improved.

  In the present invention, three layers of the intermediate layer, the first and second layers composed of the linear low density polyethylene resin and the cyclic polyolefin resin can be formed by three-layer coextrusion. Further, four layers of the first layer and the second layer composed of an intermediate layer, a linear low density polyethylene resin layer, a linear low density polyethylene resin and a cyclic polyolefin resin can be formed by four-layer coextrusion. .

  In one embodiment of the present invention, the sealant film is laminated with a base material layer or a barrier layer by a sandwich lamination method through an intermediate layer.

  In another embodiment of the present invention, the sealant film is a layer that is laminated by coextrusion coating onto the substrate layer or barrier layer along with the intermediate layer. By using PE and the like constituting the intermediate layer and the resin constituting each layer in the sealant film and co-extrusion coating them together on the base material, high interlaminar adhesion and good film-forming stability can be obtained. As a result, non-adsorbability and heat sealability are further improved, and a beautiful film can be obtained.

3. Base material layer The base material layer constituting the non-adsorptive packaging material of the present invention may be a base material layer made of a single layer or a laminate such as a plastic film capable of ensuring strength as a packaging material, or a paper base material layer. good.
Examples of the plastic film include polyamide film, polyester film such as polyethylene terephthalate and polyethylene naphthalate, polyolefin film such as polyethylene and polypropylene, polystyrene film, polyamide film, polyvinyl chloride film, polycarbonate film, polyacrylonitrile film, polyimide A film, a polyvinyl alcohol film, a polyvinylidene chloride film, or the like is used, and it may be either stretched or unstretched, and preferably has mechanical strength and dimensional stability.

Further, a laminate made of a film made of these resins or a laminate made of two or more kinds of resins can be used by a coextrusion film forming method.
Furthermore, a vapor deposition film obtained by depositing an inorganic oxide or an organic oxide on a plastic substrate such as a polyethylene terephthalate film, a polyamide film, or a polypropylene film can be widely used.

  As the base material, resin film, metal foil, paper base material, gas barrier layer deposited with ceramics such as silicon oxide or aluminum oxide, or laminated aluminum foil can be used, and gravure printing method etc. on its surface May form a printing ink layer such as a pattern or a character.

In addition, various additives and stabilizers such as antistatic agents, ultraviolet ray preventing agents, plasticizers, lubricants and the like may be used on the surface of these base materials. Furthermore, in order to improve the adhesion to the thin film, pretreatment may be performed by corona treatment, low temperature plasma treatment, ion bombardment treatment, chemical treatment, solvent treatment, or the like.
The thickness of the plastic substrate is preferably in the range of 3 to 200 μm in consideration of suitability as a packaging material and processability.

As the paper base material constituting the paper base material layer of the present invention, any paper having various formability, flex resistance, rigidity, waist, strength, etc. is used according to the application of the paper container to be applied. be able to. For example, it is a main strength material, and various types of paper such as strong size bleached or unbleached paper, or pure white roll paper, kraft paper, paperboard, processed paper, and milk base paper can be used.

The paper base material layer may be obtained by laminating a plurality of layers of these papers. The paper base material layer has a basis weight of 80 to 600 g / m ² , preferably a basis weight of 100 to 450 g / m ² , and a thickness of 110 to 860 μm, preferably 140 to 640 μm. If it is thinner than this, the strength as a container is insufficient, and if it is thicker than this, the rigidity becomes too high, and the processing may be difficult.

  When paper or a material mainly composed of paper is used, the tear strength according to JIS P8116 is preferably 15 to 70 gf, and preferably 20 to 50 gf. As such a paper base material, pure white roll paper, coated paper, craft paper, or the like can be used.

  The substrate can be a film or paper, such as a gas barrier layer deposited with a ceramic such as silicon oxide or aluminum oxide, or a laminate of aluminum foil. A printing ink layer may be formed.

4). Intermediate Layer In the present invention, the intermediate layer is preferably a polyethylene resin (PE), for example, an LDPE layer.
This intermediate layer is located between the base material layer having the base material layer or the barrier layer and the sealant film and adheres to them, and is melted by heat sealing at the time of box making to increase the adhesive strength between the layers, Furthermore, the space | gap which arises in the level | step difference part of a container is filled, and the sealing performance of a container is improved.

As the PE for forming the intermediate layer of the present invention, any polyethylene can be used, but it exhibits a melt viscosity (fluidity) suitable for filling the voids, and has film forming suitability and processing suitability. A high-pressure low-density polyethylene resin (LDPE) having a density of 0.910 to 0.925 g / cm ³ and a melt flow rate (MFR) of 1 to 10 g / 10 min (190 ° C.) can be particularly preferably used.

  The thickness of the intermediate layer is 5 to 50 μm, preferably 5 to 40 μm, and more preferably 5 to 15 μm. If it is thinner than this, sufficient adhesive strength cannot be obtained, and the sealing performance of the container may be impaired. On the contrary, if it is thicker than this, the low-temperature sealing property is inferior, which is not preferable.

5. Barrier layer In the packaging material of the present invention, a barrier layer having a gas barrier property can be provided between the plastic substrate and the dry laminate adhesive layer as necessary. Thereby, the smell leak of the content to the exterior and the penetration | invasion of oxygen and water vapor | steam gas from the outside can be suppressed, and the quality change of a content can be prevented.
As such a barrier layer, any gas barrier film can be used depending on the application of the container to be applied.

  For example, as the gas barrier film, a metal foil such as an aluminum foil, or a laminated film of a metal foil and a plastic film can be used. In this case, excellent gas barrier properties can be obtained and light shielding properties can be obtained. Become. The thickness of the metal foil used suitably or the laminated film of metal foil and a plastic film is about 6-30 micrometers.

  Moreover, you may use the vapor deposition film which has a vapor deposition layer of an inorganic oxide or a metal as a gas barrier film. Here, preferable examples of the inorganic oxide include aluminum oxide, silicon oxide, and magnesium oxide. Moreover, aluminum etc. are mentioned as a metal used suitably. Moreover, as a base film which carries a vapor deposition layer, the resin film which consists of polyester, polyamide, a polypropylene, etc. can be used. The thickness of the vapor deposition film used suitably is about 9-40 micrometers. In addition, when a barrier layer consists of a vapor deposition film, it is preferable to laminate | stack so that the side of a vapor deposition film may contact | connect a base material layer from viewpoints, such as handling at the time of a process.

Furthermore, as the gas barrier film, a gas barrier film made of at least one of ethylene-vinyl alcohol copolymer, polyamide resin, polyvinylidene chloride resin, and polyacrylonitrile resin can be used. The thickness of these gas barrier films that are preferably used is about 5 to 30 μm.
Moreover, you may select and use 2 or more types for a barrier layer from said various gas-barrier films.

  When the packaging material of the present invention has a barrier layer, the barrier layer and the plastic base material are manufactured by sandwich lamination method using a thermoplastic resin or adhesion for dry lamination in consideration of manufacturing cost and required content resistance. It can be laminated by any method such as a dry laminating method using an agent.

  At this time, the surface of the base material layer may be subjected to surface treatment such as corona treatment, flame treatment, anchor coating treatment, etc., and the surface of the barrier layer may be subjected to in-line corona treatment, ozone treatment or the like. Good. As the thermoplastic resin used in the sandwich laminate, a resin layer made of any thermoplastic resin that can be melted by heat and fused to each other can be used. For example, LDPE, MDPE, linear low density polyethylene Resins, ionomer resins, ethylene-acrylic acid copolymers, and the like can be used.

  In the present invention, a base material layer, a barrier layer, an anchor coat layer laminated adjacently on the barrier layer, an intermediate layer laminated adjacently on the anchor coat layer, and adjacent to the intermediate layer And having a sealant film laminated.

  In this case, the anchor coat layer is an aqueous dispersion in which a polyolefin copolymer resin containing 0.01 to 5% by mass of an unsaturated carboxylic acid or an anhydride thereof is dispersed so that the number average particle diameter thereof is 1 μm or less. And the aqueous dispersion formed so that the aqueous dispersion is substantially free of the non-volatile aqueous solubilizing agent, the dry thickness on the surface of the barrier layer is 0.1 to 2 μm. It can be formed by coating and heating and drying.

6). Surface Protective Layer The packaging material of the present invention may have a layer made of any polyethylene resin (PE) on the surface opposite to the sealant film as a surface protective layer that becomes the outermost layer during box making.
The surface protective layer protects the outside of the base material layer and is bonded to the sealant film by heating at the end portion of the packaging material. As the polyethylene, LDPE, linear low density polyethylene resin, MDPE, high density polyethylene (HDPE) and the like are used, and are not particularly limited. However, from the viewpoints of sealability and processability with the sealant film of the packaging material of the present invention. LDPE and linear low density polyethylene resin are preferably used.

  Although the formation method of a surface protective layer is not specifically limited, For example, it forms by extrusion-coating molten polyethylene resin to one side of a base material layer. The surface protective layer is a layer that becomes the surface of the container, but a printing layer can be further provided on the surface, and in order to improve the adhesion of the printing ink used for the printing layer, the surface is a surface such as a corona treatment. Processing can also be performed. Although the thickness of a surface protective layer is not specifically limited, Usually, it is about 10-60 micrometers.

7). Anchor coat layer In the present invention, a base material layer, a barrier layer, an anchor coat layer laminated adjacent to the barrier layer, an intermediate layer laminated adjacent to the anchor coat layer, and the intermediate layer It can be set as the structure which has the sealant film laminated | stacked adjacent to.

  In this case, the anchor coat layer is an aqueous dispersion in which a polyolefin copolymer resin containing 0.01 to 5% by mass of an unsaturated carboxylic acid or an anhydride thereof is dispersed so that the number average particle diameter thereof is 1 μm or less. And the aqueous dispersion formed so that the aqueous dispersion is substantially free of the non-volatile aqueous solubilizing agent, the dry thickness on the surface of the barrier layer is 0.1 to 2 μm. It can be formed by coating and heating and drying.

8). Use of packaging material The packaging material using the sealant film of the present invention can be suitably used in order to form a container that is particularly required to maintain the quality of the contents.
Production of a container from a packaging material using the sealant film of the present invention is usually performed as follows. That is, after printing as necessary on the surface of the packaging material of the present invention, it is punched out, and the end face is skived and hemmed so that the contents do not come into contact with the end face. Heat seal by heating, flame heating, etc. to make a container.

  The shape of the container may be determined as appropriate according to the use and purpose, and examples thereof include a gable top type, a brick type, a flat type, and a cylindrical paper can such as a rectangular container or a round shape. Etc. For example, a polyethylene cap, a pull tab-type opening mechanism, or the like may be appropriately provided at the spout of the container.

The contents of the container are also not particularly limited, and even if it is solid, for example, coffee powder or sugar, or gel, liquid, for example, drinks such as liquor, fruit juice drinks, various beverages such as mineral water, soy sauce , Liquid seasonings such as sauces and soups, or various liquid foods and drinks such as curry, stew and soups, edible oils, machine oils, adhesives, adhesives and other chemicals, cosmetics, pharmaceuticals and other sundries, In addition, chemical products such as shampoo, rinse, and detergent may be used.
Next, the present invention will be specifically described with reference to examples.

[Example 1]
(1) Using LLDPE (Ube Maruzen Polyethylene Co., Ltd., Umerit 0520F) as a base resin, silica (average particle size: 4.9 μm) is added in an amount of 10% by mass, and an inorganic filler-containing masterbatch It was created. 30% by mass of the master batch, 30% by mass of LLDPE (manufactured by Ube Maruzen Polyethylene Co., Ltd., Umerit 0520F) and 40% by mass of cyclic olefin copolymer (TOPAS 8007F-500, manufactured by Polyplastics Co., Ltd.) Layers were prepared.

(2) LDPE (manufactured by Nippon Polyethylene, Novatec LC522), LLDPE (manufactured by Prime Polymer Co., Ltd., ULTZEX 1520L), and cyclic olefin copolymer as the first layer (TOPAS 8007F-500 manufactured by Polyplastics Co., Ltd.) Using a resin composition for an inorganic filler-containing LLDPE layer described in (1) above, an LDPE layer of 5 μm / LLDPE layer of 17.5 μm is obtained using the resin composition for an inorganic filler-containing LLDPE layer described in (1) above. A sealant film having a thickness of 40 μm comprising four layers of / first layer 5 μm / second layer 7.5 μm was formed. The obtained sealant film had a beautiful film surface without gel lump. In the description of the laminate in the present specification, “/” indicates that the left and right layers are laminated and integrated.

(3) Using a two-component curable urethane adhesive, polyethylene terephthalate (PET) having a thickness of 12 μm was laminated on an aluminum vapor-deposited PET film having a thickness of 12 μm by a dry lamination method to form a gas barrier film. The amount of adhesive applied at this time was such that the thickness of the adhesive was 3 g / m ² as a dry film.

(4) The surface of the LDPE of the sealant film obtained in the above (2) and the surface of the aluminum vapor deposited PET of the gas barrier film prepared in the above (3) are opposed to each other, and a 20 μm thick LDPE (manufactured by Nippon Polyethylene, Novatec LC600A) is extruded and sandwich laminated to obtain the packaging material of the present invention consisting of PET / adhesive for dry lamination / aluminum-deposited PET / LDPE / (LDPE layer / LLDPE layer / first layer / second layer). It was.

[Comparative Example 1]
A packaging material was prepared in the same manner as in Example 1 except that an LLDPE layer was used instead of the first layer.

[Comparative Example 2]
A packaging material was produced in the same manner as in Example 1 except that an LLDPE layer was used instead of the second layer.

[Comparative Example 3]
A packaging material was prepared in the same manner as in Example 1 except that LLDPE was used instead of the first and second layers.

[Comparative Example 4]
A packaging material was produced in the same manner as in Example 1 except that the first layer was used instead of the second layer.

[Comparative Example 5]
Packaging material as in Example 1 except that the second layer was blended with 30% by mass of masterbatch, 60% by mass of LLDPE and 10% by mass of cyclic olefin copolymer (TOPAS 8007F-500 manufactured by Polyplastics Co., Ltd.). Was made.

[Comparative Example 6]
A packaging material was produced in the same manner as in Example 1 except that the second layer was blended with 30% by mass of master batch and 70% by mass of cyclic olefin copolymer (TOPAS 8007F-500 manufactured by Polyplastics Co., Ltd.).

[Adsorption test]
Using the packaging materials of Example 1 and Comparative Examples 1 to 6, a 130 mm × 170 mm bag-shaped paper container was prepared and filled with 100 ml of a menthol-ethanol solution prepared so that the menthol concentration was 5 μg / ml.
After storing for 2 weeks in an atmosphere at 50 ° C., the menthol content in the solution was measured by the GC / MS method. From the difference between the measured value and the menthol content before storage, the amount of menthol adsorbed per 1 cm ² of the inner wall of the paper container was determined.
In the paper container made of the packaging material of Example 1, the adsorption amount of menthol was suppressed to a low value. In contrast, the paper container made of the packaging material of Comparative Example 1 adsorbed a large amount of menthol.

[Heat sealability test]
Using the packaging materials of Example 1 and Comparative Examples 1 to 6, the sheet was cut to 130 mm × 170 mm and the two layers were overlapped with each other, and the heat sealer (TP-701S HEAT manufactured by Tester Sangyo Co., Ltd. was used.
SEAL TESTER) at 160 ° C. for 1 second under a pressure of 1 kgf / cm ² .
100 ml of a menthol-ethanol solution prepared so as to have a menthol concentration of 5 μg / ml was filled. Measure the seal strength before and after storage at 50 ° C for 2 weeks.
The seal part before and after storage was cut out into a strip shape having a width of 15 mm, and the sealed seal part was peeled off using a Tensilon tensile tester (RTC-1310A manufactured by Orientec Co., Ltd.), and the seal strength was measured. The tensile speed at this time was 300 mm / min.
The menthol adsorption test results and heat seal test results are shown in Table 1 below.

All of the packaging materials of Example 1 have a small amount of adsorption, and can maintain the sealing strength even after storage.
Comparative example 1: Menthol adsorption amount increases.
Comparative Example 2: Since the adhesion between the cyclic polyolefin and LLDPE is weak, the sealing strength after storage is weakened.
Comparative example 3: Menthol adsorption amount increases.
Comparative Example 4: Since the sealing strength is weak, it is difficult to use as a paper container.
Comparative Example 5: Since the adhesion between the cyclic polyolefin and LLDPE is weak, the seal strength after storage becomes weak.
Comparative Example 6: Since the sealing strength is weak, it is difficult to use as a paper container.

1. Base material layer Intermediate layer 3. First layer made of linear low density polyethylene resin and cyclic polyolefin resin 4. Second layer composed of linear low density polyethylene resin and cyclic polyolefin resin Surface protective layer 6. 6. Adhesive resin layer Barrier layer 8. Linear low density polyethylene resin layer

Claims (4)

A linear low density polyethylene resin layer, a first layer composed of a linear low density polyethylene resin and a cyclic polyolefin resin, and the first layer are a linear low density polyethylene resin and a cyclic polyolefin resin. A second layer composed of a linear low-density polyethylene resin and a cyclic polyolefin-based resin having different mixing ratios is a three-layer sealant film provided in this order,
The ratio of the cyclic polyolefin resin in the first layer is 90 to 99% by mass, and the ratio of the linear low density polyethylene resin is 1 to 10% by mass.
The ratio of the cyclic polyolefin resin in the second layer is 30 to 50% by mass, and the ratio of the linear low-density polyethylene resin is 45 to 65% by mass .   The sealant film according to claim 1, wherein the second layer contains an inorganic filler.   A packaging material using the sealant film according to claim 1 as a seal layer.   A container formed by box-forming the packaging material according to claim 3 so that the sealant film is an innermost layer.

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